Oxidation Resistant Nickel Aluminide Coating on Niobium Alloy C103 for High Temperature Aerospace Applications

Abstract

Owing to its fairly higher melting point (2468°C) and superior thermal conductivity, Niobium alloys are rendered as candidate material for high temperature applications, where state of the art Nickel base super alloys cannot be used. Its applications possess wide range of aerospace components mainly encompassing aircraft exhaust chambers, thrust augmenters, rocket engines and other industries such as chemical and petrochemical. The only limitation with niobium alloys is their inferior oxidation resistance, which can be tackled by developing a high temperature oxidation resistant coating. In this regard, Nickel Aluminide (NiAl) having a melting point of 1638°C embraces a paramount importance amongst the coating categories. In this study, NiAl was synthesized using vacuum melting and strip casting followed by ball milling. The powder was coated on C-103 Niobium alloy specimens using air plasma technique and evaluated for high temperature stability. It was deduced that the coating was exceptionally stable up to 1234 °C in ambient conditions.