Abstract: A ceramic material powder for a translucent ceramic is molded with a binder, and the resulting green compact is embedded in a ceramic powder having the same composition with the ceramic material powder. After removing the binder, the green compact embedded in the ceramic powder is fired in an atmosphere having an oxygen concentration higher than that in the removal procedure of the binder and thereby yields a translucent ceramic represented by Formula I: Ba{(SnuZr1-u)xMgyTaz}vOw, Formula II: Ba(ZrxMgyTaz)vOw or Formula III: Ba{(SnuZr1-u)x(ZntMg1-t)yNbz}vOw. The translucent ceramic has a refractive index of 1.9 or more and is paraelectric.

Abstract: A ceramic material powder for a translucent ceramic is molded with a binder, and the resulting green compact is embedded in a ceramic powder having the same composition with the ceramic material powder. After removing the binder, the green compact embedded in the ceramic powder is fired in an atmosphere having an oxygen concentration higher than that in the removal procedure of the binder and thereby yields a translucent ceramic represented by Formula I: Ba{(SnuZr1-u)xMgyTaz}vOw, Formula II: Ba(ZrxMgyTaz)vOw or Formula III: Ba{(SnuZr1-u)xZntMg1-t)yNbz}vOw. The translucent ceramic has a refractive index of 1.9 or more and is paraelectric.

Abstract: A ceramic material powder for a translucent ceramic is molded with a binder, and the resulting green compact is embedded in a ceramic powder having the same composition with the ceramic material powder. After removing the binder, the green compact embedded in the ceramic powder is fired in an atmosphere having an oxygen concentration higher than that in the removal procedure of the binder and thereby yields a translucent ceramic represented by Formula I: Ba{(SnuZr1-u)xMgyTaz}vOw, Formula II: Ba(ZrxMgyTaz)vOw or Formula III: Ba{(SnuZr1-u)x(ZntMg1-t)yNbz}vOw. The translucent ceramic has a refractive index of 1.9 or more and is paraelectric.

Abstract: A ceramic material powder for a translucent ceramic is molded with a binder, and the resulting green compact is embedded in a ceramic powder having the same composition with the ceramic material powder. After removing the binder, the green compact embedded in the ceramic powder is fired in an atmosphere having an oxygen concentration higher than that in the removal procedure of the binder and thereby yields a translucent ceramic represented by Formula I: Ba{(SnuZr1-u)xMgyTaz}vOw, Formula II: Ba(ZrxMgyTaz)vOw or Formula III: Ba{(SnuZr1-u)xZntMg1-t)yNbz}vOw. The translucent ceramic has a refractive index of 1.9 or more and is paraelectric.

Abstract: A piezoelectric ceramic material having excellent mechanical strength, excellent resistance to chemicals, and excellent moisture resistance. The piezoelectric ceramic material contains lead oxide, wherein a closed region observed under a transmission electron microscope and defined by a plurality of crystal grains which constitute the sintered piezoelectric ceramic material and are adjacent to one another is predominantly formed of an amorphous phase.

Abstract: A fine powder heat treating apparatus which includes a container rotated by an electric motor, a quantity of rolling media disposed in the container and a heater provided for heating the container and the rolling media, wherein the rolling media are mixed with each other as the container is rotated and a finely powdered raw material in a fluid state containing fine powder and a liquid component is supplied from a raw material discharge pipe.

Abstract: A heat treatment apparatus for ceramics is adapted to heat treat a ceramic raw material such as a slurry for obtaining a pulverized ceramic material. The apparatus comprises a drum body (1) which is transversely supported and rotated about its axis, and a number of rolling media (2) which are stored and stirred in the drum body (1). The drum body (1) has a pyramidal inner surface, so that the rolling media (2) are strongly stirred following rotation of the drum body (1), whereby the ceramic raw material is heat treated and pulverized effectively.

Abstract: A dielectric ceramic composition for high frequencies comprises a main component of a TiO.sub.2 -ZrO.sub.2 -Sn.sub.2 O system and contains, as additives, not more than 7 wt % of ZnO, not more than 10 wt % of NiO, and not more than 7 wt % of one metal oxide selected from the group consisting of Nb.sub.2 O.sub.5, Ta.sub.2 O.sub.5, WO.sub.3 and Sb.sub.2 O.sub.5. The main component consists essentially of 22 to 43 wt % of TiO.sub.2, 38 to 58 wt % of ZrO.sub.2, and 9 to 26 wt % of SnO.sub.2.

Abstract: A dielectric ceramic composition for microwave applications consists essentially of a sintered mixture represented by the general formula:(1-x)MgTiO.sub.3 --x(Ca.sub.1-y Me.sub.y)TiO.sub.3wherein Me is at least one rare earth element selected from the group of Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu, and wherein x and y are molar fractions of respective components and take values within the following respective ranges: 0.03.ltoreq.x.ltoreq.0.15, 0.001.ltoreq.y.ltoreq.0.06. The composition is a fine-grained, dence ceramic and enables to produce microwave devices with high permittivity, high quality factor and small temperature coefficient of resonance frequency.

Abstract: A dielectric ceramic composition for high frequencies consisting essentially of 83 to 99.8 wt% of a basic composition composed of 22 to 43 wt% of titanium dioxide, 38 to 58 wt% of zirconium dioxide and 9 to 26 wt% of stannic oxide, and 0.2 to 17 wt% of one or two addditives selected from the group consisting of lanthanum oxide, cobaltic oxide and zinc oxide. The dielectric ceramic composition has high permittivity and high Q and is suitable for use as dielectric resonators in microwave bandpass filters, or as antennas employed at microwave frequencies, or as substrates for microwave circuits.