Mediaspace scheduled maintenance: Aug 25, 2026 07:00 - 12:00 AM. During this time, videos will be temporarily unavailable. Check status updates.

Lecture

Diffusion in Alloys

Description

This lecture covers the diffusion phenomena in alloys, including chemical diffusion, phase separation, and diffusion in ionic crystals. Topics include calculation of diffusion coefficients, heterodiffusion, and the effect of thermodynamic activity gradients on transport. The lecture also discusses mutual diffusion, the concept of chemical potential, and the Kirkendall effect in alloys.

This video is available exclusively on Mediaspace for a restricted audience. Please log in to MediaSpace to access it if you have the necessary permissions.

Watch on Mediaspace

Official source

Related concepts (32)

Diffusion

Diffusion is the net movement of anything (for example, atoms, ions, molecules, energy) generally from a region of higher concentration to a region of lower concentration. Diffusion is driven by a gradient in Gibbs free energy or chemical potential. It is possible to diffuse "uphill" from a region of lower concentration to a region of higher concentration, like in spinodal decomposition. Diffusion is a stochastic process due to the inherent randomness of the diffusing entity and can be used to model many real-life stochastic scenarios.

Convection–diffusion equation

The convection–diffusion equation is a combination of the diffusion and convection (advection) equations, and describes physical phenomena where particles, energy, or other physical quantities are transferred inside a physical system due to two processes: diffusion and convection. Depending on context, the same equation can be called the advection–diffusion equation, drift–diffusion equation, or (generic) scalar transport equation.

Molecular diffusion

Molecular diffusion, often simply called diffusion, is the thermal motion of all (liquid or gas) particles at temperatures above absolute zero. The rate of this movement is a function of temperature, viscosity of the fluid and the size (mass) of the particles. Diffusion explains the net flux of molecules from a region of higher concentration to one of lower concentration. Once the concentrations are equal the molecules continue to move, but since there is no concentration gradient the process of molecular diffusion has ceased and is instead governed by the process of self-diffusion, originating from the random motion of the molecules.

Chemical potential

In thermodynamics, the chemical potential of a species is the energy that can be absorbed or released due to a change of the particle number of the given species, e.g. in a chemical reaction or phase transition. The chemical potential of a species in a mixture is defined as the rate of change of free energy of a thermodynamic system with respect to the change in the number of atoms or molecules of the species that are added to the system.

Fick's laws of diffusion

Fick's laws of diffusion describe diffusion and were first posited by Adolf Fick in 1855 on the basis of largely experimental results. They can be used to solve for the diffusion coefficient, D. Fick's first law can be used to derive his second law which in turn is identical to the diffusion equation. A diffusion process that obeys Fick's laws is called normal or Fickian diffusion; otherwise, it is called anomalous diffusion or non-Fickian diffusion.

Related lectures (34)

Irreversible Processes, Transport

Explores irreversible processes and transport phenomena related to heat, pressure, and chemical potential differences in isolated systems.

Phase Equilibria: Understanding Vapor-Liquid Separation

Provides an overview of vapor-liquid phase diagrams and their role in separation processes, focusing on phase equilibria and the Gibbs phase rule.

Diffusion and Transport Phenomena

Explores diffusion, transport phenomena, Fick's law, thermal and electrical transport, Onsager's relations, and thermoelectric effects.

Thermodynamics: Exploring Thermodynamic Potentials and Equilibrium States

Covers thermodynamic potentials and their role in system equilibrium with reservoirs.

Diffusion in Fluids: Understanding Mass Transport