纳米颗粒添加量对Ni-P-Al_2O_3化学复合镀层耐蚀性的影响

Influence of Addition of Nano-particles on Corrosion Resistance of Ni-P-Al_2O_3 Composite Coatings

采用化学复合镀的方法在铝合金表面制备了Ni-P-Al2O3复合镀层,采用电化学测试及中性盐雾试验研究了不同纳米Al2O3颗粒添加量对镀层的耐蚀性能以及腐蚀演化过程的影响,采用扫描电镜(SEM)观察了镀层的表面形貌,用EDS分析镀层的化学成分,用X荧光测厚仪测量镀层的厚度。结果表明,磁力搅拌分散条件下,镀层耐蚀性随纳米颗粒添加量的变化存在一个最佳范围,即约为2～3g.L-1,所得镀层可以耐中性盐雾48h,在35℃的5%NaCl溶液中浸泡后腐蚀较为均匀。

Ni-P-Al2O3 composite coatings on aluminum alloy were prepared by electroless composite plating. The influence of the addition of nano-Al2O3 particles on the corrosion resistance of composite coatings was studied by electrochemical tests and salt spray test. The surface morphology of coatings was observed with scanning electron microscopy （SEM）. The chemical composition was analyzed by EDS. The thickness of composite coatings was measured by X-ray fluorescence thickness gauge. The results indicate that the addition of nano-Al2O3 in solution has optimum values of about 2～3g·L-1 by using dispersion method of magnetic stirring. The composite coating obtained can protect aluminum alloy from corroding for more than 48h in the salt spray test, and the corrosion morphology is more uniform after immersion in 5%NaCl solution in 35 ℃.