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采用连续氧化和非连续氧化两种方式,对比研究了Fe_3Al在800～1200℃空气中的氧化规律和机制。分析了Fe_3Al在非连续氧化过程中发生Pest的机制。首次发现了Fe_3Al在1000℃氧化/硫化环境中的灾难性腐蚀现象,提出了提高Fe_3Al抗高温氧化/硫化的关键在于促进合金中Al的扩散,避免基体中严重贫Al区的形成;促进Al选择氧化,提高氧化膜的塑性和粘附性。 研究了电沉积-反应烧结氧化物薄膜改善合金的抗氧化性能和氧化膜的粘附性的机制。离子注入Y改善了氧化膜的粘附性,提高了Fe_3Al的抗高温氧化性能;但同时促进了S向氧化膜/基体界面的扩散,因而不能有效地提高Fe_3Al的抗高温氧化/硫化性能。包埋渗Al改善了基体自愈氧化膜的能力,提高了Fe_3Al的抗高温腐蚀性能,但存在氧化膜不致密、易脱落等缺点。首次应用高能量密度等离子体对Fe_3Al进行了微晶化处理,发现表面微晶化后氧化形成了塑性和粘附性皆极佳的微晶氧化膜,使Fe_3Al在高温氧化/硫化环境中的抗腐蚀性可与在空气中的抗氧化性相媲美。指出了在不同文献中对晶粒细化的作用得出相反结论的原因。提出了晶粒度等级影响氧化膜性质的新机制。首次提出微晶合金氧化动力学应服从四次方规律,导出了相应的公式,并得到实验结果的一致验证。
Continuous oxidation and discontinuous oxidation were used to study the oxidation mechanism and mechanism of Fe 3 Al in air at 800 ~ 1200 ℃. The mechanism of Pest in the non-continuous oxidation of Fe 3 Al was analyzed. For the first time, the catastrophic corrosion of Fe_3Al in an oxidation / sulfidation at 1000 ℃ was first observed. The key to improve the oxidation / sulfidation of Fe_3Al was to promote the diffusion of Al in the alloy and avoid the formation of severely depleted Al in the matrix. Oxidation, improve the plasticity of the oxide film and adhesion. The mechanism of the electrodeposition - reaction sintering oxide film to improve the oxidation resistance of the alloy and the adhesion of the oxide film was studied. Ion-implanted Y improved the adhesion of the oxide film and improved the high-temperature oxidation resistance of Fe 3 Al. However, the diffusion of S into the oxide film / matrix interface was promoted at the same time, and thus the high temperature oxidation / curing performance of Fe 3 Al could not be effectively improved. The infiltration of Al improves the ability of the matrix to self-heal the oxide film and improves the high-temperature corrosion resistance of Fe_3Al, but there is a defect that the oxide film is not dense and easily peeled off. For the first time, high energy density plasma was used to micro-crystallize Fe 3 Al. It was found that the micro-crystallized oxide film with excellent plasticity and adhesion was formed after the micro-crystallization of the surface and the oxidation resistance of Fe 3 Al in high temperature oxidation / Corrosivity is comparable to the oxidation resistance in the air. The reasons why the effect of grain refinement in different literatures draw the opposite conclusion are pointed out. A new mechanism of grain size grade affecting the properties of oxide films was proposed. It is first proposed that the oxidation kinetics of the microcrystalline alloy should obey the law of the fourth power and the corresponding formulas have been derived and the experimental results have been verified.