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在1350℃快速寿命试验过程中,Fe-23Cr-6Al合金中的铝减少到约1wt％时,氧化皮形成许多富铁的氧化物瘤子,瘤子迅速长大使试验丝烧断。添加0.15wt％La、0.15wt％Ce或0.60wt％Y使合金中铝的消耗速度减小,寿命提高4～6倍。含稀土合金的a-Al_2O_3氧化皮不形成隆起,因而其粘附性极好,合金的氧化速度不因温度循环变化而加快。无隆起的氧化皮不易发生破裂和形成瘤子,这使合金的恒温氧化速度也被减小。此外,保护性良好的氧化皮还阻止空气中的氮进入合金形成AlN。这些是含稀土合金铝耗缓慢的原因。高温氧化时稀土形成内氧化物,在初期氧化膜中有稀土的富集。
During the rapid life test at 1350 ° C, the scale formed in the Fe-23Cr-6Al alloy decreased to about 1 wt%, and the scale formed many iron-rich oxide neoplasms. The rapid growth of the neighbors ruptured the test wire. Addition of 0.15wt% La, 0.15wt% Ce or 0.60wt% Y reduced the consumption rate of aluminum in the alloy by 4-6 times. The a-Al 2 O 3 scale with rare earth alloy does not form a bulge, so its adhesion is excellent, the oxidation rate of the alloy is not accelerated by the temperature cycling. No uplift of the scale is not easy to rupture and the formation of tumor, which makes the alloy thermostat oxidation rate is also reduced. In addition, a well-protected scale also blocks nitrogen in the air from entering the alloy to form AlN. These are the reasons for the slow depletion of aluminum with rare earth alloys. Rare earth oxides formed during high temperature oxidation, rare earth enrichment in the initial oxide film.