【摘要】 以硅粉、石墨粉为包埋原料及MgO、Al2O3和B2O3等为促渗剂,采用二次固渗工艺在C/C复合材料表面制备了Si—α-SiC—β-SiC复合涂层。并采用X射线衍射(XRD)和扫描电子显微镜(SEM)对复合涂层进行了表征。结果表明:一次固渗后的涂层为Si-β-SiC涂层,两次固渗后可以获得致密的Si—α-SiC—β-SiC复合涂层,涂层厚约300μm,具有致密的表面和断面结构,没有开裂和孔隙等缺陷。氧化性能测试表明:在1500℃的静态空气气氛下氧化200h后,Si—α-SiC—β-SiC复合涂层能对C/C复合材料进行有效保护,涂层试样的失重仅为4.42×10-4g.cm-2。更多还原

【Abstract】 High performance oxidation resistant Si—α-SiC—β-SiC coatings for C/C composites were prepared by a two-step pack cementation method using silicon,graphite powders as source materials and Al2O3,MgO,B2O3 as infiltration additives.The as-prepared multi-coatings are characterized by XRD and SEM.Results show that Si—β-SiC coatings are obtained after the first step pack cementation;and the Si—α-SiC—β-SiC multi-coatings can be achieved after the second step pack cementation.The as-prepared Si—α-SiC—β-SiC multi-coatings with the thickness of about 300μm possess of dense surface and cross-section microstructures.No pin-holes and microcracks are observed.Isothermal oxidation tests in air at 1500℃ show that the weight loss of the as-obtained Si—α-SiC—β-SiC coating coated C/C composites after 200h is only 4.42×10-4g·cm-2.更多还原