Studies and Characterization of Electroless Ni-Mo-P Alloy Coating

Abstract

An endeavor has been made to deposit ternary Ni–Mo–P coatings autocatalytically utilizing nickel sulphate and sodium molybdate as nickel and molybdenum sources, separately, and sodium hypophosphite as a lessening operator. These coatings were deposited utilizing a soluble citrate based shower and were contrasted and plain Ni–P coatings. The two coatings were described for their structure, morphology and hardness. Results obtained from EDX analysis showed that binary Ni–P alloy contains 12.74 wt.% of phosphorus. Incorporation of molybdate had reduced the phosphorus content to about 1.09 wt.% in ternary Ni–Mo–P deposits. Apart from phosphorus and nickel contents, a trace of sulphur were noticed in ternary Ni–Mo–P deposit. Structural examination carried out by XRD studies revealed the presence of a broad peak with a calculated grain size of 2.88 nm for binary Ni-P alloy, where as a sharp peak with a grain size of 27.4 nm is obtained for ternary Ni–Mo–P alloy. Microhardness measurements were made for as-deposited and heat treated coatings. Hardness is increase till 400?C and then decreases as like ternary Ni-Mo-P coatings.