Tailoring the Composition and Structure of Nb-, Si-, and B-Doped Mo-Based Composite Materials in the Self-Propagating High-Temperature Synthesis Metallurgy Process

Abstract

We have examined for the first time the feasibility of producing cast Nb-, Si-, and B-doped Mo-based composite materials by a spin-casting self-propagating high-temperature synthesis metallurgy method and obtained new results regarding control over their composition and structure. In synthesis, we used combinations of a highly exothermic (MoO3/Nb2O5/Al/Si/B) and a low-exothermic (Mo/Nb/Si/B) composition. We have assessed the effect of the ratio of the ratio of the highly exothermic and low-exothermic compositions (α) and acceleration (a) on the composition and structure of the cast composite materials. The mixtures have been shown to be capable of combustion at up to 80% low-exothermic composition. The combustion products have cast form in the range 0 ≤ α ≤ 65%. At α in the range from 0 to 40% and accelerations from 40g to 400g, the combustion products have the form of a two-layer ingot: the lower layer (Mo–Nb–Si–B) consists of the required product and the upper layer (Al2O3) is a slag product. The optimal parameters for the preparation of cast Mo–Nb–Si–B materials are α = 20–30% and a > 100g.