CHEMISTRY · Multi-part · AP · Chemistry · Compound Structure and Properties · Compound Structure and Properties
Problem
A materials scientist is designing a strong, corrosion-resistant structural alloy based on iron. The alloy will contain chromium (radius 128 pm) and carbon (radius 70 pm) in addition to iron (radius 126 pm).
The scientist must balance mechanical strength with sufficient electrical conductivity for certain monitoring systems embedded in the structure.
(a) For each added element (Cr and C), predict whether it will occupy lattice sites by substitution or by filling interstitial spaces, and justify each prediction using atomic radii.
(b) Discuss qualitatively how the presence of each element is expected to affect the electrical conductivity of the alloy compared with pure iron.
(c) Propose one modification to the alloy composition or processing that could help maximize conductivity without significantly sacrificing strength, and defend your proposal using the metallic bonding model.