Preparation of self-bonded products on the base of Fe-Si₃N₄ at low temperature

The Fe-Si₃N₄ powder, synthesized by flashing combustion process, is considered as a new-style raw material for the high temperature condition, but its fine performance has not been recognized. The Fe-Si₃N₄ powder less than 74μm was made into samples of 50 mm in diameter and 80 mm in height under a molding pressure of 250 kN. The apparent porosity, bulk density and strength resistance of the samples were measured by drilling a cylinder of 36mm in diameter and 50mm in height in the samples, which were sintered at 1 500℃ for 3 h under the air condition. SEM, EDS and X-ray diffraction were employed to study the sintered samples. All the results showed that with Fe-Si₃N₄ as the raw material and no subsidiary materials, a refractory on the base of Fe-Si₃N₄ could be prepared at low temperature under the air condition with the combining action of Fe₃Si, which originated from the material and was made by the reaction between Fe and Si₃N₄.