添加剂SiO2在等离子喷涂陶瓷涂层及其激光重熔中的作用研究

系统研究了添加剂 Si O2 在等离子喷涂陶瓷涂层及其激光重熔中的作用 .添加剂 Si O2 的 液相烧结 作用在高熔点 Zr O2 陶瓷涂层中比较明显 ,而在较低熔点 Al2 O3陶瓷中不明显 .在激光重熔中 ,Si O2 能降低 Zr O2 熔化层应力并阻碍裂纹扩展 ;在 Al2 O3陶瓷涂层中 ,Si O2 还能使熔化层晶粒均匀化 ,并在晶粒间形成连续玻璃质抑制裂纹形成、阻碍裂纹扩展 .而 Al2 O3陶瓷涂层中的Ti O2 ,激光处理时生成 Ti Al2 O5,此相导致熔化层产生巨大的不对称应力使之易出现裂纹 ,但其能提高涂层的致密度和耐磨性

Influences of Additive SiO2 in Plasma Sprayed Ceramic Coatings and Subsequent Laser Remelting

The influences of additive SiO 2 in the plasma sprayed ceramic coatings and subsequent laser remelting have been investigated in this paper. The liquid sintering effect of SiO 2 is considerably obvious in the ceramic coating ZrO 2 of a high melting point, while this effect is not apparent in Al 2O 3 coating possessing a relatively low melting point. During laser remelting, the additive SiO 2 can not only reduce the cooling stress of the remelted layer in ZrO 2 coating, but also hinder the spreading of cracks. While in Al 2O 3 coating, in addition to the above effects, SiO 2 can further make the grain size distribution more uniform and form a continuous glass like matter around the grain boundaries, thus the formation and spreading of cracks will be suppressed. As to TiO 2, during laser remelting, it will react with Al 2O 3 transforming into TiAl 2O 5 that possesses a large anisotropic coefficient of expansion, thus it will lead to a big and asymmetrical stress and finally some cracks occur in the remelted layer.