Studies on Ni-Mo-P Coatings by Electroless Deposition

Abstract

This paper describes the performance of Ni-P and Ni-Mo-P alloy coatings deposited by electroless plating on the aluminum alloy 5052 to evaluate the corrosion resistance, thermal stability and electro-conductivity of coating assemblies. Corrosion behaviors of the obtained deposits in a 0.5M H2SO4 environment were investigated. The crystalline state and morphologies of Ni-P and Ni- Mo-P alloys were examined by field emission scanning electron microscopy (FE-SEM). The experimental results indicate that the Ni-Mo-P coating operated at 70°C and pH 9.0 has a nanocrystalline structure and its corrosion resistance in a 0.5M H2SO4 environment can be enhanced by the co-deposition of Mo as compared to Ni-P films. It has also been found that the Ni-Mo-P ternary alloys reveal good thermal stability after annealing at 400°C. Based on the excellent performance of Ni-Mo-P ternary alloys, these alloys have a potential to be applied to precision mould, optical parts mould, and surface metallization of substrates.

Effect of ultrasonication and Na2MoO4 content on properties of electroless Ni–Mo–P coatings

“…Recently, for accelerate improving the functions of these depositions, add Mo, W, Cu, Zn, Co, Al 2 O 3 , CNTs, etc. to coatings help to content special application such as thermal stability, wear resistance, corrosion resistance, hardness and some physical capabilities such as solderability, magnetic function and polishability [6][7][8][9][10][11][12][13][14][15].…”

“…Ni–W–P coatings show better corrosion resistance, wear resistance, hardness and electrical resistance than Ni–P coatings [17-20]. Mo demonstrates similar properties to W and can enhance electroless Ni–P matrix, exhibiting the properties which are similar to those in Ni–W–P coating [7,9,21].…”