Method for Coating Metal Surfaces, Substrates Coated in This Way, and Use Thereof

Patent metadata

Field	Value
Publication number	US-2017009351-A1
Application number	US-201515113489-A
Country	US
Kind code	A1
Filing date	Jan 22, 2015
Priority date	Jan 23, 2014
Publication date	Jan 12, 2017
Grant date	—

Abstract

The invention relates to a method for coating metal surfaces with an acidic aqueous conversion composition which contains: in total 0.01 to 1 g/l of TiF 6 2+ , ZrF 6 2+ and/or HfF 6 2 calculated as ZrF 6 2+ , 0 or 0.01 to 1 g/l in each case of Fe 2+ , Mn and/or Zn ions, of which at least one type of these ions is present in a content range from 0.01 to 1 g/l, 0 or 0.01 to 2 g/l of organic polymer and/or copolymer, 0 or 0.01 to 2 g/l of ultrafme particulate SiO 2 , approximately 0 or 0.01 to 10 g/l of at least one surfactant, approximately 0 or 0.05 to 10 g/l of anions of carbonate, nitrate and/or sulphate, and 0 or 0.001 to 2 g/l of carboxylate and/or sulphonate anions, wherein the content of molybdate and/or of P-containing oxy anions is in each case <0.1 g/l or is approximately 0 g/l, and wherein the composition has a pH value in the range from 2.5 to 6.5. The invention also relates to a corresponding coating and to the use of the substrates coated in this way.

First claim

1 - 22 . (canceled)

23 . A method of coating a substrate comprising the steps of:
contacting a metallic surface of a substrate with an aqueous acidic conversion composition to produce a coating on the metallic surface, wherein the aqueous acidic conversion composition is a solution or a dispersion comprising:
a total content of 0.01 to 1 g/L of TiF 6 2+ , ZrF 6 2+ and/or HfF 6 2+ ions, calculated as ZrF 6 2+ ;
0 or 0.01 to 1 g/L of at least one type of ions selected from the group consisting of Mn and Zn ions;
0 or 0.01 to 2 g/L of an organic polymer and/or an organic copolymer which is stable at a pH of <6.5, based on the solids content;
0 or 0.01 to 2 g/L of particulate SiO 2 with an average particle diameter <0.3 μm, based on the solids content;
about 0 or 0.01 to 10 g/L of at least one surfactant;
about 0 or 0.05 to 10 g/L of anions selected from the group consisting of carbonate, nitrate and sulfate;
0 or 0.001 to 2 g/L of at least of type of anions selected from the group consisting of carboxylate and sulfonate, which cause little or no impairment of the layer-forming process, calculated as the corresponding anions;
<0.1 g /L of at least one component selected from the group consisting of molybdate, calculated as MoO 4 2+ , and a P-containing oxyanion, calculated as PO 4 3+ ; and
wherein the aqueous acidic conversion composition has a pH in the range of 2.5 to 6.5.

24 . The method according to claim 23 , wherein the aqueous acidic conversion composition further comprises:
a total content of 0.03 to 5 g/L of lithium, sodium and/or potassium ions; 0 or 0.05 to 5 g/L of ammonium ions; a total content of about. 0 or 0.05 to 0.3 g/L of Co and/or Ni ions; 0 or 0.01 to 0.8 g/L of chlorate, calculated as ClO 3 − , nitrite, calculated as NO 2 and/or peroxide, calculated as H 2 O 2 ; 0 or 0.01 to 0.5 g/L of free fluoride, calculated as F − ; and 0 or 0.01 to 0.2 g/L of vanadate ions, calculated as VO 4 3− .

25 . The method according to claim 23 , wherein the coating has a layer thickness of 0.3 to 3 μm.

26 . The method according to claim 25 , wherein the coating has a total application of elementary zirconium and/or titanium, measured as an element, in a range of 1 to 300 mg/m 2 as measured by X-ray fluorescence analysis.

27 . The method according to claim 23 , wherein the coating is colored, iridescent or gray.

28 . The method according to claim 23 , wherein the coating is a replacement for an alkali phosphate coating.

29 . The method according to claim 23 further comprising diluting one or two concentrates with water by a dilution factor in a range of 5:1 to 40:1 to prepare the aqueous acidic conversion composition used in the coating step.

30 . The method according to claim 23 , wherein the step of contacting the metallic surface of the substrate with the aqueous acidic conversion composition occurs for a period of time in a range of 1 second to 10 minutes.

31 . The method according to claim 23 , wherein the metallic surface is at a temperature in a range of 5° C. to 90° C. when brought into contact with the aqueous acidic conversion composition.

32 . The method according to claim 23 , wherein the aqueous acidic conversion composition is at a temperature in a range of 35° C. to 70° C., when brought into contact with the metallic surface of the substrate.

33 . The method according to claim 23 further comprising cleaning the metallic surface of the substrate before the contacting step.

34 . The method according to claim 23 , wherein the aqueous acidic conversion composition further comprises at least one surfactant thereby enabling cleaning of the metallic surface of the substrate in the same step as the contacting step.

35 . The method according to claim 23 further comprising (i) rinsing the coating with water or with an aqueous after-rinse solution comprising at least one component selected from the group consisting of silane, an organic polymer and an organic copolymer; and (ii) optionally enameling the coating.

36 . The method according to claim 23 further comprising (i) drying the coating if the coating does not contain an organic polymer or an organic copolymer; and (ii) optionally enameling the coating without a subsequent rinsing with water or with an aqueous after-rinse solution comprising at least one component selected from the group consisting of silane, an organic polymer and an organic copolymer.

37 . The method according to claim 23 wherein, if the coating does contain an organic polymer and/or an organic copolymer, then the coating is not further contacted with a primer, enamel or adhesive.

38 . The method according to claim 23 further comprising (i) rinsing the coating with at least one of water and an aqueous after-rinse solution; and (ii) subsequently contacting the coating with at least one component selected from the group consisting of primer, enamel and adhesive.

39 . The method according to claim 38 , wherein the aqueous after-rinse solution comprises at least one of each: a) cation selected from alkaline earth metal, aluminum, titanium, yttrium and heavy metal cations, b) an organic polymer and/or an organic copolymer, c) silane, silanol, siloxane and/or polysiloxane and/or d) complex fluoride.

40 . A method for coating a substrate comprising the steps of:
contacting a metallic surface of the substrate with an aqueous acidic conversion composition to produce a coating on the metallic surface; optionally rinsing the coating with water, and/or optionally rinsing with an aqueous composition comprising an organic polymer and/or organic copolymer that is stable at a pH of <6.5, a zirconium complex fluoride and/or silane; and enameling the coating; wherein the aqueous acidic conversion composition is a solution or a dispersion consisting essentially of:
a total content of 0.01 to 1 g/L of TiF 6 2+ , ZrF 6 2+ and/or HfF 6 2+ ions, or only ZrF 6 2+ ions, calculated as ZrF 6 2+ ;
0 or 0.01 to 1 g/L of at least one type of ions selected from the group consisting of Mn and Zn ions;
0 or 0.01 to 2 g/L of an organic polymer and/or an organic copolymer which is stable at a pH of <6.5, based on the solids content;
optionally 0.01 to 2 g/L of particulate SiO 2 with an average particle diameter <0.3 μm, based on the solids content;
optionally 0.01 to 10 g/L of at least one surfactant that is essentially phosphate-free and essentially phosphonate-free.

41 . A metallic surface of a substrate coated by the method of claim 1 .

42 . The method according to claim 23 , wherein the method is a substitute for an alkali phosphating method or a zinc phosphating method.

Assignees

• Chemetall Gmbh

Inventors

• Demeyere Korneel
• Willumeit Thomas
• Walter Manfred

Classifications

• C23C22/34 Primary

  containing fluorides or complex fluorides · CPC title

• C23C22/44 Primary

  containing also fluorides or complex fluorides · CPC title

• C23C22/364

  containing also manganese cations · CPC title

• C23C22/361 Primary

  containing titanium, zirconium or hafnium compounds · CPC title

• C23C22/83

  Chemical after-treatment · CPC title