等离子喷涂Al_2O_3+13wt%TiO_2陶瓷涂层的激光重熔处理

Laser remelting of plasma sprayed Al_2O_3+13wt%TiO_2ceramic coating

本文用Ｘ射线衍射、扫描电镜和显微硬度研究了等离子喷涂Ａｌ２Ｏ３ ＋ １３ｗｔ％ ＴｉＯ２ 陶瓷涂层激光重熔处理后陶瓷熔化层的组织结构及硬度变化特征。激光重熔区亚稳相∪Ａｌ２Ｏ３ 转变成为稳定相α－ Ａｌ２Ｏ３ ；ＴｉＯ２ 与Ａｌ２Ｏ３ 反应生成ＴｉＡｌ２Ｏ５。陶瓷熔化层致密、无孔隙、少裂纹或无裂纹；熔化层硬度有较大提高，且随激光能量密度的增大而增大，而涂层设计对其影响很小。此外，激光重熔能极大地提高陶瓷涂层的耐磨性。

The microstructure and microhardness of the laser remelted layer of the plasma sprayed Al 2O 3+13wt.%TiO 2ceramic coatings have been investigated using x ray diffraction,scanning electronic microscope and microhardness measurements.After laser remelting,the metastable  Al 2O 3 in the remelting layer has transferred into stable phase α-Al 2O 3,meanwhile,the phase TiO 2 reacts with Al 2O 3 and transfers to TiAl 2O 5.The remelted layer becomes very dense,porous free and only a few or even no cracks exist.The hardness of the laser remelting layer has been largely developed and furthermore increases as the output energy density of laser goes up,however it is almost independent of the coating design.Additionally,the wear resistance of the ceramic coating has been greatly improved by laser remelting.