| 摘要: |
| 为研究Co改性铝化物涂层在室温环境中的耐蚀性，利用包埋法渗Co和气相沉积渗Al（两步法）制备出两种不同Co含量的Co改性铝化物涂层，采用XRD、SEM、EDS分析涂层的组织结构。结果表明： 850 ℃和1 000 ℃渗Co涂层外层和内层均为γ(Ni, Co)相，内层有氮化物/碳化物相析出。Co改性铝化物涂层与简单NiAl涂层结构一致，外层为β(Co, Ni)Al相，内层为互扩散区含有大量的富Cr(W)相。简单NiAl涂层的自腐蚀电流为0.04 μA/cm2，约为Co改性铝化物涂层的十分之一。这说明在涂层中添加Co降低涂层的耐蚀性，一方面因为Co的腐蚀电位（－0.28 V）低于Ni的腐蚀电位（－0.25 V），另一方面因为渗Co过程中产生的夹杂物与涂层电位不一致，容易成为微阴极区，加速涂层的腐蚀。 |
| 关键词: 镍基高温合金 铝化物涂层 渗Co 组织结构 电化学 |
| DOI：10.11933/j.issn.1007-9289.2015.05.018 |
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| 基金项目: |
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| Microstructure and Corrosion Behavior of Co Modified Aluminide Coatings on Ni-based Superalloy |
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FAN Qixiang, WANG Tiegang, LIU Yanmei, JIANG Sumeng, GONG Jun, SUN Chao1,2
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1a. College of Mechanical Engineering, 1b. Tianjin Key Laboratory of High Speed Cutting and Precision Machining, Tianjin University of Technology and Education;2. Division of Materials Surface and Engineering, Institute of Metal Research, Chinese Academy of Sciences
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| Abstract: |
| To investigate the corrosion resistance of the Co modified aluminide coatings, two Co modified aluminide coatings with different Co contents were prepared by a twostep process first depositing Co by pack cementation and then aluminizing by chemical vapour deposition. XRD, SEM and EDS were used to analye the composition and microstructure of the coatings. The results show that both the outer and inner layers of the Co coating deposited at 850 ℃ and 1 000 ℃ are γ(Ni, Co) phase, with some nitrides/carbides dispersed in the inter layer. The Co modified aluminide coatings have similar structure with the simple aluminide coatings. The outer layer is β(Co, Ni)Al phase, and the inner layer is the interdiffusion zone abundant with Cr(W) rich phases. The corrosion current of the simple auminide coating is 0.04 μA/cm2, which is nearly one tenth of the two Co modified aluminide coatings. This demonsteates that the addition of Co decreases the corrosion resistance of the simple aluminide coating. On the one hand, it is because the corrosion potential of Co (－0.28 V) is lower than that of Ni (－0.25 V), on the other hand, the corrosion potential of the inclusions produced during the deposition of Co differs from that of the coating, thus tends to be negative polarity microarea, accelerating the corrosion of coating. |
| Key words: Ni-based superalloy aluminide coating deposition of Co microstructure electro-chemical |
