仪器结构件用2A12铝合金表面Ni-P化学镀层的形貌与硬度

Morphology and Hardness of Ni-P Electroless Coatings Prepared on 2A12 Aluminium Alloy Used for Instrument Structural Components

为了提高铝合金的硬度,以仪器结构件用2A12铝合金为基体制备Ni-P化学镀层。采用称重法、螺旋测微器、扫描电镜和显微硬度计等测试方法和仪器,研究了沉积时间对镀层的沉积速率、厚度、形貌及硬度的影响。结果表明:随着沉积时间的延长,镀层的沉积速率明显降低,厚度逐渐增加,但增厚速率变慢;镀层的结构未发生变化,仍为胞状结构,但表面胞状物的平均直径变大;镀层的表面粗糙度逐渐增大,硬度先增大后减小。当沉积时间为90min时,镀层的硬度达到5.80GPa,是2A12铝合金硬度的4倍以上,说明Ni-P化学镀层能较大幅度地提高2A12铝合金的硬度。

Ni P electroless coatings were prepared on 2A12 aluminium alloy used for instrument structural components in order to improve the hardness of aluminium alloy. The influence of deposition time on the deposition rate, thickness, morphology and hardness of electroless coatings was investigated by using weighing method, micrometer caliper, scanning electron microscope and microhardness tester. Results showed that with the extension of deposition time, the deposition rate decreased obviously, and the thickness increased gradually, but thickening speed slow down. There was no change in the structure of electroless coatings, but average diameter of cellular substance on the surface of electroless coatings was increased. The surface roughness increased gradually and the hardness increased first and then decreased. The highest hardness of electroless coating （5.80 GPa） was achieved when deposition time was 90 rain, which was 4 times higher than that of 2A12 aluminium alloy, indicating that the hardness of 2A12 aluminium alloy can be significantly improved by Ni-P electroless coating.