锆合金包壳水侧SiC涂层研究

研究了聚碳硅烷（PCS）粉末的高温裂解特性及PCS粉末与锆粉间的化学反应机理，并在900 ℃制备了SiC涂层。研究发现，900 ℃开始，PCS裂解产物由无定形态SiC向结晶态转变。不同温度下，PCS粉末与锆粉的混合物发生一系列化学反应，产物为ZrC、Zr₂Si、Si₃Zr₅，通过调节反应温度，可控制该化学反应的程度，进而实现对涂层成分的调节。采用先驱体转化法（PIP）在锆合金包壳表面制备了SiC涂层，经PCS溶液浸涂-裂解3次循环可得到SiC陶瓷层，厚度为4 μm，涂层成分为SiC，ZrC为过渡层。划痕法测试得到涂层附着力等级为1～2级。

Study on SiC Coating on Waterside of Zirconium Alloy Cladding

The pyrolysis characteristics of polycarbosilane (PCS) powder at high temperature and the chemical reaction mechanism between PCS powder and zirconium powder were studied, and SiC coating was prepared at 900 ℃. It is found that the pyrolysis products of PCS change from amorphous SiC to crystalline state at the beginning of 900 ℃. At different temperatures, a series of chemical reactions take place between the mixture of PCS powder and zirconium powder. The products are ZrC, Zr₂Si and Si₃Zr₅. By adjusting the reaction temperature, the extent of chemical reaction can be controlled and the composition of the coating can be adjusted. SiC coating was prepared on zirconium cladding surface by precursor infiltration pyrolysis (PIP). The SiC ceramic layer is obtained by dipping in PCS solution and pyrolytic cracking at 900 ℃ for three cycles and its thickness is 4 μm. The composition of the coating is SiC and ZrC is the transition layer. Scratch method was used to test the adhesion of the coatings, and the adhesion grade is 1-2.