Oxidation features of sintered SiC composites deposited on E110 alloyat 1200 °c in air for fuel cladding studies

Abstract

Protective coatings are designed to reduce oxidation under extreme reactor temperature conditions. This study involves the application of a SiC coating on an E110 (Zr-1Nb) substrate in an atmosphere of air and argon by selective laser sintering (SLS) technique in which high-temperature oxidation test (HT-Ox) was performed on samples at a temperature of 1200 °C in air for 600 seconds. Calculated mass gained after HT-Ox test gave 34.6 mg/cm2, 31.1 mg/cm2, and 22.8 mg/cm2 for uncoated E110 alloy, SiC-E110 sintered in air and SiC-E110 sintered in an argon atmosphere respectively. X-ray diffraction (XRD) phase studies show the formation of more than 90% ZrO2 on the uncoated E110 alloy after HT-Ox. SiO2 and YAlO3 accounted for more than 50% of the oxides formed on the surfaces of samples coated with SiC after a HT-Ox test. Higher coating hardness's with lower indentation depths were consistently observed in the SiC coated specimen before and after HT-Ox tests proving stability in the coated samples while higher indentation depths and sudden quadrupling in hardness was recorded in E110 alloy before and after HT-Ox respectively. SiC coating on Zr-alloy plays a significant role in reducing oxidation, especially in coatings fabricated in an inert environment.