Molten salts electrochemical synthesis of Cr<inf>2</inf>AlC

Authors: Abdelkader, A.M.

Journal: Journal of the European Ceramic Society

Volume: 36

Issue: 1

Pages: 33-42

eISSN: 1873-619X

ISSN: 0955-2219

DOI: 10.1016/j.jeurceramsoc.2015.09.003

Abstract:

The unique combination of electrical, mechanical and chemical properties of MAX phase ceramics makes them attractive for energy and structural industrial applications. Here, an inexpensive and simple electrochemical deoxidation process is used to produce high quality, homogeneous micron-size particles of one of the most widely studied MAX phases, Cr2AlC. The process used cathode precursors made of cheap and available oxides of both chromium and aluminum and applied a constant potential difference in molten NaCl-CaCl2 as the electrolyte. It was found that the reduction mechanism took an unusual pathway through the formation of sub-stoichiometric oxides and oxycarbide phases that did not necessarily involve reactions between the cathode and the electrolyte. The Cr2AlC powder produced could be easily pressed into a monolithic bulk that have 4.8±0.8GPa hardness and showed excellent oxidation resistance at temperatures below 1100°C. The method is quite generally applicable to the preparation of other MAX phases. Implications are drawn considering the industrial scale-up of this method for the low-cost production of MAX ceramics.

Source: Scopus

Molten salts electrochemical synthesis of Cr<sub>2</sub>AlC