Laser-beam modification of oxide thermal barrier coatings deposited by plasma spraying in air

摘要

This work describes the influence of laser treatment on the structure and some properties of Al{sub}2O{sub}3, Al{sub}2O{sub}3 + 5%Ni, Al{sub}2O{sub}3 - (95%Ni + 5%Al), Al{sub}2O{sub}3 + 5%Ni - (95%Ni + 5%Al) and Al{sub}2O{sub}3 + 5%Ni + CrAl layer oxide ceramic coatings of about 100 μm thickness deposited by air plasma spraying on a heat-resistant alloy with a nickel matrix. It has been stated that laser remelting of power density 0.01-0.2 × 10{sup}9Wm{sup}(-2) and scanning rate within 5-7 m min{sup}(-1) ensures good quality of ceramic coatings in comparison with not-remelted coatings. Laser treated ceramic coatings have a better thermal conductivity than as deposited layers. As shown by model calculations, after laser treatment, they show a smaller temperature drop over a given thickness. The erosion resistance of the coatings, however, is greater after laser treatment.