ZrO_(2)颗粒浓度对钕铁硼Ni-P/ZrO_(2)复合镀层耐蚀性的影响

Effect of ZrO_(2) Particles Concentration on Corrosion Resistance of Ni-P/ZrO_(2) Composite Coatings on NdFeB

采用化学镀技术在钕铁硼表面制备出Ni-P/ZrO_(2)复合镀层,并研究了ZrO2颗粒浓度对复合镀层中ZrO_(2)颗粒含量、复合镀层的形貌、孔隙率和耐蚀性的影响。结果表明,ZrO_(2)颗粒浓度在0.5~4.0 g/L范围内时,复合镀层的耐蚀性随着ZrO_(2)颗粒浓度增加逐步改善,在不同腐蚀介质中的平均腐蚀速率都呈现减小的趋势,主要归因于复合镀层中ZrO_(2)颗粒含量升高以及复合镀层表面趋于光滑平整,且孔隙率明显降低。但ZrO_(2)颗粒浓度超过一定限度后,复合镀层中ZrO_(2)颗粒含量下降,加之孔隙率升高和表面平整度有所下降,导致耐蚀性变差。ZrO_(2)颗粒浓度为4.0 g/L制备的复合镀层具有良好的耐蚀性,但在不同腐蚀介质中其耐蚀性存在一定的差异。该复合镀层腐蚀前后的形貌差异不太明显,而钕铁硼腐蚀前后的形貌有明显的差异,表明该复合镀层在不同腐蚀介质中的耐蚀性明显好于钕铁硼。

Ni-P/ZrO_(2) composite coatings were prepared on the surface of NdFeb by electroless plating,and the effect of ZrO_(2) particles concentration on the content of ZrO_(2) particles in composite coatings,the morphology,porosity and corrosion resistance of composite coatings were studied.The results showed that when ZrO_(2) particle concentration was in the range of 0.5~4.0 g/L,the corrosion resistance of composite coatings was gradually improved with the increase of ZrO_(2) particle concentration,and the average corrosion rate in different corrosive media presents a trend of decrease,which was mainly attributed to the increase of the content of ZrO_(2) particles in composite coatings,more uniform surface and significantly reduced porosity.However,when the ZrO_(2) particles concentration exceeds a certain limit,the content of ZrO_(2) particles in composite coatings decreased,along with the increase of porosity and the decrease of surface roughness,resulting in the deterioration of corrosion resistance.The composite coating prepared with 4.0 g/L ZrO_(2) particles exhibited good corrosion resistance,but its corrosion resistance varies in different corrosive media.The morphology difference of the composite coating before and after corrosion was not very significant,while the morphology difference of NdFeB before and after corrosion was significantly different,indicating that the corrosion resistance of this composite coating in different corrosive media was obviously better than that of NdFeB.