High current density zinc chloride electrogalvanizing process and composition
US5656148A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 2, 1995 |
| Grant date | Aug 12, 1997 |
| Priority date | — |
| Expiry date | Mar 2, 2015 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC25D3/22
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
An electrogalvanizing process and composition are disclosed for reducing high current density dendrite (HCD) formation and edge burn and controlling high current density roughness, grain size and orientation of a zinc coating obtained from a zinc halide aqueous acidic electrogalvanic coating bath. A low molecular weight polyoxyalkylene glycol homopolymer or copolymer based on 3 to about 4 carbon atom alkylene oxides as a grain refining agent in combination with a sulfonated condensation product of naphthalene and formaldehyde which is used as an antidendritic agent. A glycol compound comprising a high molecular weight polyoxyalkylene glycol homopolymer or copolymer, a depolarizer such as an aniline compound, and a carbamate compound comprising a di-lower alkyl dithio carbamyl lower alkyl sulfonic acid may also be used, optionally in combination with an aldehyde and/or a grain refining agent such as a low molecular weight polyoxyalkylene glycol homopolymer or copolymer and/or an antidendritic agent comprising a sulfonated condensation product of naphthalene and formaldehyde. HCD zinc coatings applied according to the process described herein will be smoother when using a sulfonated …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.