Parametric optimization and pre-treatment process for electroless Ni–P on low carbon steel

• Main Authors: Lee,Wei-Hsiang, 李維祥
• Other Authors: Hsu,Chun-Yao
• Format: Others
• Language: zh-TW
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/14527267472068584799

碩士 === 龍華科技大學 === 機械工程系碩士班 === 103 === Electroless Ni-P deposits are widely used in the chemical, mechanical and electronic industry, due to their good wear- and corrosion-resistance and desired electrical properties. This paper examines the optimization of the electroless Ni-P parameters on low carbon steel (0.04%) substrates using the Taguchi method. The NiSO4·6H2O (20 g/L), NaH2PO2∙H2O (25 g/L), Na2C4H4O4∙6H2O (15 g/L) are maintained at constant values. The effect of the electroless Ni-P parameters, such as the deposition temperature (85, 90, 95oC), the pH value of the solution (4, 5, 6), and the deposition time (10, 20, 30 min) on the deposition rates, hardness, friction coefficient and polatization resistance tests, are studied. This study obtains the performance characteristics for electroless Ni-P parameters with grey theory prediction design that is, deposition temperature = 90oC, pH value=5 and deposition time=10 min. In the confirmation run, the hardness is 253.4 HV, the friction coefficient is 0.25, and corrosion current is 1.019×10-6 A/cm2. Pre-treatment (roughening and activation processes) of the surface may provide a better adhesion between the Ni–P plating layer and the substrate. In this work, the rough surface on low carbon steel substrates was prepared using the sandblasting and plasma etching roughening treatment method, respectively, and then the surface was electroless Ni-P coated. Experimental result shows that, the hardness is 292.4 HV and 296.0 HV, the friction coefficient is 0.23 and 0.16, and corrosion current is 0.462 ×10-6 A/cm2 and 0.390 ×10-6 A/cm2, respectively.