烧结钕铁硼电镀锌铁合金工艺与耐蚀性能

Technology and Corrosion Resistance of Electrodeposited Zn-Fe Alloys onto Nd-Fe-B Sintered Magnets

摘要:

采用弱酸性氯化物镀液在钕铁硼基体上制备了高耐蚀性的锌铁合金镀层，讨论主要工艺参数对镀层铁含量的影响，优化工艺条件。采用盐雾试验（NSS）、SEM和电化学方法研究镀层的耐蚀性能和耐蚀机理。结果表明，优化工艺条件后合金镀层含铁质量分数为0.92%，钝化后在质量分数3.5%的NaCl溶液中出白锈时间达到196 h。合金镀层对钕铁硼基体起到阳极保护的作用，镀层结晶致密，填补了钕铁硼基体的固有缺陷，同时又为获得致密的钝化膜创造了条件，减少了镀层表面的缺陷，使镀层整体具有极高的电阻，提高了其耐蚀性能。

Abstract:

High corrosion resistance Zn-Fe alloy coatings were electroplated onto NdFeB sintered magnet from a weak acid chloride solution. The influences of the main electroplating technological parameters on Fe content in the coating were investigated to optimize the process conditions. Meanwhile, the corrosion resistance and its mechanism were investigated by NSS, SEM and electrochemical tests. The result shows that the optimized Zn-Fe alloy (Fe content 0.92%) coated NdFeB can stand for 196 h against neutral 3.5wt% NaCl salt spray without any white rust. The function of the coating for NdFeB substrate is anodic protection. The coating with dense crystal can fill intrinsic defects of NdFeB substrate and provide favorable conditions for getting compact passivation film. The better corrosion resistance is attributed to the less surface defects and high electric resistance.