Engineering English
Diffusion
Materials Engineering · Chemical Engineering · Last updated: July 30, 2026 · How this entry was written
Definition: Diffusion is the net movement of atoms from a region of higher concentration to one of lower concentration driven by thermal energy. It is a fundamental mechanism for phase transformations and homogenization in alloys.
Example in context
“Understanding diffusion is essential for predicting phase transformation kinetics in metallic systems.”
“Difüzyonun anlaşılması, metalik sistemlerde faz dönüşüm kinetiğini tahmin etmek için gereklidir.”
Where engineers use it
Diffusion is referenced when modeling composition changes during thermal processing and in predicting growth rates of new phases. An engineer needs diffusion data to design heat treatment cycles that achieve target microstructures and avoid undesirable segregation.
In Chemical Engineering
The spontaneous spreading of molecules from a region of higher concentration to one of lower concentration through random molecular motion. It is the fundamental molecular mechanism behind most mass transfer operations.
“Inside the porous catalyst pellet, slow diffusion of reactant to the inner active sites limited the observed reaction rate far more than the intrinsic kinetics.”
Practice: can you use “Diffusion” at work?
A new metal composition shows unexpected segregation after casting. The engineer must use diffusion principles to explain the concentration gradient and propose a suitable heat treatment to reduce it.
Show a model answer
“Diffusion governs the rate at which atoms redistribute during thermal processing.”
“Diffusion” in 21 languages
| English | Diffusion |
|---|---|
| Turkish | difüzyon |
| French | diffusion |
| German | Diffusion |
| Spanish | difusión |
| Chinese | 扩散 |
| Arabic | انتشار |
| Portuguese | difusão |
| Russian | диффузия |
| Japanese | 拡散 |
| Italian | diffusione |
| Vietnamese | khuếch tán |
| Hindi | प्रसार |
| Thai | การแพร่ |
| Indonesian | difusi |
| Korean | 확산 |
| Bengali | প্রসারণ |
| Dutch | diffusie |
| Swedish | diffusion |
| Finnish | diffuusio |
| Ukrainian | дифузія |
Frequently asked questions
What does Diffusion mean in engineering?
Diffusion is the net movement of atoms from a region of higher concentration to one of lower concentration driven by thermal energy. It is a fundamental mechanism for phase transformations and homogenization in alloys. In Materials Engineering, the term carries a usage-frequency rating of 10/10 in the Engineering English library.
How do you pronounce Diffusion?
Diffusion is pronounced /dɪˈfjuːʒən/ (IPA). The Engineering English app plays audio for the term and checks your pronunciation with speech recognition.
How is Diffusion used in a sentence?
Example from an engineering context: “Understanding diffusion is essential for predicting phase transformation kinetics in metallic systems.”
This entry is one of 7,806 terms in the Engineering English iOS app — with quizzes, spaced repetition and pronunciation checking.
Get the app on the App Store