Additive for alkaline zinc plating

Patent metadata

Field	Value
Publication number	US-10731267-B2
Application number	US-201515322861-A
Country	US
Kind code	B2
Filing date	Jul 1, 2015
Priority date	Jul 4, 2014
Publication date	Aug 4, 2020
Grant date	Aug 4, 2020

Abstract

The present invention refers to a process for the electrolytic deposition of a zinc or zinc alloy coating on a metallic substrate, a zinc coated metallic substrate having a specific gloss as well as an aqueous alkaline plating bath for the electrolytic deposition of a zinc or zinc alloy coating on a metallic substrate and the use of a zinc plating bath additive in a process for the electrolytic deposition of a zinc or zinc alloy coating on a metallic substrate and for improving the optical appearance and/or the adhesion of a zinc or zinc alloy coating on a metallic substrate.

First claim

The invention claimed is:

1. A process for the electrolytic deposition of a zinc or zinc alloy coating on a metallic substrate, the process comprises:
a) providing an aqueous alkaline plating bath comprising
i) a source of zinc ions,
ii) a source of hydroxide ions, and
iii) a zinc plating bath additive that comprises at least one compound of formula (I),

wherein R is C 4 -C 6 -alkyl; G 1 is selected from monosaccharides with 4 to 6 carbon atoms; x is in the range of from 1 to 4 and refers to average values, and

b) placing a metallic substrate in the aqueous alkaline plating bath such that a zinc or zinc alloy coating is formed on the metallic substrate by electrolytic deposition.

2. The process according to claim 1 , wherein the source of zinc ions is zinc oxide and/or the zinc ions are present in the aqueous alkaline plating bath in an amount of from 2.0 to 30.0 g/L bath.

3. The process according to claim 1 , wherein the source of hydroxide ions is sodium hydroxide and/or the hydroxide ions are present in the aqueous alkaline plating bath in an amount of from 50.0 to 250.0 g/L bath.

4. The process according to claim 1 , wherein in the general formula (I) G 1 is selected from monosaccharides with 5 or 6 carbon atoms; and x is in the range of from 1 to 2.

5. The process according to claim 1 , wherein in the general formula (I) R is C 4 -alkyl; G 1 is glucose and/or xylose and/or arabinose and x is in the range of from 1 to 1.8.

6. The process according to claim 1 , wherein the zinc plating bath additive is present in the aqueous alkaline plating bath in an amount of from 0.1 to 10.0 g/L bath.

7. The process according to claim 1 , wherein the aqueous alkaline plating bath has a pH of from 12.0 to 14.0.

8. The process according to claim 1 , wherein the aqueous alkaline plating bath further comprises at least one additive selected from the group consisting of a brightener, a basic brightener, a mixture of a brightener and a basic brightener, a water-soluble polymer, a leveling agent, water softener, a complexing agent, and a source of cyanide ions.

9. The process according to claim 1 , wherein in b) the electrolytic deposition is carried out at a temperature of from 10 to 40° C.

10. The process according to claim 1 , wherein in b) the electrolytic deposition is carried out at a current density of from 0.05 to 15.0 A/dm 2 .

11. The process according to claim 1 , wherein the zinc or zinc alloy coating formed on the metallic substrate has a thickness of from 2.0 to 30.0 μm.

12. The process according to claim 1 , wherein said metallic substrate is a cast iron substrate.

13. An aqueous alkaline plating bath, comprising:
a source of zinc ions;
a source of hydroxide ions; and
at least one compound of the general formula (I),

wherein
R is C 4 -C 6 -alkyl: G 1 is selected from monosaccharides with 4 to 6 carbon atoms; x is in the range of from 1 to 4 and refers to average values;
wherein the aqueous alkaline plating bath is capable of electrolytic deposition of a zinc or zinc alloy coating on a metallic substrate.

Assignees

• Basf Se

Inventors

• Bauer Frederic
• Urban Tobias
• Eskuchen Rainer
• Maksym Lukas
• Schriefers Yvonne

Classifications

• C25D3/22 Primary

  of zinc · CPC title

• C25D3/565

  containing more than 50% by weight of zinc · CPC title

• C25D3/24 Primary

  from cyanide baths · CPC title