化学气相沉积SiC涂层反应特性及沉积过程的模拟研究

Simulation Study on Reaction Characteristics and Deposition Process of SiC Coating Prepared by Chemical Vapor Deposition

借助基于有限元原理的COMSOL软件和分子动力学模拟原理的Reax FF软件对化学气相沉积技术制备SiC涂层的反应特性及沉积过程进行模拟研究,为高温抗氧化复合涂层体系中SiC中间层的工艺优化及制备提供理论支持。结果表明,化学气相沉积SiC涂层过程包括前驱体三氯甲基硅烷(CH_(3)SiCl_(3))的扩散过程和热解反应过程,SiC涂层在扩散过程不会生长,仅从10^(−4)s后的热解反应过程开始生长,沉积生长过程同时伴随涂层的解离。随着入射粒子能量的增大,单位时间内沉积到基底表面的Si和C粒子数不断增加。提高粒子入射能量有利于提高SiC涂层的致密度,当入射粒子能量大于2 eV时可以实现SiC涂层的均匀生长,而当入射能量高于6 eV时,解离的Si和C粒子数量增大,不利于SiC涂层的生长。综合而言,当入射能量为3 eV时,化学气相沉积的SiC涂层综合性能最佳。

In order to provide theoretical support for the process optimization and preparation of SiC intermediate layer in high-temperature oxidation resistance composite coating system,the reaction characteristics and deposition process of SiC coating prepared by chemical vapor deposition technology were simulated using COMSOL software and Reax FF software,that based on the finite element principle and the molecular dynamics simulation principle,respectively.The results indicated that the chemical vapor deposition process of SiC coating include the diffusion process and the thermal decomposition reaction process of precursor trichloromethylsilane(CH_(3)SiCl_(3)).The SiC coating does not grow during the diffusion process,it only starts to grow from the thermal decomposition reaction process after 10^(−4)s,that is accompanied with the dissociation process of SiC coating.With the increase of incident particle energy,the number of Si and C particles deposited on the substrate surface per unit time continuously increases.Increasing the incident energy of particle is beneficial to improve the density of SiC coating.The uniform growth of SiC coating can be achieved when the incident energy of particles is higher than 2 eV.However,the number of dissociated Si and C particles increases when the incident energy is higher than 6 eV,which is not conducive to the deposition of SiC coating.In summary,the comprehensive properties of SiC coating prepared by chemical vapor deposition technology are the best when the incident energy is 3 eV.