1. In sintering of glass spheres with a radius of 15 mm, it took 200 min at 627°C and 10 min at 677°C to get a shrinkage of 5%. Calculate the viscosity of the glass and the activation energy of sintering. The surface energy of the glass is 0.3 J/m2.
2. A powder compact with a size of 1 mm is known to be sintered in one hour at 1600C. Assuming that densification occurs by lattice diffusion with an activation energy of 500 kJ/mol, plot the dependence of the required sintering temperature against powder size for one hour sintering. Assume negligible grain growth.