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2020 | Buch

Lectures on Kinetic Processes in Materials

verfasst von: Prof. Han-Ill Yoo

Verlag: Springer International Publishing

Enthalten in: Springer Professional "Wirtschaft+Technik" , Springer Professional "Technik" , Springer Professional "Wirtschaft"

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Über dieses Buch

This book provides beginning graduate or senior-level undergraduate students in materials disciplines with a primer of the fundamental and quantitative ideas on kinetic processes in solid materials. Kinetics is concerned with the rate of change of the state of existence of a material system under thermodynamic driving forces. Kinetic processes in materials typically involve chemical reactions and solid state diffusion in parallel or in tandem. Thus, mathematics of diffusion in continuum is first dealt with in some depth, followed by the atomic theory of diffusion and a brief review of chemical reaction kinetics. Chemical diffusion in metals and ionic solids, diffusion-controlled kinetics of phase transformations, and kinetics of gas-solid reactions are examined. Through this course of learning, a student will become able to predict quantitatively how fast a kinetic process takes place, to understand the inner workings of the process, and to design the optimal process of material state change.

Provides students with the tools to predict quantitatively how fast a kinetic process takes place and solve other diffusion related problems;Learns fundamental and quantitative ideas on kinetic processes in solid materials;Examines chemical diffusion in metals and ionic solids, diffusion-controlled kinetics of phase transformations, and kinetics of gas-solid reactions, among others;Contains end-of chapter exercise problems to help reinforce students' grasp of the concepts presented within each chapter.

Inhaltsverzeichnis

Frontmatter

Chapter 1. Diffusion in Continuum

Abstract

Understanding and control of the atomic mobility in materials makes one of the fundamentals of the discipline of materials engineering in general. A typical manifestation of the atomic mobility is the phenomenon of diffusion, and the diffusion rate is a measure of the atomic mobility. Here, we will learn an empirical rate law, Fick’s first law to describe the phenomenon of diffusion and mathematics to solve the diffusion equation, and Fick’s second law for the concentration as a function of position and time in continuum. We will have come to understand the nature of solutions to the diffusion equation and how to solve the diffusion equation analytically or graphically.

Han-Ill Yoo

Chapter 2. Atomic Theory of Diffusion

Abstract

From the continuum point of view, diffusivity is a measure of mean square displacement in a given diffusion time, thus having the unit of m²/s. Here, the meaning of diffusivity is explored from the discrete atomic point of view. Consequently, we will have come to understand how diffusion occurs in an assembly of discrete atoms and how it varies with the thermodynamic variables of the system.

Han-Ill Yoo

Chapter 3. Chemical Reaction Kinetics

Abstract

In materials systems, chemical reaction is quite often combined with diffusion process in parallel or in tandem. We will review the basic concepts of chemical reaction kinetics including adsorption/evaporation kinetics, and learn the absolute reaction rate theory to understand the temperature effect on the reaction rate. Review of the interface thermodynamics is followed by the adsorption isotherms.

Han-Ill Yoo

Chapter 4. Diffusion in Concentration Gradients

Abstract

This chapter is concerned with the phenomenon of interdiffusion (or chemical diffusion) under a concentration (or chemical) gradient in a binary system. When the self-diffusivities of the two components are different, there arises a global drift of the matrix in the interdiffusion or mixing zone, which consequentially results in a single interdiffusion or chemical diffusion coefficient (Kirkendall effect). We will analyze this effect phenomenologically and atomistically to understand the interrelationship between the component self-diffusivities and the common chemical diffusivity and the thermodynamic and atomistic inner-workings behind. This is the climax of the diffusion story of a non-charged particles system.

Han-Ill Yoo

Chapter 5. Kinetics of Phase Transformation: Initial Stage

Abstract

For a phase to transform, a daughter phase should first be conceived out of the mother phase, which is either via nucleation or via spinodal decomposition. Here, we will learn the classic basic ideas on the kinetics of these two conception processes: one is “small in extent and large in degree” involving downhill diffusion and the other “large in extent and small in degree” involving uphill diffusion. The role of the interfacial energy and strain energy will be revealed.

Han-Ill Yoo

Chapter 6. Kinetics of Phase Transformation: Later Stage

Abstract

Nucleation of a daughter phase is followed by growth and later on coarsening to finish up a phase transformation. There are three types of growth processes depending on without/with phase change and without/with composition change. We will first learn the kinetics of these three types of growth processes, e.g., (i) grain growth; (ii) nuclei growth of a single-component daughter phase; and (iii) both normal solidification of a binary liquid and precipitate growth from a solid solution. Then follows the overall rate of transformation, in terms of nucleation rate and growth rate, leading to Johnson-Mehl-Avrami equation and the Ostwald-ripening kinetics leading to a cubic rate law.

Han-Ill Yoo

Chapter 7. Diffusion in Ionic Solids

Abstract

In charged particles systems or ionic solids, diffusion is always accompanied by charge transfer, thus leading to electrochemical phenomena depending on the nature of electrodes. We will learn how to describe mass/charge transport phenomena in terms of mobile charged components with actual charges and in terms of mobile structure elements with effective charges and the resulting electrical properties, ionic and electronic conductivities. There arises flux coupling to keep the local charge neutrality, which results in another type of chemical diffusivity called the Nernst-Planck type, in comparison with the Darken-type earlier in Chap. 4. The self-diffusivities are discussed on the basis of the equilibrium defect structure of a given system as well as the chemical or ambipolar diffusion in concentration gradients and nonstoichiometry re-equilibration kinetics in terms of the Nernst-Planck-type chemical diffusivity.

Han-Ill Yoo

Chapter 8. Kinetics of Gas/Solid Reaction: Diffusion-Controlled Case

Abstract

When a metal is exposed to an oxidizing gas, say, oxygen, a tarnishing layer or oxide forms upon the metal. When a metallic alloy is exposed, an oxide of the less noble component of the alloy may form internally. Thermodynamics of oxidation is discussed, and then kinetics of such external and internal oxidation are examined when the overall kinetics is diffusion-controlled. This leads to the famous parabolic rate law with the parabolic rate law constant which can be derived in terms of the Nernst-Planck-type combination of the partial conductivities or self-diffusivities of the mobile components. The present kinetic idea may be extended to solid/solid reactions with minor modifications.

Han-Ill Yoo

Backmatter

Titel: Lectures on Kinetic Processes in Materials
verfasst von: Prof. Han-Ill Yoo
Verlag: Springer International Publishing
Electronic ISBN: 978-3-030-25950-1
Print ISBN: 978-3-030-25949-5
DOI: https://doi.org/10.1007/978-3-030-25950-1

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