Ultra-high temperature oxidation resistance of a novel (Mo, Hf, W, Ti)Si2 ceramic coating with Nb interlayer on Ta substrate

In order to solve the challenge of recyclability of tantalum substrates in high temperature oxidation environments, a novel MoSi2-WSi2-HfSi2-TiSi2 composite ceramic coating containing an Nb interlayer was prepared on the surface of tantalum substrate by a three-step method. The mix ceramic silicide coating exhibited superior performance and effective protection for 10.2 hat 1800 degrees C, possibly due to the formation of an outer SiO2-HfO2-HfSiO4 composite oxide film with low oxygen permeability, moderate viscosity and thermal expansion coefficient, as well as good self-healing ability. Furthermore, the coating successfully passed 537 thermal cycles from room temperature to 1800 degrees C. The presence of Nb interlayer significantly mitigated the thermal mismatch between the ceramic coating and the tantalum substrate, and the bidirectional diffusion of Nb element during the high temperature oxidation and thermal shock process further reduced the tendency of the coating to crack.

Automated summary

A novel composite ceramic coating was prepared on tantalum substrate using a three-step method to address the challenge of recyclability in high temperature oxidation environments. The coating exhibited superior performance and effective protection, possibly due to the formation of a composite oxide film with low oxygen permeability, moderate viscosity, thermal expansion coefficient, and good self-healing ability. The presence of an Nb interlayer mitigated thermal mismatch and reduced coating cracking.