Electrospark Deposition for Depot- and Field-Level Component Repair and Replacement of Hard Chromium Plating

Electrospark Deposition ESD is a microwelding process capable of depositing a wide variety of metal or ceramicmetal coatings onto components using small, portable equipment. This project investigated ESD repair of different types of weapons components that have been subjected to localized damage such as wear, gouging or corrosion pitting. Currently, there are either no repairs available for such components and they have to be replaced or else the components are completely overhauled using complicated electroplating or thermal spray processes. ESD offers the possibility of performing repairs just on the damaged areas, in some cases without removing the component from the aircraft or ship. Extensive materials studies have been conducted on Inconel 718 in which pre-designed defects have been introduced and then repaired by ESD of similar material. Axial fatigue testing on ESD-treated coupons showed no loss of fatigue strength and wear testing indicated that the ESD-repaired areas demonstrated excellent wear resistance. ESD repairs on actual components from gas turbine engines, tanks and ship components were demonstrated.