Study on behavior of NiAl coating with different Ni/Al ratios

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• 作者：Qiong Wu ^{queong@126.com queong@gmail.com} ; Shusuo Li ; Yue Ma ; Shengkai Gong ; ^{gongsk@buaa.edu.cn}
• 关键词：Nickel aluminide ; Bond coat ; DC magnetron sputtering ; Diffusion ; Superalloy ; Microstructure
• 刊名：Vacuum
• 出版年：2013
• 出版时间：July, 2013
• 年：2013
• 卷：93
• 期：Complete
• 页码：37-44
• 全文大小：2255 K

文摘

¦Â-NiAl coatings with different Ni/Al ratios were deposited on K403 superalloy substrates via magnetron sputtering. The phase transformation and diffusion phenomenon of the NiAl/Ni-based superalloy system after vacuum annealing at 900 and 1000?¡ãC were analyzed using X-Ray diffraction (XRD), field emission scanning electron microscope (FE-SEM) and energy dispersive X-ray spectrometry (EDS). The effect of coating concentrations on the outward diffusion behavior of substrate elements was discussed. The high Cr concentrations in the Al-rich NiAl coatings were caused by the intense interdiffusion between Al and Cr. The Ti, W and Mo partitioned to ¦Ã¡ä-Ni₃Al in the coatings. Several possible reasons for the formation of ¦Ã¡ä-Ni₃Al at the surface of Ni-rich NiAl coating were identified, including: diffusion behavior of W and Mo in ¦Â-NiAl, destabilizing effect of substrate elements on ¦Â-NiAl, and diffusion rates of Ni and Al in ¦Â-NiAl. The volume change in ¦Â???¦Ã¡ä transformation process shows Ni uphill diffused to the ¦Ã¡ä-Ni₃Al islands at the surface of Ni-rich NiAl coatings. The IDZ (interdiffusion zone) thickness and precipitates in IDZ were related to the Al initial concentrations in the coatings.