The development of the induction heating apparatus is seriously required with the rapid increase of the demand of induction heating apparatus. Even though the RF high power ceramic capacitor is one of the key devices, the domestic production of the capacitor has not been achieved because of the lack of fabrication technology.
$CaTiO_3$ is one of the major raw materials of MLCC(Multilayer Ceramic Capacitor). To use it as a dielectric material of high power MLCC, the composition of the commercial $CaTiO_3$ was varied to decrease the sintering temperature and the TCC(Temperature Coefficient of Capacitance). Then, the physical and electrical properties were investigated. Experimental composition systems were $CaTiO_3＋xTiO_2(x=0~1)$, $xCaTiO_3＋(1-x)MgTiO_3(x=0~1)$, and $xCaTiO_3＋(1-x)CaZrO_3(x=0~1)$. These three mixture materials have different characteristics. $TiO_2$ has independent grain structure with $CaTiO_3$. $MgTiO_3$ has multiphase structure with $CaTiO_3$. $CaZrO_3$ forms solid solution with $CaTiO_3$. The variables were sintering temperature and mixing ratio. The $CaTiO_3＋TiO_2$ system showed mechanical mixture characteristics and microstructure. As the amount of $MgTiO_3$ was increased in the $CaTiO_3＋MgTiO_3$ system, more $MgTiO_3$ and $TiO_2$ vaporized and more porous microstructure was formed. The $CaTiO_3＋CaZrO_3$ system showed one phase microstructure and mixture characteristics. Series of experiments showed that $CaZrO_3$ was the best mixing material.
The second experiment part was the fabrication of MLCC using tape casting method. Sintering aids, such as $TiO_2$, $La_2O_3$, $Nd_2O_3$, PbO, $Al_2O_3$, $SiO_2$, $B_2O_3$ and MgO were added in order to decrease the sintering temperature. The unit capacitor was designed and fabricated with 12 dielectric layers and 11 electrode layers being stacked each other with the size of 50mm × 50mm. The slurry was provided by addition of proper amount of binder system and solvent and ball milling. The best processing condition for the slurry preparation was established by varying the processing variables. The green tapes fabricated using the tape casting were covered with Ag-Pd electrodes. The unit capacitor had dielectric constant 200, loss factor 0.2%, TCC -750ppm/K.
