Solid-Gas Reaction during Sintering of Si_3N_4 Ceramics (Part 5)-Mass Change of Si_3N_4 Ceramics during Sintering under N_2 Gas Flow in a Non-Carbon-Element Furnace-

摘要

The mass change reaction of Si_3N_4 ceramics during sintering in a non-carbon-element furnace was investigated in a flowing N_2 gas environment as a function of the oxygen partial pressure, p(O_2) in the range from 2.0 X10~(-4) to 3.0 X 10~3 Pa. There were four different P(O_2) regions in the mass change reaction: passive oxidation, passive to active transition, active oxidation, and vaporization. It was concluded that the major reactions for the vaporization region are Si_3N_4 (s) + 3SiO_2 (l) -> 6SiO (g) + 2N_2 (g) and Si_3N_4 (s) -> 3Si (g) + 2N_2 (g).