Escudero M L, González-Carrasco J L, García-Alonso C, Ramírez E
Centro Nacional de Investigaciones Metalúrgicas, C.S.I.C., Madrid, Spain.
Biomaterials. 1995 Jun;16(9):735-40. doi: 10.1016/0142-9612(95)99703-o.
Preoxidation treatment of MA 956 superalloy at 1100 degrees C produces a fine and tightly adherent alpha-alumina layer at the surface, which provides the alloy with an excellent barrier against a great variety of aggressive environments. In this work the protective capacity of the alumina/alloy system is evaluated in a physiological medium by means of electrochemical impedance spectroscopy. The electrochemical response of the material is modelled by equivalent circuits which provide the most relevant corrosion and protection parameters applicable to MA 956 in both preoxidized and as-received conditions (passivated state). The high protective capacity of preoxidized MA 956 superalloy holds for long-term tests, which indicates that the corrosion phenomena, if any, would be characterized by very slow kinetics. The corrosion resistance of the preoxidized material is at least two orders of magnitude higher than that of the non-treated alloy.
MA 956高温合金在1100℃下进行预氧化处理，会在表面生成一层细小且紧密附着的α-氧化铝层，这为该合金提供了优异的屏障，使其能抵御多种侵蚀性环境。在本研究中，通过电化学阻抗谱在生理介质中评估了氧化铝/合金体系的防护能力。材料的电化学响应通过等效电路进行建模，该等效电路提供了适用于预氧化和原始状态（钝化状态）的MA 956的最相关腐蚀和防护参数。预氧化的MA 956高温合金在长期测试中具有很高的防护能力，这表明如果存在腐蚀现象，其特征将是动力学非常缓慢。预氧化材料的耐腐蚀性比未处理合金至少高两个数量级。
