摘要
采用5kW连续CO2激光器对经等离子喷涂的NiCoCrAlY结合层和ZrO2陶瓷层进行二次重熔处理,并利用金相显微镜、扫描电镜、电子探针和显微硬度计对激光熔敷涂层进行了显微结构、元素分布以及显微硬度观察与测试.结果表明:多道搭接工艺能降低熔敷涂层气孔率.ZrO2陶瓷层稀释度低,与基体结合完好.并观察到NiCoCrAlY合金层中存在明显的对流图案.加入了TiO2-Al-Ti添加剂的ZrO2陶瓷层激光重熔后得到了无裂纹的定向生长柱状晶,并且呈现一次枝晶平均间距为2 3μm的表层和平均间距为3 8μm的次表层结构.
The development of a new type of thermal barrier coatings on stainless steel. Involves procoating by a plasma-spraying process and subsequent laser remelting. A 5 kW CW CO_2 laser was used to produce NiCoCrAlY bond coating and zirconia ceramic coating with double remelting. The microstructure, chemical composition and microhardness of the coatings have been studied by SEM, EPMA and microhardness measurement. The results show that porosity of laser cladding coatings decrease during multirunning process. The ZrO_2 coating had low dilution rate and adhesion integrity with the substrates. The convection patterns were observed in laser cladding NiCoCrAlY alloy coatings. The micrograph of ZrO_2 coatings with TiO_2-Al-Ti dopants is oriented columnar grains, and the space between dendrites is respectively 2.3 μm of top layer and 3.8 μm of subsurface layer.
出处
《材料科学与工艺》
EI
CAS
CSCD
2003年第4期347-350,共4页
Materials Science and Technology
基金
国家自然科学基金资助项目(59995440)
辽宁省自然科学基金资助项目(2001101021).
