Critical Factors Affecting the Pitting Corrosion Resistance of Additively Manufactured Nickel Alloy in Chloride Containing Environments

Abstract

Abstract Precipitation-hardened nickel-based alloys have a long tradition in oilfield applications. Due to their high strength, good ductility and excellent environmentally assisted cracking resistance they have been successfully used for wellhead components, artificial lift applications and directional drilling tools particularly in demanding environments where superior corrosion resistance is necessary. Additive manufacturing is breaking into the oil and gas industry with current research efforts focused on demonstrating suitability for manufacturing components that were previously impossible to produce with conventional subtractive manufacturing processes without compromising material properties such as strength, ductility and corrosion resistance. The pitting corrosion resistance of a selective laser melted Nickel alloy having a similar chemical composition to alloy 718 (UNS N07718) in chloride-containing solutions has been evaluated by electrochemical methods. Results from cyclic potentiodynamic polarization curves demonstrate that, with comparable surface quality, the additively manufactured Nickel alloy behaves similar with regard to pitting corrosion susceptibility to UNS N07718 wrought material in chloride containing environments.