Coated metal and method

Claim 2

AN AQUEOUS COATING COMPOSITION FOR APPLICATION TO, AND CURING ON A METAL SUBSTRATE, THEREBY PREPARING AN ADHERENT WATER INSOLUBLE, ALKALI AND CORROSION RESSISTANT AS WELL AS SUBSTANTIALLY RESINFREE COATING ON SAID SUBSTRATE, WHICH COMPOSIRION BEFORE CURING COMPRISES AN INTIMATE MIXTURE IN AQUEOUS LIQUID MEDIUM OF: A. A HEXAVALENT-CHROMIUM-PROVIDING SUBSTANCE, SUPPLIED BY ABOUT 80 TO 100 WEIGHT PERCENT CHROMIC ACID AND PROVIDING ABOVE 5 BUT BELOW ABOUT 100 GRAMS PER LITER OF CHROMIUM, EXPRESSED AS CRO3, B. ABOVE 50 BUT BELOW ABOUT 500 GRAMS PER LITER OF LIQUID MEDIUM OF PULVERULENT METAL SELECTED FROM THE GROUP CONSISTING OF ZINC, ALUMINUM, MIXTURES THEREOF AND ALLOYS OF SAME, SAID COMPOSITION, HAVING A WEIGHT RATIO OF CHROMIUM, EXPRESSED AS CRO3, TO PULVERULENT METAL OF BETWEEN ABOUT 1:1 AND 1:15: C. BELOW ABOUT 50 VOLUME PERCENT BUT SUBSTANTIALLY ABOVE 25 VOLUME PERCENT, BASED ON THE VOLUME OF THE TOTAL LIQUID OF THE AQUEOUS LIQUID MEDIUM, OF WATER SOLUBLE ORGANIC LIQUID SUBSTANCE THAT MAINTAINS LIQUIDITY ABOVE 100*C. AND IS SELECTED FRON THE GROUP CONSISTING OF TRIAND TETRAETHYLENE GLYCOL, DI-, AND TRIPROPYLENE GLYCOL, AND THE WATER SOLUBLE LOW MOLECULAR WEIGHT ETHERS OF ALL SUCH FOREGOING GLYCOLS, DIACETONE ALCOHOL, THE WATER SOLUBLE LOW MOLECULAR WEIGHT ETHERS OF DIETHYLENE GLYCOL, AND MIXTURES OF THE FOREGOING: AND D. ABOVE ABOUT 0.0005 VOLUME PERCENT, BASIS TOTAL VOLUME OF SAID COATING COMPOSITION, OF DISPERSING AGENT.

Claim 3

heating said substrate at a temperature, and for a period of time, sufficient to vaporize volatile substituents from said aqueous coating composition and deposit on said surface said coating.

Claim 4

heating said substrate at a temperature, and for a period of time, sufficient to vaporize volatile substituents from said aqueous coating composition and deposit on said surface said coating.

Claim 5

heating said substrate at a temperature, and for a period of time, sufficient to vaporize volatile substituents from said coating composition and deposit on said surface a composition residue and pulverulent metal, thereby preparing said substrate for welding with a coating providing corrosion resistance and weldable electroconductivity.

Claim 6

heating said substrate at a temperature, and for a period of time, sufficient to vaporize volatile substituents from said coating composition and deposit on said surface a composition residue and pulverulent metal, thereby preparing said substrate for welding with a coating providing corrosion resistance and weldable electroconductivity.

Claim 7

The coating composition of claim 1 wherein said organic liquid substance is selected from the group consisting of dipropylene glycol, tripropylene glycol monomethyl ether, tetraethylene glycol, diethylene glycol monoethyl ether, dipropylene glycol monomethyl ether, and mixtures of the foregoing.

Claim 8

heating said substrate at a temperature and for a period of time sufficient to vaporize volatile substituents from said coating composition and deposit on said surface a substantially water insoluble and resin-free coating of said residue and pulverulent metal, said coating providing corrosion resistance and weldable electroconductivity thereon;

Claim 9

heating said substrate at a temperature and for a period of time sufficient to vaporize volatile substituents from said coating composition and deposit on said surface a substantially water insoluble and resin-free coating of said residue and pulverulent metal, said coating providing corrosion resistance and weldable electroconductivity thereon;

Claim 10

contacting at least a porition of said one article with another article of metal to be welded;

Claim 11

contacting at least a porition of said one article with another article of metal to be welded;

Claim 12

The coating composition of claim 1 wherein said chromium-providing-substance supplies not substantially above about 60 grams per liter of chromium, expressed as CrO3, and said composition has a weight ratio of chromium, expressed as CrO3, to pulverulent metal of between about 1:4 and 1:9.

Claim 13

The coating composition of claim 1 wherein said pulverulent metal is zinc flake and said flake is present in an amount above about 150 grams per liter of said coating composition.

Claim 14

passing an electrical resistance welding current through said articles of metal and said coating thereon at the zone selected for welding; and

Claim 15

passing an electrical resistance welding current through said articles of metal and said coating thereon at the zone selected for welding; and

Claim 16

fusing said articles together in said zone of said welding.

Claim 17

fusing said articles together in said zone of said welding.

Claim 18

The coating composition of claim 1 wherein said organic liquid substance is present in an amount above about 20 volume percent.

Claim 19

A pulverulent metal containing precursor constituent adapted for blending into chromium-containing aqueous blend for preparing a substantially resin-free, liquid coating composition for metal substrates, said coating composition having a ratio of chromium, expressed as CrO3, to pulverulent metal of between about 1:1 and 1:15, wherein said precursor constituent consists of pulverulent metal the preponderance of which is zinc flake, water soluble organic liquid substance that maintains liquidity at 100*C. and is selected from the group consisting of tri, and tetraethylene glycol, di-, and tripropylene glycol, and the water soluble low molecular weight ethers of all such foregoing glycols, diacetone alcohol, the water soluble low molecular weight ethers of di-ethylene glycol, and mixtures of the foregoing, and 0-3 weight percent basis the total weight of said precursor constituent, of dispersing agent, and wherein said precursor constituent has a weight ratio of said organic liquid substance to said pulverulent metal of between about 1:2.5 - 1:0.3.

Claim 20

A pulverulent metal containing precursor constituent adapted for blending into chromium-containing aqueous blend for preparing a substantially resin-free, liquid coating composition for metal substrates, said coating composition having a ratio of chromium, expressed as CrO3, to pulverulent metal of between about 1:1 and 1:15, wherein said precursor constituent consists of pulverulent metal the preponderance of which is zinc flake, water soluble organic liquid substance that maintains liquidity at 100*C. and is selected from the group consisting of tri, and tetraethylene glycol, di-, and tripropylene glycol, and the water soluble low molecular weight ethers of all such foregoing glycols, diacetone alcohol, the water soluble low molecular weight ethers of di-ethylene glycol, and mixtures of the foregoing, and 0-3 weight percent basis the total weight of said precursor constituent, of dispersing agent, and wherein said precursor constituent has a weight ratio of said organic liquid substance to said pulverulent metal of between about 1:2.5 - 1:0.3.

Claim 21

The coating composItion precursor constituent of claim 6 wherein said pulverulent metal is 80-100 percent zinc flake by weight.

Claim 22

The coating composition precursor constituent of claim 6 wherein said organic liquid substance is selected from the group consisting of dipropylene glycol, tripropylene glycol monomethyl ether, tetraethylene glycol, diethylene glycol monoethyl ether, dipropylene glycol monomethyl ether, and mixtures of the foregoing.

Claim 23

The coating composition precursor constituent of claim 6 wherein said dispersing agent contributes between about 0.2-0.9 weight percent of same and said constituent has a weight ratio of organic liquid substance to pulverulent metal of between about 1: 2 and 1:0.8.

Claim 24

A coated metal substrate having on the surface thereof an adherent alkali and corrosion resistant water-insoluble and substantially resin free coating, which coating comprises above 10 but not substantially above about 5,000 milligrams per square foot of coated substrate of pulverulent metal selected from the group consisting of zinc, aluminum, mixtures thereof, and alloys of same in intimate mixture with the residue from a substantially resin-free hexavalent-chromium-containing aqueous coating composition containing a hexavalent-chromium-providing substance, below about 50 volume percent but substantially above 15 volume percent, basis total composition liquid, of water soluble organic liquid substance that maintains liquidity above 100*C and is selected from the group consisting of tri-, and tetraethylene glycol, di-, and tripropylene glycol, and the water soluble low molecular weight ethers of all such foregoing glycols, diacetone alcohol, the water soluble low molecular weight ethers of diethylene glycol, and mixtures of the foregoing, and said coating composition provides said residue with not above about 500 milligrams per square foot of coated substrate of chromium, wherein said coating contains a weight ratio of chromium, as chromium, to pulverulent metal of not substantially above about 0.5:1, and said residue is obtained by applying to said metal surface said hexavalent-chromium-containing composition and heating said substrate at a temperature, and for a period of time, sufficient to vaporize volatile substituents from said coating composition and deposit on said surface said residue.

Claim 25

A coated metal substrate having on the surface thereof an adherent alkali and corrosion resistant water-insoluble and substantially resin free coating, which coating comprises above 10 but not substantially above about 5,000 milligrams per square foot of coated substrate of pulverulent metal selected from the group consisting of zinc, aluminum, mixtures thereof, and alloys of same in intimate mixture with the residue from a substantially resin-free hexavalent-chromium-containing aqueous coating composition containing a hexavalent-chromium-providing substance, below about 50 volume percent but substantially above 15 volume percent, basis total composition liquid, of water soluble organic liquid substance that maintains liquidity above 100*C and is selected from the group consisting of tri-, and tetraethylene glycol, di-, and tripropylene glycol, and the water soluble low molecular weight ethers of all such foregoing glycols, diacetone alcohol, the water soluble low molecular weight ethers of diethylene glycol, and mixtures of the foregoing, and said coating composition provides said residue with not above about 500 milligrams per square foot of coated substrate of chromium, wherein said coating contains a weight ratio of chromium, as chromium, to pulverulent metal of not substantially above about 0.5:1, and said residue is obtained by applying to said metal surface said hexavalent-chromium-containing composition and heating said substrate at a temperature, and for a period of time, sufficient to vaporize volatile substituents from said coating composition and deposit on said surface said residue.

Claim 26

The coated metal substrate of claim 10 wherein said residue is the residue remaining after heating applied coating at a temperature above about 400*F. and for a time of at least about 1 second.

Claim 29

The method of claim 12 wherein said substrate is heated at a substrate temperature above about 400*F and for a time of at least about one second.

Claim 30

The method of claim 13 wherein said aqueous coating composition is applied to said surface in an amount sufficient to provide from about 10 to about 200 milligrams per square foot of said pulverulent metal, said aqueous coating composition further providing from about 5 to about 15 milligrams per square foot of chromium, and said coated metal substrate is subsequently topcoated.

Claim 33

The method of claim 15 wherein said substrate is heated at a temperature in excess of about 400*F. and for a time of at least about one second.

Claim 34

A weldable metal substrate prepared for electrical resistance welding according to the method of claim 15.

Claim 35

The weldable metal substrate of claim 17 wherein said substrate prepared for electrical resistance welding is the substrate of a metallic stud.

Claim 38

THE METHOD OF CLAIM 19 WHEREIN SAID COATING IS DEPOSITED ON THE SUBSTRATE OF A WELDABLE METAL STUD AND THEREAFTER SAID STUD IS ELECTRICALLY RESISTANCE WELDED TO ANOTHER ARTICLE OF METAL.

Claim 39

A welded metal article prepared according to the method of claim 20.