The invention relates to the technical field of
dielectric ceramic powder preparation processes, in particular to a multilayer
ceramic capacitor, high-activity nano
barium titanate powder for the multilayer
ceramic capacitor and a preparation method of the high-activity nano
barium titanate powder, and the method comprises the following steps: (1) reacting soluble
barium salt with a precipitator to obtain
barium carbonate precursor particles with high specific surface area; (2) uniformly
coating the surfaces of the
barium carbonate precursor particles with nano
titanium dioxide particles by using a
supercritical fluid flash evaporation technology to form a composite precursor; and (3) carrying out
solid-
phase synthesis reaction on the composite precursor, and
sintering to obtain the nano
barium titanate powder. Through the synergistic effect of two means of high-activity precursor preparation and nanoscale uniform
coating, the composite precursor with extremely high specific surface area,
surface energy and microcosmic uniformity is prepared, the thermal
sintering temperature is effectively reduced, abnormal growth of
crystal grains and lattice
distortion are restrained, and the preparation method has the advantages that the preparation process is simple, and the preparation cost is low. The tetragonality of the nano
barium titanate powder is obviously improved.