Thermally sprayed metal coatings on wood or wood composite surfaces

Abstract

The present invention provides a method of depositing one or more layers of metal coatings onto an organic substrate. The method includes providing a source of a jet of molten metal particles having an average temperature within a predetermined range, an average velocity within a predetermined range. The jet of molten droplets is then directed at a surface of an organic substrate thereby depositing a metal coating on said organic substrate surface. The source of droplets is spaced from the organic substrate a pre-determined distance, and the average velocity and the average temperature are selected for a given metal such that the temperature of the molten metal particles is very close to the melting point of the metal as the molten droplets coat the surface of the organic substrate to minimize damage to the organic substrate.

1 . method of depositing one or more layers of metal coatings onto an organic substrate, the method comprising:
 a) providing a source of a jet of molten metal particles having an average temperature within a predetermined range, an average velocity within a predetermined range; and   b) directing said jet of molten metal particles at a surface of an organic substrate thereby depositing a metal coating on said organic substrate surface, said source being spaced from said organic substrate a pre-determined distance, and said average velocity and said average temperature being selected for a given metal such that the temperature of the molten metal particles is very close to the melting point of the metal as the molten droplets coat the surface of the organic substrate to minimize damage to the organic substrate.   
     
     
         2 . The method of  claim 1  wherein the metal coating has a thickness between about 100 and about 500 micrometers. 
     
     
         3 . The method of  claim 1  wherein the molten metal particles are selected from the group consisting of aluminum and its alloys, copper and its alloys, silver and its alloys, zinc, tin, stainless steel and any combination thereof. 
     
     
         4 . The method of  claim 1  wherein the organic substrate is hard wood. 
     
     
         5 . The method of  claim 1  wherein the jet of molten metal particles are provided by a wire arc spray gun. 
     
     
         6 . The method of  claim 1  wherein, subsequent to step (b), the organic substrate is post-treated with a sealant. 
     
     
         7 . The method of  claim 6  wherein the sealant is selected from the group consisting of: acrylic coatings, epoxy coatings, silicone coatings, alkyd coatings, urethane coatings and polyvinyl fluoride. 
     
     
         8 . The method of  claim 1  wherein the organic substrate is selected from the group consisting of: Hard Maple, Oak, Birch, Ash, Mahogany family, Beech, and any other hard woods. 
     
     
         9 . The method of  claim 1  wherein the organic substrate is a polymer-wood fibers composite. 
     
     
         10 . The method of  claim 1  wherein the wood is chosen to have a moisture content Kiln dried to that woods industries standards. 
     
     
         11 . The method of  claim 1  wherein a first coating is deposited onto the organic substrate, followed by a second coating deposited onto the first coating. 
     
     
         12 . The method of  claim 1  wherein the metal of the second coating has a higher melting point than the metal of the first coating. 
     
     
         13 . The method of  claim 1  including directing a gas jet at said substrate to cool the deposited metal coating. 
     
     
         14 . The method of  claim 13  wherein said gas jet is an air jet.