Research on sintering performance of high purity metal vanadium powders

The grain size and morphology of high purity metal vanadium powders were observed by electron probe, the vanadium billets were pressed by oil hydraulic press, and the crushing force curves were measured by the universal machine to study the optimum pressing pressure for vanadium billets. Then, the high purity vanadium powders were treated by hot pressing sintering and cold isostatic pressing + vacuum sintering, respectively, to study the effect of sintering process on the sintering performance and mechanical property of vanadium powder products. The results show that, in the cold isostatic pressing with vacuum sintering process, the density of raw compact increases with the increase of pressing pressure. When the pressure increases to 280 MPa, the density and relative density of raw compacts are 3.99 g·cm^-3 and 66.94%, respectively, and the density and relative density of products after vacuum sintering are 5.28 g·cm^-3 and 88.59%, respectively. With the pressure increasing from 80 MPa to 200 MPa, the compressive strength increases significantly from 0.4 MPa to 6.0 MPa; when the pressure increases to 280 MPa, the compressive strength slowly increases to 7.4 MPa. The relative density of products by hot pressing sintering is higher than that by cold isostatic pressing + vacuum sintering, and the density and relative density of products by hot pressing sintering at 280 MPa reach to 5.51 g·cm^-3 and 92.91%, respectively.