前驱体转化法制备TiSi2/YSZ陶瓷涂层

采用聚硅氮烷前驱体作为基体,添加惰性填料(YSZ)和活性填料(TiSi2)制备涂层浆料,在310s不锈钢表面利用前驱体转化法制备TiSi2/YSZ陶瓷涂层。通过TGA、XRD和SEM对涂层的物相组成和微观形貌进行了表征,并研究了TiSi2含量对涂层的隔热性能以及耐高温性能的影响。结果表明,所制备的涂层厚度在15~35μm之间,由于前驱体树脂裂解过程中的体积收缩,未添加TiSi2的涂层表面分布有大量裂纹且涂层部分脱落。裂解过程中,TiSi2氧化生成TiO2与SiO2后可使TiSi2体积膨胀,弥补了前驱体树脂的体积收缩。因此随着TiSi2含量的增加,涂层脱落面积减少,表面裂纹密度降低,当TiSi2的体积分数达41%时,涂层内部无裂纹产生,该涂层样品在1200℃氧化25h后金属基底氧化增重降低88.8%,并表现出良好的隔热性能和抗热震性能。

Preparation of TiSi2/YSZ Ceramic Coatings by Preceramic Polymer Pyrolysis

TiSi 2/YSZ ceramic coating was prepared on 310s steel by preceramic polymer pyrolysis with coating slurry consisting of matrix(polysilazane),active filler(TiSi 2)and passive filler(YSZ).The microstructure and phase composition of coating were characterized by TGA,XRD and SEM,heat-insulating property and high temperature performance of coating with different contents of TiSi 2 was also investigated.The results show that,the thickness of the prepared coatings are between 15-35μm,due to the shrinkage of the precursor during pyrolysis,many cracks distribute on surface of the sample without TiSi 2.TiSi 2 will form TiO 2 and SiO2 after being oxidized which have the larger volume,hence it can compensate for the shrinkage of precursor which lead to less defects on the coating as the addition of the TiSi 2.When the volume fraction of TiSi 2 reach 41%,no cracks distribute in the coating,and this sample reduce 88.8%oxidation weight gain of substrate after being oxidized for 25 h at 1200℃,meanwhile it exhibits excellent heat-shielding performance and thermal shock resistance.