无机熔盐镀铝层的制备与性能研究

利用AlCl3-NaCl-KCl三元无机熔盐体系在Q235低碳钢基体上进行了镀铝试验,并就不同电镀工艺对铝镀层表面 形貌、厚度、结构、结合力及耐蚀性能等进行了研究。结果表明,AlCl3-NaCl-KCl无机熔盐体系镀铝层为银白色,并呈现均 匀、细小的针片状生长特征。铝镀层的厚度随电流密度和电镀时间的增加而增大;在低电流密度下,铝镀层主要由(200)面 结构组成;在高电流密度下,铝镀层易形成(111)面的结构。铝镀层与碳钢基体问的结合力随镀层厚度的增加而减少,但均 大于30 N。在3．5％NaCl的水溶液中,铝镀层具有较好的耐蚀性能。铝镀层的最佳工艺为电流密度3．3-4．0 A/dm2,电镀时间 45-90 min。

Preparation and properties of aluminum coating electroplated by inorganic molten salts

Aluminum electroplating on Q235 carbon steel from AlCl3-NaCl-KCl inorganic molten salt was carried out, and the surface morphology, thickness, structure, adhesion and corrosion resistance of aluminum coating were observed and determined. The results show that the aluminum coating on Q235 carbon steel deposited from AlCl3-NaCl-KCl inorganic molten salt is gray, smooth, uniform and with small needle-like or granular characters. The thickness of aluminum coating increases obviously with the increasing of current density and prolongation of electroplating time. At lower current density, (200) plane structure is reliable to be formed in the coating, but the aluminum coating is in (111) plane structure under higher current density. The adhesion of aluminum coating with the substrate decreases with the coating thickness, but greater than 30 N. The aluminum coating has a very higher corrosion resistance in 3.5% NaCl aqueous solution under the optimum current density of 3.3~4.0 A/dm2 and electroplating time of 45-90 minutes.