JP3445879B2 - Dielectric porcelain composition - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dielectric ceramic composition, specifically, a dielectric material suitably used for a multilayer capacitor, a multilayer LC filter, a dielectric resonator, and the like. It relates to a porcelain composition. 2. Description of the Related Art Conventionally, as a dielectric porcelain composition used for a dielectric resonator or the like, for example, Japanese Unexamined Patent Publication No. Sho 57-69
As disclosed in Japanese Patent Application Publication No. 607, a dielectric material obtained by adding 1 to 26 wt% of ZnO to 100 wt% of a composition satisfying 3.9 ≦ x ≦ 4.1 in BaO-xTiO ₂ and mixing and firing the same. Porcelain compositions are known. However, in the above-mentioned conventional dielectric porcelain composition, if the firing temperature is not as high as 1200 ° C., it is difficult to obtain a dense porcelain, and the electrical characteristics also vary. It was easy. Therefore, an object of the present invention is to provide a dielectric ceramic composition which can be densified at a low firing temperature and has good electric characteristics. [0004] The dielectric ceramic composition of the present invention has a general formula (Ba _1-x , Zn)
_x ) On-n (Ti _1-y , Si _y ) O ₂ (However, 0.05
≦ x ≦ 0.25, 0.01 ≦ y ≦ 0.15, 3 ≦ n ≦
Bi is added to Bi ₂ with respect to 1 mol of the basic composition represented by 6).
0.003 to 0.035 mol part in terms of O ₃ , Mn is Mn
0.0005 to 0.0050 parts by mole O ₂ terms, characterized in that it contains from 0.002 to 0.040 parts by mol of Ag with Ag ₂ O conversion. The reasons for limiting the composition range of the basic composition as described above are as follows. If n is smaller than 3 or larger than 6, it will not be densified by firing at 950 ° C. or lower. On the other hand, if x is smaller than 0.05, densification does not occur by firing at 950 ° C. or lower, and if it exceeds 0.25, the Q value is low, a resonance point cannot be found, and the resistivity deteriorates. On the other hand, if y is less than 0.01, densification does not occur by firing at 950 ° C. or less, and if it exceeds 0.15, the Q value is low, no resonance point can be found, and the resistivity deteriorates. . The reasons for limiting the composition ranges of the Bi, Mn, and Ag components as described above are as follows. B
When i is smaller than 0.003 mol part in terms of Bi ₂ O ₃ , 9
If it is not densified by firing at 50 ° C. or lower, and if it exceeds 0.035 mol part, the Q value is low, no resonance point can be found, and the resistivity deteriorates. Further, Mn is 0.1 in terms of MnO ₂ .
If it is smaller than 0005 mol part, it will not be densified by firing at 950 ° C. or less, and if it exceeds 0.0050 mol part, Q value will be low, resonance point will not be found and resistivity will be deteriorated. When Ag is smaller than 0.002 mol part in terms of Ag ₂ O, the composition does not densify by firing at 950 ° C. or less,
If the amount exceeds 0.040 mol part, the Q value is low, a resonance point cannot be found, and the resistivity deteriorates. Hereinafter, the present invention will be described based on examples and comparative examples. First, BaCO ₃ and TiO ₂
Is calculated with Ba and Ti respectively, and weighed in equimolar amounts,
These were dispersed in a ball mill using ZrO ₂ beads and water as a dispersion medium and wet-mixed. Next, after dehydrating and drying this mixture, in air, at 800 to 1200 ° C.
It was calcined for 4 hours. This calcined product was dispersed under the same conditions as in the previous dispersion, wet-pulverized, and the pulverized particles thus obtained were confirmed to be uniform particles of 0.3 μm or less by SEM observation and a particle size distribution meter, and then dehydrated. Drying gave a powder. Next, the above powder and TiO ₂ , ZnO, S
iO ₂ , MnO ₂ , Bi ₂ O ₃ and Ag ₂ O were weighed so as to have a predetermined ratio as shown in Table 1 below, and were wet-mixed in a ball mill in the same manner as described above. Dehydrate, dry, and in the air at 600 ° C to 900 ° C, 4
Temporarily baked for hours. The calcined product was wet-pulverized, dehydrated and dried in the same manner as above. Next, polyvinyl alcohol was added to the dried product and granulated with a 60 mesh sieve.
The granulated material is packed in a mold and 15mmφ ×
Molded into two sizes of height 1 mm and 15 mmφ x height 6 mm (molding pressure: 1 to 3 t / cm ² ), and fired in air at a temperature in the range of 900 to 1200 ° C depending on the composition. A sintered body having each composition shown in Table 1 was obtained. The degree of densification of the obtained sintered body was evaluated by an ink test. Next, 15 mmφ x 1 mm height
An Ag electrode material paste was applied to both surfaces of a sintered body (disc-like shape) of a molded body having a size of, and baked to form a silver electrode. This was used as a sample for measuring the relative permittivity ε _r , the temperature coefficient τε of the capacitance, and the resistivity. [Table 1] [0010] In Table 1, samples without an asterisk indicate examples having compositions within the range of the present invention, and samples with an asterisk have compositions outside the range of the present invention. 13 shows a comparative example. The electrical characteristics of the sample with electrodes obtained as described above were measured. Relative permittivity ε
_r was measured at 25 ° C. and 1 MHz using an LCZ meter. Further, the temperature coefficient τε of the capacitance (ppm /
° C.) is put these electrodes with the sample in a constant temperature bath, changing the temperature to 85 ° C. from 20 ° C., and based on the capacitance at ₂₀ ℃ (C 20), which the electrostatic capacity at 85 ° C. (C ₈₅ ), and was calculated based on the following equation. Also,
The resistivity (Ω · cm) was calculated from the insulation resistance value of the sample measured at 150 ° C. and the sample size. [0011] In the case of a sintered body of a molded body having a size of 15 mmφ × 6 mm in height, a waveform at a resonance point of the dielectric cylinder resonator is measured by a dielectric cylinder resonator method (measured at 25 ° C.). Was used to calculate the Qf product. In addition, the resonance frequency was 3.5-4.5 GHz. The above evaluation results and measurement results are shown in Table 1 above. As is clear from these results, the dielectric ceramic composition of the present invention has 9
It can be densified at a sintering temperature of 50 ° C. or less, and a sample with an electrode manufactured from the obtained sintered body has a relative dielectric constant of ε.
_r , Qf product and resistivity were high. In the above Examples and Comparative Examples,
The composition of the sintered body was determined by ICP analysis of the sintered body after firing.
It turned out that it is almost the same as the composition at the time of compounding. Also,
In the above embodiment, the raw material powder is obtained by mixing, calcining, and pulverizing BaCO ₃ and TiO _2. Instead of the raw material powder, the starting material has a particle size of 0.3 μm or less. Similar results were obtained using commercially available BaTiO ₃ . BaCO ₃ , TiO ₂ , ZnO, SiO ₂ ,
MnO ₂ , Bi ₂ O ₃ and Ag ₂ O are all mixed at once,
It may be calcined. Also, instead of MnO ₂ , MnO,
It is also possible to use Mn ₃ O ₄ , MnCO ₃ , Mn (OH) _{2 and the} like. Also, Ag or the like can be used instead of Ag ₂ O. As described above, according to the dielectric ceramic composition of the present invention, Bi, Mn and Ag are added to the basic composition.
Containing a certain amount can be densified at a low firing temperature of 950 ° C. or less, so that power costs, furnace materials, sheaths, setters, and other costs can be reduced, and inexpensive Cu,
Ag or the like can be used as the electrode. In particular, considering use in a high frequency region (GHz band), since Ag is a conductor material having a low resistivity as is well known, it is very significant that it can be integrally fired with an Ag conductor.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Koichi Chaen 6-16-20 Ueno, Taito-ku, Tokyo Taiyo Yuden Co., Ltd. (56) References JP-A-9-40459 (JP, A) JP-A-4 -300245 (JP, A) JP-A-60-119010 (JP, A) JP-A-63-151657 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C04B 35/46

Claims (1)

(57) [Claims] [Claim 1] A general formula: (Ba _1-x , Zn _x ) On
(Ti _1-y , Si _y ) O ₂ (provided that 0.05 ≦ x ≦ 0.
25, 0.01 ≤ y ≤ 0.15, 3 ≤ n ≤ 6) 1 mol of Bi in terms of Bi ₂ O ₃ with respect to 1 mol of the basic composition.
003 to 0.035 mol part, Mn is 0.1% in terms of MnO ₂ .
A dielectric ceramic composition comprising 0005 to 0.0050 mol parts of Ag, and 0.002 to 0.040 mol parts of Ag in terms of Ag ₂ O.