Diffusion Interaction of Molybdenum Silicides with E110 Alloy

The kinetics of the diffusion interaction of a hypereutectic alloy of molybdenum silicides Mo5Si3 + MoSi2 with a reactor alloy of E110 grade based on zirconium is experimentally investigated. The structural and phase states of diffusion pairs subjected to vacuum annealing at 1100, 1200, and 1300°C for 3, 6, and 9 h are studied by scanning electron microscopy and energy-dispersive X-ray spectral microanalysis. In the entire investigated temperature range and for all exposures, zirconium silicides are formed due to diffusion interaction at the interface between the alloys of molybdenum and zirconium silicides. The silicon-transfer process is the primary diffusion process in the interaction of an alloy based on zirconium and molybdenum silicides. No signs of zirconium diffusion into molybdenum silicides are found, and the diffusion of molybdenum into zirconium is significantly limited. The features of the structure and chemical composition of the silicide phases formed in the region of diffusion interaction are revealed. A comparative analysis of the regions of diffusion interaction of silicides Mo5Si3 and MoSi2 with a zirconium alloy is carried out. The effective kinetic parameters of the processes of diffusion interaction at different temperatures, as well as the parameters of the temperature dependence of the effective parabolic constant of growth of the layer of intermediate phases arising during the annealing of diffusion pairs, are determined.