NENG 301 Thermodynamics and Kinetics of Nanomaterials

Save this PDF as:

Size: px
Start display at page:

Download "NENG 301 Thermodynamics and Kinetics of Nanomaterials"


1 NENG 301 Thermodynamics and Kinetics of Nanomaterials Prof. Y. Alex Xue CNSE, SUNY Polytechnic Institute office: CESTM B230C phone: office hours: Tuesdays 1:00 2:30 PM Course Website:

2 From the course catalogue Applications of first, second, and third laws of thermodynamics to open and closed systems. Thermodynamics of multicomponent, multiphase chemical and biological systems are reviewed. Applies the concepts of reaction rate, stoichiometry and equilibrium to the analysis of materials systems. Rate expressions from reaction mechanisms and equilibrium or steady state assumptions are used. Design of reactions via synthesis of kinetics, transport phenomena, and mass and energy balances are covered. Introduction to diffusional processes. Prerequisite(s): satisfactory completion of AMAT 311, NENG 120/122

3 What is Thermodynamics? Thermodynamics is a funny subject. The first time you go through it, you don't understand it at all. The second time you go through it, you think you understand it, except for one or two small points. The third time you go through it, you know you don't understand it, but by that time you are so used to it, it doesn't bother you any more. The Laws of Thermodynamics, in brief -- Arnold Sommerfeld 0th: "You must play the game." 1st: "You can't win." 2nd: "You can't break even, except at absolute zero." 3rd: "You can't get to absolute zero."

4 Course learning objectives The overall learning objectives for this course are the following: The student will demonstrate understanding of the basic structure of thermodynamics, including state functions and process variables; extensive and intensive properties; and the First, Second and Third Laws of Thermodynamics The student will be able to develop, manipulate, and utilize relationships between thermodynamic variables and apply these relations to gases, liquids and solids The student will demonstrate understanding of how thermodynamic processes determine the equilibrium structures of materials at the macroscale, the microscale, and the nanoscale The student will learn how the kinetics of physical and chemical processes are dictated by thermodynamic driving forces The student will learn how to address important scientific and engineering problems by thermodynamic and kinetic analyses At the beginning of each book chapter covered I will provide you with a list of specific learning objectives for that chapter

5 Subjects to be covered Background Why Study Thermodynamics The Structure of Thermodynamics The Laws of Thermodynamics Thermodynamic Variables and Relations Equilibrium in Thermodynamic Systems Unary Heterogeneous Systems Multicomponent Homogeneous Non-reacting Systems Solutions Multicomponent Heterogeneous Systems Thermodynamics of Phase Diagrams Multicomponent Multiphase Reacting Systems Capillarity Effects in Thermodynamics Introduction to Kinetic Processes: Diffusion, Oxidation,

6 Textbook and other readings Textbook: R. DeHoff, Thermodynamics in Materials Science (Second Edition, CRC Press, Taylor & Francis Group, 2006) available at the University Bookstore I will follow the textbook very closely: make sure you read it!!! Extra readings on kinetics: D.A. Porter and K.E. Easterling, Phase Transformations in Metals and Alloys Other readings may be distributed from time to time All non-textbook readings will be made available on the course web site

7 Group exercises, exams and grading Group exercises: Six sessions Administered RANDOMLY You will be working collaboratively on problems in class NO MAKE-UP exercise Group ordered according to last name initial Group I: B,C,W (7) Group II: D, E, F, Y (7) Group III: G,J, T (7) Group IV: K, M, U (7) Group V: N, S (6) Group VI: P, R (6) There will be one comprehensive final exam Grades will be based on the final exam (40%), and participation in group exercise (6 x 10%).

8 Academic dishonesty Academic dishonesty refers to plagiarism, cheating, multiple submission, forgery, sabotage, falsification, unauthorized collaboration, and bribery Academic dishonesty will not be tolerated in this course Any incidence of academic dishonesty will result in an automatic failure of at least the assignment if not the course and will be reported in writing to the CNSE Office for Student Services

9 Lectures and Slides Lectures will be MWF 10:25 to 11:20; attendance is expected and mandatory corollary: it would be foolish for you to miss lectures! Lecture slides will be posted on the course website each week It is possible/probable that I may prepare too many slides to fit into a 55 minute class period; in this case, I will halt the presentation wherever it is and pick up from that spot at the beginning of the next lecture

10 Student multitasking activities Ragan et al (2014)

11 Sana and Weston (2013) Justification Students who multitask in class average 11% lower when quizzed on material immediately afterword. Students who are surrounded by laptops scored 17% lower. Freid (2008) Students who used laptops spent considerable time multitasking and the laptop use posed a significant distraction to both users and fellow students. The level of laptop use was negatively related to self-reported understanding of course material and overall course performance. Mueller and Oppenheimer (2014) Student who take notes on laptops tend to transcribe lectures verbatim rather than processing information and reframing it in their own words. Laptop notetakers performed worse on conceptual questions.


13 Some comments on subject matter Classes on thermodynamics have a certain reputation for being difficult If you have never seen this stuff before, it can be somewhat challenging However, it is not rocket science or advanced quantum mechanics: thermodynamics and kinetics are founded in real-life experiences Also: thermodynamics and kinetics are important foundations for a wide variety of scientific and technical subjects If you are in nanotechnology, you will see this stuff for the rest of your career you must know this!!

14 Some other thoughts You will find the sequence of NENG 301, 302 and 303 to be difficult please study accordingly and hard! Lectures will start at 10:25 sharp don t be late Don t hesitate to ask questions (if something is puzzling you, it is just as likely to be puzzling to someone else) Group exercise if you do not actually and actively participate in the problem solving yourself, you will not be able to solve them on the exams Need extra help? Check out a Physical Chemistry textbook from the Science Library Or the famous Feymann Lectures in Physics for the more adventurous

15 NENG 301 Lecture 1 Basic concepts of thermodynamics (DeHoff, Chap. 1) Look to the north. Keep looking. There's nothing coming from the south. 15

16 Learning objectives for Chapter 1 At the end of this chapter you will be able to: Understand the breadth of thermodynamics as an essential subject in science and engineering Understand the concept of equilibrium as it pertains to thermodynamics Understand the meaning of terms such as system, surroundings, boundary, and properties from a thermodynamics viewpoint Understand the concept of phase in a thermodynamics sense Understand the concept of a unary phase diagram and how it can be used to predict structure as a function of the state of a system Appreciate the concept of equilibrium maps as products of thermodynamic analyses 16

17 What is Thermodynamics? The study of energy transformations and the relationships among physical properties of substances which are affected by these transformations. -- K. Wark, Thermodynamics, 5th Edition (1988) Classical (phenomenological) thermodynamics Deals with macroscopic systems, without recourse to the nature of the individual particles and their interactions Requires no hypothesis about detailed structure of matter on the atomic scale, thus laws are not subject to change as knowledge concerning nature of matter is discovered Statistical thermodynamics Based on statistical behavior of large groups (ensembles) of individual particles, and postulates that values of macroscopic properties merely reflect some sort of statistical behavior of enormous ensembles Quantum thermodynamics: properties and interactions depend on the distribution of electrons and their energies 17

18 Why is the study of thermodynamics important? 1. Thermodynamics is pervasive 2. Thermodynamics is comprehensive 3. Thermodynamics is established 4. Thermodynamics provides the basis for organizing information about how matter behaves 5. Thermodynamics enables the generation of maps in equilibrium states that can be used to answer a prodigious range of questions of practical importance in science and industry 18

19 How is thermodynamics pervasive? Thermodynamics applies to every volume element of all systems at all times How is thermodynamics comprehensive? Systems: metals, ceramics polymers, composites, solids, liquids, gases, solutions, crystals with defects Applications: structural materials, electronic materials, corrosion-resistant materials, nuclear materials, biomaterials, nanomaterials Influences: thermal, mechanical, chemical, interfacial, electrical, magnetic 19

20 How is thermodynamics established? J. Willard Gibbs: On the Equilibrium of Heterogeneous Substances was a 300-page paper published between 1875 and 1878 You flip through the pages and it reads, more or less, like a modern physical chemistry textbook Just about everything that we are covering in this course can be traced to Gibbs A theory is the more impressive the greater the simplicity of its premises, the more different kinds of things it relates, and the more extended its area of applicability. Therefore the deep impression that classical thermodynamics made upon me. It is the only physical theory of universal content which I am convinced will never be overthrown, within the framework of applicability of its basic concepts. (A. Einstein) 20

21 How does thermodynamics provide a basis for organizing information on how matter behaves? Thermodynamics provides a mechanism for describing the properties of scientifically and technologically important systems It allows you to take database information and apply it to an even wider collection of real-life problems A huge amount of information has been collected, is stored in databases, and is available for use 21

22 22

23 What are maps of equilibrium states and why are they important? Thermodynamics permits the generation and understanding of maps that describe the structure and properties of matter at equilibrium in terms of important variables These maps present relatively simple pictures of equilibrium structure, even though the quantitative calculation of the steps leading to those structures may be exceedingly complex Numerous real-life scientific and technological problems can thus be studied and performance predicted through the examination of one or two relatively simple equilibrium maps 23

24 The Generic Question Addressed by Thermodynamics We will want to consider the following process: System A is in equilibrium with its surroundings (Surroundings I) The surroundings are changed (Surroundings II) Will System A transform to System B, and what will be its properties? 24

25 What do we mean by equilibrium Thermodynamic equilibrium a condition in which the thermal (temperature), mechanical (pressure), and chemical (concentration) characteristics do not change with time No net flows of matter, no phase changes, no unbalanced potentials (a.k.a. driving forces ) within a system Characteristics of a system at thermodynamic equilibrium no changes with respect to time: dx/dt = 0 when a system is in thermodynamic equilibrium it will not change when it is isolated from its surroundings? Note the distinction with steady state no changes with respect to time, but the system changes when it is isolated from its surroundings T high T low 25

26 Kinds of Equilibrium Equilibrium A system is in thermodynamic equilibrium if it is not capable of a finite spontaneous change to another state without a finite change in the state of the environment Thermal: equality of temperature across the system boundary Mechanical: equality of pressure across the system boundary Phase Equilibrium: no tendency for net transfer of one or more species from one phase to another Chemical: no tendency for chemical reaction 26

27 Some important (if obvious) concepts System: any region of the universe, large or small, that is being considered in our analysis Boundary: the interface between the system and its surroundings Surroundings: regions outside the boundaries of the system but can alter the system by interacting with it Properties: Physical characteristics that define the condition of the system and its surroundings 27

28 What is a phase (a really important concept) A phase is a physically distinctive form of matter, such as a solid, liquid, gas or plasma A phase of matter ( a region of materials) is characterized by having relatively uniform chemical and physical properties Phases are separated from each other by a (usually) distinct boundary or interface A single phase may or may not have regions separated by surfaces or interfaces, but two phases are always separated by a surface or interface The phases that develop due to materials synthesis or processing can have a huge impact on the properties and/or performance of those materials 28

29 Unary phase diagrams These simple unary (single component) phase diagrams show the stability of a particular phase under different conditions (P and T) Water (left) can exist in at least three phases depending on temperature and pressure -- thermodynamics can predict behavior when conditions change Molybdenum (right, atomic number 42) shows qualitative behavior that is similar, but there are major quantitative differences 29

30 Thermodynamic Basis for Equilibrium Maps In phenomenological thermodynamics each system is a structureless glop that is endowed with properties. 30

31 Equilibrium Map #1a: Phase Diagram (Ge/Si) Liquid (L) L+S Solid (S) 31

32 Equilibrium Map #1b: Phase Diagram (Al/Si) 32

33 Aluminum-rich side of the Al-Si phase diagram A simple binary eutectic with limited solubility of aluminum in silicon and limited solubility of silicon in aluminum. Eutectic point indicates The chemical composition and temperature corresponding to the lowest melting point Of the solid mixture. 33

34 Equilibrium Map #1c: Phase Diagram (Ag/Mg) 34

35 Equilibrium Map #2: Gas Phase Equilibria This equilibrium gas composition map shows the equilibrium partial pressure of oxygen (P O2 ) as a function of the chemical composition (carbon, hydrogen and oxygen) of the system Dashed lines = oxygen isobars that give a specific oxygen partial pressure as a function of C, H and O composition 35

36 The equilibrium partial pressure of oxygen and the boundary of carbon deposition region in gas mixtures for the C-H-O diagram at temperatures ranging from 400 to 1000 C. Broken lines show the boundary of carbon deposition region; therefore, carbon deposition is expected in carbon-rich composition beyond the lines. 36

37 Equilibrium Map #3: Predominance Diagram This predominance diagram shows the effects of oxygen and sulfur partial pressure on the equilibrium phase that forms on copper 37

38 38

39 Equilibrium Map #4: Defect Diagram This type of diagram shows the dependence of a variety of mobile charges (electrons/holes) and crystal defects (vacancies/interstitials, neutral/ionized) on O 2 partial pressure 39

40 Equilibrium Map #5: Pourbaix Diagram corrosion passivation immune to corrosion A Pourbaix diagram is the potential/ph (hydrogen ion concentration) diagram that maps out possible stable phases of an aqueous electrochemical system. Example here shows the chemical equilibria that exist in an electrochemical system as a function of electrode potential and ph value 40

41 So how do we get there? All of these useful equilibrium maps are developed from relationships developed from the principles and strategies of thermodynamic In order to understand them, we first need to understand the scientific basis of thermodynamics (laws + definitions) Next we will have to learn how to compute properties from these laws/definitions 41