(1. 湖南科技大學(xué) 新材料制備及應(yīng)用技術(shù)研究所，湘潭 411201；
2. 廈門理工學(xué)院 機械工程系，廈門 361024)
摘 要: 采用噴霧干燥和真空燒結(jié)技術(shù)制備MoSi2團聚顆粒，以MoSi2團聚粉末為原料，通過大氣等離子噴涂法制備二硅化鉬涂層，借助XRD、掃描電鏡及能譜對團聚體粉末在等離子焰流中的熔化特性和涂層的組織結(jié)構(gòu)進行研究。結(jié)果表明：團聚粉末在1 200 ℃真空熱處理1 h后，粉末的流動性和松裝密度分別提高55.6%和42.0%，適合等離子噴涂用。MoSi2顆粒經(jīng)過高溫等離子焰流后，粉末熔化充分，大多數(shù)團聚體粉末發(fā)生燒結(jié)過程，顆粒的平均粒度減小，形成較致密的球形顆粒。在噴涂過程中，部分四方相MoSi2(t)轉(zhuǎn)變?yōu)榱较郙oSi2 (h)或氧化形成了少量的Mo5Si3相，涂層中的富鉬相呈“網(wǎng)狀”組織結(jié)構(gòu)。
關(guān)鍵字: MoSi2涂層；噴霧干燥；等離子噴涂；熔化特性
its melting characteristics in plasma arc
（1. Advanced Materials Synthesis and Application Technology Institute,
Hunan University of Science and Technology, Xiangtan 411201, China;
2. Department of Mechanical Engineering, Xiamen University of Technology, Xiamen 361024, China）
Abstract:The MoSi2 powder used for air plasma spraying was prepared by spray drying and vacuum sintering. By using MoSi2 powders as the raw powders, MoSi2 coating was prepared using air plasma spraying. The melting characteristics of MoSi2 powders in the plasma arc and the microstructures of the coating were studied by scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). The results show that, when the powders are sintered at 1 200 ℃ for 1 h, the mobility and loose density of powders increase by 42.0% and 55.6%, respectively. Most MoSi2 particles occur during the sintering process, and the average particle sizes of the powders decrease after the MoSi2 powders pass through the high temperature plasma flame. MoSi2 particles are fully melted and the dense spherical particles are formed. Duri, ng air plasma spraying, part of the tetragonal MoSi2 (t) phase changes into MoSi2 (h) crystal structure or oxidize to form Mo5Si3 phase. The microstructure of molybdenum-rich phase in the MoSi2 coating is similar to the “mesh” structure.
Key words: MoSi2 coating; spray-drying; plasma spraying; melting characteristics
