材料期刊网

观察分析了不同稀土添加量高铬铸铁的铸态微观组织；通过对不同氧化温度和保温时间下不同稀土添加量的高铬铸铁高温氧化过程的对比，探讨了含稀土高铬铸铁抗高温氧化机制。研究结果表明：随着稀土元素的加入，高铬铸铁组织中晶粒得到了明显细化，碳化物形状发生了变化；高铬铸铁单位面积上氧化增重随时间变化遵循抛物线规律；稀土质量分数为0％～0．3％时，高铬铸铁的抗高温氧化性随着稀土含量的增加而提高，但当稀土质量分数超过0．3％，其抗高温氧化性降低。含稀土高铬铸铁抗高温氧化机制：在高温阶段，扩散主体从阳离子逐渐转变为阴离子，减缓了氧化膜的生长速度，抑制应力的产生，从而阻止了氧化膜起皱，有效地防止裂纹。

The cast microstructure of high chromium cast iron with different RE adding was analyzed. According to the comparison of experiment results under variable conditions （different oxidation-temperature, duration of holding time and kinds of RE）, the mechanism of oxidation resistance of high chromium cast iron at high-temperature was discussed. It can be concluded that the grain is refined and the shape of carbide is changed; the oxidation weight （per area） changes over time following the rule of a parabola; the oxidation resistance of high chromium cast iron at high-temperature is improved as the quality percentage of RE （below 0.3 %） is increased, while oxidation resistance of high chromium cast iron is reduced as the quality percentage of RE exceeds 0.3%. The mechanism of oxidation resistance of high chromium cast iron adding RE at high-temperature is as follows： as the majority of the diffusion is gradually transformed from positive ion to negative ion, it can slow down the growth rate of the oxidation-film; since the appearance of the stress is restrained, oxidation-film wrinkles and cracks are effectively prevented.