Kinetic Metallization of Interior Diameter Bores

The low temperature and pressure Kinetic Metallization (KM) process, compliant with the recent MIL-STD-3021 cold spray materials deposition standard, allows coating and dimensional restoration of interior diameter (ID) surfaces. The unique attribute of the Kinetic Metallization process for preheating the powder particles to enhance ductility allows high quality coating depositions in small-bore components with very short sonic nozzles. Currently Inovati has developed a KM ID Gun that can deposit coating normal to the surface of the bore down to interior diameters of 80-mm, with depth-to-diameter ratios exceeding 10-to-1. These ID deposition guns, when used with KM systems, can deposit the full range of coatings including structural aluminum alloys for rebuilding damaged forgings, superalloys for corrosion and/or oxidation protection, and hard-phase carbide coatings for wear resistance. This paper presents a case study for rebuilding of damaged 7075-Al forged landing gear outer cylinders requiring ID coating repairs of 0.020-0.030 inches in thickness. A separate study focuses on tungsten-carbide cobalt (WC-Co) on steel liners and actuating cylinders for replacing hard chrome coatings and repairing worn cylinder bores.