Conversion of MAX phase single crystals in highly porous carbides by high temperature chlorination
Résumé
We show that combining high temperature chlorination with the chemical sensitivity of the A-atom planes of single crystals of some nano-lamellar MAX phases allows one to synthesize highly porous and electrically conducting carbides. Focusing on the case of porous Cr 3 C 2 , we present the dependence of the layer morphology, structure and formation kinetics on processing parameters such as temperature and time. The determination of the Raman signature of Cr 3 C 2 and Cr 7 C 3 allows us to follow the creation and elimination of the various phases as a function of processing time. Electrical resistivity and magnetoresistance data versus temperature and magnetic field are also presented and analyzed.