关键词: 反应烧结, 氮化硅, 浸渍强化

Abstract: Infiltration strengthening is an effective means to improve the mechanical properties of Reaction Bonded Silicon Nitride(RBSN). In this paper, porpous RBSN compacts are infiltrated with three kinds of salt solutions: Re(NO3)yZr(NO3)4and A12(SO4)3. The thermodynamics of infiltration is that the wetting angle is less than 90 The infiltration amount obeys Poiseill Law, After the compacts are infiltrated with Re(NO3)4and Ai2(SO4)3, the fexural strength is increased largely, but Zr(NO3)4decreases the strength. This is because RexOyand Al2O3from the respective decomposition of Re(NO3)yand Al2(SO4)3can promote the sinter of Si3N4powders, decrease the sizes of pores and blunt the tips of cracks. On the contrary ZrO2from Zr(NO3)4enables Si3N4to decompose at high temperature.

Key words: reaction bonded silicon nitride (RBSN) infiltration strengthing