2A97 Al-Cu-Li合金在鋁酸鹽和磷酸鹽電解液中等離子電解氧化膜的性能Properties of plasma electrolytic oxidation coatings formed on 2A97 Al-Cu-Li alloy using aluminate and phosphate electrolytes

采用交流雙脈沖電流制度對2A97 Al-Cu-Li合金分別在鋁酸鹽和磷酸鹽電解液中進行等離子電解氧化處理的研究，分析所得膜層的微觀結構和相組成，并采用電化學極化曲線和摩擦試驗對兩種電解液中所得膜層的耐腐蝕性能和耐磨性能進行評價。結果表明：在兩種電解液中所得膜層表面存在大量餅狀結構，膜層由內外兩層構成，兩層之間分布大量微孔，膜層的相組成主要為α、γ、δ-Al₂O₃，鋁酸鹽電解液中所得膜層有較多的α-Al₂O₃。磷酸鹽電解液中所得膜層的耐腐蝕性高于相應的鋁酸鹽中所得膜層的耐腐蝕性。磷酸鹽電解液中所得膜層具有較低的摩擦因數，與膜層中含有的P元素有關。然而，鋁酸鹽電解液中所得膜層具有更高的耐磨性，是因為鋁酸鹽膜層中含有更多硬度較高的α-Al₂O₃。

The plasma electrolytic oxidation of 2A97 Al-Cu-Li alloy was carried out by pulsed bipolar current regime, in aluminate and phosphate electrolytes, respectively. The microstructure and phase composition of the produced coatings were analyzed by SEM and XRD, and the corrosion and wear properties of the coatings from the two electrolytes were evaluated by electrochemical polarization curves and dry sliding wear tests. The results show that pancake structures dominate the surface of the coatings from both electrolytes, and the coatings consist of an inner and an outer layer in their cross sections, and there are large amount of big pores between the two layers. The main phase compositions of the coatings are α, γ, δ-Al₂O₃, however, higher amount of α-Al₂O₃ is found in the coating from aluminate electrolyte. The coating from phosphate electrolyte exhibits higher corrosion resistance than a similar coating from aluminate electrolyte. The coating from the phosphate electrolyte shows lower coefficient of friction, possibly due to the incorporation of P in the coating. However, the coating from the aluminate electrolyte has higher wear resistance because more α-Al₂O₃ is found in the coating from aluminate electrolyte.

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