Effects of crucible materials on the H2 reduction of MoO3

The present study examined how different crucible materials (W, Mo, corundum, and 310S high-temperature-resistant stainless steel) affected hydrogen-reduced molybdenum trioxide, focusing on the resulting Mo powder's morphology, particle size and impurity content. The findings revealed that the sublimation ratio of MoO 3 during gas-phase reduction varied depending on the crucible material. This variation influenced the number of reactants involved, even under constant H 2 flow, which in turn impacted the morphology of the resulting Mo powder. During the solid-phase reduction process, Mo powder was uniformly distributed and spherical when either Mo or 310S was used as the crucible material. However, when W or corundum was used, the Mo powder exhibited different degrees of sintering. This suggested that W and corundum affected the Mo powder's growth process, leading to particle refinement, as well as agglomeration and sintering. When different crucible materials and forms of MoO 3 were used in H 2 reduction process to produce Mo powder, impurity elements followed distinct trends. In gas-phase reduction product, Al and W contents obviously decreased. On the other hand, in solid-phase reduction product, P and K levels notably reduced. However, Fe, a primary component of 310S high-temperature-resistant steel, easily diffused into the product, causing a rise in its content.