石墨抗氧化SiC涂层的制备与性能

Preparation and Oxidation Behavior of SiC Coating for Graphite Materials

以SiC、Si和酚醛树脂为主要原料,通过浸涂和气相渗硅两步法在石墨表面制备了SiC抗氧化涂层。利用XRD、SEM研究了涂层的相组成与形貌。结果表明,气相渗硅后涂层的主相为α-SiC、β-SiC和Si,其中Si是气相渗硅过程中残留的。涂层与基体之间具有过渡结构,致密度良好。抗氧化和抗热震实验表明:由气相渗硅工艺制备的SiC涂层结构致密,具有良好的抗氧化性能,1200℃空气条件下氧化16 h后试样每小时增重量约为2.18 mg/cm^2。涂层具有良好的抗热震性能,经1000~25℃循环热震15次后试样质量变化率仅为–0.17%。

Using SiC, Si and thermosetting phenol resin as raw materials, the SiC coating for protecting graphite materials from oxidation was prepared by a vapor silicon infiltration process(VSI). SEM and XRD analyses show that a dense SiC coating with a C/SiC gradient inner layer as bonding layer which is well combined with the out layer SiC coating is obtained. The main phases of the coating are α-SiC, β-SiC and Si, and Si is residual after the VSI process. Anti-oxidation and thermal shock resistance experiments reveal that the as-obtained SiC coating can effectively protect graphite. After oxidation in air at 1200 °C for 16 h, the mass gain of the sample is about 2.18 mg/cm^2. The coating has good thermal shock resistance, and after thermal shock between 1000 °C and 25 °C for 15 cycles, the mass loss of the coating is only –0.17 wt%.