脉冲激光重熔对YSZ涂层微观结构的影响

Effect of Pulse Laser Remelting on Microstructure of YSZ Coating

本文采用电子束物理气相沉积技术在Ni基单晶基体表面制备双层结构的热障涂层后,采用脉冲Nd∶YAG(钇铝石榴石晶体)激光对其进行表面改性处理,分别研究了脉冲宽度和脉冲频率对重熔钇稳定氧化锆涂层(yttria-stabilised-zirconia,YSZ)微观结构及孔隙率的影响。结果发现:激光重熔的YSZ陶瓷层会在快速冷却过程中形成裂纹等缺陷,激光束的脉冲宽度和频率会显著地影响到涂层微观结构,脉冲宽度的增加会使重熔陶瓷层表面紧密、孔隙减少,脉冲频率的增加会使重熔陶瓷层表面的孔隙率先减小后增大。

In this paper,electron beam physical vapor deposition technique was adopted to prepare double structure thennal barrier coatings on Ni-based single crystal substrate.A Nd:YAG pulse laser was used to modify the surface of the as-deposited samples.The effect of pulse width and frequency on microstructure and porosity of laser remelted YSZ coating was investigated.The results revealed that crack was formed during the rapid cooling process of laser remelting.Microstructure of the coatings would be significantly impacted by the pulse width and pulse frequency of laser beams.Increase of pulse width could make the coating surface compact and reduce pore size.Porosity would first decrease then increase with the enhance of pulse frequency.