Diffusion in Solids. Why is it an important part of processing? How can the rate of diffusion be predicted for some simple cases?
|
|
- Dwight Miller
- 6 years ago
- Views:
Transcription
1 Diffusion in Solids ISSUES TO ADDRESS... How does diffusion occur? Why is it an important part of processing? How can the rate of diffusion be predicted for some simple cases? How does diffusion depend on structure and temperature? 1
2 Review: Types of solid solutions Cu-Ni Fe-Fe 3 C What are the atomic structures of the Cu-Ni solid solution? What about the Fe-Fe 3 C solid solution (austenite)? Are these the same?
3 Solute atoms in Alloys Two outcomes if impurity (B) added to host (A): Solid solution of B in A (i.e., random dist. of point defects) OR Substitutional solid soln. (e.g., Cu in Ni) Interstitial solid soln. (e.g., C in Fe) Solid solution of B in A plus particles of a new phase (usually for a larger amount of B) Second phase particle --different composition --often different structure. 3
4 Diffusion Diffusion - Mass transport by atomic motion Mechanisms Gases & Liquids random (Brownian) motion Solids vacancy diffusion or interstitial diffusion 4
5 Interdiffusion: In an alloy, atoms tend to migrate from regions of high concentration to regions of low concentration Initially Diffusion After some time Adapted from Figs. 5.1 and 5., Callister 7e. 5
6 Self-diffusion: In an elemental solid, atoms also migrate. Label some atoms D C A B Diffusion After some time C A B D 6
7 Vacancy Diffusion: Diffusion Mechanisms atoms exchange with vacancies applies to substitutional impurities atoms rate depends on: --number of vacancies --activation energy to exchange. increasing elapsed time 7
8 Diffusion Simulation Simulation of interdiffusion across an interface: Rate of substitutional diffusion depends on: --vacancy concentration --frequency of jumping. (Courtesy P.M. Anderson) 8
9 Diffusion Mechanisms Interstitial diffusion smaller atoms can diffuse between atoms. Adapted from Fig. 5.3 (b), Callister 7e. More rapid than vacancy diffusion 9
10 Processing Using Diffusion Case Hardening: --Diffuse carbon atoms into the host iron atoms at the surface. --Example of interstitial diffusion is a case hardened gear. Adapted from chapter-opening photograph, Chapter 5, Callister 7e. (Courtesy of Surface Division, Midland-Ross.) Result: The presence of C atoms makes iron (steel) harder. Surface hardness makes it harder to initiate cracks better fatigue resistance 10
11 Doping silicon with phosphorus for n-type semiconductors: Process: 0.5 mm 1. Deposit P rich layers on surface. Processing Using Diffusion. Heat it. silicon 3. Result: Doped semiconductor regions. magnified image of a computer chip light regions: Si atoms silicon light regions: Al atoms Adapted from chapter-opening photograph, Chapter 18, Callister 7e. 11
12 Diffusion How do we quantify the amount or rate of diffusion? moles(or mass)diffusing mol kg J Flux or surfacearea time cm s m Measured empirically Make thin film (membrane) of known surface area Impose concentration gradient Measure how fast atoms or molecules diffuse through the membrane s J M At l A dm dt M = mass diffused time J slope 1
13 Steady-State Diffusion Rate of diffusion independent of time Flux proportional to concentration gradient = dc dx C 1 C 1 Fick s first law of diffusion C C J D dc dx if linear dc dx x 1 x x C x C x C x 1 1 D diffusion coefficient 13
14 Example: Chemical Protective Clothing (CPC) Methylene chloride is a common ingredient of paint removers. Besides being an irritant, it also may be absorbed through skin. When using this paint remover, protective gloves should be worn. If butyl rubber gloves (0.04 cm thick) are used, what is the diffusive flux of methylene chloride through the glove? Data: diffusion coefficient in butyl rubber: D = 110 x10-8 cm /s surface concentrations: C 1 = 0.44 g/cm 3 C = 0.0 g/cm 3 14
15 Example (cont). Solution assuming linear conc. gradient C 1 paint remover glove x 1 x t b 6D C skin J Data: - D dc dx C D x D = 110 x 10-8 cm /s C 1 = 0.44 g/cm 3 C = 0.0 g/cm 3 x x 1 = 0.04 cm C x 1 1 J (110 x 10-8 cm (0.0 g/cm 0.44 g/cm /s) (0.04 cm) 3 3 ) 1.16 x 10-5 g cm s 15
16 Diffusion and Temperature Diffusion coefficient increases with increasing T. D D 0 Q d exp or D D0 RT exp D = diffusion coefficient [m /s] D 0 = pre-exponential [m /s] Q d = activation energy [J/mol or ev/atom] R = gas constant [8.314 J/mol-K] k B = Boltzmann s constant = R/N A = 8.617x10-5 ev/k T = absolute temperature [K] Qd k T B 17
17 Diffusion and Temperature D has exponential dependence on 1/T 10-8 T(C) D (m /s) D interstitial >> D substitutional C in a-fe C in g-fe Al in Al Fe in a-fe Fe in g-fe K/T Adapted from Fig. 5.7, Callister 7e. (Date for Fig. 5.7 taken from E.A. Brandes and G.B. Brook (Ed.) Smithells Metals Reference Book, 7th ed., Butterworth-Heinemann, Oxford, 199.) 18
18 Example: At 300ºC the diffusion coefficient and activation energy for Cu in Si are D(300ºC) = 7.8 x m /s Q d = 41.5 kj/mol What is the diffusion coefficient at 350ºC? D transform data ln D Temp = T 1/T lnd lnd lnd 0 lnd Q R 1 d 1 T D ln D 1 and Q R d lnd T T1 lnd 0 Q R d 1 T1 19
19 Example (cont.) D D 1 exp Q R d 1 T 1 T 1 T 1 = = 573 K T = = 63 K D (7.8 x m 41,500 J/mol /s) exp J/mol-K 1 63K 1 573K D = 15.7 x m /s 0
20 Non-steady State Diffusion The concentration of diffucing species is a function of both time and position C = C(x,t) In this case Fick s Second Law is used Fick s Second Law C t D C x 1
21 Non-steady State Diffusion Copper diffuses into a bar of aluminum. Surface conc., C s of Cu atoms bar pre-existing conc., C o of copper atoms C s Adapted from Fig. 5.5, Callister 7e. B.C. at t = 0, C = C o for 0 x at t > 0, C = C S for x = 0 (const. surf. conc.) C = C o for x =
22 Solution: C x,t C C C s o o 1 erf x Dt C(x,t) = Conc. at point x at time t erf (z) = error function z e y 0 dy erf(z) values are given in Table 5.1 3
23 Solution: C x, t C C C s o o 1 erf x Dt erfc x Dt C(x,t) = Conc. at point x at time t erf (z) = error function z e y 0 dy erf(z) values are given in Table 5.1 C S C(x,t) C o 4
24 Non-steady State Diffusion Sample Problem: An FCC iron-carbon alloy initially containing 0.0 wt% C is carburized at an elevated temperature and in an atmosphere that gives a surface carbon concentration constant at 1.0 wt%. If after 49.5 h the concentration of carbon is 0.35 wt% at a position 4.0 mm below the surface, determine the temperature at which the treatment was carried out. C( x, t) Co x Solution: use Eqn erf Cs Co Dt 5
25 Solution (cont.): C( x,t ) C C C s o o 1 erf x Dt t = 49.5 h x = 4 x 10-3 m C x = 0.35 wt% C s = 1.0 wt% C o = 0.0 wt% C( x, t) C C C s o o erf x Dt 1 erf( z) erf(z) =
26 Solution (cont.): We must now determine from Table 5.1 the value of z for which the error function is An interpolation is necessary as follows z erf(z) z z z 0.93 Now solve for D z x Dt D x 4z t D x 4z t (4 x 10 (4)(0.93) 3 m) (49.5 h) 1h 3600s.6 x m /s 7
27 Solution (cont.): To solve for the temperature at which D has above value, we use a rearranged form of Equation (5.9a); from Table 5., for diffusion of C in FCC Fe D o =.3 x 10-5 m /s Q d = 148,000 J/mol T Qd R( lnd lnd) o T (8.314 J/mol- K)(ln.3x10 148,000 J/mol 5 11 m /s ln.6x10 m /s) T = 1300 K = 107 C 8
28 Summary Diffusion FASTER for... open crystal structures materials w/secondary bonding smaller diffusing atoms lower density materials Diffusion SLOWER for... close-packed structures materials w/covalent bonding larger diffusing atoms higher density materials 31
Chapter 5: Diffusion
Chapter 5: Diffusion ISSUES TO ADDRESS... How does diffusion occur? Why is it an important part of processing? How can the rate of diffusion be predicted for some simple cases? How does diffusion depend
More informationChapter 5: Diffusion
Chapter 5: Diffusion ISSUES TO ADDRESS... How does diffusion occur? Why is it an important part of processing? How can the rate of diffusion be predicted for some simple cases? How does diffusion depend
More informationPreparation of Materials Lecture 6
PY3090 Preparation of Materials Lecture 6 Colm Stephens School of Physics PY3090 6 iffusion iffusion Mass transport by atomic motion Mechanisms Gases & Liquids random (Brownian) motion Solids vacancy diffusion
More informationPY2N20 Material Properties and Phase Diagrams
PYN0 Material Properties and Phase iagrams Lecture 7 P. Stamenov, Ph School of Physics, TC PYN0-7 iffusion iffusion Mass transport by atomic motion Mechanisms Gases & Liquids random (Brownian) motion Solids
More informationChapter 5: Diffusion. Introduction
Chapter 5: Diffusion Outline Introduction Diffusion mechanisms Steady-state diffusion Nonsteady-state diffusion Factors that influence diffusion Introduction Diffusion: the phenomenon of material transport
More informationCHAPTER 5: DIFFUSION IN SOLIDS
CHAPTER 5: DIFFUSION IN SOLIDS ISSUES TO ADDRESS... How does diffusion occur? Why is it an important part of processing? How can the rate of diffusion be predicted for some simple cases? How does diffusion
More information10/7/ :43 AM. Chapter 5. Diffusion. Dr. Mohammad Abuhaiba, PE
10/7/2013 10:43 AM Chapter 5 Diffusion 1 2 Why Study Diffusion? Materials of all types are often heat-treated to improve their properties. a heat treatment almost always involve atomic diffusion. Often
More informationN = N A ρ Pb A Pb. = ln N Q v kt. 지난문제. Below are shown three different crystallographic planes for a unit cell of some hypothetical metal.
지난문제. Below are shown three different crystallographic planes for a unit cell of some hypothetical metal. The circles represent atoms: (a) To what crystal system does the unit cell belong? (b) What would
More information10/8/2016 8:29 PM. Chapter 5. Diffusion. Mohammad Suliman Abuhaiba, Ph.D., PE
Chapter 5 Diffusion 1 2 Home Work Assignments 10, 13, 17, 21, 27, 31, D1 Due Tuesday 18/10/2016 3 rd Exam on Sunday 23/10/2016 3 Why Study Diffusion? Materials of all types are often heattreated to improve
More information11/2/2018 7:57 PM. Chapter 5. Diffusion. Mohammad Suliman Abuhaiba, Ph.D., PE
Chapter 5 Diffusion 1 2 Bonus Outsource a software for heat treatment Install the software Train yourself in using the software Apply case studies on the software Present your work in front of your colleagues
More informationCHAPTER 5 DIFFUSION PROBLEM SOLUTIONS
CHAPTER 5 DIFFUSION PROBLEM SOLUTIONS 5.5 (a) Briefly explain the concept of a driving force. (b) What is the driving force for steady-state diffusion? (a) The driving force is that which compels a reaction
More informationCHAPTER 6 OUTLINE. DIFFUSION and IMPERFECTIONS IN SOLIDS
CHAPTER 6 DIFFUSION and IMPERFECTIONS IN SOLIDS OUTLINE 1. TYPES OF DIFFUSIONS 1.1. Interdiffusion 1.2. Selfdiffusion 1.3.Diffusion mechanisms 1.4.Examples 2. TYPES OF IMPERFECTIONS 2.1.Point Defects 2.2.Line
More informationDiffusion and Fick s law. Prof.P. Ravindran, Department of Physics, Central University of Tamil Nadu, India
Diffusion and Fick s law 1 Prof.P. Ravindran, Department of Physics, Central University of Tamil Nadu, India http://folk.uio.no/ravi/pmat2013 Diffusion, flux, and Fick s law 2 Diffusion: (1) motion of
More informationImperfections: Good or Bad? Structural imperfections (defects) Compositional imperfections (impurities)
Imperfections: Good or Bad? Structural imperfections (defects) Compositional imperfections (impurities) 1 Structural Imperfections A perfect crystal has the lowest internal energy E Above absolute zero
More informationDefects and Diffusion
Defects and Diffusion Goals for the Unit Recognize various imperfections in crystals Point imperfections Impurities Line, surface and bulk imperfections Define various diffusion mechanisms Identify factors
More informationChapter 5: Atom and Ion Movements in Materials
Slide 1 Chapter 5: Atom and Ion Movements in Materials 5-1 Slide 2 Learning Objectives 1. Applications of diffusion 2. Stability of atoms and ions 3. Mechanisms for diffusion 4. Activation energy for diffusion
More informationdiffusion is not normally subject to observation by noting compositional change, because in pure metals all atoms are alike.
71 CHAPTER 4 DIFFUSION IN SOLIDS 4.1 INTRODUCTION In the previous chapters we learnt that any given atom has a particular lattice site assigned to it. Aside from thermal vibration about its mean position
More informationChapter 5. Imperfections in Solids
Chapter 5 Imperfections in Solids Chapter 5 2D Defects and Introduction to Diffusion Imperfections in Solids Issues to Address... What types of defects arise in solids? Can the number and type of defects
More informationCHAPTER 4 DIFFUSIVITY AND MECHANISM
68 CHAPTER 4 DIFFUSIVITY AND MECHANISM 4.1 INTRODUCTION The various elements present in the alloys taken for DB joining diffuse in varying amounts. The diffusivity of elements into an alloy depends on
More informationModeling Diffusion: Flux
Modeling Diffusion: Flux Flux (#/area/time): J = 1 A dm dt Directional Quantity y Jy kg atoms m 2 or s m 2 s Jx Jz x z Flux can be measured for: --vacancies and interstitials --host (A) atoms --impurity
More information(12) 1. Just one True and False question and a couple of multiple choice calculations, circle one answer for each problem, no partial credit.
(1) 1. Just one True and False question and a couple of multiple choice calculations, circle one answer for each problem, no partial credit. The next page is left blank for your use, but no partial will
More informationMaterial Science. Prof. Satish V. Kailas Associate Professor Dept. of Mechanical Engineering, Indian Institute of Science, Bangalore India
Material Science Prof. Satish V. Kailas Associate Professor Dept. of Mechanical Engineering, Indian Institute of Science, Bangalore 560012 India Chapter 5. Diffusion Learning objectives: - To know the
More informationLearning Objectives. Chapter Outline. Solidification of Metals. Solidification of Metals
Learning Objectives Study the principles of solidification as they apply to pure metals. Examine the mechanisms by which solidification occurs. - Chapter Outline Importance of Solidification Nucleation
More informationChapter 4: Imperfections (Defects) in Solids
Chapter 4: Imperfections (Defects) in Solids ISSUES TO ADDRESS... What types of defects exist in solids? How do defects affect material properties? Can the number and type of defects be varied and controlled?
More informationQuestion Grade Maximum Grade Total 100
The Islamic University of Gaza Industrial Engineering Department Engineering Materials, EIND 3301 Final Exam Instructor: Dr. Mohammad Abuhaiba, P.E. Exam date: 31/12/2013 Final Exam (Open Book) Fall 2013
More informationCHAPTER 5 IMPERFECTIONS IN SOLIDS PROBLEM SOLUTIONS
CHAPTER 5 IMPERFECTIONS IN SOLIDS PROBLEM SOLUTIONS Vacancies and Self-Interstitials 5.1 Calculate the fraction of atom sites that are vacant for copper at its melting temperature of 1084 C (1357 K). Assume
More informationStudent Name: ID Number:
Student Name: ID Number: DEPARTMENT OF MECHANICAL ENGINEERING CONCORDIA UNIVERSITY MATERIALS SCIENCE - MECH 1/ - Sections T & X MIDTERM 003 Instructors: Dr. M.Pugh & Dr. M.Medraj Time Allowed: one (1)
More informationLN Introduction to Solid State Chemistry. Lecture Notes No. 9 DIFFUSION
3.091 Introduction to Solid State Chemistry Lecture Notes No. 9 DIFFUSION * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * Sources for Further Reading:
More informationAeronautical Engineering Department
Jordan University of Science and Technology Engineering collage Aeronautical Engineering Department Manual for: Material Science and Engineering / 8th edition Ahmed Mustafa El-Khalili CHAPTER 5 DIFFUSION
More informationMSE 170 Midterm review
MSE 170 Midterm review Exam date: 11/2/2008 Mon, lecture time Place: Here! Close book, notes and no collaborations A sheet of letter-sized paper with double-sided notes is allowed Material on the exam
More informationCHAPTER 5 IMPERFECTIONS IN SOLIDS PROBLEM SOLUTIONS ev /atom = exp. kt ( =
CHAPTER 5 IMPERFECTIONS IN SOLIDS PROBLEM SOLUTIONS Vacancies and Self-Interstitials 5.1 Calculate the fraction of atom sites that are vacant for copper at its melting temperature of 1084 C (1357 K). Assume
More informationJ = D C A C B x A x B + D C A C. = x A kg /m 2
1. (a) Compare interstitial and vacancy atomic mechanisms for diffusion. (b) Cite two reasons why interstitial diffusion is normally more rapid than vacancy diffusion. (a) With vacancy diffusion, atomic
More informationMicroelettronica. Planar Technology for Silicon Integrated Circuits Fabrication. 26/02/2017 A. Neviani - Microelettronica
Microelettronica Planar Technology for Silicon Integrated Circuits Fabrication 26/02/2017 A. Neviani - Microelettronica Introduction Simplified crosssection of an nmosfet and a pmosfet Simplified crosssection
More informationDiffusion phenomenon
Module-5 Diffusion Contents 1) Diffusion mechanisms and steady-state & non-steady-state diffusion 2) Factors that influence diffusion and nonequilibrium transformation & microstructure Diffusion phenomenon
More informationHomework #4 PROBLEM SOLUTIONS
Homework #4 PROBLEM SOLUTIONS 4.2 Determination of the number of vacancies per cubic meter in gold at 900 C (1173 K) requires the utilization of Equations (4.1) and (4.2) as follows: N V N exp Q V kt N
More informationDepartment of Mechanical Engineering University of Saskatchewan. ME324.3 Engineering Materials FINAL EXAMINATION (CLOSED BOOK)
Department of Mechanical Engineering University of Saskatchewan ME32.3 Engineering Materials FINAL EXAMINATION (CLOSED BOOK) Instructor: I. N. A. Oguocha Date: 17 December, 200. Time: 3 Hours Reading Time:
More informationatoms = 1.66 x g/amu
CHAPTER 2 Q1- How many grams are there in a one amu of a material? A1- In order to determine the number of grams in one amu of material, appropriate manipulation of the amu/atom, g/mol, and atom/mol relationships
More informationCrystal Defects. Perfect crystal - every atom of the same type in the correct equilibrium position (does not exist at T > 0 K)
Crystal Defects Perfect crystal - every atom of the same type in the correct equilibrium position (does not exist at T > 0 K) Real crystal - all crystals have some imperfections - defects, most atoms are
More information12/10/09. Chapter 4: Imperfections in Solids. Imperfections in Solids. Polycrystalline Materials ISSUES TO ADDRESS...
Chapter 4: ISSUES TO ADDRESS... What are the solidification mechanisms? What types of defects arise in solids? Can the number and type of defects be varied and controlled? How do defects affect material
More informationImpurities in Solids. Crystal Electro- Element R% Structure negativity Valence
4-4 Impurities in Solids 4.4 In this problem we are asked to cite which of the elements listed form with Ni the three possible solid solution types. For complete substitutional solubility the following
More informationMaterials Science. Imperfections in Solids CHAPTER 5: IMPERFECTIONS IN SOLIDS. Types of Imperfections
In the Name of God Materials Science CHAPTER 5: IMPERFECTIONS IN SOLIDS ISSUES TO ADDRESS... What are the solidification mechanisms? What types of defects arise in solids? Can the number and type of defects
More informationAtom and Ion Movements in Materials
Atom and Ion Movements in Materials Chapter 5 Have You Ever Wondered? Aluminum oxidizes more easily than iron, so why do we say aluminum normally does not rust? What kind of plastic is used to make carbonated
More informationChapter 19: Thermal Properties
Chapter 19: Thermal Properties One type of thermostat a device that is used to regulate temperature utilizes the phenomenon of thermal expansion. The heart of this thermostat is a bimetallic strip strips
More informationPhysical Metallurgy Friday, January 28, 2011; 8:30 12:00 h
Physical Metallurgy Friday, January 28, 2011; 8:30 12:00 h Always motivate your answers All sub-questions have equal weight in the assessment Question 1 Precipitation-hardening aluminium alloys are, after
More informationSection 4: Thermal Oxidation. Jaeger Chapter 3. EE143 - Ali Javey
Section 4: Thermal Oxidation Jaeger Chapter 3 Properties of O Thermal O is amorphous. Weight Density =.0 gm/cm 3 Molecular Density =.3E molecules/cm 3 O Crystalline O [Quartz] =.65 gm/cm 3 (1) Excellent
More informationIntroduction to Engineering Materials ENGR2000 Chapter 19: Thermal Properties. Dr. Coates
Introduction to Engineering Materials ENGR2000 Chapter 19: Thermal Properties Dr. Coates Chapter 19: Thermal Properties ISSUES TO ADDRESS... How do materials respond to the application of heat? How do
More informationAnnouncements. Chapter 19-1
Announcements Quiz in lecture on Wednesday Chapter 18 Electrical Properties Chapter 19 Thermal Properties Also an anonymous end-of-term survey Also on Wednesday Hand out a study guide for the final exam
More informationPROPERTIES OF MATERIALS IN ELECTRICAL ENGINEERING MIME262 IN-TERM EXAM #1
IN-TERM EXAM #1, Oct 17 th, 2007 DURATION: 45 mins Version τ CLOSED BOOK McGill ID Name All students must have one of the following types of calculators: CASIO fx-115, CASIO fx-991, CASIO fx-570ms SHARP
More informationHOMEWORK 6. solutions
HOMEWORK 6. SCI 1410: materials science & solid state chemistry solutions Textbook Problems: Imperfections in Solids 1. Askeland 4-67. Why is most gold or siler jewelry made out of gold or siler alloyed
More informationN = N A Al A Al. = ( atoms /mol)(2.62 g /cm 3 ) g /mol. ln N v = ln N Q v kt. = kt ln v. Q v
4.3 alculate the activation energy for vacancy formation in aluminum, given that the equilibrium number of vacancies at 500 (773 K) is 7.57 10 23 m -3. The atomic weight and density (at 500 ) for aluminum
More informationCRYSTAL STRUCTURE, MECHANICAL BEHAVIOUR & FAILURE OF MATERIALS
MODULE ONE CRYSTAL STRUCTURE, MECHANICAL BEHAVIOUR & FAILURE OF MATERIALS CRYSTAL STRUCTURE Metallic crystal structures; BCC, FCC and HCP Coordination number and Atomic Packing Factor (APF) Crystal imperfections:
More informationPoint Defects. Vacancies are the most important form. Vacancies Self-interstitials
Grain Boundaries 1 Point Defects 2 Point Defects A Point Defect is a crystalline defect associated with one or, at most, several atomic sites. These are defects at a single atom position. Vacancies Self-interstitials
More informationImperfections in Solids. Imperfections in Solids. Point Defects. Types of Imperfections
Imperfections in Solids In this topic we will try to answer the following questions: What types of defects arise in solids? Are these defects undesirable? How do defects affect material properties? Can
More informationImperfections, Defects and Diffusion
Imperfections, Defects and Diffusion Lattice Defects Week5 Material Sciences and Engineering MatE271 1 Goals for the Unit I. Recognize various imperfections in crystals (Chapter 4) - Point imperfections
More informationCHAPTER 4: Oxidation. Chapter 4 1. Oxidation of silicon is an important process in VLSI. The typical roles of SiO 2 are:
Chapter 4 1 CHAPTER 4: Oxidation Oxidation of silicon is an important process in VLSI. The typical roles of SiO 2 are: 1. mask against implant or diffusion of dopant into silicon 2. surface passivation
More informationDept.of BME Materials Science Dr.Jenan S.Kashan 1st semester 2nd level. Imperfections in Solids
Why are defects important? Imperfections in Solids Defects have a profound impact on the various properties of materials: Production of advanced semiconductor devices require not only a rather perfect
More informationPhysics of Materials: Defects in Solids. Dr. Anurag Srivastava. Indian Institute of Information Technology and Manegement, Gwalior
: Defects in Solids Dr. Anurag Srivastava Atal Bihari Vajpayee Indian Institute of Information Technology and Manegement, Gwalior What you have learnt so far? Properties of Materials affected by defects
More informationPoint coordinates. x z
Point coordinates c z 111 a 000 b y x z 2c b y Point coordinates z y Algorithm 1. Vector repositioned (if necessary) to pass through origin. 2. Read off projections in terms of unit cell dimensions a,
More informationChapter 7: Dislocations and strengthening mechanisms. Strengthening by grain size reduction
Chapter 7: Dislocations and strengthening mechanisms Mechanisms of strengthening in metals Strengthening by grain size reduction Solid-solution strengthening Strain hardening Recovery, recrystallization,
More informationKinetics. Rate of change in response to thermodynamic forces
Kinetics Rate of change in response to thermodynamic forces Deviation from local equilibrium continuous change T heat flow temperature changes µ atom flow composition changes Deviation from global equilibrium
More informationPhase Transformation of Materials
2009 fall Phase Transformation of Materials 10.08.2009 Eun Soo Park Office: 33-316 Telephone: 880-7221 Email: espark@snu.ac.kr Office hours: by an appointment 1 Contents for previous class Interstitial
More informationLecture 7: Solid State Reactions Phase Diagrams and Mixing
Lecture 7: Solid State Reactions Phase Diagrams and Mixing Prof Ken Durose, Univ of Liverpool Text book for this lecture: Callister Materials Science and Engineering Learning objectives 1.Solid state reactions
More informationME 254 MATERIALS ENGINEERING 1 st Semester 1431/ rd Mid-Term Exam (1 hr)
1 st Semester 1431/1432 3 rd Mid-Term Exam (1 hr) Question 1 a) Answer the following: 1. Do all metals have the same slip system? Why or why not? 2. For each of edge, screw and mixed dislocations, cite
More informationISSUES TO ADDRESS...
Chapter 5: IMPERFECTIONS IN SOLIDS School of Mechanical Engineering Choi, Hae-Jin Materials Science - Prof. Choi, Hae-Jin Chapter 4-1 ISSUES TO ADDRESS... What are the solidification mechanisms? What types
More informationChapter 18: Electrical Properties
Chapter 18: Electrical Properties ISSUES TO ADDRESS... How are electrical conductance and resistance characterized? What are the physical phenomena that distinguish conductors, semiconductors, and insulators?
More informationMSE 230 Fall 2007 Exam II
1 Purdue University School of Materials Engineering MSE 230 Fall 2007 Exam II November 8, 2007 Show All ork and Put Units on Answers Name: KEY Unique name or email : Recitation Day and Time: Recitation
More informationDefinition and description of different diffusion terms
Definition and description of different diffusion terms efore proceeding further, it is necessary to introduce different terms frequently used in diffusion studies. Many terms will be introduced, which
More information1. Use the Ellingham Diagram (reproduced here as Figure 0.1) to answer the following.
315 Problems 1. Use the Ellingham Diagram (reproduced here as Figure 0.1) to answer the following. (a) Find the temperature and partial pressure of O 2 where Ni(s), Ni(l), and NiO(s) are in equilibrium.
More informationThe Diffusion Equation I L2 10/31/06
The Diffusion Equation I 3.205 L2 10/31/06 1 Fick s Laws of Diffusion Fick s first law r J = "D#c The diffusivity, D, is a second-rank tensor Fick s second law "c "t = #$ % J r 3.205 L2 10/31/06 2 Self-diffusion
More informationChapter 5. UEEP2613 Microelectronic Fabrication. Diffusion
Chapter 5 UEEP613 Microelectronic Fabrication Diffusion Prepared by Dr. Lim Soo King 4 Jun 01 Chapter 5 Diffusion...131 5.0 Introduction... 131 5.1 Model of Diffusion in Solid... 133 5. Fick s Diffusion
More informationPoint coordinates. Point coordinates for unit cell center are. Point coordinates for unit cell corner are 111
Point coordinates c z 111 Point coordinates for unit cell center are a/2, b/2, c/2 ½ ½ ½ Point coordinates for unit cell corner are 111 x a z 000 b 2c y Translation: integer multiple of lattice constants
More informationSection 4: Thermal Oxidation. Jaeger Chapter 3
Section 4: Thermal Oxidation Jaeger Chapter 3 Properties of O Thermal O is amorphous. Weight Density =.0 gm/cm 3 Molecular Density =.3E molecules/cm 3 O Crystalline O [Quartz] =.65 gm/cm 3 (1) Excellent
More informationChanging the Dopant Concentration. Diffusion Doping Ion Implantation
Changing the Dopant Concentration Diffusion Doping Ion Implantation Step 11 The photoresist is removed with solvent leaving a ridge of polysilicon (the transistor's gate), which rises above the silicon
More informationCHAPTER 8: Diffusion. Chapter 8
1 CHAPTER 8: Diffusion Diffusion and ion implantation are the two key processes to introduce a controlled amount of dopants into semiconductors and to alter the conductivity type. Figure 8.1 compares these
More informationPart IB Paper 3: MATERIALS. Examples Paper 3 : Materials Processing - fssued 01 Controlling Microstructure and Properties
ENGINEERING TRIPOS Part IB Paper 3: MATERIALS SECOND YEAR Examples Paper 3 : Materials Processing - fssued 01 Controlling Microstructure and Properties -1 NOV 2')13 Straightforward questions are marked
More informationMSE 230 Fall 2003 Exam II
Purdue University School of Materials Engineering MSE 230 Fall 2003 Exam II November 13, 2003 Show All Work and Put Units on Answers Name: Key Recitation Day and Time: Recitation Instructor s Name: 1 2
More informationCreep and High Temperature Failure. Creep and High Temperature Failure. Creep Curve. Outline
Creep and High Temperature Failure Outline Creep and high temperature failure Creep testing Factors affecting creep Stress rupture life time behaviour Creep mechanisms Example Materials for high creep
More informationPoint Defects in Metals
CHAPTER 5 IMPERFECTIONS IN SOLIDS PROBLEM SOLUTIONS Point Defects in Metals 5.1 Calculate the fraction of atom sites that are vacant for lead at its melting temperature of 327 C (600 K). Assume an energy
More informationIntroduction to Materials Science
EPMA Powder Metallurgy Summer School 27 June 1 July 2016 Valencia, Spain Introduction to Materials Science Prof. Alberto Molinari University of Trento, Italy Some of the figures used in this presentation
More informationMaterials of Engineering ENGR 151 CORROSION ELECTRICAL PROPERTIES
Materials of Engineering ENGR 151 CORROSION ELECTRICAL PROPERTIES more anodic (active) more cathodic (inert) GALVANIC SERIES Ranking of the reactivity of metals/alloys in seawater Platinum Gold Graphite
More informationFrom sand to silicon wafer
From sand to silicon wafer 25% of Earth surface is silicon Metallurgical grade silicon (MGS) Electronic grade silicon (EGS) Polycrystalline silicon (polysilicon) Single crystal Czochralski drawing Single
More informationChapter 10, Phase Transformations
Chapter Outline: Phase Transformations Heat Treatment (time and temperature) Microstructure Kinetics of phase transformations Homogeneous and heterogeneous nucleation Growth, rate of the phase transformation
More informationMICROCHIP MANUFACTURING by S. Wolf
MICROCHIP MANUFACTURING by S. Wolf Chapter 13: THERMAL- OXIDATION of SILICON 2004 by LATTICE PRESS Chapter 13: THERMAL-OXIDATION of SILICON n CHAPTER CONTENTS Applications of Thermal Silicon-Dioxide Physical
More information3. A copper-nickel diffusion couple similar to that shown in Figure 5.1a is fashioned. After a 700-h heat treatment at 1100 C (1373 K) the
ENT 145 Tutorial 3 1. A sheet of steel 1.8 mm thick has nitrogen atmospheres on both sides at 1200 C and is permitted to achieve a steady-state diffusion condition. The diffusion coefficient for nitrogen
More informationEE 5344 Introduction to MEMS. CHAPTER 3 Conventional Si Processing
3. Conventional licon Processing Micromachining, Microfabrication. EE 5344 Introduction to MEMS CHAPTER 3 Conventional Processing Why silicon? Abundant, cheap, easy to process. licon planar Integrated
More informationIntroduction to Engineering Materials ENGR2000 Chapter 4: Imperfections in Solids. Dr. Coates
Introduction to Engineering Materials ENGR000 Chapter 4: Imperfections in Solids Dr. Coates Learning Objectives 1. Describe both vacancy and self interstitial defects. Calculate the equilibrium number
More informationElectrical conductivity
Electrical conductivity Ohm's Law: voltage drop (volts = J/C) C = Coulomb A (cross sect. area) ΔV = I R Resistivity, ρ and Conductivity, σ: -- geometry-independent forms of Ohm's Law resistance (Ohms)
More informationChapter 8 Strain Hardening and Annealing
Chapter 8 Strain Hardening and Annealing This is a further application of our knowledge of plastic deformation and is an introduction to heat treatment. Part of this lecture is covered by Chapter 4 of
More informationCarburization: A study on the Case Hardening of Steels. By, Hans Cocks
Abstract Carburization: A study on the Case Hardening of Steels By, Hans Cocks The objective of this report is to examine and identify the case depth of differently cooled but equivalently carburized specimens.
More informationCME 300 Properties of Materials. ANSWERS Homework 2 September 28, 2011
CME 300 Properties of Materials ANSWERS Homework 2 September 28, 2011 1) Explain why metals are ductile and ceramics are brittle. Why are FCC metals ductile, HCP metals brittle and BCC metals tough? Planes
More informationDoping and Oxidation
Technische Universität Graz Institute of Solid State Physics Doping and Oxidation Franssila: Chapters 13,14, 15 Peter Hadley Technische Universität Graz Institute of Solid State Physics Doping Add donors
More information8 The intermetallic diffusion mechanism in composite Pd
8 The intermetallic diffusion mechanism in composite Pd membranes 8.1 Introduction Intermetallic diffusion is the migration of the elements in the porous metal support (mostly Fe, Cr and Ni) into the Pd
More informationDefect in crystals. Primer in Materials Science Spring
Defect in crystals Primer in Materials Science Spring 2017 11.05.2017 1 Introduction The arrangement of the atoms in all materials contains imperfections which have profound effect on the behavior of the
More informationChapter 16 Corrosion and Degradation of Materials
Chapter 16 Corrosion and Degradation of Materials Concept Check 16.1 Question: Would you expect iron to corrode in water of high purity? Why or why not? Answer: Iron would not corrode in water of high
More information3.40 Sketch within a cubic unit cell the following planes: (a) (01 1 ) (b) (112 ) (c) (102 ) (d) (13 1) Solution
3.40 Sketch within a cubic unit cell the following planes: (a) (01 1 ) (b) (11 ) (c) (10 ) (d) (13 1) The planes called for are plotted in the cubic unit cells shown below. 3.41 Determine the Miller indices
More informationLecture 20: Eutectoid Transformation in Steels: kinetics of phase growth
Lecture 0: Eutectoid Transformation in Steels: kinetics of phase growth Today s topics The growth of cellular precipitates requires the portioning of solute to the tips of the precipitates in contact with
More informationAtomic Transport & Phase Transformations. PD Dr. Nikolay Zotov
Atomic Transport & Phase Transformations PD Dr. Nikolay Zotov Atomic Transport & Phase Transformations Part II Lecture Diffusion Short Description 1 Introduction; Non-equilibrium thermodynamics 2 Diffusion,
More informationCRYSTAL GROWTH, WAFER FABRICATION AND BASIC PROPERTIES OF Si WAFERS- Chapter 3. Crystal Structure z a
CRYSTAL GROWTH, WAFER FABRICATION AND BASIC PROPERTIES OF Si WAFERS- Chapter 3 Crystal Growth, Si Wafers- Chapter 3 z a C y B z a y Crystal Structure z a y Crystals are characterized by a unit cell which
More informationDiffusion & Crystal Structure
Lecture 5 Diffusion & Crystal Structure Diffusion of an interstitial impurity atom in a crystal from one void to a neighboring void. The impurity atom at position A must posses an energy E to push the
More informationPhysical Properties of Materials
Physical Properties of Materials Manufacturing Materials, IE251 Dr M. Saleh King Saud University Manufacturing materials --- IE251 lect-7, Slide 1 PHYSICAL PROPERTIES OF MATERIALS 1. Volumetric and Melting
More information