二氧化锆空心微球制备技术的主要进展

Main advances in preparation technology of zirconia hollow microspheres

二氧化锆空心球形粉末是制备隔热防护涂层的一种重要原料,其中粉末的特点决定了涂层的性能,高质量的二氧化锆空心球形粉末的制备成为行业关注的热点。本综述分析了二氧化锆空心微球的国内外研究现状,介绍了二氧化锆空心微球的主要制备方法,包括模板法、溶剂热法、喷雾干燥法和等离子体烧结法等,并对它们的优缺点进行了简要总结。模板法在ZrO2空心微球形貌的控制上表现出色,但是存在模板合成及后续去除过程繁琐等问题,并且对于制备工艺的要求较高,容易造成材料的浪费以及空心微球的破坏。溶剂热法的反应条件相对苛刻,涉及到产品的后续分离及洗涤、干燥等过程,难以进行批量化制备。喷雾干燥法是批量制备球形空心颗粒的有效方法,但是制备得到的空心颗粒存在强度低、喷涂过程中易破损等问题。相对于其他制备方法,喷雾干燥法和等离子体烧结法联用制备得到的球形空心颗粒因具有球形度高、流动性好且粒度分布可控等优势,更有利于应用于涂层的喷涂制备上。

Zirconia hollow microspheres have attracted more attention because of their excellent performance,which combines the advantages of the properties of zirconia and hollow structural materials,such as low thermal conductivity,ablation resistance,and chemical corrosion resistance.Zirconia hollow microspheres is an important feedstock for preparing thermal barrier coatings.The thermal barrier coating prepared by zirconia hollow microspheres has the characteristic of excellent insulation and corrosion resistance.The performance of the coating is determined by the characteristics of the powder.The preparation of high quality zirconia hollow spherical powder has become a hot topic in the industry.In this work,the research status of the preparation technology of zirconia hollow spherical powder is analyzed,and the main preparation approaches are introduced,including templating,solvothermal,spray drying,and plasma sintering.In addition,the characteristic of these approaches is briefly summarized.Templating method contributes to obtaining hollow zirconia spheres with perfect morphology.However,some problems such as difficulty both in template synthesis and subsequent template removal,which can cause the material waste and damage to hollow particles.For solvothermal method,the reaction conditions are relatively harsh,and it also involves cumbersome process,such as separation,washing and drying process,which makes it difficult to batch preparation of hollow microspheres.The spray drying method is an effective approach for batch preparation of hollow microspheres.However,the hollow microspheres prepared by spray drying possesses have low strength and become easy to be damaged during application.Importantly,it is considered that the hollow microspheres prepared by spray drying combined with plasma sintering process have the advantages of high sphericity,good fluidity,and controllable particle size distribution,which are more conductive to preparation of coatings.