Sealing anodized aluminum using a low-temperature nickel-free process
US10138566B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 13, 2017 |
| Grant date | Nov 27, 2018 |
| Priority date | — |
| Expiry date | Apr 6, 2037 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC25D11/04
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
The inventive two-step process operates at low temperature, without any toxic heavy metals, to provide excellent sealing on anodized aluminum substrates, especially those aluminum substrates comprising silicon. The first step of the process seals the anodized surface and the second step passivates the anodized surface. The process allows for corrosion resistance in anodized aluminum and anodized aluminum alloys to be achieved that is comparable to traditional nickel based sealants, without the toxicity of nickel. The process additionally does not require any excessive temperatures, as required by hot water sealing processes. The composition used for the sealing step comprises soluble lithium ions, fluoride ions, and preferably, a complexing agent comprising phosphines, phosphonates and/or polymers of acrylic acid. The composition used for the passivation step comprises metal ions and preferably a complexing agent comprising phosphines, phosphonates and/or polymers of acrylic acid.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.