Characterization of silicon-based chromium (VI) replacement coatings by using time-of-flight secondary ion mass spectrometry and salt spray tests
Year: 2024
Type: article
Abstract: This paper proposes an innovative approach to characterizing silicon-based chromium (VI) replacement coatings on an Al substrate using, correlatively salt spray tests and time-of-flight secondary ion mass spectrometry (ToF-SIMS) performed in profile mode by a gas cluster ion beam source (GCIB). While salt spray tests show the difference in anticorrosion behavior, ToF-SIMS provides molecular information on the entire coating and even down to the interface with the Al substrate. ToF-SIMS revealed Si2O2+ and AlOSi+ fragments which both contribute to understanding the differences in the anticorrosion performance found in the salt spray tests. Si2O2+ moieties relate to the cross-linking density of the coating and subsequently determines the barrier properties. AlOSi+ originates from the interface and characterizes the actual “conversion” of Al at the interface by the deposited layer. Differences in the profile of Si2O2+ and AlOSi+ explained the respective anticorrosion performance. From the tested coatings PCT161 showed the highest intensity for both Si2O2+ and AlOSi+ while simultaneously performing the best in the salt spray test. These observations highlight that Si2O2+ and AlOSi+ fragments are good indicators of anticorrosion performance and are confirmed by salt spray tests. Moreover, PCT161 and PCT146 are true conversion coatings capable of replacing chromium-based systems.
Institution: Materia Nova
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $1,000
OpenAlex ID: W4401945787