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1. (WO2018132233) SEALING ANODIZED ALUMINUM USING A LOW-TEMPERATURE NICKEL-FREE PROCESS

Pub. No.:    WO/2018/132233    International Application No.:    PCT/US2017/067493
Publication Date: Fri Jul 20 01:59:59 CEST 2018 International Filing Date: Thu Dec 21 00:59:59 CET 2017
IPC: C23C 22/40
C23C 22/42
C23C 22/44
C25D 11/24
Applicants: MACDERMID ACUMEN INC.
Inventors: SALSA, Sara
ANGELI, Patrizia
Title: SEALING ANODIZED ALUMINUM USING A LOW-TEMPERATURE NICKEL-FREE PROCESS
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.