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在热分析仪上采用增重法对稀土含量不同的低合金钢进行抗高温氧化实验,利用扫描电镜(SEM)进行氧化形貌观察。结果表明,温度为1050℃和1150℃时,恒温氧化动力学均符合抛物线规律,氧化膜具有保护性,稀土含量为0.0134%和0.0095%的低合金钢氧化反应激活能比不含稀土的低合金钢分别提高了71%和57%。在1050℃时稀土含量为0.0134%和0.0095%的低合金钢氧化速率常数比不含稀土的低合金钢降低了30%和20%,在1150℃时降低了7%和3%。稀土的添加提高了低合金钢的反应激活能,降低了氧化速率常数,提高低合金钢的抗高温氧化性能,并且稀土含量越高,抗高温氧化性能越强;在1250℃时生成的氧化膜保护性差,含稀土的钢氧化速率快,不利于提高低合金钢的抗氧化性。稀土的加入细化了氧化膜的晶粒,增强了氧化膜与基体的粘附性,使氧化膜不易脱落。
Adopting the weight gain method on the thermal analyzer, the low-alloy steel with different RE content was subjected to high temperature oxidation test, and the oxidation morphology was observed by scanning electron microscopy (SEM). The results show that the oxidation kinetics at constant temperature of 1050 ℃ and 1150 ℃ are in accordance with the law of parabola, and the oxide film is protective. The activation energy of the low alloy steel with 0.0134% and 0.0095% rare earths is lower than that of the low alloy without rare earth Steel increased 71% and 57% respectively. The oxidation rate constants of low alloyed steels with RE contents of 0.0134% and 0.0095% at 1050 ℃ are reduced by 30% and 20%, respectively, and are reduced by 7% and 3% at 1150 ℃ respectively. The addition of rare earth increases the reaction activation energy of low alloyed steel, decreases the oxidation rate constant and improves the high temperature oxidation resistance of low alloyed steel. The higher the content of rare earth is, the stronger the high temperature oxidation resistance is. The oxide film formed at 1250 ℃ Poor protection, rare earth-containing steel oxidation rate is not conducive to improving the oxidation resistance of low-alloy steel. The addition of rare earth grain refinement of the oxide film, enhanced adhesion of the oxide film and the matrix, the oxide film is not easy to fall off.