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在铝酸钠电解液中利用等离子体电解氧化(PEO)技术对铸态A356合金进行处理制备耐磨、耐蚀涂层。采用3种不同浓度的铝酸钠溶液(2、16和24 g/L NaAlO_2)以及硅酸盐溶液(用以比较)制备涂层。利用球-块式干摩擦微动磨损试验(对磨材料为碳化钨)和电化学试验评价涂层的磨损和耐蚀性能。结果表明,在24 g/L NaAlO_2溶液中处理480 s形成的氧化膜涂层具有最佳的保护性能。该涂层在30 N载荷下摩擦1800 s,其磨损率仅约为~4.5×10~(-7) mm~3/(N·m)。同时,该涂层具有很低的腐蚀电流密度(约为8.81×10~(-9) A/cm~2)。该实验发现,尽管膜层中α-Al_2O_3含量很低,涂层的致密程度和单层结构保证了其优异的性能。
In the sodium aluminate electrolyte using plasma electrolytic oxidation (PEO) technology for processing the as-cast A356 alloy wear-resistant, corrosion-resistant coating. Coatings were prepared using 3 different concentrations of sodium aluminate solution (2, 16 and 24 g / L NaAlO 2) and silicate solutions (for comparison). Wear and corrosion resistance of the coating was evaluated using a ball-and-block dry friction fretting wear test (tungsten carbide for the worn material) and electrochemical tests. The results show that the oxide film coating formed by 480 s in 24 g / L NaAlO 2 solution has the best protection performance. The coating rubs at 1800 s for 30 s and its wear rate is only ~ 4.5 × 10 -7 mm 3 / (N · m). At the same time, the coating has a very low corrosion current density (about 8.81 × 10 -9 A / cm 2). The experiment found that, despite the low content of α-Al 2 O 3 in the coating, the denseness of the coating and the single-layer structure ensure its excellent properties.