A materials scientist is comparing two potential alloy systems
CHEMISTRY · Multi-part · GCSE · Chemistry · Bonding, Structure and the Properties of Matter · Bonding, Structure and the Properties of Matter
Problem
A materials scientist is comparing two potential alloy systems.
System I: Nickel–copper
Nickel atomic radius = 124 pm Copper atomic radius = 128 pm
System II: Nickel–carbon
Nickel atomic radius = 124 pm Carbon atomic radius = 67 pm
(a) Calculate the percent difference in atomic radius between Ni and Cu. Show your work.
(b) On the basis of your result in part (a), determine whether extensive substitutional solid solubility is expected for the Ni–Cu system. Justify your answer in terms of atomic-size criteria.
(c) Carbon is small enough to occupy interstitial sites in close-packed metallic lattices. Explain, with reference to the size disparity between Ni and C, why an interstitial alloy rather than a substitutional alloy is expected for the Ni–C system.