Influence of novel ammonium-modified zinc-free phosphate nanofillers on anticorrosive features of primer-less polyurethane top-coating compositions

Autor: Krzysztof Kowalczyk, Katarzyna Przywecka, Barbara Grzmil
Rok vydání: 2018
Předmět:
Zdroj: Journal of Coatings Technology and Research. 16:401-414
ISSN: 1935-3804
1547-0091
DOI: 10.1007/s11998-018-0119-7
Popis: Anticorrosive polyurethane coating compositions were compounded using novel zinc-free nanosized phosphates: aluminum ammonium phosphates (AAP) or calcium aluminum ammonium phosphates (CAAP). For comparison, a nanosized strontium phosphate (SP), AAP/SP mixtures, and a microsized zinc phosphate (ZP) were tested. Paints containing ammonium-modified phosphates exhibited similar or a slightly higher viscosity than systems with SP or ZP. Nevertheless, coatings with the AAP or CAAP reached significantly better gloss and adhesion to a steel substrate as well as a slightly higher hardness. Results of a salt spray test showed that anticorrosive properties of the coatings containing AAP/SP mixtures were markedly better in relation to the systems containing solely AAP, CAAP, SP, or ZP. Electrochemical tests revealed the best barrier/anticorrosive features for AAP (electrochemical impedance spectroscopy and potentiodynamic polarization) or SP and CAAP (a novel electrochemical noise technique).
Databáze: OpenAIRE