To provide a sintering assistant by which a densified dielectric porcelain composition can be obtained without injuring characteristics even when sintered at low temperature.
The sintering assistant has a first component containing two or more kinds of M1 compounds (M1 is an alkaline metal, however), a second component containing a M2 compound (M2 is an element in Group V and Group VI, however), a third component containing a M3 compound (M3 is at least one selected among Ba, Ca, Sr, Mg, Mn, B, Al and Zn, however) and a fourth component containing oxide of Si or a compound becoming the oxide of Si by calcination. When the composition ratio from the first component to the fourth component: (the first component, the second component, the third component, the fourth component) is expressed by a tetrahedron composition diagram expressed by a point A: (100, 0, 0, 0), a point B: (0, 100, 0, 0), a point C: (0, 0, 100, 0) and a point D: (0, 0, 0, 100), the sintering assistant is characterized by that the composition ratio is satisfactorily located in a region except on a BCD face surrounded by the point B, the point C and the point D.
SATO AKIRA
NOMURA TAKESHI
