1. If grain growth is affected by gas diffusion in pores with a constant pressure, what is the activation energy of grain growth?
2. Describe possible techniques (as many as possible) to suppress pore/ boundary separation during sintering.
3. Consider a system where densification occurs by lattice diffusion and grain growth by surface diffusion. How can you determine the optimum size of the starting powder in view of sintering and powder production cost? If you adopt hot pressing to produce sintered compacts, do you expect the optimum powder size to change? If so, how?