Method for imparting tarnish protection or tarnish protection with color appearance to silver, silver alloys, silver films, silver products and other non precious metals

A method of surface coating a metallic object comprising:

• if existing silver sulfide tarnish is present on the object, removing substantially all of the existing silver sulfide tarnish by application of a chemical agent that reverses a chemical reaction by which the silver sulfide tarnish is formed by reaction of silver and sulfur;
• ultrasonically cleaning the object with immersion in a solvent;
• uniformly dispersing selected nanoparticles over the surface of the object by sonicating the object in an ultrasonic bath containing the selected nanoparticles;
• rinsing the object with solvent upon removal from the ultrasonic bath to inhibit formation of large agglomerates;
• drying the object with a flow of gas;
• optically inspecting the object for the presence of agglomeration;
• applying a barrier layer conformal coating;
• applying a protective layer conformal coating.