Effect of Mo Oxides on the Phase Composition and Characteristics of Mo-10Re Pre-Alloyed Powders Co-Reduced with NH4ReO4.

Abstract

Mo-Re pre-alloyed powders are crucial raw materials in fabricating Mo-Re alloys, and their properties can significantly impact the properties of the resulting alloys. The powders are usually produced by the co-reduction of a mixture of Mo and Re oxides. However, it remains unclear if the overall characteristics of the produced Mo-Re powders rely on the different combinations of the Mo and Re oxide precursors. Therefore, in this work, a comparative study is conducted on the co-reduction processes of different Mo oxides together with NH4ReO4, along with its influence on the size distribution and phase composition of the resulting Mo-10Re pre-alloyed powders. The results show that MoO3 is more promising than MoO2 as a precursor material. The powders fabricated using MoO3, when compared to MoO2, have a much more uniform size distribution, with a primary particle size ranging from 0.5-4 μm. In addition, it is also beneficial to achieve atomic-scale homogeneous mixing with Mo and Re elements and the formation of a solely Mo(Re) solid solution if MoO3 is used as a precursor oxide. In contrast, such desirable features were not identified when using the MoO2 route. The reason for this discrepancy may relate to whether Mo-O-Re metallurgical bonding has formed during the co-reduction process.