激光熔敷氧化锆热障涂层微观结构研究

采用5KW连续CO_2激光器对Ni基高温合金上二次重熔NiCoCrAlY和ZrO_2陶瓷层进行了研究。结果表明:激光快速熔化和凝固获得定向外延生长、紧密堆积的柱状晶氧化锆陶瓷层。NiCoCrAlY结合层与柱状晶之间存在氧化铝层,保证了柱状晶与NiCoCrAlY层的联结。激光重熔ZrO_2层由四方相和立方相组成,经快速冷却由高温保留至室温。

Study on laser clad zirconia thermal barrier coatings

A new type of thermal barrier coatings is being studied for gas turbine blades by laser cladding on Ni-base super-alloy substrates. A 5KW CW CO2 laser was used to produce NiCoCrAlY bond coatings and zirconia ceramic coatings with double remelting. The results show that during rapid melting and solidification in laser process, the oriented epitaxial growth, closely packed columnar structure could be obtained by controlling laser parameters. An alumina layer which exists between the NiCoCrAlY layer and columnar ceramic layer provides for the adherence of them. The ceramic coatings made by laser remelting were predominantly composed of a mixture of cubic and tetragonal phases, which can be retained by rapid cooling to room temperature.