激光重熔改性等离子喷涂陶瓷涂层的组织及其耐腐蚀性能

Microstructure and corrosion characteristics of plasma-sprayedceramic coating by laser remelting of nano-Al_2O_3 modifying

以纳米Al2O3粉末为填料,采用激光重熔等离子喷涂陶瓷涂层技术,在45号钢表面制备了纳米改性Al2O3+13%(质量分数)TiO2/nano Al2O3复合陶瓷涂层。用X射线衍射仪、扫描电镜研究了纳米Al2O3改性后的陶瓷涂层的组织及涂层的耐腐蚀性能。结果表明,在激光的作用下,原等离子喷涂层Al2O3+13%TiO2的片层状组织得以消除;激光重熔区亚稳相γ Al2O3转变为稳定相α Al2O3,重熔层由α Al2O3和TiO2组成。与等离子喷涂Al2O3及Al2O3+13%TiO2陶瓷涂层相比,纳米Al2O3改性后的Al2O3+13%TiO2/nano Al2O3陶瓷涂层致密化程度明显提高,耐腐蚀性能也得到了明显的改善。

Using nano -Al_2O_3 powder material as the coating stuff, laser was employed to remelt the plasma spraying coating. Composite ceramic coating of Al_2O_3+13%TiO_2/nano -Al_2O_3 was formed on 45~# steel surface. The microstructure of laser-remelting nano-Al_2O_3 composite ceramic coating was investigated by using X-ray diffraction and scanning electronmicroscopy, and the corrosion behavior of the coatings was studied. The results show that lamella structure characteristic of plasma-sprayed coatings is eliminated after the laser-remelting. The metastable γ -Al_2O_3 in the remelting area transfers into stable phase of α -Al_2O_3 and composite ceramic coating consists of α -Al_2O_3 and TiO_2 on Al_2O_3+13%TiO_2/ nano -Al_2O_3 coatings. So laser-remelting nano -Al_2O_3 ceramic coating has higher densification and better corrosion resistance than plasma sprayed Al_2O_3 and Al_2O_3+13%TiO_2 coatings does.