The main chemical composition of Inconel 600 superalloy is (mass fraction, %): C0.069, Cr16.40, Al 0.14, Ti 0.16, Mn 0.37, Fe 9.80, and the rest is Ni. The alloy material was cut into 10 mm × 10 mm × 3 mm samples with WEDM, and then polished with 600-2000 mesh sandpaper. Soak the sample in a beaker filled with acetone, put it into an ultrasonic device for ultrasonic cleaning, and finally clean it with alcohol and dry it in an oven.
According to the HB 5258-1983 standard, the isothermal oxidation test was carried out on the Inconel 600 alloy. Place the treated sample in an Al2O3 crucible that has been pre-fired to constant weight, keep the sample in contact with the holding point (line) on the inner wall of the crucible, and cover the crucible in advance to avoid splashing of scale during high-temperature oxidation, which will affect the test results accuracy. The constant temperature test adopts a box-type heat treatment furnace, and the test temperatures are 900, 950 and 1000 °C respectively (the temperature control accuracy is ±5 °C). The oxidation weight gain of the alloy was determined by the static weight gain method, and the kinetic curve was drawn. After oxidation for a selected time (2.5, 12, 25, 50, 100 hours), the crucible was taken out, cooled to room temperature, and weighed on a DT-100 photoelectric analytical balance (error 0.01 mg). Three parallel samples were used at each test point.
After oxidation, the composition, phase distribution and morphology of the Inconel alloy 600 alloy oxide film were comprehensively analyzed using TESCAN MIRA3 field emission scanning electron microscope and its attached energy dispersive spectrometer, PANalytical X-ray diffractometer and Nordlys Max2 EBSD detector.
According to the test results, Figure 1 shows the isothermal oxidation kinetics curves of Inconel 600 alloy at 900 °C, 950 °C and 1 000 °C. At three different oxidation temperatures, the oxidation weight gain rate of the sample gradually slowed down as the oxidation time prolonged, and the higher the oxidation temperature, the faster the oxidation weight gain rate. The whole curve shows the rule that the slope changes from large to small with the prolongation of oxidation time. Under the same oxidation time, the oxidation temperature increases and the oxidation speed increases. After oxidation for 100 h, the average oxidation rates of Inconel 600 alloy at 900 °C, 950 °C and 1 000 °C were 0.065, 0.113 and 0.181 g/(m2·h), respectively. According to the HB 5258-2000 standard, Inconel 600 alloy is completely anti-oxidation below 900 °C, and it is anti-oxidation within the range of 950-1000 °C.