Low temperature Type II hot corrosion is a serious problem for low cycle fatigue (LCF) failure of advanced turbine disk alloys operating at increased temperatures. Accordingly, the present effort studied 15–20 µm corrosion resistant Cr₂AlC sputter coatings on Low Solvus High Refractory (LSHR) disk alloy LCF test specimens. These were cycled to failure at 840/−430 MPa and 0.33 Hz, after 500 h oxidation and 50 h of Mg-Na₂SO₄ hot salt corrosion, all at 760 °C. The coating successfully prevented hot corrosion pitting that was responsible for a 90% decrease in uncoated LCF specimens. However, fractography identified unintentional 15–30 µm deep defects produced by grit blast surface preparation of coated samples. These acted as failure origins and introduced anomalous life reduction for some coated test specimens. Furthermore, the presence and growth of an undesirable Cr₇C₃ second phase diminished protectiveness by promoting internal oxidation and embrittlement of the coating.

低温II型热腐蚀是在高温下运行的先进涡轮盘合金低循环疲劳（LCF）失效的严重问题。因此，目前的研究工作是在低溶剂高耐火性（LSHR）圆盘合金LCF测试样品上研究15–20 µm的耐腐蚀Cr ₂ AlC溅射涂层。经过500 h氧化和50 h Mg-Na ₂ SO ₄循环，它们在840 / -430 MPa和0.33 Hz下循环失效。全部在760°C下进行热盐腐蚀。涂层成功地防止了热腐蚀点蚀，这导致未涂覆的LCF试样减少了90％。但是，断层扫描发现涂层样品的喷砂表面处理产生了意外的15–30 µm的深层缺陷。这些充当了故障的根源，并导致某些涂层测试样品的异常寿命降低。此外，不期望的Cr ₇ C ₃第二相的存在和生长通过促进涂层的内部氧化和脆化而降低了保护性。