Insights into a novel refractory multi principal element alloy (Mo98W2)85Nb10(TiHf)5 and advancements in oxidation resistance upto 1300 °C through silicide coatings

Abstract

In the present work, a novel refractory multi-principal element alloy (Mo98W2)85Nb10(TiHf)5 was developed through comprehensive material testing, including high-temperature exposure and oxidation resistance assessments. It was found that after pack siliconizing, the samples could withstand high temperatures up to 1300 °C with a marginal weight change of 0.255 mg/cm2 during four hours holding time. The overall activation energy for the coating process was found to be 123 kJ/mol, which is a consequence of the decreased atomic mobility of silicon and other atoms to overcome sluggish diffusion phenomena. Minor addition of hafnium created a peg effect in the outer silica scale, which improved its oxidation resistance covering coating cracks. The findings of this research provide valuable insights into the potential applications of such alloys with silicide coatings in high-temperature environments, such as aerospace, energy, and high-temperature manufacturing processes.