Chemical Vapor Infiltration (CVI) is one of the most promising methods for production of high-quality CMCs. To fabricate CMC with SiC matrix, different precursors are currently used. Methylsilane (CH₃SiH₃) is now considered as an alternative to haloid precursors. Principal advantages of methylsilane (MS) are: (1) environmental safety of the process due to absence of chlorine and chemical stability of MS at room temperature; (2) lowering of the process temperature down to 650-800 °С, which allows densification of preforms made from nonrefractory metals and low-temperature ceramics. One of the most important problems in CVI research is finding the optimal technological parameters providing minimal infiltration time and required quality. A possible way of solving these problems is in combination of experimental study and numerical simulations. In the present work, 1D modelling of isothermal CVI for MS precursor was used to describe phenomena in the porous preform. Porous medium of such preform includes many pore systems with different scales. The mathematical model of the preform densification included description of gas mixture transport inside these pore systems, SiC deposition kinetics, and evolution of porous medium. Species transport is simulated accounting for diffusion and convection (including phase transition-induced convection). In this work, we analysed the influence of the CVI operating conditions on distributions of species concentrations and pressure along the preform thickness during the process as well as on the process duration, average residual porosity and distribution in the preform of the residual porosity. Besides, the present work reports on the experimental research of such preforms densification by isothermal CVI. Experimental process was studied at different temperatures. The obtained CMC samples were characterized for their composition, microstructure and residual porosity. Computational results are compared with experimental observations.

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1. Ceramic Composites With SiC Matrix Produced By Liquid Silicon Infiltration Process For Frictional Applications