Structure of Mo/Mo silicide composites infiltrated with molten Ni and subsequently compacted by HIP

Reactions during infiltration of Mo/Mo silicide wires with Ni and subsequent compaction with HIP were qualitatively assessed in this work. Intense reactions of Ni with Mo/Mo silicide composites were recorded. The extent of these reactions is determined by the amount of available Ni. If excessive Ni is available, Mo and Mo silicides are dissolved with detrimental effect on the composite structure. If less Ni is applied and the intimate contact of Ni with Mo/Mo silicides is shortened substantially, less intense reaction takes place providing the structure with MoSi2 laths crystallized in Ni2Si matrix and ternary MoNiSi appearing as intermediate phase between Mo5Si3 and Ni2Si matrix. HIP moves the system further to equilibrium. Additional diffusion leads to the growth of ternary MoNiSi phase on the cost of Ni2Si binary and Mo silicide phases. HIP improved the structural integrity of the Mo/Mo silicide/Ni composite, however, the oxidation resistance of newly formed phases should be further examined. K e y w o r d s: Mo silicides, infiltration, hot isostatic pressing, structural analysis