常压烧结制备ZrN（ZrON）-SiAlON复合陶瓷

摘要

以粉煤灰（≤74μm）、锆英石（≤44μm）和活性炭为原料，采用碳热还原氮化法在1550℃保温6 h合成了ZrN-SiAlON复合材料。以加工成的ZrN-SiAlON复合微粉为主原料，加入聚乙烯醇结合剂，分别在1450、1500和1550℃下埋炭粉常压烧结1 h制备ZrN（ZrON）-SiAlON复合陶瓷，研究了烧成温度对复合陶瓷相组成、显微结构和烧结性能的影响。结果表明：1）控制烧成温度可以制备出不同组成的β-SiAlON基复合陶瓷；在1550℃保温1 h制备的复合陶瓷的主晶相为ZrN、ZrON和β-SiAlON（z＝2，Si4Al2O2N6）；2）从不同温度烧后试样的微观结构中均能观察到ZrN（ZrON）、β-SiAlON和一种铁硅系化合物存在，且ZrN（ZrON）颗粒均匀地分布于β-SiAlON基质中；3）提高烧成温度会使复合陶瓷的收缩率增大，当烧成温度由1450℃升至1550℃时，试样的体积收缩率由19．4％增加至40．3％。%ZrN-SiAlON composite materials were synthesized at 1 550℃for 6 h via a carbothermal reduction nitridation route using fly ash (≤74 μm),zircon (≤44 μm)and active carbon as starting materials.The processed ZrN-SiAlON composite micropowders were mixed with polyvinyl alcohol as binder to prepare ZrN(ZrON)-SiAlON composite ceramics by carbon-embedded pressureless firing at 1 450,1 500 and 1 550℃ for 1 h,respectively.Influences of firing temperature on the phase compositions,microstructure and sin-tering properties were investigated.The results show that:(1)β-SiAlON based composite ceramics with dif-ferent compositions can be prepared by controlling firing temperature,and the main crystalline phases of the specimen fired at 1 550 ℃for 1 h involve ZrN,ZrON and β-SiAlON(z=2,Si4Al2O2N6);(2)ZrN(ZrON),β-SiAlON and a Fe-Si based compound can be observed in the microstructures of the specimens fired at different temperatures,and ZrN(ZrON)particles distribute homogeneously in the β-SiAlON matrix;(3)rai-sing firing temperature can increase the shrinkage of the ceramics,and the volume shrinkage increases from 19.4% to 40.3% when the firing temperature rises from 1 450 ℃ to 1 550 ℃.