原始粉末是影响等离子喷涂热障涂层组织结构和性能的主要因素之一。Y_2O_3稳定ZrO_2(Yttria stabilized zirconia,YSZ)空心球形粉末综合了熔融破碎粉末的预合金化效果好和团聚烧结粉末的流动性好的优点。采用该粉末制备的YSZ热障涂层的隔热性能、抗热震性能以及抗烧结性能等均显著提高,是目前综合性能最为优异的热障涂层之一。结合国内外研究情况,文章主要介绍了喷雾干燥法、等离子球化法以及模板法制备等离子喷涂用YSZ空心球形粉末的原理和优缺点;同时,对等离子喷涂过程中YSZ空心球形粉末熔滴的飞行特性、铺展凝固行为以及YSZ空心球形粉末制备涂层组织结构及性能的研究进行了概述;最后,指出了目前研究中存在的问题并对其未来的研究方向进行了展望。
Powder morphology is one of the main factors which affects the microstructure and performance of plasma sprayed thermal barrier coatings.Yttria stabilized zirconia(YSZ)hollow spherical powders(HOSP)combine the advantages of good prealloying of fused-crushed powders and flowability of agglomerated-sintered powders.The sprayed coatings made from YSZ HOSP achieve significantly improved heat insulation,thermal shock resistance and sintering resistance,and thus have become the promising candidate fot thermal barrier coatings with excellent comprehensive performance.The principle,merits and drawbacks of the YSZ HOSP preparation methods,including spray drying,plasma spheroidization and template method,are summarized according to the current situation of domestic and foreign researches.Meanwhile,the movement characteristics and spreading solidification behavior of HOSP molten droplet,the microstructure and performance of sprayed coatings are discussed.Finally,the unresolved issues and the future development trend of this field are proposed.