激光重熔纳米氧化锆热障涂层的抗热冲击性能
Investigation of thermal shock resistance of the nanostructured zirconia thermal barrier coatings treated by laser glazing
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摘要: 采用纳米氧化锆团聚粉末和等离子喷涂技术制备了纳米氧化锆涂层,试验研究了激光重熔工艺参数(激光比能量)对纳米氧化锆涂层抗热冲击性能的影响.结果表明,激光重熔工艺参数对重熔涂层的抗热冲击性能影响显著,采用合适的工艺参数(激光比能量),可以使重熔涂层获得最佳的抗热冲击性能.不同激光重熔工艺参数处理的涂层形成的组织结构不同,使得涂层的抗热冲击性能不同.合适的激光重熔工艺参数下涂层表现出高的抗热冲击性能,主要是因为重熔后的涂层组织结构有利于热应力的释放以及其相结构在高温冲击下具有良好的稳定性.Abstract: The nanostructured zirconia coatings were pre-pared using nanostructured zirconia powder by plasma spray process,and then the coatings were treated by laser glazing. The effect of laser glazing process parameters (laser input energy density) on the thermal shock resistance was investigated. It is shown that the thermal shock resistance of coating is significantly changed with the different laser glazing process parameters. Excellent properties of thermal shock resistance can be achieved under optimized process parameters. It is indicated that the microstructures are different while using different process parameters, which results in different thermal shock resistance of zirconia coating. The surface morphology and microstructure of laserglazed coating are beneficial to the release of thermal stress,and the phase composition is stable during thermal shock. It is believed those are responsible for the improvement of thermal shock resistance of zirconia coatings after laser glazing treatment.