Study Of Phase The Si <sub> 3 </ Sub> N <sub> 4 </ Sub> (si <sub> 2 </ Sub> On <sub> 2 </ Sub>)-sic Composite

Composite is one kind of multiphase material which consists of the consecutive matrix a,nd the reinforcement phase. Large quantity of consecutive distributing-phase is called matrix-phase and the oblique distributing-phase is called dispersed-phase. SisN SiaONa SiC, a composite with excellent properties, has extensive applications and developmental potentials, in which the SisN^SiaONa) is the matrix-phase and the SiC is the dispersed-phase. The method of quasi-static nitrification employed in preparing Si3N4(Si2ON2)-SiC composite has features of simple process, low cost and excellent properties. This paper explores the influences of the amount of sintering aids, amount of Si powder as additive, particle grading of SiC and thescheme of nitrification on the matrix-phase, and the strength of the composite in the process of preparing SisN SizONa SiC. The thermal shock resistance of the prepared material is explored too.Processing parameters were comprehensively investigated to achieve better mechanical strength and microstructure, experimental results indicate that suitable amount of sintering aids can promote the development of SiaN SiaONa) and increase the crystal size, while excessive sintering aids amount will exert a side effect; biding phase increases obviously with Si powder additive which greatly improve thestrength of the composite. Changing the grading of SiC particles not only affects the strength and pile density, but also modifies the phase compositions and microstructure of the material. With the reducing ofSiC particles, the strength of the material increases obviously. The nitrification scheme has the greatest influence on phase compositions and microstructure 'of Si3N4(Si2ON2)-SiC, after two continuous nitrification reacting peak and short-time high-temperature treating, the best properties can be obtained; and the residual strength of the composite is much higher after the thermal shock resistance test, which shows that the material possesses excellent thermal shock resistance.