Corrosion resistant coatings containing an amorphous phase

Abstract

The disclosure relates to the forming mineralized coatings on metal surfaces and to methods of forming such coatings. The coating can include a wide range of compounds and normally at least a portion of the coating corresponds to an amorphous phase. The coating and method are particularly usefull in providing a corrosion resistant coating or film upon a metallic surface. This aspect of the disclosure involves the formation of a corrosion resistant “mineralized” layer of tailored composition upon a metal substrate.

The following is claimed:  
     
         1 . An amorphous mineralized surface comprising a cation and an inorganic oxide wherein the amount of oxygen is less than the stoicheometric.  
     
     
         2 . A mineralized layer consisting essentially of the oxide network phase  
       A x B y O z —nH 2 O  
       wherein A comprises a modifier cation comprising at least one member selected from the group of Group I, II and III metals, B comprises a network forming cation wherein the values of x, y and z are greater than 0. So long as the ratio of y:z is less than or equal to 4:1.  
     
     
         3 . A transparent corrosion resistant mineralized layer comprising at least one phase obtained by contacting a silicate containing material with a metal surface at a pH ranging from about 9 to at least 11 wherein the amount of oxygen is less than stoichiometric.  
     
     
         4 . The mineralized layer of    claim 3    wherein the metal surface comprises at least one member selected from the group consisting of iron, steel, zinc, magnesium, aluminum, vanadium, calcium, beryllium, manganese, cobalt, nickel, copper, brass, bronze, zirconium, thallium, chromium, and alloys thereof.  
     
     
         5 . The mineralized surface of    claim 1    in which cations comprise one or more metals selected from the class consisting Group I, Group II, Group III, transition metals and rare earth metals of the Periodic Chart of the Elements.  
     
     
         6 . The mineralized surface of    claim 5    in which the cations comprise an alkaline earth metal.  
     
     
         7 . The mineralized layer of    claim 2    in which anions comprise at least one member selected from the group consisting of selected from the group consisting of one or more of the anions selected from the group consisting of water soluble salts and/or oxides of tungsten, molybdenum, chromium, titanium, zircon, vanadium, phosphorus, aluminum, iron, boron, bismuth, gallium, tellurium, germanium, antimony, niobium (also known as columbium), magnesium and manganese, mixtures thereof, among others, and more especially, salts and oxides of silicon, aluminum and iron can be employed.  
     
     
         8 . The mineralized layer of    claim 4    wherein the metal surface comprises zinc and the silicate comprises sodium silicate.  
     
     
         9 . The mineralized layer of    claim 2    wherein the contacting comprises providing the silicate to the metal surface in the form of at least one member selected from the group consisting of a paint, coating or gel.  
     
     
         10 . The mineralized surface of    claim 1    wherein the surface consist essentially of a complex oxide of the form: 
 MxNyOt, wherein “M” represents one or more cationic elements having a covalency factor of less than about 0.5 that functions to balance the charge of the complex oxide, “N” represents one or more lattice forming elements having a covalency factor greater than about 0.15 that functions as the structural component of the complex oxide and optionally wherein the NyOt carries single or multiple crystal structures; and wherein x, y and t comprise any number the total of which balances the charge of the complex oxide.  
 
     
     
         11 . The mineralized surface of    claim 10    wherein the covalency factor of M is less than about 0.33 and the covalency factor N is greater than about 0.33.  
     
     
         12 . The mineralized surface of    claim 3    wherein the metal surface comprises zinc and the silicate comprises sodium silicate.  
     
     
         13 . The mineralized surface of    claim 3    wherein the carrier comprises PAO or polyurethane and the silicate comprises about 1 to 30 wt. % of the carrier.  
     
     
         14 . The mineralized surface of    claim 12    wherein the surface is heat treated at a temperature of about 125 to about 175 C.  
     
     
         15 . The mineralized surface of    claim 1    wherein the Si(2p) photoelectron binding energy, measured by X-ray Photoelectron Spectroscopy, is higher than 102.1, but less than 103.3 eV, wherein the spectra identifies the mineralized species and wherein the binding energy is higher due to the accumulation of a silica oxide network.