Synthesis and Characterization of Electroless Ni–P/Ni–Mo–P Duplex Coating with Different Thickness Combinations

Abstract

In this work, a novel duplex Ni-P/Ni-Mo-P coating upon the aluminum (Al) substrate was synthesized via an electroless plating, i.e., the binary Ni-P coating as a transition layer and the ternary Ni-Mo-P coating on the top. It was found that the duplex coating was of a high hardness, large elastic modulus, low porosity and excellent corrosion resistance. In addition, experimental results revealed that for a total 20 lm coating thickness, the duplex coating with a 7 lm of the Ni-Mo-P coating exhibited the best corrosion resistance in 0.5 mol/L sulfuric acid solution, which was attributed to its compact structure and low porosity. This duplex Ni-P/Ni-Mo-P coating with a thin ternary Ni-Mo-P layer is expected to solve the problem of low deposition rate of ternary alloy coating and thereby may expand applications of Al and its alloys in the fields of machine manufacture and corrosion environment.

Optimizing Electroless Plating of Ni–Mo–P Coatings Toward Functional Ceramics

“…As one can observe, all the spectra are similar and show nickel (Ni), phosphorous (P) and molybdenum (Mo) elements corresponding to XRD analysis. The element composition of the coatings is ~ 84.8% Ni [34], while P content is ~ 1.9%, which corresponds to low P (1-5%) coating [30,46], and ~ 13.3% Mo. According to Guo et al [46], there is a direct relation between P content and crystallinity of Ni-P coating due to the low solubility of P in Ni.…”

“…Moreover, the hypophosphite source of P is known for the reducing property [29]. For improving the mechanical properties such as hardness and corrosion resistance, Mo can be added during electroless plating to form a ternary alloy [30] given its anti-pitting properties [31,32]. Besides, Mo can enhance stability and solubility in the Ni phases and enhance the thermal stability [24,33,34].…”

Development of Nano-tetragonal Zirconia-Incorporated Ni–P Coatings for High Corrosion Resistance

“…The mechanical and tribological properties of the coatings can be improved by the uniform dispersion of such composites [6]. The corrosion resistance of the electroless nano-composite coatings such as Ni-Fe-P [7], Ni-P-TiO 2 [8], ternary alloys of Cu/Zn/Sn with Ni-P coating [9], Ni-P-nano-SiO 2 composite coating [10], Ni-P-PTFE [11], SiC-NiP coatings [12] and Ni-Mo-P [13] would be better than that of the bare Ni-P coating. The nano-composite incorporation can also enhance tribological and metallurgical properties of the Ni-P coatings.…”

Partially Overlapped Reduction Kinetics of Low-Grade Pyrolusite by Mixture of Cellulose and Lignin

“…[8][9][10][11][12][13][14] The results showed that biomass can reduce manganese oxide of the ore at temperatures below 600 o C with a degree of reduction more than 95 %. For example, Cheng et al [8] reported that low-grade manganese dioxide ores can be totally reduced by biomass cornstalk at 500 °C.…”