二硅化钼喷涂粉末的制备及其涂层组织结构

Preparation of Spraying Powders and Microstructure of Molybdenum Disilicide Coating

以粒度为1-2μm的MoSi2粉末为原料,采用喷雾干燥和真空烧结制备了喷涂用MoSi2团聚粉末.分别用平均粒度为9.68μm的MoSi2粉末和团聚造粒MoSi2粉末（38-72μm）为喂料,大气等离子喷涂制备了二硅化钼涂层,分析了涂层的微观组织结构.研究结果表明,喷雾干燥造粒后的近球形粉末在1300℃真空烧结1h后,粉末流动性和松装密度分别为17.1s/50g和2.16g/cm3,比烧结前分别增加了57.0%和46.0%.平均粒度为9.68μm的MoSi2粉末制备的涂层主要是由Mo和Mo5Si3等富钼相组成.团聚粉末制备的涂层主要由MoSi2相组成,涂层较致密,内部出现了类似＂网状＂的组织结构.

With the size of 1-2μm MoSi2 powder as raw material,MoSi2 powder ideal for air plasma spraying was prepared by spray drying and vacuum sintering.By using MoSi2 powders（9.68μm） and agglomeration powders（38-72μm） as the spray feedstock,MoSi2 coatings were successfully prepared using air plasma spraying.The phase composition and microstructure of the coating were studied.The results show that the mobility and loose density of the agglomeration powders sintered at 1300℃ for 1h are 17.1s/50g and 2.1g/cm3,respectively.Compared with the unsin-tered powders,the mobility and loose density of the sintered agglomeration powders increase by 57.0% and 46%,re-spectively.XRD patterns shows the main phases are Mo and Mo5Si3 phases in the coating prepared by the powders with the size of 9.68 μm.In case of spraying with agglomeration powders,the main phase of the dense coating is MoSi2.The ＂mesh＂ microstructure of molybdenum-rich phase is produced in the coating prepared by the agglomeration powders.