Pulsed Waterjet Roughening of Cast Iron and Aluminum Alloy for Automotive Engine Remanufacturing with Plasma Transferred Wire Arc Coating

This study utilized the high-pressure pulsed waterjet process and paired it with the plasma transferred wire arc technology to develop a novel technique to remanufacture damaged engine cylinder bores. The objective of this research was to eliminate the need for expensive bond-coats such as Ni-Al by optimizing the surface roughness profile of the substrate to provide acceptable mechanical bonding between the coating and the substrate. In this study, a high chrome stainless steel wire (Metcoloy #2) was plasma spray coated on a wide range of pulsed waterjet roughened surface profiles generated on grey cast iron and cast aluminum A380 alloy, the two most common engine materials. The pulsed waterjet greatly increased the adhesion strength between the substrates and the Metcoloy #2 coating. The increase in adhesion strength is a result of the formation of favorable mechanical anchoring points. Optimal pulsed waterjet parameters were determined to avoid the production of a copious roughness profile which resulted in a coating that mirrored the roughened surface profile. Additionally, if the roughness profile produced by the pulsed waterjet was insignificant the coating was removed in its entirety during detachment-based failure.