温度对化学镀 Ni-P 合金层形貌、硬度及耐蚀性的影响

目的揭示在70~95℃施镀温度范围,Ni-P合金镀层显微形貌的变化规律,并探讨表面形貌结构、合金硬度及耐蚀性能的相关性。方法以施镀温度为变量,通过化学沉积的方法制备Ni-P合金镀层。对镀层表面形貌进行表征,测试镀层硬度,并采用盐酸为腐蚀介质进行浸泡,以相对腐蚀速率表征镀层的耐蚀性。结果在70~95℃的施镀温度范围内,随着温度升高,镀层形貌先趋于致密和平整,而后表面粗化,镀层的硬度和耐蚀性均呈现先提高、后降低的趋势。最佳镀层形貌和硬度值出现在85℃,耐蚀性最好的施镀温度区间为85~90℃。结论当镀液p H值为4.5±0.1,施镀时间为3 h时,施镀的最佳温度为85℃。此条件下制备的镀层表面平整且均匀致密,硬度高,耐蚀性能优异。

Influence of Plating Temperature on the Morphology, Hardness and Corrosion Resistance of Electroless Ni-P Alloy Plating

ABSTRACT:Objective The variation trend of surface morphology of the Ni-P alloy coating was studied in the plating temperature range of 70~95 ℃. In addition, the correlations between alloy hardness, corrosion resistance and surface morphology were dis-cussed. Methods Ni-P alloy coatings were prepared by chemical deposition at different plating temperatures. The surface morpholo-gy of Ni-P coatings was characterized by SEM. The hardness of Ni-P coatings was determined. And the corrosion resistance of Ni-P coatings was also characterized by the relative corrosion rate through soaking the samples in chlorhydric acid. Results In the plat-ing temperature range of 70~95 ℃, with the increase of the deposition temperature, the surface morphology of Ni-P coatings ten-ded to be denser and smoother at first and then surface coarsening occurred. Both the hardness and corrosion resistance of the Ni-P coatings first increased and then decreased with the increasing deposition temperature. The best surface morphology and the maxi-mum hardness were obtained at 85 ℃ and the deposition temperature range for good corrosion resistance was 85~90 ℃. Conclu-sion The Ni-P coatings with flat, dense and smooth surface, high hardness and good corrosion resistance were prepared at 85℃ for 3 h when the solution pH value was 4. 5±0. 1.