Microstructure of reaction-bonded silicon nitride fabricated under static nitrogen pressure

In this study, reaction-bonded silicon nitride (RBSN) was fabricated using static nitriding system. This technique may be advantageous in commercialization. Reactive nitrogen gas was supplied as a static state using computer-controlled gas delivery system instead of a dynamic flowing state. Nitridation rates obtained at the early stage of reaction rate were proportional to the reactive gas pressures. The sequence of the nitridation reactions was as follows: (1) outside, (2) inside and (3) intermediate region of the specimen. The results were obtained from the coloration of the cross-sectioned specimens that had various nitridation rates.