温度对CVD法在纤维表面制备BN涂层的影响

Effect of Temperature on Preparing Boron Nitride Interface on Fiber Surface by Chemical Vapor Deposition

采用BCl_3-NH_3-H_2体系,在不同温度下通过化学气相沉积法在SiC纤维表面沉积BN涂层。研究温度对BN涂层的沉积速率、形貌、组成以及结构的影响。结果表明:在低温阶段(700~900℃),生长速率随着温度的增加而增大,该结果与阿仑尼乌斯定律相一致,计算得出该反应表观活化能为57.2kJ/mol。涂层表面光滑致密,沉积均匀,沉积速率受表面反应控制。在900℃时,反应速率达到最大值(174nm/h),此时,反应速率由表面反应控制转变为物质运输控制。在高于900℃时,由于气相成核的缘故,沉积速率随着温度的增加而减小,涂层变得疏松粗糙。BN涂层为化学计量比1∶1的乱层结构,有序度随着制备温度的升高而增大。

Boron nitride interface was deposited on SiC fibers by chemical vapor deposition at different temperatures from BCl 3-NH 3-H 2 mixtures.The effect of temperature on deposition rate,morphology,composition and structure of the interface was studied.The results show that in the low temperature range of 700-900℃,the deposition rate increases with increasing temperature complying with Arrhenius law,and the apparent active energy calculated is 57.2kJ/mol.The interface is smooth and dense and uniformly deposited on fibers,the deposition rate is controlled by surface reaction.At 900℃,the deposition rate reaches a maximum(174nm/h),at the same time,surface reaction control is changed to be mass-transportation control.Above 900℃,the deposition rate decreases with the increasing temperature due to the gas-phase nucleation,and the interface surface becomes loose and rough.BN interface is turbostratic structure with stoichiometric ratio 1∶1,and the order degree increases with increasing temperature.