Capacitors and high dielectric constant ceramics therefor

A ceramic material exhibiting a small temperature coefficient of capacitance across the temperature range of -55.degree. C. to 125.degree. C. when compared to the capacitance measured at room temperature at 1 KHz or 1 MHz, depending upon the capacitance of the material, and a dielectric constant in excess of 105, when measured at room temperature at 1 KHz or 1 MHz, which material has a composition encompassed within the formula;

• (Bi.sub.2 O.sub.2) 2+(A.sub.m-1 B.sub.m Mn.sub..gamma. O.sub.3m+.delta.+1).sup.2+
• wherein A consists essentially of at least one element selected from the group consisting of Ca, Sr, Ba, Bi and Pb, and B consists essentially of at least one element selected from the group consisting of Nb, Ta, and Ti, and at least part of B is replaced with a single pair of mixed ions selected from the group consisting of
• C.sub.1/3.sup.2+ D.sub.2/3.sup.5+ ( 1)
• E.sub.1/4.sup.1+ D.sub.3/4.sup.5+ ( 2)
• F.sub.1/2.sup.3+ D.sub.1/2.sup.5+, (3)
• F.sub.2/3.sup.3+ G.sub.1/3.sup.6+ ( 4)
• C.sup.2+ are selected from the group consisting of a Mg.sup.2+, Zn.sup.2+, Ni.sup.2+, Co.sup.2+, and Cd.sup.2+,
• D5+ ions are selected from the group consisting of Nb.sup.5+ and Ta.sup.5+ ;
• E.sup.+ ions are selected from the group consisting of Li.sup.+, Na.sup.+, K.sup.+, Cu.sup.+, and Ag.sup.+ ;
• F.sup.3+ ions are selected from the group consisting of Cr.sup.3+, Fe.sup.3+, Al.sup.3+, Ga.sup.3+, Tl.sup.3+, As.sup.3+, Sb.sub.3+, Y.sup.3+, Lu.sup.3+, Yb.sup.3 a.sup.+, Tm.sup.3+, Er.sup.3+, Ho.sup.3+, Dy.sup.3+, Tb.sup.3+, Gd.sup.3+, Eu.sup.3+, and Sm.sup.3 .sup.+ ;
• and
• G.sup.6+ ions are selected from the group consisting of W.sup.6+ and Mo.sup.6.sup.+ ;
• and wherein m is greater than 1, .gamma. is greater than 0, and .delta., the oxide contribution of manganese oxide, is greater than 0.

The dielectric ceramic exhibiting a small temperature coefficient of capacitance across the temperature range of -55.degree. C. to 125.degree. C. when compared to the capacitance measured at room temperature at 1 KHz or 1 MHz, depending upon the capacitance of the material, and a dielectric constant in excess of 105, when measured at room temperature at 1 KHz or 1 MHz, which material has a composition encompassed within the formula;

• (Bi.sub.2 O.sub.2).sub.2+ (A.sub.m-1 B.sub.m Zr.sub..beta. O.sub.3m+.delta.+1).sup.2-
• wherein A consists essentially of at least one element selected from the group consisting of Na, Ca, Sr, Ba, and Bi, and B consists essentially of at least one element selected from the group consisting of Nb, Ta, and Ti, and at least part of B is replaced with a single pair of mixed ions selected from the group consisting of
• C.sub.1/3.sup.2+ D.sub.2/3.sup.5+, (1)
• E.sub.1/4.sup.1+ D.sub.3/4.sup.5+, (2)
• F.sub.1/2.sup.3+ D.sub.1/2.sup.5+, (3)
• F.sub.2/3.sup.3+ G.sub.1/3 ( 4)
• wherein:
• C.sup.2+ ions are 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 .sup.+ ;
• D.sup.5+ ions are selected from the group consisting of Nb.sup.5+ and Ta.sup.5+ ;
• E+ions are selected from the group consisting of Li.sup.+, Na.sup.+, K.sup.+, Cu.sup.+, and Ag.sup.+ ;
• .sup.+ ions are selected from the group consisting of Cr.sup.3+, Fe.sup.3+, Al .sup.3+, Ga.sup.3+, Tl.sup.3+, As.sup.3+, Sb.sub.3+, Y.sup.3+, Lu.sup.3+, Yb.sup.3+, Tm.sup.3+, ER'.sup.3+, Ho.sup.3+, Dy.sup.3+, Tb.sup.3+, Gd.sup.3+, Eu.sup.3+, and Sm.sup.3 .sup.+ ;
• and
• G.sup.6+ ions are selected from the group consisting of W.sup.6+ and Mo.sup.6 .sup.+ ;
• and wherein m is greater than 1, .beta. is greater than 0, and .delta., the oxide contribution of zirconia, is greater than 0.

A ceramic material exhibiting a small temperature coefficient of capacitance across the temperature range of -55.degree. C. to 125.degree. C. no greater than 35 ppm/C when compared to the capacitance measured at room temperature at 1 KHz or 1 MHz, depending upon the capacitance of the material, and a dielectric constant in excess of 105, when measured at room temperature at 1 KHz or 1 MHz, and a dissipation factor no greater than 0.1% when measured at room temperature and 1 KHz or 1 MHz, which material has a composition encompassed within the formula;

• (Bi.sub.2 O.sub.2).sup.2+ (A.sub.m-1 B.sub.m Mn.sub..gamma. Zr.sub.62 O.sub.3m+.delta.+1).sup.2-
• wherein A consists essentially of at least one element selected from the group consisting of Na, K, Ca, Sr, Ba, Bi, and Pb, and B is replaced with a single pair of mixed ions selected from the group consisting of
• C.sub.1/3.sup.2+ D.sub.2/3.sup.5+, (1)
• E.sub.1/4.sup.1+ D.sub.3/4.sup.5+, (2)
• F.sub.1/2.sup.3+ D.sub.1/2.sup.5+, (3)
• and
• F.sub.2/3.sup.3+ G.sub.1/3.sup.6+ ( 4)
• wherein:
• C.sup.2+ ions are 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 .sup.+ ;
• D.sup.5+ ions are selected from the group consisting of Nb.sup.5+ and Ta.sup.5+ ;
• E+ions are selected from the group consisting of Li.sup.+, Na.sup.+, K.sup.+, Cu.sup.+, and Ag.sup.+ ;
• F.sup.3+ ions are selected from the group consisting of Cr.sup.3+, Fe.sup.3+, Al.sup.3+, Ga.sup.3+, Tl.sup.3+, As.sup.3+, Sb.sub.3+, Y.sup.3+, Lu.sup.3+, Yb.sup.3+, Tm.sup.3+, Er.sup.3+, Ho.sup.3+, Dy.sup.3+, Tb.sup.3+, Gd.sup.3+, Eu.sup.3+, and Sm.sup.3 .sup.+ ;
• and
• G.sup.6+ ions are selected from the group consisting of W.sup.6+ and Mo.sup.6 .sup.+ ;
• and wherein m is greater than 1, .beta. is greater than 0, .gamma. is greater than 0, and .delta., the oxide contributions of zirconia and manganese oxide, is greater than 0.