Effects of Y₂O₃ on the microstructures and wear resistance of Si-Al-Y co-deposition coatings prepared on Ti-Al alloy by pack cementation technique

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• 作者：Yongquan Li ; Faqin Xie ; Xiangqing Wu ; Xuan Li
• 关键词：Ti&ndash ; Al alloy ; Si&ndash ; Al&ndash ; Y co-deposition coating ; Y2O3 ; Coating structure ; High temperature wear resistance
• 刊名：Applied Surface Science
• 出版年：15 December, 2013
• 年：2013
• 卷：287
• 期：Complete
• 页码：30-36
• 全文大小：3101 K

文摘

Si-Al-Y co-deposition coatings were prepared on a Ti-Al alloy by pack cementation process at 1050 for 4 h. The effects of pack Y₂O₃ content (from 0 to 5 wt%) on the microstructure and constituent phases of the co-deposition coatings were studied, the wear resistance of the substrate and the coated specimens were also compared at 600 掳C in air. The results showed that the pack Y₂O₃ content imposed strong influences on both coating structures and phase constituents. The coatings prepared with the pack mixtures containing 1 and 2 wt% Y₂O₃ were composed of an TiSi₂ out layer, an (Ti, X)₅Si₄ and (Ti, X)₅Si₃(X represents Nb and Cr)middle layer, an TiAl₂ inner layer and an Al-rich interdiffusion zone. However, the constituent phases changed into TiSi₂,(Ti, X)₅Si₄ and (Ti, X)₅Si₃ in the out layer of the coating prepared with the pack mixture containing 3 wt% Y₂O₃. Moreover, (Ti, X)₅Si₄ and (Ti, X)₅Si₃ phases were observed in the outer layers of the coatings prepared with the pack mixtures containing 0 and 5 wt% Y₂O₃. The coating growth could be catalyzed obviously when the content of Y₂O₃ in the pack mixtures increased from 1 to 2 wt%, but this phenomenon was not observed when further increased the pack Y₂O₃ content to 3 or 5 wt%. Si-Al-Y co-deposition treatment improved the surface hardness and wears resistance of the Ti-Al alloy significantly. The wear resistance of the tested samples could be sorted in the following sequence: 1% Y₂O₃-coating > no RE-coating > bare Ti-Al alloy.