(Ti0.5Nb0.5)5AlC4: A New-Layered Compound Belonging to MAX Phases

A new-layered compound, (Ti0.5Nb0.5)(5)AlC4, which belongs to MAX phases was discovered. The new-layered carbide was synthesized by reactive hot pressing of Ti, Nb, Al, and C powders. The crystal structure was determined by the combination of X-ray diffraction and transmission electron microscopy analyses, which consists of a 5(Ti, Nb)-C bond chain linked by an Al layer. The lattice parameters are a=3.100 A, c=28.89 A, with Ti(Nb)1 at (0, 0, 0), Ti(Nb)2 at (1/3, 2/3, 0.0877), Ti(Nb)3 at (2/3, 1/3, 0.1723), Al at (0, 0, 0.25), C1 at (2/3, 1/3, 0.0463), and C2 at (0, 0, 0.1566).