Molybdenum And Molybdenum-Zirconium Carbide Parts Fabricated By Plasma Spray Forming

This article prepares Mo-ZrC composite spray powder by cladding. With this powder and the commercial molybdenum powder, Mo-ZrC parts were fabricated by plasma spraying forming (PSF) followed by hot-isostatic pressing (HIP). The effects of the plasma spraying parameters on the density and microstructure of the deposits was analyzed. Microstructure changes of PSF products before and after HIPing were investigated. The relative density, micro-hardness and tensile strength of the products were detected. This paper can be mainly concluded as follows:1) With the mothed of cladding, we can parpare Mo-ZrC composite powder with good performance.the powder distributes evenly, and is linked closely. The mobility is21.7s/50g,and can meet the needs of the plasma spraying forming.2) When the spray distance doesn’t change,and the spraying power is too low, formed parts can be observed not to melt the particles. With the spraying power increases, the number of unmeltedparticles in the sediments reduced. When the distance is150mm, the spraying power35kW, the density can be88.5%. The spray distance of the parts also has a great impact. The larger the spray distance is, the higher density is. But to a certain stage, the increase of the distance will reduce the density.3) The particle of the composite parts after PSM and HIP can be refined. The ZrC was evenly distributed, and Partially filled the gap between the molybdenum particles. The transgranular rupture could be found in its fracture surface. The relative density, tensile strength,macrohardness of the composite parts increased to89.7%,123MPa,275HV.4) Pores and gaps of PSF deposits mitigated or eliminated after the process of HIP. And after the process of HIP, the relative density, tensile strength, macrohardness of the composite parts improved significantly.