Highly active liquid melts used to form coatings
View Patent ↗An alloy suitable for coating metal surfaces is provided in which the alloy provides a liquid melt which contains a fraction of dissolved oxide forming additives as deoxidizers. The alloyed combination of elements in the liquid melt resists compound formation thus preserving the chemical activity of the individual elements. In a coating application, the alloy may form a coating that can interact with and remove the oxide or residual oxide coating of the base metal to be coated, i.e., scrub the surface of the metal clean. This results in increased coating bond strength and the ability to bond effectively to normally difficult alloys such as stainless steel, refractory metals (W, Ti, Ta etc.), or aluminum alloys which form protective oxide layers.
1. A method of forming a metallic coating on an oxidized metal surface layer comprising:
providing an atomized glass forming iron based metallic coating alloy wherein said alloy includes deoxidizing elements and an oxygen seeking nonmetal/metalloid, wherein said alloy consists of iron, manganese, chromium, molybdenum, tungsten, boron, carbon and silicon, wherein the elements are combined and present at a total of 100 wt %; and
forming a metallic coating containing a fraction of metallic glass at a thickness of 40 mil to 110 mil by high velocity oxy fuel spray by melting said iron based metallic coating alloy to a liquid state;
applying said liquid melt of said iron based metallic coating alloy to said oxidized metal surface, wherein said oxidized metal surface comprises a native oxide layer and removing said oxidized metal surface layer with said liquid melt of said iron based metallic coating alloy to provide a metal surface that is relatively clean of said oxidized metal surface layer and susceptible to receipt of a metallic coating and wherein said deoxidizing elements remove oxygen from the metal surface layer and said deoxidizing elements are present in said alloy melt such that said deoxidizing elements remain dissolved in said alloy melt to retain an affinity for oxygen and no primary precipitates are allowed to be formed in said alloy melt from said deoxidizing elements; and
applying an iron based metallic coating alloy to said metal surface that is relatively clean of said oxidized metal surface layer wherein said iron based metallic coating has an ASTM C633 bond strength of at least about 12,000 psi without using a bond coat and said bond strength is present at said coating thickness from 40 mil to 110 mil and wherein failure of said coating does not occur at a coating/metal surface interface.
2. The method of claim 1 wherein said step of melting said iron based alloy to a liquid state comprises forming a liquid state with no precipitates of said deoxidizing elements existing in said liquid state.
3. A method of forming a metallic coating on an oxidized metal surface layer comprising:
providing an atomized glass forming iron based metallic coating alloy wherein said alloy includes deoxidizing elements and an oxygen seeking nonmetal/metalloid, wherein said alloy consists of iron, manganese, chromium, molybdenum, tungsten, boron, carbon and silicon, wherein the elements are combined and present at a total of 100 wt %; and
forming a metallic coating containing a fraction of metallic glass at a thickness of 40 mil by wire arc spray by melting said iron based metallic coating alloy to a liquid state;
applying said liquid melt of said iron based metallic coating alloy to said oxidized metal surface, wherein said oxidized metal surface comprises a native oxide layer and removing said oxidized metal surface layer with said liquid melt of said iron based metallic coating alloy to provide a metal surface that is relatively clean of said oxidized metal surface layer and susceptible to receipt of a metallic coating and wherein said deoxidizing elements remove oxygen from the metal surface layer and said deoxidizing elements are present in said alloy melt such that said deoxidizing elements remain dissolved in said alloy melt to retain an affinity for oxygen and no primary precipitates are allowed to be formed in said alloy melt from said deoxidizing elements; and
applying an iron based metallic coating alloy to said metal surface that is relatively clean of said oxidized metal surface layer wherein said iron based metallic coating has an ASTM C633 bond strength of at least 5501 psi without using a bond coat and said bond strength is present at said coating thickness from 40 mil and wherein failure of said coating does not occur at a coating/metal surface interface.
4. The method of claim 3 wherein said step of melting said iron based alloy to a liquid state comprises forming a liquid state with no precipitates of said deoxidizing elements existing in said liquid state.