Zirconium-silicide coating on zircaloy-4 substrate for accident tolerance: Effects on oxidation resistance and boiling

Abstract In this research, the cladding substrate, Zircaloy-4 was coated with a 3-μm zirconium silicide (ZrSi 2 ). At 700 °C in air, the ZrSi 2 coating prevented thermal oxidation and thereby protected the underlying Zicaloy-4 substrate. In contrast, uncoated Zircaloy-4 surface developed an oxide layer that was a few micrometers thick. To investigate the effects of the coating on boiling characteristics, a pool-boiling experiment with saturated water, and a Leidenfrost experiment at low Weber number were conducted under atmospheric pressure. Thermal oxidation of the ZrSi 2 -coated surface did not affect critical heat flux or Leidenfrost temperature, but thermal oxidation of the uncoated Zircaloy-4 substrate affected its boiling parameters. A thin ZrSi 2 coating can be applied easily to a Zircaloy-4 substrate, and may be considered for use in nuclear reactors.