Surface and interface segregation in the oxidation of metals
Surface and interface segregation in the oxidation of metals
复制标题
金属氧化中的表面和界面偏析
DOI：
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发表时间：
2000
期刊：
影响因子：
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通讯作者：
H. Grabke
中科院分区：
文献类型：
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作者：
H. Grabke
为了保护高温合金免受腐蚀，必须形成一层生长缓慢、致密、附着力良好的氧化膜。在高温下，铬(Cr2O_3)或氧化铝(Al_2O_3)都能起到保护膜的作用。本文主要用俄歇电子能谱研究了氧化膜成核、生长和附着过程中的表面和界面现象，描述了这些现象，并对其机理进行了讨论。反应元素(Ce，Y，La，Ti，Zr…)的合金化对形核、生长和粘结起到了积极的作用。在很小的浓度下。在氧化物生长机制中，它们以氧化态作用，在氧化物成核过程中偏析在金属表面，在氧化物晶界中偏析。氮和碳等非金属元素通过与铬的中间共偏析促进了Cr2 O3的形核，而硫则阻碍了Cr2 O3的形成。硫在金属/氧化物界面形成的空洞和裂纹表面的偏析使结垢性能恶化。有害的硫可以在反应元素(氧化物和硫氧化物)形成的沉淀物及其界面上被清除。
For the protection of high-temperature alloys against corrosion, a slowly growing, dense, well-adherent scale must be formed. At elevated to high temperatures either chromia (Cr 2 O 3 ) or alumina (Al 2 O 3 ) can act as such a protective scale. Surface and interface phenomena in the nucleation, growth and adherence of oxide scales have been studied, mainly by AES; these phenomena are described and their mechanisms are discussed. Various positive effects on nucleation, growth and adherence are exerted by alloying with reactive elements (i.e. Ce, Y, La, Ti, Zr ...) in small concentrations. They are acting in their oxidized state, segregated on the metal surface in oxide nucleation and segregated in oxide grain boundaries in the oxide growth mechanism. Non-metal elements such as nitrogen and carbon can enhance Cr 2 O 3 nucleation by intermediate co-segregation with chromium, in contrast sulphur impedes chromia formation. Segregation of sulphur to the surface of voids and cracks forming at the metal/oxide interface deteriorates the scale adherence. The detrimental sulphur can be scavenged in precipitates formed by the reactive elements (oxides and oxysulphides) and at their interfaces.