The transient oxidation behavior of magnetron-sputtered chromium-coated Zircaloy-4 was studied in steam up to 1600 °C, and the microstructural evolution of the coating-substrate system after oxidation was investigated. Coating failure and corresponding rapid oxidation of coating and substrate occurred at 1300–1400 °C. It was mainly caused by the thickness decrease of the outer dense Cr₂O₃ scale, the ZrCr eutectic reaction, the ZrCr interdiffusion, and the precipitation of ZrO₂ along unoxidized Cr grain boundaries. The phase transformation of tetragonal ZrO_2−x to cubic ZrO_2−y increased the oxidation rate of the Zircaloy-4 substrate at ~1500 °C through the higher oxygen diffusion coefficient in the cubic phase.

研究了磁控溅射镀铬 Zircaloy-4 在高达 1600 °C 的蒸汽中的瞬态氧化行为，并研究了氧化后涂层-基材系统的微观结构演变。涂层失效和相应的涂层和基材的快速氧化发生在 1300-1400°C。这主要是由于外部致密的Cr ₂ O ₃氧化皮厚度减小、Zr Cr 共晶反应、Zr Cr 相互扩散以及沿未氧化的Cr 晶界析出ZrO ₂造成的。四方ZrO _2−x到立方ZrO _2−y的相变 通过立方相中更高的氧扩散系数，提高了 Zircaloy-4 基材在 ~1500 °C 时的氧化速率。