Y2O3掺杂ZrSiO4涂层的微观组织和相结构研究

本文采用大气等离子喷涂成功制备了ZrSiO4及Y2O3掺杂ZrSiO4涂层，研究了Y2O3掺杂后ZrSiO4涂层微观组织结构、力学性能，并研究了涂层在1300 ℃下的烧结行为。结果表明，等离子喷涂ZrSiO4涂层主要由ZrSiO4、t-ZrO2、少量的m-ZrO2及无定型SiO2组成，而等离子喷涂ZrSiO4-5%Y2O3涂层主要由c-ZrO2、少量ZrSiO4相及无定型SiO2组成。相较于ZrSiO4涂层，Y2O3掺杂略微提高了ZrSiO4-5%Y2O3涂层的硬度和断裂韧性。在1300 ℃高温烧结48 h后等离子喷涂ZrSiO4涂层中(t,m)-ZrO2和无定型SiO2反应生成重新ZrSiO4相，该反应伴随着体积收缩，使得涂层中存在着大量孔隙和裂纹。相较于纯ZrSiO4涂层， ZrSiO4-5%Y2O3涂层中主要是c-ZrO2相和ZrSiO4相，添加Y2O3有助于涂层中的ZrO2保持在立方相（c-ZrO2），提高了ZrO2的高温相稳定性。

Effect of Y2O3 doping on microstructure and phase structure of plasma-sprayed ZrSiO4 coatings

In this paper, ZrSiO4 and Y2O3 doped ZrSiO4 coatings were successfully prepared by atmospheric plasma spraying. The microstructure, mechanical properties and sintering behavior at 1300 °C of coatings were investigated. The results showed that plasma-sprayed ZrSiO4 coating was mainly composed of ZrSiO4, t-ZrO2, a small amount of m-ZrO2 and amorphous SiO2 phases, while the ZrSiO4-5%Y2O3 coating contained c-ZrO2, a small amount of ZrSiO4 phase and amorphous SiO2. Compared with ZrSiO4 coating, Y2O3 doping slightly improved the hardness and fracture toughness of ZrSiO4-5%Y2O3 coating. After sintered at 1300 °C for 48 h, (t,m)-ZrO2 reacted with amorphous SiO2 to form new ZrSiO4 phase in plasma-sprayed ZrSiO4 coating accompanied by volume shrinkage, resulting in a large number of pores and cracks in the coating. In contrast, c-ZrO2 phase and ZrSiO4 phase were the main phases in the ZrSiO4-5%Y2O3 coating. The addition of Y2O3 helped the ZrO2 in the coating to maintain the cubic phase (c-ZrO2), which improved the high-temperature phase stability of ZrO2.