Diffusion in Solids - Engineering Materials I

These flashcards cover key terms and concepts related to diffusion in solids, including definitions and principles guiding atomic motion in materials.

Diffusion

The phenomenon of material transport by atomic motion.

Interstitial Diffusion

Migration of atoms from an interstitial position to a neighboring empty position; typically involves small atoms such as H, C, N, and O.

Vacancy Diffusion

Interchange of an atom from its normal lattice position to an adjacent vacant lattice site.

Fick's First Law

Describes steady-state diffusion and states that diffusion flux is proportional to the concentration gradient.

Fick's Second Law

Describes non-steady state diffusion and how concentration changes with time.

Concentration Gradient

The slope of the concentration profile curve which indicates the rate of change of concentration with respect to position.

Self-Diffusion

Diffusion of atoms within an elemental solid, where the atoms migrate within their own structure.

Interdiffusion

The process where atoms from different metals diffuse into each other.

Diffusion Coefficient (D)

A parameter that quantifies the rate at which atoms diffuse; its value depends on the temperature and the materials involved.

Activation Energy (Qd)

The minimum amount of energy required to facilitate diffusion, influencing the diffusion coefficient.

Steady-State Diffusion

A condition where the diffusion flux does not change with time.

Non-Steady State Diffusion

A situation where the diffusion flux and concentration gradient vary with time.

Carburizing

A heat treatment process that increases the carbon content of steel surfaces to enhance hardness.

IC Fabrication

The process of creating integrated circuits, which relies on solid-state diffusion to incorporate impurities into semiconductor materials.

Gaussian Error Function

A mathematical function used in the solution of diffusion equations describing concentration changes over time.

Diffusion Paths

Different routes through which atoms can migrate, including through dislocations and grain boundaries.

Concentration Profile

A graphical representation of the concentration of diffusing species as a function of distance.