Hydrogen Sorption Kinetics of SiC-Coated Zr-1Nb Alloy

Abstract

This paper describes the influence of silicon carbide (SiC) coating on hydrogen sorption kinetics of zirconium alloy E110 (Zr-1Nb). Amorphous SiC coating of 1.5-μm thickness was deposited on Zr-1Nb alloy substrate by direct current magnetron sputtering of composite cathode. Hydrogen absorption by SiC-coated Zr-1Nb alloy significantly decreased due to low hydrogen permeability of the coating. Hydrogenation tests show that SiC coating provides protective properties against hydrogen permeation in the investigated temperature range of 350–450 °C. It was shown that hydrogenation of uncoated Zr-1Nb leads to formation of δ hydrides at 350 °C and δ and γ hydrides at higher temperatures whereas in the SiC-coated Zr-1Nb alloy only δ hydrides formed. Gradient hydrogen distribution through the SiC coating and H trapping in the carbon-rich interface was observed. The adhesion strength of the coating was ~5 N. Hydrogenation up to 450 °C for 5 h does not degrade the adhesion properties during scratch testing.