# US 5,700,525 A · Passivation method and composition for galvanized metal surfaces

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- Number: US 5,700,525 A
- Document ID: US5700525A
- Status: Granted
- Kind: A
- Application number: 08/594,883
- Filed: 1996-02-07
- Granted: 1997-12-23
- Earliest claimed: 1995-03-29
- Assignees: BetzDearborn Inc.
- Inventors: Jiangbo Ouyang; William L. Harpel
- Web page: https://patentgrep.com/patent/US5700525A

## CPC

- C23C 22/08: Orthophosphates
- C23C 22/42: containing also phosphates
- C23C: COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL (making metal-coated products by extrusion B21C23/22; covering with metal by connecting pre-existing layers to articles, see the relevant places, e.g. B21D39/00, B23K; metallising of glass C03C; metallising mortars, concrete, artificial stone, ceramics or natural stone C04B41/00; enamelling of, or applying a vitreous layer to, metals C23D; treating metal surfaces or coating of metals by electrolysis or electrophoresis C25D; single-crystal film growth C30B; by metallising textiles D06M11/83; decorating textiles by locally metallising D06Q1/04)

## Abstract

Compositions and methods for passivating galvanized metal surfaces are disclosed. The addition of a paraffin wax, preferably emulsified with nonionic surfactants to commercial passivation treatment (non-chrome) enhances passivation.

## Claims

### Claim 1

A process for passivating a galvanized metal surface with a substantially chromium free passivation treatment comprising including in said substantially chromium free passivation treatment from about 0.1% to about 20% by weight of a paraffin wax having a melting point of from about 90.degree. to 200.degree. F. and from about 1% to about 20% by weight of one or more nonionic surfactants having HLB values of from about 2 to about 18.

### Claim 2 (depends on 1)

The process of claim 1 wherein said substantially chromium free passivation treatment comprises from about 0.5 to 50% by weight phosphoric acid, from about 0.1 to 5% by weight boric acid and optionally from about 0.1 to 5% by weight molybdic acid.

### Claim 3

A process for passivating a galvanized metal surface with a substantially chromium free passivation treatment comprising including in said substantially chromium free passivation treatment from about 0.1% to about 20% by weight of a paraffin wax having a melting point of from about 90.degree. to 200.degree. F. and from about 1% to about 20% by weight of one or more nonionic surfactants having HLB values of from about 2 to 18 and about 0.1 to 1% by weight of a tetrafluoroethylene fluorocarbon polymer dispersion.

### Claim 4 (depends on 3)

The process of claim 3 wherein said substantially chromium free passivation treatment comprises from about 0.5 to 50% by weight phosphoric acid, from about 0.1 to 5% by weight boric acid and optionally from about 0.1 to 5% by weight molybdic acid.