Abstract: A treated rotor is provided by a method in which a surface of a ferrous rotor having cooling elements is heat-treated to produce a microporous, outermost surface layer, then the heat-treated rotor is coated by electrodepositing a coating layer of an electrocoat coating composition on the heat-treated the surface of to provide a electrocoat coating directed on the surface of the heat-treated rotor. The electrocoat coating layer has a throwpower of at least about 40% and the coating layer is continuous on cooling elements of the rotor. The microporous outermost layer is a controlled iron oxide layer.

Abstract: A method for improving the wear characteristics and corrosion resistance of a metal surface having the basic steps of:A. case hardening the metal surface by placing the metal in a fluidized bed and exposing it to a first atmosphere of nitrogen, ammonia and natural gas at a temperature between about 750.degree. F. and about 1200.degree. F. for a period between about 1 and about 5 hours, followed by exposure to a second atmosphere containing nitrogen and water at a temperature between about 750.degree. F. and about 1200.degree. F.;B. coating the metal with an aqueous coating composition consisting essentially of a polymeric additive and water; andC. allowing the coating composition retained on the metal to cure for a period between about 2 and about 48 hours.

Abstract: A method for improving the wear characteristics and corrosion resistance of a metal surface having the basic steps of:A. case hardening the metal surface by placing the metal in a fluidized bed and exposing it to a first atmosphere of nitrogen, ammonia and natural gas at a temperature between about 750.degree. F. and about 1200.degree. F. for a period between about 1 and about 5 hours, followed by exposure to a second atmosphere containing nitrogen and water at a temperature between about 750.degree. F. and about 1200.degree. F.;B. coating the metal with an aqueous coating composition consisting essentially of a polymeric additive and water; andC. allowing the coating composition retained on the metal to cure for a period between about 2 and about 48 hours.