MATSE 201 Homework 3 Due in class Thursday, October 08, 2009 (1) In the following systems, which would you expect to show complete solid-solution behavior. Justify your answers through the Hume-Rothery rules (hint, you will need to look up the crystal structures of the binary compounds) (15 pts). (a) Pt-Pd (b) Ag-Na (c) Al-Cu (d) GaAs – AlAs (e) NaCl - KCl (2) When a solid solution becomes “ ordered ” , in effect a new compound has formed. AuCu 3 shows this type of behavior where solid solutions are possible at higher temperature, whereas ordering (compound formation) occurs a lower temps. (10pts) (a) Speculate on the driving forces for ordering and disordering in this system (i.e. what physical factors are behind these tendencies). (b) Speculate on whether you would expect a mixture of AuAg 3 to show a greater or lesser tendency toward ordering and explain your reasoning. (3) An “FeO” crystalline phase (called wustite) is determined to have an actual composition of Fe 0.96
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Chemical reaction, complete solid-solution behavior, Kroger-Vink notation