铁基粉末冶金零件电镀前二次水基防锈溶液的封孔技术研究

发布时间：2018-04-05 12:44

本文选题：铁基粉末冶金零件　切入点：水基防锈溶液　出处：《表面技术》2017年04期

【摘要】：目的铁基粉末冶金零件具有特殊的疏松和多孔结构,在前处理、电镀、钝化等过程中易造成零件孔隙的酸、碱、盐等残留,镀后零件在使用过程中也易出现耐腐蚀性能下降或镀层脱落的现象。因此,对铁基粉末冶金零件孔隙进行封闭是一种提高镀层防腐蚀性能和结合性能的有效方法。方法采用一种专用的粉末冶金零件水基防锈封闭溶液,对零件孔隙进行前处理前的第一次封闭和前处理后的第二次封闭。其孔隙封闭原理是在镀前处理前,利用水基防锈溶液中的缓蚀剂、钝化剂等成分的扩散、渗透,在孔隙处发生吸附、钝化及沉淀等反应,来减轻或避免前处理过程中接触到的酸、碱等成分在孔隙的残留;再在电镀前处理后,进行第二次防锈水溶液的封闭处理,可进一步强化粉末冶金零件的钝化封闭效果。结果没有经过防锈水溶液封闭处理的白钝化锌镍合金镀层(滚镀零件),在96 h盐雾试验后,表面出现了轻微的腐蚀;经过一次防锈水溶液封闭处理的锌镍合金镀层,在120 h后出现了轻微的腐蚀;经过二次防锈水溶液封闭处理的锌镍合金镀层,在240 h后未出现腐蚀。结论粉末冶金零件经过这二次封闭处理,再进行电镀Zn-Ni合金及镀层钝化处理,可以有效提高零件表面镀层的耐腐蚀性能和结合性能。
[Abstract]:Objective Iron based powder metallurgy parts have special porous and porous structure, which can easily lead to the residue of acid, alkali and salt in the process of pretreatment, electroplating and passivation.The corrosion resistance of the parts after plating is also decreased or the coating falls off.Therefore, sealing the pores of iron-based powder metallurgy parts is an effective method to improve the corrosion resistance and bonding property of the coating.Methods A special water-based anti-rust sealing solution for powder metallurgy parts was used to seal the pores for the first time before pretreatment and the second time after pretreatment.The principle of pore sealing is to make use of the diffusion, permeation, adsorption, passivation and precipitation of corrosion inhibitor, passivator and other components in water-based antirust solution before plating.In order to reduce or avoid the residue of acid, alkali and other components in the pores in the process of pretreatment, the passivation and sealing effect of powder metallurgy parts can be further strengthened by the second anti-rust aqueous solution sealing treatment after electroplating.Results after 96 h salt spray test, the surface of white passivated Zn-Ni alloy coating was slightly corroded after 96 h salt spray test, and that of Zn-Ni alloy coating was sealed by one antirust aqueous solution.There was slight corrosion after 120 h, but no corrosion occurred after 240 h after the secondary anti-rust aqueous solution was sealed off the zinc-nickel alloy coating.Conclusion the corrosion resistance and bonding property of the coating on the surface of powder metallurgical parts can be improved effectively by means of Zn-Ni alloy electroplating and passivation treatment.
【作者单位】：珠海市玛斯特五金塑胶制品有限公司;
【分类号】：TG174.4

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