Question

The activation energy for diffusion in BCC iron is 84 kJ/mol. Which of the following explains why the carbide precipitation activation energy is slightly higher than the BCC diffusion activation energy?

a. Steel is FCC and the activation energy for FCC diffusion is higher
b. Precipitation requires the diffusional activation energy plus an additional energy to form the precipitate.
c. Precipitation requires less energy than diffusion
d. The carbide is orthorhombic which is a much higher energy than BCC

Answer 1

Answer:

• B. Precipitation require the diffusional activation energy plus an additional energy to form the precipitate.

Explanation:

Precipitation is the creation of a solid from a solution. When the reaction occurs in a liquid solution, the solid formed is called the precipitate.

The formation of a precipitate indicates the occurrence of a chemical reaction.

Precipitation of carbide requires alot of energy which the diffusion activational energy alone cannot achieve and this was calculated to be 225.6 kJ/mol.