Abstract: Bismuth-containing temperature-stable dielectric ceramics are disclosed herein that are stable over a wide range of frequencies, and thus are suitable for ceramic capacitors and microwave dielectrics. This class of materials is defined by the formula Bi.sub.2 O.sub.3 xTiO.sub.2 wherein x ranges up to 7 and the Ti.sup.4+ ion may be replaced with mixed ions of equivalent charge, thus maintaining charge balance. Suitable replacements for the Ti.sup.4+ ion are: A.sub.1/3.sup.2+ B.sub.2/3.sup.5+, R.sub.2/3.sup.3+ C.sub.1/3.sup.6+, A.sub.1/2.sup.2+ C.sub.1/2.sup.6+, R.sub.1/2.sup.3+ B.sub.1/2.sup.5+, M.sub.1/4.sup.1+ B.sub.3/4.sup.5+, and M.sub.2/5 .sup.1+ C.sub.3/5.sup.6+ ; where M.sup.+ is selected from the group consisting of Li.sup.+, Na.sup.+, K.sup.+, Cu.sup.+, and Ag.sup.+ ; A.sup.2+ is selected from the group consisting of Mg.sup.2+, Zn.sup.2+, Ni.sup.2+ , Co.sup.2+, Cu.sup.2+, and Cd.sup.2+ ; R.sup.3+ is selected from the group consisting of Cr.sup.3+, Mn.sup.3+, Fe.sup.3+, Al.sup.3+, Ga.sup.3+, Zn.sup.

Abstract: This invention relates to the production of ceramic materials which exhibit a dielectric constant in excess of 105, when measured at room temperature, and a small temperature coefficient of capacitance across the temperature range of -55.degree. to 125.degree. C., when compared to the capacitance measured at room temperature, which material has a composition encompassed within one of the following general formulae:(Bi.sub.2 O.sub.2).sup.2+ (A.sub.m-1 B.sub.m O.sub.3m+1).sup.2- ; (I)(Bi.sub.2 O.sub.2).sup.2+ (A.sub.m-1 B.sub.m Zr.sub..beta. O.sub.3m+.delta.+1).sup.2- ; and (II)(Bi.sub.2 O.sub.2).sup.2+ (A.sub.m-1 B.sub.m Mn.sub..gamma. O.sub.3m+.delta.+1).sup.2- (III)(Bi.sub.2 O.sub.2).sup.2+ (A.sub.m-1 B.sub.m Zr.sub..beta. Mn.sub..gamma. O.sub.3m+.delta.+1).sup.

Abstract: An intergranular insulation type semiconductive ceramic having a high effective dielectric constant includes an electrically insulating dielectric layer situated in the grain boundaries of an alkaline-earth metal titanate, zirconate, or combination thereof. The alkaline-earth metals are barium, strontium, and calcium. The dielectric layer is made of a mixture of bismuth oxide (Bi.sub.2 O.sub.3) and one or more metal oxides from nickel oxide (NiO), alumina (Al.sub.2 O.sub.3), and cuprous oxide (Cu.sub.2 O).