燃烧合成氮化物陶瓷基复合材料

Combustion synthesis of nitride ceramic based composites

氮化物陶瓷是应用广泛的特种陶瓷,但传统的氮化物陶瓷烧结方法极为消耗能源、生产周期长、成本高.为降低成本、能耗,采用燃烧合成工艺制备氮化物陶瓷基复合材料,包括氮化钛和六方氮化硼,燃烧合成工艺利用单质元素与氮气反应合成氮化物.研究结果表明:压坯与80MPaN2反应燃烧合成TiN制件致密度约75%,压坯为添加了TiN稀释剂和适量氧化铝的钛粉,压坯孔隙率45%;燃烧合成纯BN制件致密度为68%,BN基制件致密度为78%,压坯为添加了h BN稀释剂或SiO2添加剂的B粉压坯与80MPaN2反应合成,压坯孔隙率48%;在材料体系中,稀释剂起减小晶粒尺寸和降低燃烧温度的作用,而Al2O3和SiO2添加剂则起提高强度和相对密度的作用.

Nitride ceramic is a kind widely used of ceramics whose traditional sintering method is expensive, timeconsuming and energyconsuming. Nitride ceramic based composite parts, including TiN and hBN, were fabricated by combustion synthesis technique to decrease the cost and consume less energy. The reaction of simple substance and nitrogen to synthesize nitride is called combustion synthesis. The results showed that TiN components with 75% theoretical density were manufactured by reaction of compact and 80MPa N2. By dry pressing, compacts of TiN composite with 45% opening porosity composed with 70 μm Ti?15 μm TiN and alumina were made. BN based composite were manufactured by the reaction of BN compact and 80MPa N2. The relative density of hBN parts is 68%, the relative density of hBN and SiO2 is 78%. By cool isosmotic pressing, BN compacts with 48% porosity composed with B, hBN and SiO2 were made. In the material system, a diluent was used to decrease grain size of products and to slowdown the combustion. The effect of Al2O3 and SiO2 additives was the increase of strength and relative density of products.