化学气相沉积TaC涂层的微观形貌及晶粒择优生长

Surface morphology of TaC coating prepared by chemical vapor deposition and preferential growth mechanism of TaC grains

利用TaCl5-Ar-C3H6体系，采用X射线衍射技术和扫描电镜研究不同温度下化学气相沉积Tac涂层微观形貌及晶粒择优生长。结果表明：在800～1200℃时，随沉积温度升高，TaC颗粒从网球形逐渐转变为多角形以及金字塔形多面体，而其晶体择优取向依次从无明显择优取向向〈220〉和H〈200〉转变；利用牛长参数α和VAN DER DRIFT,MEAKIN的纳米级晶粒选择生长模型可较好地解释不同形貌的生长机制。当a=3时，薄膜会优先生长成〈200〉择优取向的金字塔品粒；当a=1．5时，则容易生长成〈220〉取向的多角形品粒。

TaC film was deposited by chemical vapor deposition technique at different temperatures with TaCl5-Ar-C3H6 system. The surface morphology and preferential growth of TaC crystals were investigated by X-ray diffractometry and scanning electron microscopy. The results show that within 800-1 200℃, TaC crystals of either ball-like particle with randomly preferential orientation, or dendrite with （220） orientation, or tetrahedral pyramid With （200） orientation are obtained with increasing of temperature. The preferential growth of TaC crystals can be fairly explained by the growth parameter a and VAN DER DRIFT model, MEAKIN model, selective evolution model at nanometric scale. The pyramidal shape crystals with （200） textures are formed at α=3, while （220） formed at a = 1.5.