摘要
以三氯甲基硅烷-氢气-氮气(MTS-H2-N2)为前驱体系统,在垂直放置的热壁反应器中利用化学气相沉积工艺制备碳化硅涂层,分析了工艺参数对碳化硅沉积速率的影响,通过扫描电子显微镜(SEM)和X射线衍射技术(XRD)分析了碳化硅纤维表面碳化硅涂层的微观形貌和晶型结构,并分析了MTS热解和沉积碳化硅过程中主要气相组分的变化。在850-1050℃的范围内,随着沉积温度的提高,碳化硅沉积速率先增大后减小,温度为1000℃时,碳化硅沉积过程由表面反应控制转变为质量传输控制;随着反应物分压逐渐升高至30 kPa,碳化硅沉积速率逐渐增加,沉积由表面活性位吸附过程转变为形核长大过程;随着滞留时间的延长,SiC沉积速率逐渐下降。SEM图显示碳化硅纤维表面碳化硅涂层光滑致密,XRD结果表明850-1050℃沉积的碳化硅为β-SiC。MTS热解过程中主要的气相组分为是CH4、C2H2、SiHCl3、SiCl2和SiCl4。
Silicon carbide(SiC)coatings were prepared by using chemical vapor deposition(CVD)with a vertical hot-wall reactor and trichloromethylsilane-hydrogen-nitrogen(MTS-H2-N2)precursor.The effect of processing parameters on deposition rates of the SiC layers was studied.The SiC coating on the SiC fiber was characterized by using scanning electron microscopy(SEM)and X-ray diffi-action(XRD).Morphology and crystal structure of the SiC coatings were investigated.The SiC deposition rate was increased firstly and then decreased with increasing temperature in the range of 850-1050°C.At 1000°C,the deposition kinetics transferred from surface reaction control to mass transfer control.As the partial pressure of the reactant was increased to 30 kPa,the SiC deposition rate was increased.The deposition process was changed from surface active site adsorption to nucleation and growth.With increasing residence time,the SiC deposition rate was gradually decreased.The SiC coating was smooth and compact.The SiC deposited at 850-1050°C was p-SiC.The main gas-phase species after MTS pyrolysis were CH4,C2H2,SiHCl3,SiCl2 and SiCl4.
作者
贾林涛
王梦千
朱界
李爱军
彭雨晴
JIA Lintao;WANG Mengqian;ZHU Jie;LI Aijun;PENG Yuqing(School of Materials Science and Engineering,Shanghai University,Shanghai 200444,China)
出处
《陶瓷学报》
CAS
北大核心
2020年第2期257-263,共7页
Journal of Ceramics
基金
国家自然科学基金(21676163,5160218)
航空科学基金(2016ZFS6001)。
关键词
化学气相沉积
碳化硅
沉积速率
气相组分
chemical vapor deposition
silicon carbide
deposition rates
gas-phase species
