Composite dielectric ceramic material having anti-reduction and high temperature stability characteristics and method for preparing same

Abstract

A composite dielectric ceramic material having anti-reduction and high temperature stability characteristics includes the main component of (1-x)(BaTiO.sub.3)-x(Ba.sub.2LiTa.sub.5O.sub.15) formulated in accordance with the relative molar ratio of up to 100 mole composite dielectric ceramics and a predetermined ratio of one or multiple oxide subcomponents corresponding to 100 moles of the main component. The oxide subcomponents of Li.sub.2TiO.sub.3, BaSiO.sub.3, (Ba.sub.0.6Ca.sub.0.4)SiO.sub.3 and SiO.sub.2 can be used as sintering aids to provide a sintering promotion effect. The oxide subcomponents of CaO, MnO, MgO can also be selected used to improve dielectric stability. More particularly, CaO has the advantages of improving the anti-reduction ability and increasing the coefficient of resistance. Therefore, with the adding of the oxide subcomponents and their interactions, the rate of change of the TCC curve of the composite dielectric ceramic material (1-x)(BaTiO.sub.3)-x(Ba.sub.2LiTa.sub.5O.sub.15) in the temperature range of 55 C.200 C. is significantly inhibited, and its dielectric constant (k-values) is also well improved.

Claims

1. A composite dielectric ceramic material comprising: main components of BaTiO.sub.3 and Ba.sub.2LiTa.sub.5O.sub.15; and Li.sub.2TiO.sub.3 to improve the dielectric characteristics of said main components, an amount of said Li.sub.2TiO.sub.3 is in the range of 0.130 moles corresponding to 100 moles of said main components.

2. The composite dielectric ceramic material as claimed in claim 1, further comprising a unary oxide selected from the group of MnO, MgO, CaO, SiO.sub.2 and their combinations, the added amount of said unary oxide is in the range of 0.110.0 moles.

3. The composite dielectric ceramic material as claimed in claim 2, wherein the rate of change of the TCC curve in the temperature range of 150200 C. is between 15.0%.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a tablet type capacitor preparation flow chart in accordance with the present invention.

(2) FIG. 2 is a sectional view of a tablet type capacitor made according to the present invention.

(3) FIG. 3 is a multilayer ceramic capacitor (MLCC) preparation flow chart in accordance with the present invention.

(4) FIG. 4 is a sectional view of a multilayer ceramic capacitor (MLCC) made according to the present invention.

(5) FIG. 5 is a dielectric characteristic measurement diagram of the composite dielectric ceramic material samples numbers 16 in accordance with the present invention.

(6) FIG. 6 is a dielectric characteristic measurement diagram of the composite dielectric ceramic material samples numbers 711 in accordance with the present invention.

(7) FIG. 7 is a dielectric characteristic measurement diagram of the composite dielectric ceramic material samples numbers 1316 in accordance with the present invention.

(8) FIG. 8 is a dielectric characteristic measurement diagram of the composite dielectric ceramic material samples numbers 12, 18, 19, 3336 and 3839 in accordance with the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

(9) Referring to FIGS. 14, a tablet type capacitor preparation flow chart, a sectional view of a tablet type capacitor, a multilayer ceramic capacitor (MLCC) preparation flow chart and a sectional view of a multilayer ceramic capacitor (MLCC) are illustrated. As illustrated, during the preparation of a tablet type ceramic capacitor, prepare an initial powder material by mixing main components (BaTiO.sub.3 and Ba.sub.2LiTa.sub.5O.sub.15) and at least one oxide subcomponent (Li.sub.2TiO.sub.3, BaSiO.sub.3, (Ba.sub.0.6Ca.sub.0.4)SiO.sub.3, SiO.sub.2, MgO, MnO and CaO) according to the formulas of Table 2 and Table 3, and calculating the molar number of each component based on the measurement unit of 100 moles. After preparation of tablet type ceramic capacitor samples, measure the dielectric characteristics or other electrical characteristics of the ceramic capacitor samples. In the preparation, BaTiO.sub.3 can be obtained by chemical reaction from BaCO.sub.3 and TiO.sub.2; Ba.sub.2LiTa.sub.5O.sub.15 can be obtained by chemical reaction from BaCO.sub.3, Li.sub.2CO.sub.3 and Ta.sub.2O.sub.5; Li.sub.2TiO.sub.3 can be obtained by chemical reaction from Li.sub.2CO.sub.3 and TiO.sub.2; BaSiO.sub.3 can be obtained by chemical reaction from BaCO.sub.3 and SiO.sub.2; (Ba.sub.0.6Ca.sub.0.4)SiO.sub.3 can be obtained by chemical reaction from BaCO.sub.3, CaCO.sub.3 and SiO.sub.2.

(10) Referring to FIG. 1 and FIG. 2 again, 20 g composite dielectric ceramic powder prepared subject to Table 2 is put in a cylindrical polyethylene bottle of diameter 50 mm and volume 200 ml, and then 200 g Zirconia oxide balls of diameter 3 mm are put in the cylindrical polyethylene bottle for use as grinding elements, and then ethanol is added to the cylindrical polyethylene bottle for use as a mixed solvent, and then the cylindrical polyethylene is rotated at 360 rpm for 612 hours to well mix the dielectric ceramic powder.

(11) The well mixed dielectric ceramic powder is then dried at 80 C. Thereafter, prepare a ceramic embryogenic tablet by: adding 5 wt % polyvinyl alcohol (PVA) aqueous binder (water solution prepared by 15 wt % PVA and 85 wt % pure water) to the prepared dielectric ceramic powder, and then well mixing the applied materials to enhance powder formability, and then using a 80 mesh stainless steel screen prepared subject to the specifications of American Society for Testing and Materials (ASTM) to screen the powder material, and then taking 0.4 g of the screened powder to cast a round embryogenic tablet of diameter 10 mm using an uniaxial molding method, and then heating the round embryogenic tablet under the atmosphere environment at 550 C. for 4 hours (at the heating rate of 5 C./min) to burn out polyvinyl alcohol (PVA) aqueous binder, and then sintering the round embryogenic tablet under a reducing atmosphere composed of 98% N.sub.2-2% H.sub.2 and 35 C. saturated water vapor at 1000 C.1400 C. (at the heating rate of 5 C./min) for 2 hours, and then applying an reoxidation heat treatment to the sintered ceramic body under 60 ppm150 ppm or the atmospheric environment at 900 C.1050 C. (at the heating rate of 5 C./min), and then using a screen-printing technique to print Ag, Cu or Ni on the sintered ceramic body so as to form an electrode on each of two opposite parallel sides of the sintered ceramic body. Tablet type capacitor samples (see FIG. 2) can thus be prepared.

(12) TABLE-US-00002 TABLE 2 Formula & Dielectric Characteristic Table EIA Sample Spec. BaTiO.sub.3 Ba.sub.2LiTa.sub.5O.sub.15 Li.sub.2TiO.sub.3 BaSiO.sub.3 (Ba.sub.0.6Ca.sub.0.4)SiO.sub.3 MgO MnO 1 X8S 97.00 3.00 2 X8R 95.00 5.00 3 X9R 90.00 10.00 4 X9R 87.50 12.50 5 X9R 85.00 15.00 6 X9R 80.00 20.00 7 X9S 74.00 26.00 8 X9T 70.00 30.00 9 X9T 60.00 40.00 10 X9T 50.00 50.00 11 X8R 97.73 2.27 4.55 12 X8R 96.34 3.66 7.32 13 X8R 94.74 5.26 1.00 14 X8R 94.74 5.26 3.00 15 X8R 94.74 5.26 5.00 16 X8R 94.74 5.26 7.00 17 X8R 94.74 5.26 10.53 18 X9R 92.86 7.14 14.29 19 X9R 92.01 7.99 15.98 20 X9R 87.93 12.07 24.14 21 X8R 94.74 5.26 2.31 22 X7R 94.74 5.26 4.62 23 X8R 94.74 5.26 2.25 24 X8R 94.74 5.26 4.50 25 X8R 97.73 2.27 1.70 26 X8R 94.74 5.26 3.95 27 X9R 92.01 7.99 15.98 28 X9R 92.01 7.99 15.98 29 X8R 92.01 7.99 15.98 30 X8R 90.62 9.38 7.04 31 X8R 92.86 7.14 4.28 1.00 32 X8R 92.86 7.14 4.28 1.50 33 X9R 92.01 7.99 15.98 2.00 34 X9R 92.01 7.99 15.98 4.00 35 X9R 96.34 3.66 7.32 1.00 36 X9S 96.34 3.66 7.32 2.00 37 X9S 92.86 7.14 4.28 0.50 38 X9R 92.86 7.14 14.29 0.25 39 X9R 92.86 7.14 14.29 0.50 40 X8R 92.86 7.14 4.50 0.50 41 X8R 92.86 7.14 4.50 1.00 42 X8R 92.86 7.14 4.50 1.50 43 X8R 94.74 5.26 3.95 0.50 44 X9S 94.74 5.26 1.00 45 X9R 94.74 5.26 3.29 1.00 46 X9R 94.74 5.26 6.58 1.00 47 X9R 94.74 5.26 10.53 1.00 48 X9S 94.74 5.26 10.53 1.00 49 X8R 94.74 5.26 10.53 1.00 50 X9R 92.86 7.14 4.28 0.50 51 X9R 92.86 7.14 4.28 1.00 0.20 55 C. 125 C. 150 C. 200 C. Sample CaO K 25 C. DF TCC TCC TCC TCC 1 1076 0.5% 4.2% 13.2% 20.3% 47.5% 2 571 0.4% 4.6% 10.6% 13.5% 35.5% 3 150 0.2% 7.1% 6.8% 8.9% 14.9% 4 116 0.7% 5.4% 6.9% 9.0% 14.4% 5 312 0.5% 5.8% 3.1% 3.1% 7.3% 6 252 0.3% 9.2% 8.6% 5.6% 8.6% 7 206 0.2% 12.3% 11.5% 12.5% 16.3% 8 192 0.1% 16.3% 13.3% 16.1% 21.6% 9 219 0.6% 17.4% 13.6% 16.5% 21.9% 10 212 1.0% 17.7% 16.7% 18.6% 25.5% 11 1665 1.5% 11.8% 12.0% 1.3% 34.4% 12 1346 1.2% 6.7% 4.2% 4.9% 27.6% 13 569 0.4% 3.1% 2.0% 9.9% 36.4% 14 755 0.5% 3.8% 2.5% 5.2% 32.1% 15 870 0.6% 1.0% 0.4% 2.6% 34.3% 16 903 1.0% 2.0% 2.6% 3.9% 32.8% 17 1088 1.1% 6.8% 5.5% 7.2% 22.5% 18 895 1.0% 3.0% 3.7% 6.0% 14.8% 19 831 0.9% 1.9% 0.3% 3.0% 13.0% 20 554 1.0% 4.5% 4.2% 0.4% 0.9% 21 961 2.2% 11.1% 3.5% 2.5% 27.4% 22 1304 1.8% 10.5% 2.3% 44.0% 24.6% 23 933 0.5% 7.0% 0.7% 2.0% 29.2% 24 1040 0.7% 7.9% 0.8% 2.8% 33.2% 25 2.00 1609 1.0% 8.7% 3.9% 3.9% 46.6% 26 2.00 1116 0.8% 7.9% 1.0% 3.5% 36.6% 27 2.00 803 0.8% 3.0% 1.4% 4.2% 11.9% 28 4.00 776 0.6% 1.6% 0.7% 1.9% 14.5% 29 10.00 659 0.5% 1.2% 4.8% 5.0% 21.3% 30 2.00 554 0.6% 0.7% 5.4% 6.9% 26.5% 31 754 0.7% 3.1% 1.9% 0.8% 19.4% 32 672 0.5% 3.7% 4.8% 3.8% 15.9% 33 709 0.8% 1.5% 0.6% 2.7% 7.1% 34 532 1.0% 1.3% 0.4% 3.0% 0.4% 35 940 1.6% 3.5% 11.6% 13.2% 11.0% 36 785 2.0% 2.2% 13.6% 18.0% 5.9% 37 705 0.7% 3.0% 2.9% 2.2% 18.0% 38 720 1.0% 1.9% 0.5% 3.2% 13.0% 39 698 1.3% 1.2% 5.1% 8.7% 7.3% 40 652 0.6% 7.2% 1.1% 0.6% 27.1% 41 677 0.7% 7.1% 0.4% 3.4% 28.7% 42 638 0.5% 6.5% 0.1% 2.0% 27.4% 43 2.00 1049 0.6% 3.6% 5.8% 2.3% 26.7% 44 2.00 4720 5.4% 15.8% 9.2% 9.2% 14.6% 45 2.00 912 0.5% 2.2% 4.2% 5.9% 18.6% 46 2.00 851 0.7% 0.1% 8.6% 10.1% 11.6% 47 2.00 952 1.1% 4.4% 7.5% 9.3% 9.0% 48 4.00 891 0.5% 5.3% 6.1% 6.3% 16.7% 49 8.00 771 0.5% 2.9% 1.7% 0.3% 24.0% 50 2.00 730 0.9% 1.2% 5.2% 5.6% 13.1% 51 789 1.0% 0.1% 5.9% 4.4% 12.7%

(13) TABLE-US-00003 TABLE 3 Formula & Dielectric Characteristic Table EIA 55 C. 150 C. 200 C. Resistivity Sample Spec. BaTiO.sub.3 Ba.sub.2LiTa.sub.5O.sub.15 Li.sub.2CO.sub.3 SiO.sub.2 CaO K 25 C. DF TCC TCC TCC (-cm) 19 X9R 92.01 7.99 15.98 831 0.9% 1.9% 3.0% 13.0% 0.62 10.sup.10 27 X9R 92.01 7.99 15.98 2.00 803 0.8% 3.0% 4.2% 11.9% 3.6 10.sup.10 28 X9R 92.01 7.99 15.98 4.00 776 0.6% 1.6% 1.9% 14.5% 5.9 10.sup.10 29 X8R 92.01 7.99 15.98 10.00 659 0.5% 1.2% 5.0% 21.3% 16.0 10.sup.10 52 X8R 94.74 5.26 3.00 2.00 1044 0.4% 5.2% 6.2% 34.8% 1.5 10.sup.10 53 X8R 94.74 5.26 3.00 1.00 2.00 1123 0.6% 6.58% 4.8% 33.3% 1.9 10.sup.10 54 X8R 94.74 5.26 3.00 1.50 2.00 1128 0.6% 5.7% 5.7% 33.5% 4.0 10.sup.10

(14) Referring to FIG. 3 and FIG. 4, during the preparation of a multilayer ceramic capacitor, prepare a composite ceramic powder material by mixing main components (BaTiO.sub.3 and Ba.sub.2LiTa.sub.5O.sub.15) and at least one oxide subcomponent (Li.sub.2TiO.sub.3, BaSiO.sub.3, (Ba.sub.0.6Ca.sub.0.4)SiO.sub.3, SiO.sub.2, MgO, MnO and CaO) according to the formulas of Table 2 and Table 3, and calculating the amount of each component based on the measurement unit of 100 moles prior to mixing. After obtained the expected composition ratio, add toluene, ethanol, plasticizers, adhesives and dispersants to the prepared composite dielectric ceramic powder sample to make a ceramic slurry, and then use a blade molding method to mold the ceramic slurry into thin ceramic green sheets of thickness 30 m, and then use a screen-printing technique to print commercial Ag, Pd or Ni metal paste on the thin ceramic green sheets embryonic strips subject to a predetermined internal electrode pattern. Thereafter, stack up the internal electrode pattern-printed thin ceramic green sheets embryonic strips, and then apply a hot water pressure to compress the stack of internal electrode pattern-printed thin ceramic green sheets embryonic strips tightly, and then cut the compressed stack of internal electrode pattern-printed thin ceramic green sheets into individual multilayer ceramic embryos, and then heat the multilayer ceramic embryo under pure N.sub.2 environment at 330 C.500 C. (at the heating rate of 2 C./min) for 612 hours to burn out organic substances completely, and then sinter the multilayer ceramic embryos under the composition of the reducing atmosphere of 98% N.sub.2-2% H.sub.2 and 35 C. saturated steam at 1000 C.1400 C. (at the heating rate of 3 C./min) for 2 hours, and then reduce the temperature to 900 C.1050 C. (at the cooling rate of 4 C./min) to receive a re-oxidation temperature heat treatment under the environment of 60 ppm150 ppm oxygen pressure or the atmospheric environment, and then slowly lower to room temperature to obtain multilayer ceramic mature embryos. Thereafter, print Ag or Cu external electrode slurry on the multilayer ceramic mature embryos over the exposed opposite ends of the internal electrodes, and then increase the temperature to about 800 C.900 C. under pure N.sub.2 environment (at the heating rate of 15 C./min), and then cool the furnace to room temperature to complete the preparation of multilayer ceramic capacitor (MLCC) samples (see FIG. 4).

(15) Referring to FIGS. 58, dielectric characteristic measurement diagrams of the composite dielectric ceramic material samples numbers 16, samples numbers 711, samples numbers 1316 and samples numbers 12, 18, 19, 33-36 and 3839 in accordance with the present invention are illustrated. The dielectric ceramic material samples numbers 16 illustrated in FIG. 5 and the dielectric ceramic material samples numbers 710 illustrated in FIG. 6 are prepared according to the multilayer ceramic capacitor (MLCC) preparation method of the present invention, however, only the main components BaTiO.sub.3 and Ba.sub.2LiTa.sub.5O.sub.15 contain no any oxide subcomponent. The objective is to show the overall dielectric characteristics and electrical properties of the composite dielectric ceramic material of the present invention under the effect of oxide subcomponents. Further, when measuring the prepared composite dielectric ceramic capacitor samples 154, use a LCR meter to measure temperature coefficient of capacitance (TCC) curve of every composite dielectric ceramic capacitor sample, and then apply AC 1V at 1 kHz to measure the variation of capacitance value relative to temperature at 55 C.200 C. and the dielectric-loss factor (DF) at room temperature.

(16) From the dielectric ceramic material samples numbers 16 illustrated in FIG. 5 and the dielectric ceramic material samples numbers 710 illustrated in FIG. 6, we can see that increasing the proportion of Ba.sub.2LiTa.sub.5O.sub.15 can get composite dielectric ceramic capacitors that have the TCC (temperature-current characteristic) curve gradually stabilized at high temperature range (150 C.200 C.). However, the measurement results of Table 2 show that the dielectric constants (k-values) of the samples have been significantly lowered with the adding of Ba.sub.2LiTa.sub.5O.sub.15. Further, from the measurement results shown in FIG. 6 and Table 2, we can see that sample 11 has the characteristics of dielectric temperature stability and high dielectric constant (k-value). The dielectric constant (k-value) of sample 11 is even slightly better than sample 1.

(17) Referring to Table 2 and FIG. 7, measurement results of samples 1316 are illustrated. From these measurement results, we can see that when the subcomponent of Li.sub.2TiO.sub.3 is selected, it not only can provide a sintering promotion effect but also can flatten the TCC curve. In the example of 100 moles composite dielectric ceramic material based on the main component of (1-x)(BaTiO.sub.3)-x(Ba.sub.2LiTa.sub.5O.sub.15) and containing 94.74 moles BaTiO.sub.3 and 5.26 moles Ba.sub.2LiTa.sub.5O.sub.15, when the ratio of the oxide subcomponent Li.sub.4TiO.sub.3 corresponding to 100 moles main component was in the range of 1.07.0 moles, the dielectric constant (k-value) was relatively increased from 569 to 755, 870 and 903 with an increase in the added amount of the oxide subcomponent Li.sub.2TiO.sub.3. Although the TCC curve falls within the norms of the EIA-X8R specification when the added amount of Li.sub.2TiO.sub.3 is in the range of 1.07.0 moles, but by the temperature coefficient of capacitance (TCC) value at 200 C., we can know that, when the added amount of Li.sub.2TiO.sub.3 was 3 moles, the highest value of the TCC value was obtained, and the TCC curve was slightly stabilized.

(18) Further, in the example of 100 moles composite dielectric ceramic material with 94.74 moles BaTiO.sub.3 and 5.26 moles Ba.sub.2LiTa.sub.5O.sub.15 where BaSiO.sub.3 was used as oxide subcomponent, as indicated in Table 2, sample numbers 2122, when the ratio of the oxide subcomponent BaSiO.sub.3 was increased from 2.31 moles to 4.62 moles, the dielectric constant (k-value) was relatively increased from 961 to 1304 and the temperature coefficient of capacitance (TCC) value at 200 C. was relatively increased with the increase in the added amount. Although increasing the amount of the oxide subcomponent BaSiO.sub.3 can effectively promote the low temperature sintering densification, the temperature coefficient of capacitance (TCC) value at 150 C. surpassed over +15% when 4.62 moles BaSiO.sub.3 was added, the overall TCC curve simply falls within the norms of the EIA-X7R specification.

(19) Similarly, when (Ba.sub.0.6Ca.sub.0.4)SiO.sub.3 was used as an oxide subcomponent, as indicated in Table 2, sample numbers 2324, it achieved the same effect of lifting the dielectric constant (k-value). When the added amount of oxide subcomponent (Ba.sub.0.6Ca.sub.0.4)SiO.sub.3 was increased from 2.25 moles to 4.50 moles, the dielectric constant (k-value) simply lifted from 933 to 1040; unlike the adding of BaSiO.sub.3, increasing the added amount of (Ba.sub.0.6Ca.sub.0.4)SiO.sub.3 still enabled the overall TCC curve to fall within the norms of the EIA-X8R specification while the dielectric loss factor (DF) value was maintained below 1.0%. In short, selecting (Ba.sub.0.6Ca.sub.0.4)SiO.sub.3 as oxide subcomponent is better than BaSiO.sub.3 in dielectric temperature stability.

(20) In the samples illustrated in Table 2, first, second and third oxide subcomponents were used to define each subcomponent, i.e., except the use of one unary oxide subcomponent, a second oxide subcomponent or two or more than two other oxide subcomponents can be added. For example, samples 12, 18, 19, 3336 and 3839 illustrated in Table 2 and FIG. 8 contained a second subcomponent and other subcomponents, showing lifted temperature coefficient of capacitance (TCC) value in the temperature range of 55 C.200 C., i.e., these samples have the characteristic of dielectric temperature stability. More particularly, when multiple different oxide subcomponents were added, the variation trend of the temperature coefficient of capacitance (TCC) value and curve was more in line with EIA-X9R specification. If we consider the complex chemical reactions and interactions among the various components during the sintering process, it is difficult to predict the amazing technical effects of the oxide subcomponents formulated in accordance with the present invention.

(21) Referring to Table 2 and FIG. 8, samples 12, 18, 19, 3336 and 3839 are illustrated. Sample 12 contained main components 96.34 moles BaTiO.sub.3-3.66 moles Ba.sub.2LiTa.sub.5O.sub.15, and a first oxide subcomponent 7.32 moles Li.sub.2TiO.sub.3 as a sintering aid. Samples 3536 were based on sample 12 with 1 mole and 2 moles second oxide subcomponent MnO respectively added. With the adding of the said different amounts of the second oxide subcomponent MnO, the dielectric constant (k-value) was reduced from 1346 to 940 and 785 respectively, however, the temperature coefficient of capacitance (TCC) values of these two samples in the temperature range of 55 C.200 C. were lifted to positive values, obtaining the characteristic of dielectric temperature stability. Sample 18 contained main components 92.86 moles BaTiO.sub.3-7.14 moles Ba.sub.2LiTa.sub.5O.sub.15, and a first oxide subcomponent 14.29 moles Li.sub.2TiO.sub.3 as a sintering aid. Samples 3839 were based on sample 18 with 0.25 mole and 0.50 mole second oxide subcomponent MnO respectively added. These samples achieved the same effects as samples 12 and 3536, i.e., with the adding of the said different amounts of the second oxide subcomponent MnO, the dielectric constant (k-value) was reduced from 895 to 720 and 698 respectively, however, the temperature coefficient of capacitance (TCC) values of these two samples in the temperature range of 55 C.200 C. were lifted to positive values, obtaining the characteristic of dielectric temperature stability. Therefore, adding the second oxide subcomponent MnO can effectively lift the temperature coefficient of capacitance (TCC) value in the temperature range of 55 C.200 C., but, the most appropriate amount of the second oxide subcomponent MnO must be relatively adjusted in accordance with the molar proportion of the main components, otherwise the temperature coefficient of capacitance (TCC) value will exceed the range of +15%.

(22) Referring to Table 2 and FIG. 7, samples 19 and 3334 are illustrated. As illustrated, when MgO was used as the second oxide subcomponent instead of MnO, an effect similar to the use of MnO was obtained. Sample 19 contained main components 92.01 moles BaTiO.sub.3-7.99 moles Ba.sub.2LiTa.sub.5O.sub.15, and a first oxide subcomponent 15.98 moles Li.sub.2TiO.sub.3 as a sintering aid. Samples 33-34 were based on sample 19 with 2 moles and 4 moles second oxide subcomponent MgO respectively added. With the adding of the said different amounts of the second oxide subcomponent MgO, the dielectric constant (k-value) was reduced from 831 to 709 and 532 respectively, however, the temperature coefficient of capacitance (TCC) values of these two samples in the temperature range of 55 C.20 C. were shifted to 0%, obtaining the characteristic of dielectric temperature stability. Therefore, adding MgO can effectively inhibit the dielectric characteristic of the main component (1-x)(BaTiO.sub.3)-x(Ba.sub.2LiTa.sub.5O.sub.15) in the temperature range of 55 C.200 C. and flatten the rate of change of the TCC curve.

(23) Further, as indicated by samples 19 and 2729 shown in Table 2 and FIG. 8, when CaO was used as the second oxide subcomponent, the anti-reduction ability of the dielectric ceramic material based on the main component of (1-x)(BaTiO.sub.3)-x(Ba.sub.2LiTa.sub.5O.sub.15) was improved, and the rate of change of the TCC curve was flattened with an increase in the added amount of CaO. Sample 19 contained main components 92.01 moles BaTiO.sub.3-7.99 moles Ba.sub.2LiTa.sub.5O.sub.15, and a first oxide subcomponent 15.98 moles Li.sub.2TiO.sub.3 as a sintering aid. Samples 2729 were based on sample 19 with 2 moles, 4 moles and 10 moles second oxide subcomponent CaO respectively added. With the adding of the said different amounts of the second oxide subcomponent CaO, the dielectric constant (k-value) was reduced from 831 to 803, 776 and 659 respectively, the dielectric loss factor (DF) value was reduced from 0.9% to 0.8%, 0.6% and 0.5% respectively, the TCC curves of these samples in the temperature range of 55 C.200 C. were shifted off-center, and the temperature coefficient of capacitance (TCC) values of these samples in the temperature range of 55 C.200 C. were reduced from 11.9% of 2 moles CaO to 14.5% of 4 moles CaO and 21.3% of 10 moles CaO.

(24) Further, according to samples 19 and 2729 as illustrated in Table 3, an increase in the added amount of the second oxide subcomponent CaO, we can observed a continuous increase in the resistivity. Samples 2729 were based on sample 19 with 2 moles, 4 moles and 10 moles second oxide subcomponent CaO respectively added. With the adding of the said different amounts of the second oxide subcomponent CaO, the resistivity was increased from 0.6210.sup.10 -cm to 3.610.sup.10 -cm, 5.910.sup.10 -cm and 16.010.sup.10 -cm respectively. However, to avoid a large decline in dielectric constant (k-value), the amount of CaO should be between 0.1 to 10.0 moles and should not exceed 10.0 moles.

(25) Further, according to samples 52, 53 and 54 illustrated in Table 3, using SiO.sub.2 as oxide subcomponent can also achieve the effects of maintaining the dielectric constant (k-value) and increasing the coefficient of resistance. Sample 52 contained main components 94.74 moles BaTiO.sub.3-5.26 moles Ba.sub.2LiTa.sub.5O.sub.15, a first oxide subcomponent 3 moles Li.sub.2TiO.sub.3 and a second oxide subcomponent 2 moles CaO. Samples 5354 were based on sample 52 with 1 mole and 1.5 moles third oxide subcomponent SiO.sub.2 respectively added. With the adding of the said different amounts of the third oxide subcomponent SiO.sub.2, the resistivity was increased from 1.510.sup.10 -cm to 1.910.sup.10 -cm and 4.010.sup.10 -cm respectively, achieving the effects of promoting sintering densification, improving the anti-reduction ability, enhancing dielectric temperature stability and avoiding deterioration and failure due to dielectric loss.

(26) Although particular embodiments of the invention have been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the invention. Accordingly, the invention is not to be limited except as by the appended claims.