Chromium carbide growth at low temperature by a highly efficient DLI-MOCVD process in effluent recycling mode - Archive ouverte HAL Access content directly
Journal Articles Surface and Coatings Technology Year : 2017

Chromium carbide growth at low temperature by a highly efficient DLI-MOCVD process in effluent recycling mode

Abstract

The effect of direct recycling of effluents on the quality of CrxCy coatings grown by MOCVD using direct liquid injection (DLI) of bis(ethylbenzene)chromium(0) in toluene was investigated. The results are compared with those obtained using non-recycled solutions of precursor. Both types of coatings exhibit the same features. They are amorphous in the temperature range 673–823 K. They exhibit a dense and glassy-like microstructure and a high hardness (> 23 GPa). Analyses at the nanoscale revealed a nanocomposite microstructure consisting of free-C domains embedded in an amorphous Cr7C3 matrix characterized by strong interfaces and leading to an overall composition slightly higher than Cr7C3. The stiffness and strength of these interfaces are mainly due to at least two types of chemical bonds between Cr atoms and free-C: (i) Cr intercalation between graphene sheets and (ii) hexahapto η6-Cr bonding on the external graphene sheets of the free-C domains. The density of these interactions was found increasing by decreasing the concentration of the injected solution, as this occurred using a recycled solution. As a result, “recycled” coatings exhibit a higher nanohardness (29 GPa) than “new” coatings (23 GPa). This work demonstrates that using bis(arene)M(0) precursors, direct recycling of effluents is an efficient route to improve the conversion yield of DLI-MOCVD process making it cost-effective and competitive to produce protective carbide coatings of transition metals which share the same metal zero chemistry.
Fichier principal
Vignette du fichier
Michau_19836.pdf (598.65 Ko) Télécharger le fichier
Origin : Files produced by the author(s)
Loading...

Dates and versions

hal-01677497 , version 1 (13-04-2018)

Identifiers

Cite

A. Michau, F. Maury, F. Schuster, R. Boichot, Michel Pons, et al.. Chromium carbide growth at low temperature by a highly efficient DLI-MOCVD process in effluent recycling mode. Surface and Coatings Technology, 2017, 332, pp.96 - 104. ⟨10.1016/j.surfcoat.2017.06.077⟩. ⟨hal-01677497⟩
185 View
761 Download

Altmetric

Share

Gmail Facebook X LinkedIn More