DENSE CERAMICS OF BATIO3 PRODUCED FROM POWDERS PREPARED BY A CHEMICALPROCESS

A sintering optimization of barium titanate ceramics from fine-grained and homogeneous reproducible powders obtained by the citric process i s presented. Different sintering parameters are studied. heating rates , final temperature, dwelling rimes at this final temperature, and inf luence of the powder deagglomeration step. The sintering is followed b y dilatometric measurements The ceramics obtained by sintering at 1230 or 1300 degrees C are fi ee of barium carbonate, the residual carbon content being estimated at about 400 ppm in the surface layer. They ex hibit a grain size close to I mu m, a structure in which the cubic and tetragonal phases coexist, and a density of about 96% of the theoreti cal density. Their permittivity and loss factor are respectively about 5000 and 2.5 X 10(-2) at 25 degrees C.