Engineering materials

Question

Name one example for each of the following? 

1-Process using interstitial diffusion:

2-Process using vacancy diffusion:

3-Diffusing specie in iron (Fe):

4-Driving force for steady-state diffusion:

5-Diffusion can occur in …materials.

(a) Solid

(b) Liquid

(c) Gascous

(D) AIl

6-the fastest diffusing species in Fe is

(a) Cr

(b) Ni

(e) W

(d) C

7-The following is not the influencing factor for diffusion process:

(a) Diffusing species

(b) Temperature

(c) electronegativity

(d) Presence of defects

8-The relation between temperature and diffusion coefficient is:

(a) Linear

(B)exponential

(c) Sinusoidal

(D) Diffusion coefficient is not related to temperature

Answer 1

1.Interstitial Diffusion Process: Carbon diffusion in steel, where carbon atoms move between iron lattice positions.

2.Vacancy Diffusion Process: Self-diffusion in a metal where vacancies in the lattice allow atoms to move through the crystal structure.

3.Diffusing Specie in Iron (Fe): Carbon is a common diffusing specie in iron, especially in the process of carburizing or in the formation of steel.

4.Driving Force for Steady-State Diffusion: The driving force for steady-state diffusion is typically a concentration gradient, where atoms or molecules move from areas of higher concentration to lower concentration until equilibrium is reached.

5.Diffusion can occur in all types of materials. So, the correct choice would be:

(d) All

6.The diffusion rate of species in a material is influenced by various factors, including the atomic size, temperature, and crystal structure. In iron (Fe), among the options provided, the fastest diffusing species is generally considered to be carbon (C).

So, the answer would be (d) C.

7.Among the given options, the factor that doesn't directly influence the diffusion process is (c) electronegativity. Electronegativity is a measure of an element's ability to attract electrons in a chemical bond, and it's not a direct determinant of the diffusion process within materials. Factors like the diffusing species, temperature, and the presence of defects play a significant role in the rate and extent of diffusion in materials.

8.The relation between temperature and diffusion coefficient is generally considered to be (b) exponential.

The diffusion coefficient tends to increase exponentially with an increase in temperature. This relationship is described by various diffusion models, such as Arrhenius equation, which shows a strong exponential dependence of diffusion coefficient on temperature.