阴极等离子电解沉积ZrO_2-Al_2O_3-Pt复合热障涂层组织及特性

Microstructure and properties of ZrO_2-Al_2O_3-Pt composite TBCs prepared by cathodic plasma electrolytic deposition

采用在阴极区添加陶瓷微珠进行阴极等离子电解的方法,可以在大面积的高温合金上沉积ZrO2-5%Al2O3弥散Pt微粒的复合热障涂层。SEM形貌观测结果表明,涂层的内层为致密结构,外层为多孔结构,涂层厚度可达200μm。XRD分析结果表明,该涂层由t-ZrO2、c-ZrO2、α-Al2O3。在1100℃空气中循环氧化结果表明,随着Pt含量的增加,ZrO2-5%Al2O3弥散Pt微粒的复合热障涂层抗高温氧化性能和抗剥落性能显著提高,隔热实验证明该涂层具有优异的隔热性能。这些优异的性能可归于弥散Pt微粒的增韧效应,垂直闭塞微孔可以松弛应力的效应。

ZrO2-5% Al2O3 composite coatings dispersed with Pt particles were prepared on large-sized super alloy surface by cathodic plasma electrolytic deposition. The SEM indicates that the total thickness of the coating can reach 200 μm and the structure of the outer layer is porous,while the inner layer is compact. The result of XRD shows that the coating is composed of c-ZrO2,t-ZrO2 and α-Al2O3.The cycle oxidation tests at 1100 ℃ reveals that high temperature oxidation resistance and spallation resistance of the ZrO2-Al2O3 composite coatings are significantly improved with the increase of the amount of Pt. The insulation test at 1100 ℃ shows that the coatings have excellent heat-shielding performance. These excellent performances can be attributed to the toughening effect caused by dispersion of Pt particles and the effect of stress relaxation caused by Vertical block microspores.