铝酸钠电解液中利用等离子体电解氧化技术在铸态A356铝合金表面制备高耐磨、耐蚀涂层（英文）

Wear and corrosion resistant coatings on surface of cast A356 aluminum alloy by plasma electrolytic oxidation in moderately concentrated aluminate electrolytes

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。

Plasma electrolytic oxidation of a cast A356 aluminum alloy was carried out in aluminate electrolytes to develop wear and corrosion resistant coatings. Different concentrations of 2, 16 and 24 g/L NaAlO2 solutions and a silicate electrolyte （for comparison） were employed for the investigation. Wear performance and corrosion resistance of the coatings were evaluated by WC （tungsten carbide） ball-on-flat dry sliding tests and electrochemical methods, respectively. The results show that the coating formed for a short duration of 480 s in 24 g/L NaAlO2 solution generated the best protection. The coating sustained 30 N load for sliding time of 1800 s, showing very low wear rate of -4.5×10^-7 mm3/（N· m）. A low corrosion current density of -8.81×10^-9 A/cm2 was also recorded. Despite low α-Al2O3 content of the coating, the compact and nearly single layer nature of the coating guaranteed the excellent performances.