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采用化学溶液法,溶解分散H38O3,CO(NH2)2及α-Si3N4微粉制成悬浮液,干燥后以氢还原氮化法制备出纳米氮化硼包覆微米氮化硅的Si3N4/BN纳米复合粉体.利用X射线衍射(XRD)和透射电子显微镜(TEM)对复合粉体的形成过程及形貌结构研究发现:当反应温度为1100℃时,包覆层中除在临近α-Si3N4颗粒表面有少量涡流状氯化硼(t-BN)生成外,其主要组成部分为非晶态BN.以上复合粉体经1450℃氮气氛下处理后,非晶态氯化硼与涡流状氮化硼转化为h-BN.所制复合粉体经1800℃热压烧结获得加工性能良好的复相陶瓷.
A solution was prepared by dissolving H38O3, CO (NH2) 2 and α-Si3N4 powders. After drying, a Si3N4 / BN nanocomposite The formation process and morphology of composite powders were investigated by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The results show that when the reaction temperature is 1100 ℃, The surface of a small amount of vortex flow boron nitride (t-BN) is generated, the main component of the amorphous BN above the composite powder after treatment at 1450 ° C under nitrogen atmosphere, amorphous boron chloride and vortex-like nitriding Boron into h-BN. The composite powder prepared by 1800 ° C hot-pressed to obtain good workability of multi-phase ceramic.