Surface Treatments of Metal Substrates

Abstract

A method is provided for treating a metal substrate. The method comprises applying a metal layer to the substrate using a thermal spray process and electrochemically treating the metal layer to form a coating.

1 . A method of treating a metal substrate to form a coating, the method comprising
 applying a metal layer on the substrate, the metal layer applied by a thermal spray process, and   electrochemically treating the metal layer.   
     
     
         2 . A method according to  claim 1 , wherein the metal substrate comprises aluminium, magnesium, titanium, niobium, lithium, zinc or alloys thereof. 
     
     
         3 . A method according to  claim 1 , wherein the thermal spray process comprises one of plasma spraying, detonation spraying, wire arc spraying, flame spraying or high velocity oxy-fuel coating spraying. 
     
     
         4 . A method according to  claim 1 , wherein after electrochemically treating the metal layer, baking the substrate. 
     
     
         5 . A method according to  claim 1 , wherein electrochemically treating the metal layer comprises anodizing, micro-arc oxidation or electrophoretic deposition. 
     
     
         6 . A method of applying a coating to a casing for a device, the method comprising
 heating a metal feedstock to form molten metal particles,   accelerating the molten metal particles towards the casing to form a metal layer on the casing, and   electrochemically treating the metal layer.   
     
     
         7 . A method according to  claim 6  wherein the metal feedstock is in powder or wire form. 
     
     
         8 . A method according to  claim 6  wherein heating the metal feedstock is achieved by electrical or chemical means. 
     
     
         9 . A method according to  claim 6 , wherein the metal casing is formed of aluminium, magnesium, titanium, niobium, lithium, sine or alloys thereof, 
     
     
         10 . A method according to  claim 6 , wherein the metal layer has a thickness of 5-50 μm. 
     
     
         11 . A method according to  claim 6 , wherein the molten metal particles have a diameter of 3-200 nm. 
     
     
         12 . A casing for a device having a coating, the casing comprising
 a metal substrata,   a first metal layer on the metal substrate, the first metal layer applied by a thermal spray process, and   a second layer termed by electrochemical treatment of the first metal layer.   
     
     
         13 . A casing according to  claim 11 , wherein he metal substrate comprises aluminium, magnesium, titanium, niobium, lithium, tine or alloys thereof. 
     
     
         14 . A casing according to  claim 11 , wherein the thermal spray process comprises one of plasma spraying, detonation spraying, wire arc spraying, flame spraying or high velocity oxy-fuel coating spraying. 
     
     
         15 . A casing according to  claim 1 , wherein electrochemically treating the metal layer comprises anodizing, electrophoretic deposition or micro-arc oxidation.