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利用真空热天平、扫描电镜和X-射线衍射仪研究了Fe-15Cr和Fe-15Cr-0.3 Ce合金在1000和1100℃的氧化行为。结果表明,在Fe-15Cr合金表面,Cr_2O_3膜形成后不久便广泛变形、频繁开裂,使富铁氧化物瘤子不断产生。与此相应,氧化动力学曲线反复发生曲折,对抛物线产生正偏离。铈使Cr_2O_3膜变形,开裂和形成瘤子的倾向减小,产生较光滑的动力学曲线,较小的氧化速率。进一步的研究发现,铈促进Cr_2O_3膜的晶粒成为柱状晶,抑制在膜表面形成新氧化物,并绽膜中(1010)、(104)、(116)等晶面具有较强的择优取向。由此推断出铈具有阻止膜中铬离子扩散、减小膜的生长应力等作用。认为这是铈减轻膜发生变形和开裂的倾向,减小氧化速率的原因。
The oxidation behavior of Fe-15Cr and Fe-15Cr-0.3Ce alloy at 1000 and 1100 ℃ was studied by vacuum thermometry, scanning electron microscopy and X-ray diffraction. The results show that Cr 2 O 3 film deforms extensively and cracks frequently on the surface of Fe-15Cr alloy, which makes the iron rich oxide tumor continuously produce. Correspondingly, the oxidation kinetic curve repeatedly twists and turns, the positive deviation from the parabola. Cerium makes the Cr 2 O 3 film deform, the tendency of cracking and formation of neoplasms is reduced, resulting in a smoother kinetic curve and a smaller oxidation rate. Further study found that the cerium promoted the grain of Cr 2 O 3 film to become columnar grain and inhibited the formation of new oxide on the surface of the film, and the preferred orientation of (1010), (104), (116) and other crystal planes in the film was stronger. It is concluded that cerium has the function of preventing the diffusion of chromium ions in the film and reducing the growth stress of the film. This is thought to be the reason that cerium tends to reduce deformation and cracking of the film and reduce the oxidation rate.