| abstract |
The invention provides a method for preparing high-density ceramics by self-propagating combustion synthesis β-SiC powder pressureless sintering, comprising the following steps: (1) mechanical activation; (2) acid washing and purification; (3) ball milling and pulping; (3) ) dry pressing; (4) pressureless sintering. The invention adopts the β-SiC powder synthesized by self-propagating combustion, and through mechanical activation, pickling and purification, the surface activation energy is improved, and the purity is improved, and a high-performance submicron-level powder suitable for sintering is prepared. Then, by controlling the sintering aids C and B and the sintering process, it is expected to use self-propagating combustion to synthesize β-SiC powder as a raw material to prepare a dense β-SiC ceramic material with excellent mechanical properties. When the content of B is 0.7wt% and the content of C is 4wt%, under the conditions of sintering temperature of 2100℃ and holding time of 90min, the density and mechanical properties of the prepared SiC ceramics are the best, and the loss on ignition rate is 7.9% , shrinkage rate 15.6%, density 3.14g/m 3 , hardness 25.62±0.92GPa, fracture toughness 4.84±0.84MPa·m 1/2 , three-point bending strength 401.74±8.66GPa. |