The invention relates to an in-situ reactive synthesized Nb4AlC3 bulk
ceramic by
hot pressing and a preparation method thereof. The Nb4AlC3 bulk
ceramic belongs to a hexagonal
system with the
space group being P63 / mmc, the single-celled lattice parameter a being 3.15, parameter c being 24.22 and the theoretical density being 7.06g / cm<3>. Al and Nb in the
crystal structure are combined with a weak
covalent bond, thus causing the Nb4AlC3 to generate shear deformation along the base surface (0001) under stress action and grains to easily kink and
spall, and then the grains show microscopic
plasticity in macroscopic view and can be mechanically processed by common tool steels. The specific preparation method of the single-phase Na4AlC3 is as follows: firstly,
niobium powders, aluminum powders and
graphite powders are used as materials which are ball milled for 12 to 24 hours under dry condition in a resin tank, then the materials are put in a
graphite die for cold molding (10 to 20 MPa) after sieving, and then the materials are sintered in vacuum or a
hot pressing furnace introduced with
argon, with the heating rate of 10 to 15 DEG C / min, the
sintering temperature of 1600 to 1700 DEG C, the heat preserving time of 60 to 120 minutes and applied pressure of 20 to 30 MPa. The Nb4AlC3 bulk
ceramic of the invention has the advantages of high purity, high
relative density, low
hardness and good rigidity under high temperature.