陶瓷先驱体聚硅氮烷(PSZ)加入Si、MoSi_2填料制备石墨抗氧化复合涂层的研究

Study on Carbon Anti Oxidation Composite Coating Prepared with the PSZ and Si-MoSi_2 Powders

采用陶瓷先驱体聚硅氮烷(PSZ)为主要原料,并加入Si、MoSi2填料,于石墨表面制备高温抗氧化涂层。借助扫描电镜和X射线衍射仪等分析手段对复合涂层的微观结构和相组成进行表征,并对涂层的抗氧化性能进行了初步研究。结果表明,涂层厚度约为30μm,内层为化学结合的SiC-Si过渡层,外层为MoSi2-SiC-SiCN氧阻挡层,涂层表面较为平整、致密,与过渡层结合紧密。涂层试样抗氧化效果与氧化温度有关,当氧化温度为1200℃时,抗氧化能力较差,氧化失重率约为10.98%,当氧化温度高于1300℃时,高温封填剂的作用发挥充分,抗氧化性能显著提高,氧化失重率仅为1.15%。

The high temperature ceramic coating against oxidation for graphite was fabricated using preceramic polymer-polysilazane （PSZ） as the main material and Si, MoSi2 powder as filler. The mierostructure and phase composition of the coating were characterized by means of SEM and XRD, and preliminarily study on its anti-oxidation ability was conducted. The results show that the thickness of the coating is about 30 μm, the transition layer of the coating was prepared with the SiC-Si, and the resisting oxidation layer with the MoSi2-SiC-SiCN respectively. The coating is uniform and densified, and the interface with graphite is excellent. The anti oxidation effect of coatings has to do with the oxidized temperature. At 1200 ℃, the sealing effect is poor and the weight-loss ratio is about 10.98%. When the temperature is higher than 1300 ℃, the high temperature sealing agent played a role and the anti oxidation ability increased obviously. The weight-loss ratio is only 1.15%.