1. SiO2 can be either a glass or a crystalline solid at room temperature. Is diffusion faster in vitreous (glassy) silica or crystalline silica? Why?
2. Consider the diffusion of C into Fe. At approximately what temperature would a specimen of Fe have to be caburized for 2 hours to produce the same diffusion result as at 900*C for 15 hours?
3. A candidate material for a turbine blade application oxidizes by diffusion of metal atoms through the oxide to the metal surface, where metal and oxygen react to form the oxide. After 10 hours at 550*C, an oxide layer 8µm thick has formed. What will the thickness be after 100 hours?