Semiconductor technology lesson outline. (Grade 9). Outline of the lesson (flow chart) on the topic: "Electric current in semiconductors Lesson plan on the topic of semiconductor materials

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Ministry of Science and Education

Department "I&WT"

EXPLANATORY NOTE

To term paper

Organization and methodology of industrial training in the subject: Materials science and electro-radio materials

On the topic: Semiconductor materials

Introduction

I . Metals and alloys, as well as electrical materials are widely used in modern technology. Modern electronic instrument making has reached such a stage of development when the important parameters of devices depend not so much on circuit solutions as on the used electro-radio materials and the perfection of technological processes for their manufacture. The material science subject consists of five sections. The first section is called general information about metals and alloys.

Metal is solid.

An alloy is a combination of 2 or more chemical elements

The component is the substances that make up the alloy.

II. Conductive materials are materials that have low resistivity.

III. Dielectric materials

Dielectrics are insulating materials.

IV. Semiconductor materials are materials that consume a small amount of energy during operation.

V. Magnetic materials - with attractive properties.

Structural steels and alloys

Structural steels are those intended for the manufacture of machine parts (machine-building steels), structures and structures (building steels).

Carbon structural steels

Carbon structural steels are classified into ordinary quality and high quality steels.

Steel ordinary qualities are produced in the following grades St0, St1, St2, ..., St6 (with an increase in the number, the carbon content increases). St4 - carbon 0.18-0.27%, manganese 0.4-0.7%.

With an increase in the conditional number of the steel grade, the ultimate strength (c) and yield strength (0.2) increase and the plasticity (,) decreases. St3sp has h \u003d 380490MPa, 0.2 \u003d 210250MPa, \u003d 2522%.

High quality carbon steels are smelted under more stringent conditions regarding the composition of the charge and the conduct of smelting and casting. Content S<=0.04%, P<=0.0350.04%, а также меньшее содержание неметаллических включений.

High-quality carbon steels are marked with numbers 08, 10, 15, ..., 85, which indicate the average carbon content in hundredths of a percent.

Low carbon steels (FROM<0.25%) 05кп, 08, 07кп, 10, 10кп обладают высокой прочностью и высокой пластичностью. в =330340МПа, 0.2 =230280МПа, =3331%.

Medium carbon steels (0.3-0.5% C) 30, 35, ..., 55 are used after normalization, improvement and surface hardening for a wide variety of parts in all industries. These steels, in comparison with low-carbon steels, have higher strength at lower plasticity (h \u003d 500600MPa, 0.2 \u003d 300360MPa, \u003d 2116%). In this regard, they should be used for the manufacture of small parts or larger, but not requiring through hardenability.

High carbon steels (0.6-0.85% C) 60, 65, ..., 85 have high strength, wear resistance and elastic properties. Springs and springs, spindles, lock washers, rolling rolls, etc. are made from these steels.

Alloy structural steels

Steels in which the total amount of alloying elements does not exceed 2.5% are classified as low-alloyed, containing 2.5-10% as alloyed, and more than 10% as highly alloyed (iron content is more than 45%).

Low-alloy steels are most widely used in construction, and alloyed steels in mechanical engineering.

Construction low-alloy steels

Low-alloyed steels are called steels containing no more than 0.22% C and a relatively small amount of non-deficient alloying elements: up to 1.8% Mn, up to 1.2% Si, up to 0.8% Cr, and others.

These steels include 09G2, 09GS, 17GS, 10G2S1, 14G2, 15KHSND, 10KhNDP and many others. Steel in the form of sheets, sectional shapes are used in construction and mechanical engineering for welded structures, mainly without additional heat treatment. Low alloy, low carbon steels weld well.

For the manufacture of pipes of large diameter, 17GS steel is used (0.2 \u003d 360MPa, w \u003d 520MPa).

Reinforcing steels

For the reinforcement of reinforced concrete structures, carbon or low-carbon steel is used in the form of a smooth or periodic profile of rods.

Steel St5sp2 - w \u003d 50MPa, 0.2 \u003d 300MPa, \u003d 19%.

Steel for cold forming

To ensure high formability, the ratio w / 0.2 of steel should be 0.5-0.65 at not less than 40%. The more carbon it contains, the worse the stamping properties of steel. Silicon, increasing the yield stress, reduces the formability, especially the drawability of steel. Therefore, cold-rolled boiling steels 08kp, 08Fkp (0.02-0.04% V) and 08Yu (0.02-0.07% Al) are more widely used for cold forming.

Structural (machine-building) case-hardened (nitrocarburized) alloy steels

For the manufacture of parts hardened by carburizing, low-carbon (0.15-0.25% C) steels are used. The content of alloying elements in steels should not be too high, but should provide the required hardenability of the surface layer and core.

Chromium steels 15X, 20X are intended for the manufacture of small products of simple shape, cemented to a depth of 1.0-1.5mm. Compared to carbon steels, chromium steels have higher strength properties with some lower ductility in the core and better strength in the case-hardened layer, sensitive to overheating, and low hardenability.

Steel 20X - w \u003d 800MPa, 0.2 \u003d 650MPa, \u003d 11%, \u003d 40%.

Chrome vanadium steels... Alloying chromium steel with vanadium (0.1-0.2%) improves mechanical properties (steel 20HF). In addition, chrome vanadium steels are less prone to overheating. They are used only for the manufacture of relatively small parts.

Typical curriculum

Typical curriculum is a document designed to implement state requirements for a minimum of the content and level of training of graduating educational institutions of secondary specialized education. It defines a general list of disciplines, and the required amount of time for their implementation, types and minimum duration of practice, an approximate list of classrooms, laboratories and workshops. The curriculum also provides for course design in no more than three disciplines throughout the entire period of study. The types of industrial practice and their duration are determined in accordance with the typical educational practice for a given specialty. The schedule of the educational process is of a recommendatory nature and can be adjusted by the educational institution with the obligatory observance of the duration of theoretical training, examination sessions, as well as the timing of the winter and summer holidays ending the academic year (see table 1).

TABLE 1

Name

educational process,

academic disciplines

Distribution by semester

Number of control

Number of hours

Distribution by courses and semesters

Exams

Course-out project

Theo-ret. busy

Laboratory practice

Materials Science

and electro-radio materials

It can be seen from the curriculum that 60 hours are allotted for the subject "Materials Science and Electro-Radio Materials". Of these, 44 are theoretical and 16 are practical. The minimum number of tests is 2 tests. There are laboratory classes. Coursework, course project, no credit. The subject "Materials Science and Electro-Radio Materials" is studied in the 2nd year. In the 3rd semester of study 18 weeks, 2 hours per week: 18 * 2 \u003d 36 hours are studied in the 3rd semester. In the 4th semester of study 12 weeks, a week for 2 hours: 12 * 2 \u003d 24 hours are studied in the 4th semester. Total for the 3rd and 4th semester: 36 + 24 \u003d 60 hours, they fully study this subject in the 2nd year.

Thematic plan

Thematic plan - is part of the curriculum. Training program - This is a document that describes the content of the studied material by years of study and sections (topics). The thematic outline consists of sections that include topics. The thematic plan divides the hours into sections out of the total hours. In the thematic plan for the subject "Materials Science and Electro-Radio Materials" in the section "Conducting Materials" 12 hours are given.

TABLE 2

Topic name	Number of hours
		Theoretical lessons
Chapter 4. Conducting materials

High conductivity materials
Superconductors and cryoconductors
Electrical conductivity of conductors
Test

Calendar-thematic plan

Calendar-thematic plan -planning an accounting document, its objectives are to determine the topic, type of method and equipment of lessons in the chosen subject. Drawing up a calendar-thematic plan is the first step in creating a lesson systematization. The original document here is the curriculum. The thematic calendar plan provides for interdisciplinary connections. If the calendar-thematic plan is consistent with the curriculum, they are guided by the thematic plan when drawing up a lesson plan. Calendar-thematic plan (see table 3).

Lesson development

Studying the curriculum, the teacher carefully analyzes each topic, which makes it possible to clearly define the content of training, establish interdisciplinary connections. On the basis of the curriculum, a calendar-thematic plan is drawn up and a lesson plan is drawn up on the basis of the calendar-thematic plan. When defining the purpose and content of the lesson, arising from the curriculum, the content of the record, skills and abilities that students must learn in this lesson are determined. Analyzing the previous lessons, and establishing to what extent their problems have been solved, they find out the reason for the shortcomings, and on the basis of this determine what changes need to be made in the conduct of this lesson. They outline the structure of the lesson and the time for each of its parts, form the content and nature of educational work during the lesson.

Lesson plan

Subject: Materials Science and Electro-Radio Materials Group 636

Topic:Classification and basic properties

a) training: To acquaint students with the concepts and basic properties of conductive materials, tell about their purpose

b) developing: Develop an interest in materials science and electro-radio materials

c) educational: Develop a need for self-education

Lesson type: Combined

Presentation method:search

Visual aids: poster No. 1, PC

Time:90 minutes

During the classes

I... Introductory part:

Written survey on two options + 3 study at the blackboard (appendix 1)

II... Main part:

1. Post the purpose of the new topic

2. Presentation of new material time 40 min.

a) Basic concepts

b) Classification of conductors

c) Scope of application

3. Answers to students' questions time 10 min.

4. Fastening of new material, time 20 min.

Written survey on 2 options + 3 study at the blackboard (Appendix 2)

III... Final part:time 3 min.

1. Summing up

2. Assignment at home: p. 440 answers to questions, independently consider topics No. 2, 3, 4, 5

3. Concluding remarks from the teacher

Teacher

Bibliography

1. Lakhtin Yu. M., Leont'eva VP Materials science. - M .: Mechanical Engineering, 1990

2. Technological processes of engineering production. Edited by S. I. Bogodukhov, V. A. Bondarenko. - Orenburg: OSU, 1996

application1

WRITTEN SURVEYaccording to 2 options

Option 1

1 . That studies the subject of materials science.

2. Types of metals.

3. Classification of metals

4. Allotropic transformation

5 ... Metal properties

Option 2

1. Determination of hardness of metals

2. Mechanical properties

3. Plastic

4. Endurance

5. Technological properties

Appendix 2 Written survey

1 - option

1. Semiconductor materials

2. Superconductors

3. Cryoprobes

4. Characteristics of semiconductor materials

5. Elasticity of materials

Option 2

1. Semiconductor materials.

2. Dielectric materials

3. Plasticity

4. Elasticity

5. Superconductors

application3

Lesson summary on the topic" Conductor Materials"

The growing role of technology and technical knowledge in the life of society is characterized by the dependence of science on scientific and technological developments, increasing technical equipment, the creation of new methods and approaches based on a technical method for solving problems in various fields of knowledge, including military-technical knowledge. The modern understanding of technical knowledge and technical activity is associated with the traditional range of problems and with new directions in technology and engineering, in particular with the technology of complex computing systems, problems of artificial intelligence, systems engineering, etc.

The specification of the concepts of technical knowledge is primarily determined by the specifics of the subject of reflection of technical objects and technological processes. Comparison of objects of technical knowledge with objects of other knowledge shows their certain commonality, extending, in particular, to such features as the presence of structure, consistency, organization, etc. Such common features are reflected by the general scientific concepts of "property", "structure", "system", "organization", etc. Of course, the common features of objects of technical, military-technical, natural science and social-scientific knowledge are reflected in such philosophical categories "matter", "motion", "cause", "effect", etc. General scientific and philosophical concepts are used both in the military and in technical sciences. but do not express their specifics. At the same time, they help to deeper, more fully comprehend the content of objects of technical, military-technical knowledge and the concepts of technical sciences reflecting them.

In general, philosophical and general scientific concepts in technical sciences act as ideological and methodological tools for the analysis and integration of scientific and technical knowledge.

A technical object is undoubtedly a part of objective reality, but a special part. Its origin and existence are associated with the social form of the movement of matter, the history of man. This determines the historical nature of the technical object. It objectifies the production functions of society, it is the embodiment of people's knowledge.

The emergence of technology is a natural historical process, the result of human production activities.

Its starting point is "human organs". Strengthening, supplementing and replacing working organs is a social necessity realized through the use of nature and the embodiment of labor functions in the transformed natural bodies.

The formation of technology takes place in the process of making tools, adapting natural bodies to achieve the goal. And a hand ax, and a tree trunk that serves as a bridge, etc. - all these are means of strengthening the individual, increasing the efficiency of his activities. A natural object performing a technical function is already a technical object in its potential. It fixes the feasibility of its device and the usefulness of constructive improvements due to the part-time work of its parts.

The practical identification of a structure as an integrity indicates the actual existence of a technical object. Its most important properties are functional usefulness, an unusual combination of materials for nature, the subordination of material properties to the relationship between the components of the system. The technical design is the connection of components; this procedure ensures the longest and most effective operation of the tool, excluding its self-destruction. A part acts as a component of a structure as an initial and indivisible unit for it. And finally, with the help of technical construction, the way of social activity achieves manufacturability. Technology is that side of social practice, which is represented by the interaction of a technical means and a transformed object, is determined by the laws of the material world and is regulated by technology.

Technical practice reveals itself in the relation of man to technology as an object, to its parts and their connections.

Operation, manufacture and design are closely related to each other and represent a kind of development of technical practice. As an object of exploitation, technology acts as a certain material and functional integrity, the preservation and regulation of which is an indispensable condition for its use. The driving contradiction of operation is the discrepancy between the conditions for the operation of equipment and its functional features. Functionality assumes constant operating conditions, and operating conditions tend to change.

Overcoming this contradiction is achieved in technology, in finding standard technological operations.

The internal contradiction of the technology is the discrepancy between the used natural processes and the needs to increase its reliability and efficiency. Overcoming this contradiction is achieved in the construction of a more perfect technique, with the help of which you can use more fundamental laws of nature. Technique is not passive in relation to technology; the means affects the end.

New technology changes technology, technology itself becomes a means of realizing the internal merits of the constructed technology.

In construction, the social essence of a technical object is most fully revealed. It synthesizes a constructive structure in accordance with the production function set by society. Technology forms a condition for the development of society, mediates its relationship to nature, is a means of resolving the contradictions between man and nature. A technical object is a carrier of production, technological functions of a person. Without technical progress, it is impossible to achieve social homogeneity of society and the all-round development of each individual.

The properties of a technical object are revealed in technical practice and are fixed in the knowledge of the methods of operation, manufacture and improvement of technology. Empirically found proportions between parts of a technical device and the formation of "technical objects", relatively stable information about technical devices, about their essential components and properties. In the form of such items, for example, descriptions of lifting and transport mechanisms, watches, the most important crafts and materials were formed.

The transition to machine technology, the transfer of working tools to mechanisms brought about the design of technical devices in life, which required the theoretical development of the concept of "machine" and the receipt of its various idealizations (kinematic pair, dynamics of forces, structure).

The formation of the concepts of technical science is influenced by the regularities revealed in the course of studying the natural sciences, in particular, theoretical mechanics. At the same time, it should be recognized that the concept of a technical design is expressed within technical knowledge. Historically, it is formed as a system of provisions about a machine, a mechanical set of parts and their regular relationship, providing the desired effect.

The formation of technical disciplines took place in various ways. Engineering disciplines about motors are based on the results of natural science, on the knowledge of the laws of nature and the application of the laws of physics to technology. Technical kinematics, machine dynamics and the theory of machine parts are of an applied nature. These disciplines were formed on the basis of theoretical mechanics and descriptive geometry, which resulted in the creation of a special language.

Technical sciences were formed not only by applying natural science to technology, but also by using the centuries-old experience of technology, understanding it and giving it a logically clear form. In this way, the sciences of various types of machines, materials science, etc. were formed. The empirical data of these technical disciplines tested in practice were preserved and included in the general science of machines. And until now, many techniques for the manufacture and operation of equipment have not received a proper theoretical foundation.

The formation of technical science put an end to the handicraft attitude towards technology, when certain mechanisms were improved in parts over many decades and even centuries. The understanding that a machine is a transformation of motion into a form necessary for production and, in essence, consisting of kinematic pairs, formed the basis for the scientific design of various technical devices in the 19th century.

From what has been said, it is clear that technical science investigates its object, although it is able to explain the functioning of handicraft, manual tools, which were created without scientific substantiation. The object of technical science is formed in the process of highlighting the essential and necessary properties of technology, designing a machine. The machine, its components, the relationship between them, their composition, the natural basis of the components and the technological process are all an object of technical science. The object of technical science is a source of scientific and technical knowledge. His research provides, in particular, constructive structures and their elements. The structure fixes stability, repeatability, necessity,

the regularity of the composition of the elements of the machine. In relation to the structure, the component of the machine appears as an element. The mental reception of a structural element is associated with abstraction from the physical dimension and the natural basis of the component. Ultimately, all scientific and technical concepts are a reflection of a technical object.

The concepts "technical object" and "object of technical science" perform a different methodological function in the philosophical analysis of technology and scientific and technical knowledge. The concept of "technical object" captures the side of the objective world that is actually changing in practice. A technical object is displayed in philosophical, social, natural and technical sciences, and each time science isolates its own subject area. The concept "object of technical science" fixes the subject of technical sciences, their relation to objective reality. The main object of technical sciences is the machine, since with its help the technological process is organized and it is regulated by it. The machine facilitates and replaces human labor, serves as a means to an end.

In technical science, the study of elements, their relationships and technical structures is primarily distinguished. For the formation of the subject of technical science, it is important to highlight, describe and explain the technical elements, their relationships and possible structures in which production functions useful for society materialize. But technical science does not end there. It includes the rules for the synthesis of new technical structures, calculation methods and design forms.

Design rules and norms, graphic and analytical calculation methods bring technical science closer to technical creativity, design and engineering work. The subject of technical sciences is formed in direct dependence on the creativity of technology. This is the specificity of technical sciences, which are a means of improving technology, rethinking natural science data, discovering technological methods and inventing technical structures.

The most important factor of technical creativity is the rules that provide for the achievement of strength and reliability of a technical device, wear resistance and heat resistance of its parts, etc. These rules form a design framework, excluding from it that which does not correspond to the criteria for the functioning of machines developed by technical science. Methods for solving problems are developed on the basis of the rules and norms of engineering activity.

The principles act as prerequisites for activity, as its organizing and guiding principle. Thus, the subject of technical sciences includes not only the laws of a technical object, but also the laws of technical design, methods, rules, norms and principles of engineering design.

Lesson methodology.

I went to room 24, I greet the students.

The introductory part of the lesson begins.

I... Introductory part:

1. Organizational moment: check according to the report time 2 min.

I check the presence of students according to the report. I take 2 minutes to check the availability of students in the lesson. Then I do a homework survey.

2. Checking homework: time 15 min.

Interview

I conduct a survey in the form of 10 questions. They include questions on the topic covered. I take 15 minutes for the test.

TEST

1 . What studies the subject of materials science

2. Conducting materials

3. Semiconductor materials

4. Dielectric materials

5. Varnishes

6. Compounds

7. Glue

8. Durability

9. Elasticity

10. Plasticity

Structural steels and alloys

Structural steels are those intended for the manufacture of machine parts (machine-building steels), structures and structures (building steels).

Carbon Structural Steels Carbon structural steels are classified into ordinary grade and high grade steels.

Steels of ordinary quality are made of the following grades St0, St1, St2, ..., St6 (with increasing number, the carbon content increases). St4 - carbon 0.18-0.27%, manganese 0.4-0.7%.

Steels of ordinary quality, especially boiling ones, are the cheapest. Steels are cast into large ingots, as a result of which liquation is developed in them and they contain a relatively large amount of non-metallic inclusions.

With an increase in the conditional number of the steel grade, the ultimate strength (sw) and yield strength (s0.2) increase and the plasticity (d, y) decreases. St3sp has sv \u003d 380490MPa, s0.2 \u003d 210250MPa, d \u003d 2522%.

From steels of ordinary quality, hot-rolled stock is produced: beams, channels, angles, rods, as well as sheets, pipes and forgings. Steel as supplied is widely used in construction for welded, riveted and bolted structures.

With increasing carbon content in steel, the weldability deteriorates. Therefore, steels St5 and St6 with a higher carbon content are used for elements of building structures that are not welded.

High-quality carbon steels are smelted under more stringent conditions with regard to the composition of the charge and the conduct of smelting and casting. Content S<=0.04%, P<=0.0350.04%, а также меньшее содержание неметаллических включений.

High-quality carbon steels are marked with numbers 08, 10, 15, ..., 85, which indicate the average carbon content in hundredths of a percent.

Low carbon steels (C<0.25%) 05кп, 08,07кп, 10,10кп обладают высокой прочностью и высокой пластичностью. sв=330340МПа, s0.2=230280МПа, d=3331%.

Steel without heat treatment is used for lightly loaded parts, critical welded structures, as well as for car parts hardened by carburizing.

Medium carbon steels (0.3-0.5% C) 30,35, ..., 55 are used after normalization, improvement and surface hardening for a wide variety of parts in all industries. Compared to low-carbon steels, these steels have higher strength and lower ductility (sw \u003d 500600MPa, s0.2 \u003d 300360MPa, d \u003d 2116%). In this regard, they should be used for the manufacture of small parts or larger, but not requiring through hardenability.

Steels with a high carbon content (0.6-0.85% C) 60, 65, ..., 85 have high strength, wear resistance and elastic properties. Springs and springs, spindles, lock washers, rolling rolls, etc. are made from these steels.

Alloy structural steels

Alloyed steels are widely used in tractor and agricultural machine building, in the automotive industry, heavy and transport machine building, to a lesser extent in machine tool building, tool and other industries. These steels are used for heavily loaded metal structures.

Steels in which the total amount of alloying elements does not exceed 2.5% are classified as low-alloyed, containing 2.5-10% as alloyed, and more than 10% as high-alloyed (iron content over 45%).

Low-alloy steels are most widely used in construction, and alloyed steels in mechanical engineering.

Alloyed structural steels are marked with numbers and letters. The two-digit numbers at the beginning of the brand indicate the average carbon content in hundredths of a percent, the letters to the right of the number indicate the alloying element. For example, steel 12X2H4A contains 0.12% C, 2% Cr, 4% Ni and refers to high quality, as indicated at the end of the grade by the letter ²A².

Structural (machine-building) improved alloy steels Steels have a high yield point, low sensitivity to stress concentrators, in products operating under multiple application of loads, a high endurance limit and a sufficient toughness margin. In addition, tempering steels have good hardenability and low sensitivity to temper brittleness.

With full hardenability, steel has better mechanical properties, especially resistance to brittle fracture - a low threshold of cold brittleness, a high value of the work of crack propagation KST and fracture toughness K1c.

Chromium steels 30X, 38X, 40X and 50X are used for medium-loaded small parts. With increasing carbon content, strength increases, but ductility and toughness decrease. The hardenability of chromium steels is low.

Steel 30Kh - sv \u003d 900MPa, s0.2 \u003d 700MPa, d \u003d 12%, y \u003d 45%.

Chrome-manganese steels. Joint alloying with chromium (0.9-1.2%) and manganese (0.9-1.2%) makes it possible to obtain steels with a sufficiently high strength and hardenability (40KhG). However, chromium-manganese steels have a lower toughness, an increased threshold of cold brittleness (from 20 to -60 ° C), a tendency to temper brittleness and austenite grain growth upon heating.

Steel 40KhGTR - sv \u003d 1000MPa, s0.2 \u003d 800MPa, d \u003d 11%, y \u003d 45%.

Chrome-silicon manganese steels. Chromosilicon-manganese steels (chromansil) have a high set of properties. Steels 20KhGS, 25KhGS and 30KhGS have high strength and good weldability. Chromansil steels are also used in the form of sheets and pipes for critical welded structures (aircraft construction). Chromansil steels are prone to reversible temper brittleness and decarburization when heated.

Steel 30KhGS - sv \u003d 1100MPa, s0.2 \u003d 850MPa, d \u003d 10%, y \u003d 45%. Chromium-nickel steels have high hardenability, good strength and toughness. They are used for the manufacture of large items of complex configuration, operating under dynamic and vibration loads.

Steel 40KhN - sw \u003d 1000MPa, s0.2 \u003d 800MPa, d \u003d 11%, y \u003d 45%.

Chromium-nickel-molybdenum steels. Chromium-nickel steels have a tendency to reversible temper brittleness, to eliminate which many small-sized parts made of these steels are cooled after high tempering in oil, and larger parts in water are additionally alloyed with molybdenum (40XH2MA) or tungsten to eliminate this defect.

Steel 40KhN2MA - sv \u003d 1100MPa, s0.2 \u003d 950MPa, d \u003d 12%, y \u003d 50%.

Chromium-nickel-molybdenum-vanadium steels have high strength, ductility and toughness and a low cold brittleness threshold. This is facilitated by the high nickel content. The disadvantages of steels are the difficulty in cutting and their high tendency to form flakes. Steel is used for the manufacture of the most critical parts of turbines and compressor machines.

Steel 38KhN3MFA - sw \u003d 1200MPa, s0.2 \u003d 1100MPa, d \u003d 12%, y \u003d 50%.

Spring steel for general use

Spring-spring steels are intended for the manufacture of springs, elastic elements and springs for various purposes. They should have high resistance to small plastic deformation, endurance limit and relaxation resistance with sufficient plasticity and toughness.

For springs of small cross-section, carbon steel 65,70,75,85 is used. Steel 85 - s0.2 \u003d 1100MPa, sw \u003d 1150MPa, d \u003d 8%, y \u003d 30%.

More often, alloy steels are used for the manufacture of springs and springs.

Steels 60S2KhFA and 65S2VA, which have high hardenability, good strength and relaxation resistance, are used for the manufacture of large, highly loaded springs and springs. Steel 65S2VA - s0.2 \u003d 1700MPa, sw \u003d 1900MPa, d \u003d 5%, y \u003d 20%. When elastic elements operate under strong dynamic loads, steel with nickel 60C2H2A is used.

For the manufacture of automotive springs, steel 50HGA is widely used, which is superior in technical properties to silicon steels. For valve springs, steel 50HFA is recommended, which is not prone to overheating and decarburization.

Ball bearing steels

For the manufacture of rolling elements and bearing rings of small sections, high-carbon chromium steel ShKh15 (0.95-1.0% C and 1.3-1.65% Cr) is usually used, and for large sections, chromium-manganese steel ShKh15SG (0.95-1.05% C, 0.9-1.2% Cr, 0.4-0.65% Si and 1.3-1.65% Mn), calcined to a great depth. The steels have high hardness, wear resistance and resistance to contact fatigue. Steels are subject to high requirements for the content of nonmetallic inclusions, since they cause premature fatigue failure. Carbide heterogeneity is also inadmissible.

For the manufacture of rolling bearing parts operating under high dynamic loads, case-hardened steels 20X2H4A and 18XGT are used. After gas carburizing, high tempering, quenching and tempering, bearing parts made of steel 20X2H4A have 58-62 HRC on the surface and 35-45 HRC in the core.

Wear resistant steels

High-manganese cast austenitic steel 110G13L containing 0.9-1.3% C and 11.5-14.5% Mn is used for parts working for wear under conditions of abrasive friction and high pressures and impacts. It has the following mechanical properties: s0.2 \u003d 250350MPa, sw \u003d 8001000MPa, d \u003d 3545%, y \u003d 4050%.

Steel 110G13L has high wear resistance only under shock loads. At low shock loads in combination with abrasive wear or with pure abrasive wear, martensitic transformation does not occur and the wear resistance of 110G13L steel is low.

For the manufacture of blades of hydraulic turbines and hydraulic pumps, ship propellers and other parts operating under wear conditions during cavitation erosion, steels with unstable austenite 30X10G10.0X14AG12 and 0X14G12M are used, which undergo a partial martensitic transformation during operation.

Corrosion-resistant and heat-resistant steels and alloys

Heat-resistant steels and alloys. An increase in the scale resistance is achieved by introducing mainly chromium into the steel, but also aluminum or silicon, i.e. Elements that are in solid solution and form protective films of oxides (Cr, Fe) 2O3, (Al, Fe) 2O3 during heating.

For the manufacture of various kinds of high-temperature installations, parts of furnaces and gas turbines, heat-resistant ferritic (12X17.15X25T, etc.) and austenitic (20X23H13, 12X25N16G7AR, 36X18H25C2, etc.) steels are used,

having heat resistance. Steel 12Kh17 - sv \u003d 520MPa, s0.2 \u003d 350MPa, d \u003d 30%, y \u003d 75%.

Corrosion-resistant steels are resistant to electrochemical corrosion.

Steels 12X13 and 20X13 are used for the manufacture of parts with increased ductility that are exposed to shock loads (valves for hydraulic presses, household items), as well as products that experience the action of slightly aggressive media (precipitation, aqueous solutions of organic acid salts).

Steel 30X13 and 40X13 are used for carburetor needles, springs, surgical instruments, etc.

Steel 15X25T and 15X28 are used more often without heat treatment for the manufacture of welded parts operating in more aggressive environments and not exposed to shock loads, at an operating temperature of at least -20 ° C.

I come to the final part of the lesson, in which I summarize the lesson. I highlight the main points of the topic, emphasize the need to learn this topic. I give out homework. I will sum up the lesson. I give grades to active students to encourage their self-education needs.

III... Final part:time 3 min.

1. Summing up

Once again, I highlight the most important information on the topic "Classification and basic properties of conductive materials."

2. Assignment at home: p. 94 to answer the questions, Problem number 3,4,6,8

3. Concluding remarks of the teacher: Say goodbye to the students.

ALL PHYSICS LESSONS Grade 11
ACADEMIC LEVEL

1st semester

ELECTRODYNAMICS

2. Electric current

LESSON 12/23

Topic. Semiconductor devices

The purpose of the lesson: to explain to students the principle of operation of semiconductor devices.

Lesson type: lesson in learning new material.

LESSON PLAN

Knowledge control		1. What causes the electronic conductivity of a semiconductor? 2. What is the reason for the hole conductivity of a semiconductor? 3. What impurities are called donor impurities? acceptor? 4. What impurity should be introduced to obtain an n-type semiconductor? p -type?
Demonstrations		Fragments of the video "Electric current in semiconductors".
Learning new material		1. Semiconductor diode. 2. How does a transistor work? 3. Application of semiconductors. 4. Integrated microcircuits.
Consolidation of the studied material		1. Qualitative questions. 2. Learning to solve problems.

STUDYING NEW MATERIAL

The semiconductor diode uses the one-way conductivity of the p-n junction. Such a diode has two contacts for connection to a circle.

It is often said that a diode has a small resistance in the forward direction and a very large resistance in the opposite direction. However, this is not an entirely accurate statement: in fact, Ohm's law does not hold for semiconductors in general and especially for electron-hole transitions. Therefore, there is no constant resistance in such conductors.

The current-voltage characteristic of a semiconductor diode is:

Semiconductor diodes are used for rectifying alternating current (this is called alternating current), as well as for the manufacture of LEDs. Semiconductor rectifiers are highly reliable and have a long service life.

Semiconductor diodes are widely used in radio engineering devices: radio receivers, video recorders, televisions, computers.

Semiconductors in transistors are extremely important.

Transistors are semiconductor devices with two p - n junctions.

The main element of the transistor is a semiconductor crystal, for example germanium, with donor and acceptor impurities introduced into it. The impurities are distributed so that between semiconductors with the same impurity (they are called emitter and collector) there remains a thin layer of germanium with an impurity of a different type - this layer is called the base.

There are two types of transistors: p -n -p -transistors (fig. A) and n -p -n -transistors (fig. B).

In a p-n-p-type transistor, there are significantly more holes in the emitter and collector than electrons, and there are more electrons in the base; in an n -p-n-type transistor, there are more electrons in the emitter and collector than holes, and there are more electrons in the base.

Consider the operation of a p - n - p -type transistor. Three leads of the transistor from sections with different types of conductivity are included in a circle as shown in the figure.

If the base potential of the p - n - p transistor is higher than the emitter potential, then no current flows through the transistor. Therefore, the transistor can function as an electronic switch. If the base potential is lower than the emitter potential, then even minor changes in the voltage between the emitter and the base lead to significant changes in the current in the collector circuit and, accordingly, to a change in the voltage across the resistor of significant resistance.

Having considered the operation of the transistor, we conclude that with the help of a transistor it is possible to amplify electrical signals.

Therefore, the transistor has become the main element of many semiconductor devices.

The dependence of the electrical conductivity of semiconductors on temperature makes it possible to use them in thermistors.

Thermistor is a semiconductor thermistor, the electrical resistance of which changes significantly with increasing temperature.

Thermistors are used as thermometers to measure temperature.

In many semiconductors, the bond between electrons and atoms is so insignificant that it is enough to irradiate the crystals with light so that they have an additional amount of free charge carriers.

Photoresistors are used in signaling and automation systems, remote control of production processes, product sorting, etc.

Semiconductor diodes and transistors are the “building blocks” of very complex devices, called integrated circuits.

Microcircuits work today in computers and televisions, mobile phones and artificial satellites, in cars, airplanes, and even in washing machines.

The integrated circuit is fabricated on a silicon wafer. The size of the plate is from a millimeter to a centimeter, and one such plate can accommodate up to a million components - tiny diodes, transistors, resistors, etc.

The important advantages of integrated circuits are high speed and reliability, as well as low cost. It is thanks to this that, on the basis of integrated circuits, it was possible to create complex, but many devices, computers and modern household appliances are available.

QUESTION TO STUDENTS DURING THE PRESENTATION OF NEW MATERIAL

First level

1.With the help of what experience can you be convinced of the one-sided conductivity of a semiconductor diode?

2. Why should the base of the transistor be very small?

3. What conductivity the base of the transistor can have?

Second level

1. Why is the collector current approximately equal to the emitter current?

2. A semiconductor diode and a rheostat are placed in a closed box. The end of the devices are brought out and connected to the terminals. How to determine which terminals belong to a diode?

FIXING THE STUDYED MATERIAL

1. How will an increase in the thickness of its base affect the operation of the transistor?

2. It is known that in each transistor there are two p - n junctions, which are connected towards each other. Is it possible to replace one transistor with two diodes included in the same way?

1. Draw the circuit for turning on the p - n - p transistor to amplify the voltage.

2. Draw the circuit for turning on the n - p - n transistor to amplify the voltage.

3. Why are two different circuits for connecting devices used to obtain the current-voltage characteristics of a semiconductor diode (see Fig. A, b)?

Solutions. In this case, the resistance of the ammeter cannot be considered infinitely small, and the resistance of the voltmeter - infinitely large. Circuit a cannot be used to measure the reverse current through the diode (almost all of the current will go through the voltmeter). The circuit cannot be used to measure forward voltage (the voltage across the ammeter is much higher than the voltage across the diode).

WHAT WE LEARNED IN THE LESSON

A transistor is an electronic device made of a semiconductor material, usually with three terminals, that allows a small input signal to control an electric current in an electrical circuit.

Using a transistor, you can amplify electrical signals.

Thermistor is a semiconductor thermistor whose electrical resistance changes significantly when the temperature rises.

A semiconductor device that uses the property of a conductor to change its resistance when illuminated is called a photoresistor.

Homework

1. Sub-1: § 16 (p. 5, 6, 7, 8); sub-2: § 8.

Рів1 № 6.6; 6.9; 6.15.

Рів2 No. 6.16; 6.17; 6.18.

Рів3 №6.28; 6.2; 6.30.

Physical properties of semiconductors Semiconductors are materials that, in terms of their specific conductivity, occupy an intermediate place between conductors and dielectrics. The main property of these materials is the increase in electrical conductivity with increasing temperature. They conduct electric current well These include metals, electrolytes, plasma ... The most used conductors are Au, Ag, Cu, Al, Fe ... They conduct electric current well These include metals, electrolytes, plasma ... The most used conductors are Au, Ag, Cu, Al, Fe ... Virtually do not conduct electric current These include plastics, rubber, glass, porcelain, dry wood, paper ... Virtually do not conduct electric current These include plastics, rubber, glass, porcelain, dry wood, paper ... Occupy intermediate conductivity position between conductors and dielectrics Si, Ge, Se, In, As Occupy an intermediate position in conductivity between conductors and dielectrics Si, Ge, Se, In, As

Physical properties of semiconductors R (Ohm) t (0 C) R0R0 metal semiconductor The conductivity of semiconductors depends on temperature. Unlike conductors, whose resistance increases with temperature, the resistance of semiconductors decreases when heated. Near absolute zero, semiconductors have the properties of dielectrics.

Electric current in semiconductors Semiconductors are substances whose resistivity decreases with increasing temperature. Semiconductors include silicon, germanium, selenium, etc. The bond between atoms is electron pair, or covalent At low temperatures, bonds do not break

Intrinsic conductivity of semiconductors Under normal conditions (low temperatures) there are no free charged particles in semiconductors, so the semiconductor does not conduct electric current. Si

"Hole" When heated, the kinetic energy of electrons increases and the fastest of them leave their orbit. During the breaking of the bond between the electron and the nucleus, a free space appears in the electron shell of the atom. At this point, a conditional positive charge is formed, called a "hole". Si hole + + free electron

Impurity conductivity of semiconductors Dosed introduction of impurities into a pure conductor makes it possible to purposefully change its conductivity. Therefore, to increase conductivity, impurities are introduced into pure semiconductors, which are donor and acceptor Impurities Acceptor Donor p-type semiconductors P-type semiconductors n-type semiconductors n-type semiconductors

Hole semiconductors (p-type) In + Si The term "p-type" comes from the word "positive", which means the positive charge of the main carriers. This type of semiconductor, in addition to the impurity base, is characterized by a hole-type conductivity. A small amount of atoms of a trivalent element (for example, indium) is added to a tetravalent semiconductor (for example, silicon). Each impurity atom forms a covalent bond with three neighboring silicon atoms. To establish a bond with the fourth silicon atom, the indium atom does not have a valence electron, so it captures a valence electron from the covalent bond between neighboring silicon atoms and becomes a negatively charged ion, as a result of which a hole is formed. The impurities that are added in this case are called acceptor impurities.

Electronic semiconductors (n-type) As Si The term "n-type" comes from the word "negative", which means the negative charge of the main carriers. This type of semiconductor has an impurity nature. In a tetravalent semiconductor (for example, silicon), an impurity of a pentavalent semiconductor (for example, arsenic) is added. In the course of interaction, each impurity atom enters into a covalent bond with silicon atoms. However, for the fifth electron of the arsenic atom, there is no place in saturated valence bonds, and it goes over to the far electron shell. There, less energy is needed to detach an electron from an atom. The electron breaks off and becomes free. In this case, the charge transfer is carried out by an electron, not a hole, that is, this type of semiconductor conducts an electric current like metals. Impurities that are added to semiconductors, as a result of which they are converted into n-type semiconductors, are called donor.

Donor impurities are impurities that donate an extra valence electron. Semiconductors with donor impurities have electronic conductivity and are called n-type semiconductors. Acceptor impurities are impurities that lack electrons to form a complete covalent bond with neighboring atoms. Semiconductors with acceptor impurities have hole conductivity and are called p-type semiconductors.

Intrinsic conductivity of semiconductors A valence electron of a neighboring atom, being attracted to a hole, can jump into it (recombine). In this case, a new "hole" is formed in its former place, which can then similarly move along the crystal.

Intrinsic conductivity of semiconductors If the strength of the electric field in the sample is zero, then the movement of the released electrons and "holes" is random and therefore does not create an electric current. Under the influence of an electric field, electrons and holes begin an ordered (counter) motion, forming an electric current. The conductivity under these conditions is called the intrinsic conductivity of semiconductors. In this case, the movement of electrons creates electronic conduction, and the movement of holes creates hole conduction.

Diode A semiconductor diode is a semiconductor device with one electrical junction and two leads (electrodes). Unlike other types of diodes, the principle of operation of a semiconductor diode is based on the p-n-junction phenomenon. The diode was first invented by John Flemming in 1904.

Types and applications of diodes Diodes are used in: converting alternating current into permanent detection of electrical signals protection of various devices against incorrect polarity switching switching of high-frequency signals stabilizing current and voltage transmission and reception of signals Transistor An electronic device made of semiconductor material, usually with three terminals, allowing input signals to be controlled current in an electrical circuit. Typically used to amplify, generate and convert electrical signals. In 1947, William Shockley, John Bardeen and Walter Brattain first created a working bipolar transistor at Bell Labs.

TABLE 2

Calendar-thematic plan

Calendar-thematic plan - planning an accounting document, its objectives are to determine the topic, type of method and equipment of lessons in the chosen subject. Drawing up a calendar-thematic plan is the first step in creating a lesson systematization. The original document here is the curriculum. The thematic calendar plan provides for interdisciplinary connections. If the calendar-thematic plan is consistent with the curriculum, they are guided by the thematic plan when drawing up a lesson plan. Calendar-thematic plan (see table 3).

Lesson development

Lesson plan

Subject: Materials Science and Electro-Radio Materials Group 636

Topic: Classification and basic properties

a) training: To acquaint students with the concepts and basic properties of conductive materials, tell about their purpose

b) developing: Develop an interest in materials science and electro-radio materials

c) educational: Develop a need for self-education

Lesson type: Combined

Presentation method: search

Visual aids: poster No. 1, PC

Time: 90 minutes

During the classes

I ... Introductory part:

1. Organizational moment: check according to the report time 2 min.

2. Checking homework: time 15 min.

Written survey on two options + 3 study at the blackboard (appendix 1)

II ... Main part:

1. Post the purpose of the new topic

2. Presentation of new material time 40 min.

a) Basic concepts

b) Classification of conductors

c) Scope of application

3. Answers to students' questions time 10 min.

4. Fastening of new material, time 20 min.

Written survey on 2 options + 3 study at the blackboard (Appendix 2)

III ... Final part: time 3 min.

1. Summing up

2. Assignment at home: p. 440 answers to questions, independently consider topics No. 2, 3, 4, 5

3. Concluding remarks from the teacher

Teacher

Bibliography

1. Lakhtin Yu. M., Leont'eva VP Materials science. - M .: Mechanical Engineering, 1990

2. Technological processes of engineering production. Edited by S. I. Bogodukhov, V. A. Bondarenko. - Orenburg: OSU, 1996

Attachment 1

WRITTEN SURVEY on 2 options

Option 1

1 . That studies the subject of materials science.

2. Types of metals.

3. Classification of metals

4. Allotropic transformation

5 ... Metal properties

Option 2

1. Determination of hardness of metals

2. Mechanical properties

3. Plastic

4. Endurance

5. Technological properties

Appendix 2

Written survey

1 - option

1. Semiconductor materials

2. Superconductors

3. Cryoprobes

4. Characteristics of semiconductor materials

5. Elasticity of materials

Option 2

1. Semiconductor materials.

2. Dielectric materials

3. Plasticity

4. Elasticity

5. Superconductors

application 3

Summary of the lesson on the topic "Conducting Materials"

In general, philosophical and general scientific concepts in technical sciences act as ideological and methodological tools for the analysis and integration of scientific and technical knowledge.

A technical object is undoubtedly a part of objective reality, but a special part. Its origin and existence are associated with the social form of the movement of matter, the history of man. This determines the historical nature of the technical object. It objectifies the production functions of society, it is the embodiment of people's knowledge.

The emergence of technology is a natural historical process, the result of human production activities.

Its starting point is "human organs". Strengthening, supplementing and replacing working organs is a social necessity realized through the use of nature and the embodiment of labor functions in the transformed natural bodies.

Technical practice reveals itself in the relation of man to technology as an object, to its parts and their connections.

Overcoming this contradiction is achieved in technology, in finding standard technological operations.

Physics lesson grade 11

Lesson topic:

“Semiconductors.

Intrinsic and impurity conductivity of semiconductors. Electric current in semiconductors "

The purpose of the lesson

To form in students the concept of the nature of electric current in semiconductors, on how to measure their properties under the influence of temperature, illumination, impurities.
To contribute to the expansion of the polytechnical outlook, to motivate to study the subject, to improve the ability to perceive and analyze technical and scientific information.
Development of the communicative competencies of students, their ability to work in a team.

Materials and equipment:

Computer, projector, electronic materials on the topic: "Semiconductors"; cards - tasks for independent work in small groups; set of semiconductor devices NPP - 2; demo galvanometer; constant current source (4V); demo switch; electric lamp 60-100W on a stand; electric soldering iron; connecting wires.

Lesson plan:

Repetition of the studied and actualization of the topic of the lesson.
Explanation of the topic material.
Independent work of students in groups.
Summing up, home assignment.

Repetition of the studied and actualization of the topic of the lesson (6min).

We must remember:

What is Electric Current?
What is the current direction?
What particles move to generate electric current in metal conductors?
Why can't an electric current arise in dielectrics?
What do you think: are there substances in nature that occupy an intermediate position in terms of their ability to conduct electric current?

Yes, these are semiconductors. Just over half a century ago, they had no noticeable practical significance. In electrical and radio engineering, they managed exclusively with conductors and dielectrics. But the situation changed dramatically when, theoretically, and then practically, the possibility of controlling the electrical conductivity of semiconductors was discovered.

What is the main difference between semiconductors and conductors and what features of their structure made it possible to widely use semiconductor devices in almost all electronic devices, which made it possible to significantly increase their reliability, greatly reduce their dimensions, and create new ones that could only be dreamed of: to create cell phones, miniature computers, etc.?

Explanation of the topic materials (15min)

Definition of semiconductors

A large class of substances, the resistivity of which is higher than that of conductors, but less than that of dielectrics and decreases very sharply with increasing temperature.

These include the elements of the periodic table: germanium, silicon, selenium, tellurium, indium, arsenic, phosphorus, boron, etc. some compounds: pigs sulphide, cadmium sulphide, copper oxide, etc.

Semiconductor structure.

The atomic structure of the silicon crystal lattice (projection on the screen);
Violation of pair-electronic bonds under the influence of external factors: an increase in temperature, illumination.

Demonstration of the dependence of the conductivity of semiconductors:

Rt 10k FS - K1

Electronic conductivity of pure semiconductor (projection)
Hole conductivity (projection)

There is a need to emphasize that holes are not real particles. In both types of semiconductor conductivity, only valence electrons move. Conductivity differs from each other only in the mechanism of the movement of electrons. Electronic conductivity is due to the direction of motion of free electrons, and hole conductivity is caused by the motion of bound electrons passing from atom to atom, alternately replacing each other in bonds, which is equivalent to the movement of holes in the opposite direction.

Thus, in semiconductors there are two types of carriers - electrons and holes, the concentrations of which in pure semiconductors are the same - intrinsic conductivity, it is small.

Impurity conductivity (projection)

The conductivity of semiconductors essentially depends on the presence of impurities in their crystals:

donor impurities - pentavalent elements that easily donate electrons (As, P) provide a quantitative advantage of electrons over holes, creating n-type conductivity;
acceptor impurities - trivalent elements (In, B) that accept free electrons, forming holes. A p-type conductivity is created.

Demonstration of impurities and conductivity of n - type and p - type:

n - type p - type

Of particular interest is the flow of current not separately in n-type or p-type semiconductors, but through the contact of two semiconductors with different types of conductivity.

Students' independent work in groups (20 min)

It is proposed to form groups of 4 students on a voluntary basis (this must be done before the start of the lesson in order to avoid chaotic movement around the office and loss of time).

Each group is given a task that must be completed. It contains questions, quality tasks of different levels, designed for both written and oral answers.

Summarizing

We listen to the answers of the representatives of the groups to the main questions of this topic, we correct possible errors. We collect written reports. Grades for work are given after studying the second part of the topic and completing repetition tasks, taking into account the CTU of each student in the group.

Home assignment: § 113; §114 of the textbook.

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