摘要
采用反应熔渗法(RMI)在密度为1.6 g/cm3的C/C复合材料上制备厚度为20~50μm的SiC-ZrC涂层。研究SiC-ZrC涂层结构以及涂层与C/C复合材料的界面相组成。结果表明:4种不同比例混合后的Zr,Si,C和ZrO_2粉末反应熔渗得到的样品涂层表面质量较好,由于反应过程先达到Si的熔点生成SiC,随着温度升高,当Zr和Si都熔融后,生成ZrC的吉布斯自由能低于SiC,故涂层由内到外呈现SiC-ZrC-SiC的三层结构,所有样品内部都熔渗了不同深度的ZrC和SiC。在偏光显微镜下SiC呈现黄绿色块状和粒状,ZrC呈现灰白色块状;粉末熔体通过共晶反应生成的Si,ZrSi_2,Zr和Zr_2Si与原料中的C以及热解炭反应最终生成SiC和ZrC,反应最终残留物中并没有发现ZrO_2。
SiC-ZrC coatings with thickness of 20？50 μm were deposited by the reactive metal infiltration （RMI） technology on C/C composites with density of 1.6 g/cm3. The microstructure of SiC-ZrC coating and phase composition of interface between SiC-ZrC coatings and C/C composites were investigated. The results show that, good performance of SiC-ZrC coatings can be obtained by reactive infiltration method on C/C composites with 4 kinds of blending powders （Zr, Si, C and ZrO2）. The temperature first reaches the melting point of Si, which reacts with C. With the temperature increassing, both Si and Zr melt, and the generating Gibbs free energy of ZrC is lower than SiC, so the coating is a three-layer structure of SiC-ZrC-SiC from inside to outside, and all samples are infiltrated with ZrC and SiC at different depths. SiC is the green granular and bulk phase, and ZrC is the white block phase under observing by polarizing microscope. SiC and ZrC are produced by the reactions of ZrSi2, Zr and Zr2Si which synthesized by melting powders eutectic reaction with C and pyrolytic carbon in the raw materials. ZrO2 is not found in the final products.
出处
《粉末冶金材料科学与工程》
北大核心
2017年第6期760-766,共7页
Materials Science and Engineering of Powder Metallurgy
基金
国家基础建设项目(GFZX0101040101-2012C20X)
