Peened Overlay Coatings

Author:  Joseph F. Loersch and James W. Neal
Source:  US Patent 4,514,469
Doc ID:  1985104
Year of Publication:  1985
Abstract:  
Disclosed are coatings which are improved by a special peening process. Uniform sized spherical steel shot, in the range 1-2.5 mm is impacted at uniform low velocities onto a coated workpiece. Peening intensities are in the range 0.30-0.60 mm N. MCrAlY high temperature coatings are particularly improved, with densities of the order of 99 percent. Physical vapor desposited coatings have surface finishes of the order of 30x10^-6 inch AA (Arithmetic Average) and plasma sprayed coatings have finishes of the order of 100x10^-6 inch AA compared to unpeened finishes of 50-60x10^-6 inch AA and 200-300x10^-6 AA respectively.