通过SEM和XRD分析研究了在不同条件下反应生成的SiC基体的微观结构和组分。结果表明，反应温度对沉积SiC晶体的取向有很大的影响，温度在1 100℃以下沉积SiC为单一取向(111)(2θ≈35°)面，温度在1 100℃以上，沉积SiC主要有两种取向(111)面和(220)(2θ≈60°)面，还有少量的(311)(2θ≈70°)面。不同条件下生成的SiC晶粒的堆积方式有所不同，这直接影响了SiC基体的性能，从而影响了其复合材料的性能。此外反应气体流量也对SiC基体和复合材料性能有很大影响。本文进行了沉积温度和气体流量对SiC基体性能影响的研究，优化了CVI—SiC工艺。
High mechanical properties and anti-oxidation stability of SiC matrix composites are dependent on high performance of CVI-SiC matrix materials.Microstructure and composition of the CVI-SiC matrix materials deposited under different CVI conditions are examined by SEM and XRD.Test results show that crystal orientation of the CVI SiC materials is much dependent on reaction temperature.When it is below 1100℃ the CVI SiC materials have single crystal orientation plane(111),and double crystal orientation planes (111,220) with a small amount of orientation plane(311) when the reaction temperature is above 1100°C.The different stacking modes of SiC crystal grain directly influence the properties of the CVI SiC materials and its composites.Moreover,the properties of the CVI-SiC matrix and composites are influenced by reagent flow.In this work,the effects of the depositing temperature and reagent flow on the properties of the SiC matrix are investigated,and the optimized process is introduced.
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