Thermogravimetry, Differential Thermal Analysis, and Mass Spectrometry Study of the Silicon Nitride–Boron Carbide–Carbon Reaction System for the Synthesis of Silicon Carbide–Boron Nitride Composites

Abstract

Thermogravimetry, differential thermal analysis, mass spectrometry, and X‐ray diffractometry were used to study the reaction process of the in situ reaction between Si3N4, B4C, and carbon for the synthesis of silicon carbide–boron nitride composites. Atmospheres with a low partial pressure of nitrogen (for example argon + 5%–10% nitrogen) seemed to inhibit denitrification and also maintain a high reaction rate. However, the reaction rate decreased significantly in a pure nitrogen atmosphere. The experimental mass spectrometry results also revealed that B4C in the Si3N4–B4C–C system inhibited the reaction between Si3N4 and carbon and, even, the decomposition of Si3N4. The present results indicate that boron could be a composition stabilizer for ceramic materials in the Si‐N‐C system used at high temperature.