On the Effect of the Electroless Nickel-Phosphorus(Ni-P) Coating Defects on the Performance of This Type of Coating in Oilfield Environments

Abstract

SUMMARY In the eighties the use of electroless nickel-phosphorus(Ni-P) coatings was largely increased in many industrial segments. In the oil industry this kind of coating has a particularly large applicability due to its outstanding resistance to CO2, H2S and aqueous brines. Therefore, it has been largely applied to valves, section pumps, production tubings, and other equipment. Nevertheless, laboratory tests performed have shown that it is essential to evaluate the quality of the coating in order to assure its field performance for it is dramatically affected by surface defect. In this paper several problems that occasionally occur in Ni-P coatings are presented. The following items of the coating are evaluated: nickel and phosphorus content, hardness, adherence, porosity, discontinuities, thickness and uniformity.