Synthesis and high temperature corrosion behaviour of nearly monolithic Ti3AlC2 MAX phase in molten chloride salt. (15th April 2021)

• Record Type: Journal Article
• Authors: Magnus, Carl; Cooper, Daniel; Jantzen, Craig; Lambert, Hugues; Abram, Tim; Rainforth, Mark
• Is Part Of: Corrosion science. Volume 182(2021)
• Publication Date: 2021-04-15
• Subjects: MAX phase -- Spark plasma sintering -- Molten salt reactor -- De-intercalation -- De-twinning -- Exfoliation; Corrosion and anti-corrosives -- Periodicals; 620.11223
• DOI: 10.1016/j.corsci.2020.109193
• Languages: English
• ISSNs: 0010-938X

Abstract

Highlights: Nearly monolithic MAX phase containing 95 wt.% Ti3 AlC2 and 5 wt.% TiCx was synthesized by spark plasma sintering under vacuum sintering conditions. The decomposition of hexagonal Ti3 AlC2 into substoichiometric cubic TiCx during synthesis is linked to high-temperature de-intercalation of Al and subsequent evaporation. Corrosion behaviour of Ti3 AlC2 from a microstructure point of view was investigated in molten LiCl–KCl salt at 600 °C under a dry Ar atmosphere. Al dissolution led to delamination of the layered structure which in turn favoured the ingress of chlorine and its subsequent intercalation into the Al–site plane to form a Ti3 C2 Cl2 exfoliation layer. Abstract: Nearly monolithic MAX phase containing 95 wt.% Ti3 AlC2 and 5 wt.% TiCx was synthesized by spark plasma sintering under vacuum sintering conditions. Corrosion behaviour of Ti3 AlC2 was investigated in molten LiCl–KCl salt at 600 °C under a dry Ar atmosphere. Evolution of microstructure and surface chemistry of the exposed sample was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and glancing angle X-ray diffraction (GAXRD). Results showed that Al dissolution led to delamination of the layered structure which favoured the ingress of chlorine and its subsequent intercalation into the Al–site plane to form a Ti3 C2 Cl2 exfoliation layer. De-twinning of the Ti3 C2 layers possibly due to Cl − anions substitution by O results in non-stoichiometric TiC0.67 formation.