AlFeCoCrNi高熵合金之高溫氧化

High Temperature Oxidation of High-entropy Alloy AlFeCoCrNi

本研究探討AlFeCoCrNi高熵合金（AFCCN）在850 ~ 1050℃之空氣氧化行為。整體而言，此合金在850 ~ 950℃之氧化動力學皆遵守拋物線律，且氧化速率常數（kp）在850 ~ 950℃間幾乎相似，但在1050℃時有加速氧化之趨勢。由顯微結構分析得知，在850℃時AFCCN主要是θ-Al2O3，而在950℃時主要生成α-Al2O3；但拉長氧化時間至720 h後，850及950℃會生成些微spinel （FeCr2O4）層。而在1050℃氧化後，合金的氧化層主要生成spinel（FeCr2O4），並使α-Al2O3層嚴重剝落。

The oxidation behavior of the high-entropy AlFeCoCrNi alloy (AFCCN) was studied over the temperature range of 850 ~ 1050 ℃ in dry air. In general, the oxidation kinetics (kp) of the alloy followed the parabolic-rate law at 850 ~ 950 ℃, however having the nearly identical oxidation rate constants at both temperature. On the other hand, the breakaway kinetics was observed at 1050 ℃. The scales formed on the AFCCN alloy consisted mostly of θ-Al2O3 at 850 ℃, while mostly α-Al2O3 formed at 950 ℃. However the scales formed a few amount of spinel at 850 ~ 950 ℃ for 720 h. The scales formed at 1050 ℃ consisted mostly of FeCr2O4 spinel, resulting in a loss of the integrity of α-Al2O3.