激光重熔等离子喷涂纳米氧化锆热障涂层组织与性能

采用等离子喷涂纳米氧化锆(ZrO_2-8%Y_2O_3)团聚粉末制备了纳米氧化锆热障涂层,利用连续CO_2激光对其进行重熔处理.以常规热障涂层作为比较对象,研究了纳米氧化锆热障涂层和激光重熔涂层的组织结构、硬度、抗热冲击性能.结果表明:纳米氧化锆热障涂层组织结构为独特的纳米-微米复合结构,主要有柱状晶和未熔融或部分熔融纳米颗粒组成;激光重熔热障涂层的组织结构为表面等轴晶+断面柱状晶.硬度试验和抗热冲击性能试验综合比较结果显示:相对于常规氧化锆热障涂层,纳米氧化锆热障涂层和激光重熔热障涂层拥有更好的性能.因此将纳米技术和激光重熔表面处理技术与等离子喷涂技术结合起来制备热障涂层是提高热障涂层性能的非常有前景的工艺方法.

MicrostructureandPropertiesofPlasmaSprayedNanostructuredThermal BarrierCoatingsBeforeandAfterLaserGlazing

The nanostructured zirconia TBCs were manufactured by atmospheric plasma spraying with the nanostructured zirconia agglomerated powders, and the CO_2 laser beam with the continuous wave was applied to the laser glazing of nanostructured TBCs. The microstructures, microhardness and thermal shock resistance of nanostructured TBCs and as-glazed TBCs were systematically investigated compared with conventional TBCs. The results show that the nanostructured TBCs exhibit a unique complex microstructure consisting of columnar grains and non-melted or partially melted nanosized particles, while the microstructure of the as-glazed coatings is a combination of the columnar grains in the fracture and the equiaxed grains on the surface. The expeirimental results of the microhardness and thermal shock resistance present that the nanostructured coatings and the as-glazed coatings possess better properties than the conventional coatings. So the hybrid process where the nanometer technology and laser glazing are combined with atmospheric plasma spraying to prepare TBCs is revealing a high potential for the improvement of TBCs properties.