Particulate metal alloy coating for providing corrosion protection

Abstract

Coatings containing particulate metal alloy are disclosed. The coatings provide corrosion protection to a substrate, such as a metal substrate. The coatings contain zinc-metal-containing alloy in flake form, most particularly an alloy flake of zinc and aluminum. The coating can be from compositions that are water-based or solvent-based. The compositions for providing the coating may also contain a substituent such as a water-reducible organofunctional silane, or a hexavalent-chromium-providing substance, or a titanate polymer, or a silica substance constituent. the coating may desirably be topcoated.

1 - 13 . (canceled) 
     
     
         14 . A coated substrate protected with a corrosion-resistant coating from a coating composition comprising:
 (A) liquid medium;   (B) zinc alloy in flake form comprising greater than 50 weight percent zinc In said alloy flake and a balance of less than 50 weight percent of non-zinc alloy metal; and   (C) a hexavalent-chromium-providing substance.   
     
     
         15 . The coated substrate of  claim 14  wherein said liquid medium is one or more of water and organic liquid. 
     
     
         16 . The coated substrate of  claim 14  wherein said zinc alloy in flake form is zinc alloyed with one or more of aluminum, tin, magnesium, nickel, cobalt and manganese. 
     
     
         17 . The coated substrate of  claim 14  wherein said zinc alloy in flake form is a zinc-aluminum-magnesium alloy flake. 
     
     
         18 . The coated substrate of  claim 14  wherein said zinc alloy in flake form is an alloy having at least about 90 percent of the flake particles with a longest dimension of less than about 15 microns and has at least about 50 percent of the flake particle with a longest dimension of less than about 13 microns, and said composition further contains non-alloyed particulate metal. 
     
     
         19 . The coating composition of  claim 14  wherein said zinc is alloyed with one or more of tin and aluminum, with said zinc alloyed with aluminum containing less than about 20 weight percent aluminum, while said zinc alloyed with tin contains not more than about 30 weight percent tin. 
     
     
         20 . The coated substrate of  claim 14  wherein said zinc alloy in flake form comprises a paste containing less than about 15 weight percent aluminum in said alloy flake, on a metals basis, and up to about 10 weight percent paste liquid, basis weight of said paste. 
     
     
         21 . The coated substrate of  claim 20  wherein said paste contains from about 85 to about 86 weight percent zinc in said alloy and from about 4 to about 8 weight percent of aluminum in said alloy, both basis 100 weight percent of said paste. 
     
     
         22 . The coated substrate of  claim 21  wherein said paste contains from about 7 to about 10 weight percent of paste liquid and contains from about 4 to about 5 weight percent of said aluminum, both basis 100 weight percent of said paste. 
     
     
         23 . The coated substrate of  claim 21  wherein said zinc-aluminum alloy paste is STAPA 4ZnAl7. 
     
     
         24 . The coated substrate of  claim 14  wherein said coating additionally comprises one or more of thickener and wetting agent, said coating is topcoated with a composition containing silica substance, and said topcoating provides silica substance from one or more of colloidal silica, organic silicate and inorganic silicate. 
     
     
         25 . A coated substrate protected with a chrome-free, corrosion-resistant coating from a coating composition comprising:
 (A) zinc alloy in flake form comprising greater than 50 weight percent zinc in said alloy flake and a balance of less than 50 weight percent of non-zinc alloy metal;   (B) a titanate polymer; and   (C) a liquid vehicle comprising organic liquid for said titanate polymer.   
     
     
         26 . The coated substrate of  claim 25  wherein said coating composition additionally comprises manganese dioxide, and said manganese dioxide is present in an amount equal to about 30 weight percent to about 100 weight percent of said zinc alloy in flake form. 
     
     
         27 . The coated substrate of  claim 25  wherein said liquid vehicle is a blend of water with organic liquid. 
     
     
         28 . The coated substrate of  claim 25  wherein said zinc alloy in flake form is zinc alloyed with one or more of aluminum, tin, magnesium, nickel, cobalt and manganese. 
     
     
         29 . The coated substrate of  claim 25  wherein said zinc alloy in flake form is a zinc-aluminum-magnesium alloy flake. 
     
     
         30 . The coated substrate of  claim 25  wherein said zinc alloy in flake form is an alloy having at least about 90 percent of the flake particles with a longest dimension of less than about 15 microns and at least about 50 percent of the flake particle with a longest dimension of less than about 13 microns, and said composition further comprises non-alloyed particulate metal. 
     
     
         31 . The coated substrate of  claim 25  wherein said zinc is alloyed with one or more of tin and aluminum, with said zinc alloyed with aluminum containing less than about 20 weight percent aluminum, while said zinc alloyed with tin contains not more than about 30 weight percent tin. 
     
     
         32 . The coated substrate of  claim 25  wherein said zinc alloy in flake form comprises a paste containing less than about 15 weight percent aluminum in said alloy flake, on a metals basis, and up to about 10 weight percent paste liquid, basis weight of said paste. 
     
     
         33 . The coated substrate of  claim 32  wherein said paste contains from about 85 to about 86 weight percent zinc in said alloy and from about 4 to about 8 weight percent of aluminum in said alloy, both basis 100 weight percent of said paste. 
     
     
         34 . The coated substrate of  claim 33  wherein said paste contains from about 7 to about 10 weight percent of paste liquid and contains from about 4 to about 5 weight percent of said aluminum, both basis 100 weight percent of said paste. 
     
     
         35 . The coated substrate of  claim 33  wherein said zinc-aluminum alloy paste is STAPA4ZnA17. 
     
     
         36 . The coated substrate of  claim 25  wherein said titanate polymer is selected from the group consisting of tetraisobutyl titanate, tetra-isopropyl titanate, tetra N-butyl titanate and mixtures thereof, and said titanate is present in an amount equal to about 9 weight percent to about 47 weight percent of said metal alloy in flake form. 
     
     
         37 . The coated substrate of  claim 25  wherein said coating is topcoated. 
     
     
         38 . A coated substrate protected with a corrosion-resistant coating from a coating composition comprising:
 (A) liquid medium;   (B) zinc alloy in flake form comprising greater than 50 weight percent zinc in said alloy flake and a balance of less than 50 weight percent of non-zinc alloy metal; and   (C) one or more of a water-soluble and water dispersible silica substance.   
     
     
         39 . The coated substrate of  claim 38  wherein said silica substance is selected from the group consisting of alkali metal silicate, organic silicate ester, colloidal silica sol, organic ammonium silicate and mixtures of the foregoing. 
     
     
         40 . The coated substrate of  claim 38  wherein said composition has a water-based-liquid medium and additionally comprises one or more of a thickening agent and metallic oxide pigment. 
     
     
         41 . The coated substrate of  claim 40  wherein said thickening agent is one or more of cellulose ether and xanthan gum and said metallic oxide pigment is one or more of zinc oxide, iron oxide and titanium oxide. 
     
     
         42 . The coated substrate of  claim 38  wherein said zinc alloy in flake form is zinc alloyed with one or more of aluminum, tin, magnesium, nickel, cobalt and manganese. 
     
     
         43 . The coated substrate of  claim 38  wherein said zinc alloy in flake form is a zinc-aluminum-magnesium alloy flake. 
     
     
         44 . The coated substrate of  claim 38  wherein said zinc alloy in flake form is an alloy having at least about 90 percent of the flake particles with a longest dimension of less than about 15 microns and at least about 50 percent of the flake particle with a longest dimension of less than about 13 microns, and said composition further contains non-alloyed particulate metal. 
     
     
         45 . The coating composition of  claim 38  wherein said zinc is alloyed with one or more of tin and aluminum, with said zinc alloyed with aluminum containing less than about 20 weight percent aluminum, while said zinc alloyed with tin contains not more than about 30 weight percent tin. 
     
     
         46 . The coated substrate of  claim 38  wherein said zinc alloy in flake form comprises a paste containing less than about 15 weight percent aluminum in said alloy flake, on a metals basis, and up to about 10 weight percent paste liquid, basis weight of said paste. 
     
     
         47 . The coated substrate of  claim 46  wherein said paste contains from about 85 to about 86 weight percent zinc in said alloy and from about 4 to about 8 weight percent of aluminum in said alloy, both basis 100 weight percent of said paste. 
     
     
         48 . The coated substrate of  claim 47  wherein said paste contains from about 7 to about 10 weight percent of paste liquid and contains from about 4 to about 5 weight percent of said aluminum, both basis 100 weight percent of said paste. 
     
     
         49 . The coated substrate of  claim 47  wherein said zinc-aluminum alloy paste is STAPA 4ZnAi7. 
     
     
         50 . The coated substrate of  claim 38  wherein said coating is topcoated.