Corrosion Resistance of Ti₃Al/BN Abradable Seal Coating

Feng Zhang^1,2，Hao Lan¹，Chuanbing Huang¹，Yang Zhou¹，Lingzhong Du¹，Weigang Zhang¹

1. State Key Laboratory of Multi-phase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences2. University of Chinese Academy of Sciences

摘 要：Ti–Al mixed powder（Ti:Al = 3:1 in atomic ratio） and Ti3 Al intermetallic alloy powder mechanically clad hexagonal BN to fabricate Ti Al/BN and Ti3Al/BN composite powders. The corresponding porous abradable seal coatings（named as TAC-1 and TAC-2, respectively） were deposited using vacuum plasma spray（VPS） technology, and their corrosion behavior was studied via salt spray corrosion and electrochemical tests. Phase compositions and microstructures of these coatings before and after corrosion were characterized by X-ray diffraction（XRD） and scanning electron microscopy（SEM） facilitated with energy dispersive X-ray spectrometer（EDS）. The results showed that spontaneous passivation of TAC-1 and TAC-2 granted the coatings excellent corrosion resistance than that of commercial Al/BN coating. Additionally, TAC-2 exhibited higher corrosion potential（Ecorr） and breakdown potential（Ebp） but a lower corrosion current density（icorr） than TAC-1. A small quantity of the corrosion product（Al（OH）3and Al O） could be detected on the surface of TAC-1, while no corrosion product appeared in TAC-2. The non-uniform elements distribution in the metal matrix of TAC-1 resulted in localized corrosion and relatively poor corrosion resistance compared to TAC-2.

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