JPH0920557A - Dielectric porcelain material - Google Patents

Abstract

(57) [Abstract] [Purpose] To be able to obtain porcelain with good dielectric properties. [Configuration] _{formula, aBaO-bLa 2 O 3 -cSm} 2
_{O 3 -dBi 2 O 3 -eTiO 2} ( where, a, b, c,
d and e are shown by mol%, and 14.2 ≦ a ≦ 19.
2, 0.20 ≦ b ≦ 13.3, 0.20 ≦ c ≦ 11.
9, 0.20 ≦ d ≦ 7.0, 62.6 ≦ e ≦ 70.6, a + b + c + d + e = 100 mol%, and 1
4.2 ≦ b + c + d ≦ 19.2, and the ZrO ₂ content is not more than 1.80 parts by weight, where 100 parts by weight is the portion represented by each composition including the amount mixed as impurities). .

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dielectric ceramic composition, and more particularly to a dielectric ceramic material for a microwave filter used in communication and broadcasting equipment.

[0002]

2. Description of the Related Art Recent advances in communication technology include mobile communication represented by car phones and mobile phones, and GPS (Glo).
Bal Positioning System) and the like are being widely spread. At the same time, these communication systems are simultaneously expanding the frequency range used and promoting frequency utilization in the microwave band.

Conventionally, a cavity resonator or an antenna has been used for a circuit used in the microwave frequency band.
However, since these are about the same size as the wavelength of microwaves, car phones, mobile phones, GPs for climbers, etc.
It was impossible to reduce the size of the device suitable for the S device. On the other hand, in recent years, a microwave filter using a dielectric resonator, a small dielectric resonator for stabilizing the frequency of an oscillator, or a dielectric porcelain is often used to downsize a circuit. Has been tried, and the spread is approaching.

The characteristics required for such a dielectric ceramic are that the permittivity (hereinafter, ε _r ) in the operating frequency band is large, that the temperature coefficient of resonance frequency (hereinafter, τ _f ) is as close to zero as possible, and This means that the dielectric loss in the wave band {hereinafter, tan δ (= 1 / Q)} is small. Since the magnitude of the dielectric loss tan δ of the dielectric material used in the microwave band is usually expressed in the form of Q × f, this is used below.

Therefore, a large value of Q × f is one of the indicators that a dielectric material is excellent. Note that f
Is the resonant frequency of the material at that time.

[0006]

The dielectric ceramics for microwaves having various compositions have been proposed so far. However, each of them has a drawback that any one of the above three characteristic items is insufficient. Therefore, in view of this point, the present inventors have a sufficiently large unloaded Q, and ε _r > 1.
_{10, | τ f | BaO-} La 2 O 3 as a composition to achieve both _{≦ 15ppm / ℃ -Sm 2 O 3} -Bi 2 O 3 -Ti
O ₂ was proposed by Japanese Patent Application No. 5-275360.

However, the crystal structure of the main phase of the porcelain having the composition proposed in the present invention becomes unstable due to the incorporation of ZrO ₂ and the existing range is narrowed, so that the dielectric properties, particularly τ _f, are deteriorated. There are drawbacks.

Therefore, the present invention is to provide a dielectric porcelain material which can suppress the generation of different phases having inferior dielectric properties and can obtain a porcelain having good dielectric properties.

[0009]

As dielectric ceramic materials for solving the above problems SUMMARY OF THE INVENTION The present inventors have BaO-R ₂ O ₃ -
In the composition region centered on 4 TiO ₂ , R is La, Sm, B
was _{i [1] aBaO-bLa 2} O 3 -cSm 2 O 3 -dB
i ₂ O ₃ -eTiO ₂ , where 14.2 ≦ a ≦ 19.2, 0.20 ≦ b ≦ 13.
3, 0.20 ≦ c ≦ 11.9, 0.20 ≦ d ≦ 7.0,
Composition within the range of 62.6 ≦ e ≦ 70.6 (mol%, a +
b + c + d + e = 100, and 14.2 ≦ b + c + d ≦
The dielectric ceramic material is characterized in that the content of ZrO ₂ is 1.80 parts by weight or less, when the composition of 19.2 is 100 parts by weight including the amount mixed as impurities).

Further, R is La, Sm, Bi and Gd. [2] aBaO-bLa ₂ O ₃ -cSm ₂ O ₃ -dB
iO ₃ -eTiO ₂ -fGd ₂ O ₃ , where 14.2 ≦ a ≦ 19.2, 0.20 ≦ b ≦ 13.
3, 0.20 ≦ c ≦ 11.9, 0.20 ≦ d ≦ 7.0,
Composition within the range of 62.6 ≦ e ≦ 70.6, 0.20 ≦ f ≦ 7.0 (mol%, a + b + c + d + e + f = 100,
And 14.2 ≦ b + c + d + f ≦ 19.2 and each composition includes the amount mixed as an impurity), the ZrO ₂ content is 1.80 parts by weight or less. Dielectric ceramic material.

Further, R is La, Sm, Bi, and B
a part of a substituted with _{Pb [3] aBaO-bLa 2} O 3 -cSm 2 O 3 -dB
iO ₃ -eTiO ₂ -gPbO, provided that 14.2 ≦ a ≦ 19.0, 0.20 ≦ b ≦ 13.
3, 0.20 ≦ c ≦ 11.9, 0.20 ≦ d ≦ 7.0,
Composition within the range of 62.6 ≦ e ≦ 70.6, 0.20 ≦ g ≦ 5.0 (mol%, a + b + c + d + e + g = 100,
14.2 ≦ a + g ≦ 19.2 and 14.2 ≦ b + c + d
Dielectric porcelain material having a ZrO ₂ content of 1.80 parts by weight or less, where ≦ 19.2 and each composition includes the amount mixed as an impurity) is 100 parts by weight.

Further, R is La, Sm, Gd, Bi,
And a portion of Ba was substituted with _{Pb [4] aBaO-bLa 2} O 3 -cSm 2 O 3 -dB
iO ₃ -eTiO ₂ -fGd ₂ O ₃ -gPbO, where 14.2 ≦ a ≦ 19.0, 0.20 ≦ b ≦ 13.
3, 0.20 ≦ c ≦ 11.9, 0.20 ≦ d ≦ 7.0,
62.6 ≤ e ≤ 70.6, 0.2 ≤ f ≤ 7.0, 0.2
Composition within the range of ≦ g ≦ 5.0 (mol%, a + b + c + d
+ E + f + g = 100, 14.2 ≦ a + g ≦ 19.2,
And 14.2 ≦ b + c + d + f ≦ 19.2 and each composition includes the amount mixed as an impurity), the ZrO ₂ content is 1.80 parts by weight or less. Dielectric ceramic material.

Further, R is La, Sm, Bi, and B
a part of a substituted with _{Sr [5] aBaO-bLa 2} O 3 -cSm 2 O 3 -dB
i ₂ O ₃ -eTiO ₂ -hSrO, however, 11.5 ≦ a ≦ 19.2,0.20 ≦ b ≦ 13.
3, 0.20 ≦ c ≦ 11.9, 0.20 ≦ d ≦ 7.0,
Composition within the range of 62.6 ≦ e ≦ 70.6, 0.20 ≦ h ≦ 3.5 (mol%, a + b + c + d + e = 100, and 13.5 ≦ a + h ≦ 19.2, and 14.2 ≦ b + c +
The dielectric ceramic material is characterized in that the content of ZrO ₂ is 1.80 parts by weight or less, where d ≦ 19.2 and each composition includes the amount mixed as impurities) is 100 parts by weight. . We found that is effective, so we came to propose here.

[0014]

[Operation] By reducing the ZrO ₂ content, during sintering,
It is possible to suppress the generation of a hetero phase rich in TiO ₂ and inferior in dielectric properties, and to obtain a porcelain having good dielectric properties.

[0015]

EXAMPLES The details of the dielectric ceramic material of the present invention will be described below based on each example.

(Example 1) First, BaCO ₃ and La ₂ O
Starting materials of ₃ , Sm ₂ O ₃ , Bi ₂ O ₃ and TiO ₂ were weighed and wet-mixed with a yttria-stabilized zirconia (hereinafter, YSZ) ball in a resin ball mill for 20 hours. At this time, the weight ratio of the powder and the ion-exchanged water used as the grinding medium was set to 1: 3. After drying the mixture,
It was calcined at 1150 ° C in the atmosphere. Further, the calcined product was wet pulverized for 2 to 160 hours by the ball mill. At this time, the weight ratio of the powder and the ion-exchanged water used as the grinding medium was set to 1: 2. Only for crushing for 20 hours, 1: 2,
There were two types of 1: 3. The pulverized product thus obtained was molded into a disk shape having a diameter of 15 mm and a thickness of about 6 mm and sintered in the atmosphere at a temperature of 1250 to 1350 ° C. to obtain a porcelain having the composition shown in Table 1.

[0017]

[Table 1] The composition _{herein, aBaO-bLa 2 O 3 -cSm} 2 O 3 -dBi 2 O 3
It was expressed as -eTiO ₂ (a + b + c + d + e = 100 mol%).

In Table 1, the samples marked with "*" in the sample numbers are shown as comparative examples. Further, the samples marked with “# 9 to 12, # 19, # 21” added to the sample numbers show the case where ZrO ₂ powder was added in the comparative example.

Next, the dielectric resonator method was used to measure the temperature dependence of the dielectric constant, the dielectric loss, and the resonance frequency of these porcelains. The temperature coefficient of resonance frequency is + 25 ~ 8
It was determined from the value of the resonance frequency at a temperature in the range of 0 ° C.
The resonance frequency was 2.2 to 3.0 GHz.

In addition, ZrO _{2 was} measured by inductively coupled plasma emission spectroscopy (hereinafter referred to as ICP) and fluorescent X-ray analysis.
The amount of contamination was checked. This is also shown in Table 1. Further, the structure of the sintered body was observed with a scanning electron microscope, and the composition of the produced phase was examined with an energy dispersive X-ray composition analyzer. About these, photograph 1 (a) of FIG.
(C) and Table 2 (results of analysis of main phase and different phase of sintered body).

[0021]

[Table 2] The photograph shown in FIG. 1 is the photograph 1 shown in Table 2.
(A), Photo 1 (b) and Photo 1 (c). Picture 1
It is understood that (a) is the composition of Sample No. 1 in which the amount of ZrO ₂ mixed is 0.12 wt%, and almost only the main phase is a single phase. Photo 1 (b) shows the composition of sample No. 7, ZrO
_{2 The} mixed amount is 1.12 wt%. In this sample 7,
It can be seen that in addition to the main phase, a TiO ₂ phase in which ZrO _{2 is} slightly solid-dissolved is formed. In Photo 1 (b), this phase looks dark. Photo 1 (c) shows the composition of Sample No. 8, and the amount of ZrO ₂ mixed is 1.98 wt%. It can be seen that there are more out-of-phases.

From these examples, it is understood that the deterioration of ε _r , Q × f, and │τ _f │ of the dielectric ceramics progresses as the ZrO ₂ content increases. Further, from the observation of the structure and the composition analysis, it is easily inferred that the deterioration of the dielectric property is related to the formation of the TiO ₂ phase in which ZrO ₂ is formed as a solid solution with the inclusion of ZrO _2. .

(Example 2) BaCO ₃ , La ₂ O ₃ and S
Starting materials of m ₂ O ₃ , Gd ₂ O ₃ , Bi ₂ O ₃ and TiO ₂ were weighed and wet-mixed for 20 hours by a resin ball mill with YSZ balls having various average densities shown in Table 3.

[0024]

[Table 3] At this time, the weight ratio of the powder and the ion-exchanged water used as the grinding medium was set to 1: 3. After this mixture was dried, it was calcined at 1150 ° C. in the atmosphere. Further, the calcined product was wet pulverized for 20 hours using a ball mill and YSZ balls. At this time, the weight ratio of the powder and the ion-exchanged water used as the grinding medium was set to 1: 2. Hereinafter, the sintered body obtained in the same manner as in Example 1 was subjected to the same measurement as in Example 1, and the results shown in Table 3 were obtained.

In Table 3, the sample marked with "* 24" attached to the sample number indicates a comparative example. "* 1" in the YSZ ball density / g / cm ³ column is a steel ball coated with urethane resin. "*" In the ZrO ₂ · wt% column
"2" indicates the detection limit by ICP.

(Example 3) Barium chloride dihydrate 1.0
Oxine was added to an aqueous solution of 0 mol, lanthanum chloride heptahydrate 0.05 mol, samarium chloride hexahydrate 0.70 mol, bismuth chloride 0.25 mol, and titanium tetrachloride 4.00 mol while adjusting the pH, Ba ²⁺ , La ³⁺ , Sm ³⁺ , B
A ^{coprecipitate} of i ³⁺ and Ti ⁴⁺ was obtained. The precipitate was washed, filtered, dried and heated at 1000 ° C. for 1 hour. By this heating, the precipitate is thermally decomposed and Ba (L
a, Sm, Bi) ₂ Ti ₄ O ₁₂ solid solution powder was obtained.

Next, with respect to 100 parts by weight of this powder, 90
1 part by weight of ion-exchanged water and 10 parts by weight of a 5 wt% polyvinyl alcohol aqueous solution were added, and the steel balls coated with urethane resin were crushed and mixed for 1 hour with a resin ball mill. Then, the obtained slurry was spray-heat dried to obtain a sintered body porcelain in the same manner as in Example 1. Then, for these porcelains, dielectric constant, dielectric loss,
And the temperature dependence of the resonance frequency was measured. The temperature coefficient of the resonance frequency was obtained from the value of the resonance frequency in the temperature range of +25 to 80 ° C. The resonance frequency is 2.2 to 3.
It was 0 GHz. Further, the amount of ZrO ₂ mixed in was examined by ICP. This is also shown in Table 4.

[0028]

[Table 4] In Table 4, the sample marked with “* 24” attached to the sample number indicates a comparative example. “* 2” in the ZrO ₂ · wt% column indicates the detection limit by ICP. YS
“* 3” in the column of Z ball density / g / cm ³ indicates that in Example 3
Use co-precipitated powder from. Steel balls coated with urethane resin are used only for crushing after calcination and binder mixing.

For comparison, BaCO ₃ and La ₂ O are also used.
Starting materials of ₃ , Sm ₂ O ₃ , Bi ₂ O ₃ , and TiO ₂ were weighed, and the powder obtained in the same manner as in Example 1 was molded,
Sintering was performed. For these, the same measurement as above was performed.

(Example 4) First, BaCO ₃ and La ₂ O
Starting materials of ₃ , Sm ₂ O ₃ , Bi ₂ O ₃ , TiO ₂ , and Gd ₂ O ₃ were weighed and wet-mixed with a YSZ ball in a resin ball mill for 160 hours. At this time, the weight ratio of the powder and the ion-exchanged water used as the grinding medium was set to 1: 3.
After the mixture is dried, it is heated to 1150 ° C in the atmosphere.
And calcined. Further, the calcined product is 2 to 2 by the ball mill.
It was wet-milled for 160 hours. At this time, the weight ratio of the powder and the ion-exchanged water used as the grinding medium was set to 1: 2. Only in the case of crushing for 20 hours, there were two types of 1: 2 and 1: 3. The pulverized material thus obtained has a diameter of 15 mm and a thickness of about 6
mm disk shape, 1250-135 in air
Sintering was performed at a temperature of 0 ° C. to obtain porcelain having the composition shown in Table 5. The composition _{herein, aBaO-bLa 2 O 3 -cSm} 2 O 3 -dBi 2 O 3
-ETiO ₂ -fGd ₂ O ₃ (a + b + c + d + e + f = 100 mol%).

[0031]

[Table 5] In addition, in Table 5, the sample of "* 34" added to the sample number indicates a comparative example.

Next, with respect to these porcelains, the dielectric resonator method was used to measure the temperature dependence of the dielectric constant, the dielectric loss, and the resonance frequency. The temperature coefficient of resonance frequency is + 25 ~ 8
It was determined from the value of the resonance frequency at a temperature in the range of 0 ° C.
The resonance frequency was 2.5 to 3.0 GHz. Further, the amount of ZrO ₂ mixed in was examined by ICP. This is also shown in Table 5.

Example 5 BaCO ₃ , PbO, La ₂
Starting materials of O ₃ , Sm ₂ O ₃ , Bi ₂ O ₃ and TiO ₂ were weighed according to each composition, and a dielectric ceramic was obtained by the same method as that shown in Example 5. Here, the composition _{aBaO-bLa 2 O 3 -cSm 2} O 3 -dBiO 3 -
eTiO ₂ -gPbO, (a + b + c + d + e + g = 100 mol%).

Next, the same measurements as those shown in Example 4 were performed on these porcelains, and the measurement results shown in Table 6 were obtained.

[0035]

[Table 6] In Table 6, "* 36, * 3" added to the sample number.
The sample “8” represents a comparative example.

(Example 6) BaCO ₃ , PbO, La ₂
O ₃ , Sm ₂ O ₃ , Gd ₂ O ₃ , Bi ₂ O ₃ , TiO ₂
The starting raw material of (1) was weighed according to each composition, and a dielectric ceramic was obtained by the same method as that shown in Example 5. Here, the composition _{aBaO-bLa 2 O 3 -cSm 2} O 3 -dBiO 3 -
eTiO ₂ -fGd ₂ O ₃ -gPbO, (a + b + c + d + e + f + g = 100 mol%).

Then, the same measurements as those shown in Example 4 were performed on these porcelains, and the measurement results shown in Table 7 were obtained.

[0038]

[Table 7] In Table 7, "* 40, * 4" added to the sample number
The sample "2" indicates a comparative example.

Example 7 BaCO ₃ , SrO, La ₂
Starting materials of O ₃ , Sm ₂ O ₃ , Bi ₂ O ₃ and TiO ₂ were weighed according to each composition, and a dielectric ceramic was obtained by the same method as that shown in Example 5. Here, the composition _{aBaO-bLa 2 O 3 -cSm 2} O 3 -dBi 2 O 3
-ETiO ₂ -hSrO, (a + b + c + d + e + h = 100 mol%).

Then, the same measurements as those shown in Example 4 were performed on these porcelains, and the measurement results shown in Table 8 were obtained.

[0041]

[Table 8] In Table 8, “* 44, * 4” added to the sample number.
The sample “6” represents a comparative example.

As is clear from each example, ZrO ₂
When the content exceeds 1.80 parts by weight, Q × f and τ _f are significantly deteriorated. Also, ε _r is deteriorated. Therefore, the ZrO ₂ content is preferably 1.80 parts by weight or less. When the ZrO ₂ content exceeds 1.00 parts by weight, | τ _f | often exceeds 15 ppm / ° C. Therefore, 1.00 parts by weight or less is more preferable as the dielectric filter material.

[0043]

As described above with reference to the embodiments, according to the dielectric ceramic material of the present invention, by reducing the ZrO ₂ content, a hetero phase rich in TiO ₂ and having poor dielectric properties is formed during sintering. Can be suppressed, and a porcelain having good dielectric characteristics can be obtained.

[Brief description of drawings]

1 (a) to 1 (c) are electron micrographs showing a grain structure of a sintered body.

Claims (5)

[Claims] 1. A general formula, aBaO-bLa ₂ O ₃ -cS.
_{m 2 O 3 -dBi 2 O 3} -eTiO 2 ( where, a, b,
c, d, and e are shown by mol%, 14.2 ≦ a ≦ 1
9.2, 0.20 ≦ b ≦ 13.3, 0.20 ≦ c ≦ 1
1.9, 0.20 ≦ d ≦ 7.0, 62.6 ≦ e ≦ 70.
Within the range of 6, a + b + c + d + e = 100 mol%, and 14.2 ≦ b + c + d ≦ 19.2, each composition including a portion mixed as an impurity) is 100.
A dielectric ceramic material having a ZrO ₂ content of 1.80 parts by weight or less when expressed as parts by weight. 2. A general formula, aBaO-bLa ₂ O ₃ -cS
m ₂ O ₃ -dBiO ₃ -eTiO ₂ -fGd ₂ O ₃ (however, a, b, c, d, e, and f are mol%, 14.2
≦ a ≦ 19.2, 0.20 ≦ b ≦ 13.3, 0.20 ≦
c ≦ 11.9, 0.20 ≦ d ≦ 7.0, 62.6 ≦ e ≦
70.6, within the range of 0.20 ≦ f ≦ 7.0, a + b + c
+ D + e + f = 100 mol%, and 14.2 ≦ b + c +
d + f ≦ 19.2, and when the portion represented by each composition includes the amount mixed as an impurity) is 100 parts by weight, the ZrO ₂ content is 1.80 parts by weight or less. Dielectric porcelain material. 3. The general formula, aBaO-bLa ₂ O ₃ -cS.
_{m 2 O 3 -dBiO 3 -eTiO 2} -gPbO ( However,
a, b, c, d, e, and g are mol%, 14.2 ≦ a
≦ 19.0, 0.20 ≦ b ≦ 13.3, 0.20 ≦ c ≦
11.9, 0.20 ≦ d ≦ 7.0, 62.6 ≦ e ≦ 7
0.6, 0.20 ≦ g ≦ 5.0, a + b + c +
d + e + g = 100 mol%, 14.2 ≦ a + g ≦ 19.
2 and 14.2 ≦ b + c + d ≦ 19.2, and each composition includes the amount mixed as an impurity), the ZrO ₂ content rate is 1.80 when the part represented by 100 parts by weight.
A dielectric ceramic material characterized by being less than or equal to parts by weight. 4. The general formula, aBaO-bLa ₂ O ₃ -cS.
_{m 2 O 3 -dBiO 3 -eTiO 2} -fGd 2 O 3 -g
PbO (provided that a, b, c, d, e, f, and g are mol%, 14.2 ≦ a ≦ 19.0, 0.20 ≦ b ≦ 13.
3, 0.20 ≦ c ≦ 11.9, 0.20 ≦ d ≦ 7.0,
62.6 ≤ e ≤ 70.6, 0.2 ≤ f ≤ 7.0, 0.2
Within the range of ≦ g ≦ 5.0, a + b + c + d + e + f + g =
100, 14.2 ≦ a + g ≦ 19.2, and 14.2 ≦
b + c + d + f ≦ 19.2, and the ZrO ₂ content is 1.80 parts by weight or less, where 100 parts by weight is the portion represented by each composition including the amount mixed as an impurity). Dielectric porcelain material. 5. A general formula, aBaO-bLa ₂ O ₃ -cS
_{m 2 O 3 -dBi 2 O 3} -eTiO 2 -hSrO ( however, a, b, c, d, e, and h is the mole%, 14.2
≦ a ≦ 19.0, 0.20 ≦ b ≦ 13.3, 11.5 ≦
a ≦ 19.2, 0.20 ≦ b ≦ 13.3, 0.20 ≦ c
≦ 11.9, 0.20 ≦ d ≦ 7.0, 62.6 ≦ e ≦ 7
0.6, 0.20 ≦ h ≦ 3.5, a + b + c +
d + e = 100 mol%, and 13.5 ≦ a + h ≦ 19.
2 and 14.2 ≦ b + c + d ≦ 19.2, and each composition includes the amount mixed as an impurity), the ZrO ₂ content is 1.8 when the part represented by 100 parts by weight.
A dielectric ceramic material characterized by being 0 parts by weight or less.