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通过透射电镜对Fe-25％Cr-6％Al-RE(富镧)合金氧化行为进行研究.结果表明:经1200℃恒温2h纯氧中氧化,合金中镧以六方La_2O_3微小颗粒沉淀在氧化膜中α—Al_2O_3晶粒的顶端及晶界上。它们阻碍铝向表面扩散,抑制氧化膜的侧向生长;在1200℃/室温之间热循环氧化历程.稀土组元加快了合金的内氧化。它们以氧化铝、氧化镧形式出现,在靠近氧化膜/金属界面,立方La_2O_3颗粒平行于晶界并在合金基体上沉积。
The oxidation behavior of the Fe-25% Cr-6% Al-RE (La-rich) alloy was investigated by transmission electron microscopy.The results show that lanthanum is precipitated on the oxide film by hexagonal La 2 O 3 fine particles after being oxidized in pure oxygen at 1200 ℃ for 2h, In α-Al_2O_3 grain top and grain boundaries. They impede the diffusion of aluminum to the surface, inhibit the lateral growth of the oxide film, and thermally cycle the oxidation at 1200 ℃ / room temperature.The rare earth elements accelerate the internal oxidation of the alloy. They appear in the form of aluminum oxide and lanthanum oxide. In the vicinity of the oxide film / metal interface, the cubic La 2 O 3 particles are parallel to the grain boundaries and deposited on the alloy matrix.