Identification of carbon-containing phases in electrodeposited hard Fe–C coatings with intentionally codeposited carbon
Kristof Marcoen (Vrije Universiteit Brussel, OCAS)
Mélanie Gauvin (OCAS)
Ansbert De Cleene (OCAS)
Jacob Obitsø Nielsen (Fiberline Composites A/S, Technical University of Denmark (DTU))
Kitty Baert (Vrije Universiteit Brussel)
Herman Terryn (Vrije Universiteit Brussel, TU Delft - Team Arjan Mol)
Joost De Strycker (OCAS)
Tom Hauffman (Vrije Universiteit Brussel)
Karen Pantleon (Technical University of Denmark (DTU))
More Info
expand_more
Other than for strictly personal use, it is not permitted to download, forward or distribute the text or part of it, without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license such as Creative Commons.
Abstract
Electrodeposition from an environmentally friendly iron sulfate electrolyte with citric acid as carbon source has gained attention recently, because of excellent mechanical properties of the resulting Fe–C coatings with intentionally codeposited high-carbon concentrations. While being very attractive as protective coatings and sustainable alternatives for hard chrome coatings, comprehensive understanding of the coatings' chemical constitution including the type and location of carbon-containing phases is still lacking. The amount of codeposited carbon of up to about 0.8 wt.% significantly exceeds the solubility of carbon in ferrite, although carbon-free ferrite is the only unambiguously reported phase in as-deposited Fe–C coatings so far. In the present work, time-of-flight secondary ion mass spectrometry, X-ray photoelectron spectroscopy, and soft X-ray emission spectroscopy have been applied to identify the carbon-containing phases, which are present as minor secondary phases in the coatings but are known to have an important influence on the coatings' properties. Three carbon-containing phases could be distinguished, homogeneously distributed in the nanocrystalline ferrite base material. Iron acetates, amorphous carbon, and carbides were found in both as-deposited and annealed Fe–C coatings up to 300°C, but their fraction changes during postdeposition annealing.