Combustion synthesis and compaction of Si3N4–TiN composite powder

The possibilities for combustion synthesis of TiN–Si3N4 composite powders were investigated using different titanium silicides (TiSi, Ti5Si3, TiSi2) as initial raw materials. Thermodynamic analysis and relevant experiments have shown that at relatively low nitrogen pressure (up to 5 MPa) Ti5Si3 is the most suitable compound for this purpose. Optimum experimental conditions for synthesizing two-phase silicon-free TiN–Si3N4 (containing 30–35 wt.% TiN) composite powders with characteristic sizes of approximately 5–10 μm were determined. Compact discs of 50 mm diameter were fabricated using hot pressing technique. Microstructural features of the composite powder and hot pressed samples were investigated, i.e. biaxial flexure strength.