Preparation of Spraying Powders and Microstructure of Molybdenum Disilicide Coating

Abstract

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.