JPH11209179A - Dielectric porcelain composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To promote sintering and to obtain a high porcelain density and a high Q value by using Ba, Sr, Mg, W and an Fe family metal as essential components and adding a specified amt. of a boric acid compd. SOLUTION: The piezoelectric porcelain compsn. contains a principal component contg. at least Mg and W as metallic elements and having a compsn. of oxides of the metallic elements by molar ratio represented by the formula (where A is at least one of an Fe family metal and Zn, 0<=a<=1, 0.01<=b<=0.7, 0.40<=x<=0.05, 0.15<=y<=0.30, 0.20<=z<=0.30 and x+y+z=1) and 0.005-0.2 pt.wt. (expressed in terms of B2 O3 ) boric acid compd. based on 100 pts.wt. of the principal component. About 0.005-1 pt.wt. at least one selected from a phosphorus compd., a silicon compd. and an alkali metallic compd. may be contained. The boric acid compd. is, e.g. B2 O3 , colemanite, CaB2 O4 , ZnB2 O4 . The phosphorus compd. is, e.g. H3 PO4 or P2 O5 .

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 having a high relative dielectric constant and a high Q value in a high frequency region such as a microwave and a millimeter wave, and more particularly to a high frequency dielectric such as a dielectric resonator, a filter and a capacitor. The present invention relates to a dielectric porcelain composition suitable for electronic parts for use, MIC dielectric substrates, millimeter wave waveguides, and the like.

[0002]

2. Description of the Related Art In the high frequency region such as microwaves and millimeter waves, dielectric ceramics are widely used for dielectric resonators, MIC dielectric substrates, and the like. Recently, dielectric waveguides have been applied to millimeter wave waveguides.

As this kind of dielectric porcelain, for example, Zr
O ₂ —SnO ₂ —TiO ₂ based material, BaO—TiO ₂ based material, (Ba, Sr) (Zr, Ti) O ₃ based material and B
a (Zn, Ta) O ₃ -based materials and the like are known, and these materials have a frequency of 500 MHz to 5 GHz by various improvements.
The dielectric constant is 20 to 40 and the Q value is 1000 to 300 at z.
0 (Qf = 15000 or less), and the temperature coefficient (τf) of the resonance frequency has a characteristic near 0 ppm / ° C.

[0004]

However, recently, there has been a tendency to use higher frequencies,
Dielectric materials are required to have better dielectric properties, especially improved Q values. However, at present, the above-mentioned conventional dielectric material does not have a practically high Q value in a used frequency range of 10 GHz.

[0005] In order to solve such problems, the present applicant has disclosed at least Ba, Sr, Mg and W as metal elements, as disclosed in Japanese Patent Application Laid-Open No. 9-270366. The composition formula based on the molar ratio of the element oxide is expressed as x {(1-a) BaO.aSrO} .y} (1-
b) When expressed as MgO · bAO｝ · zWO ₃ (A is at least one of iron group metals and Zn),
When x, y and z are 0 <a <1, 0.01 ≦ b ≦ 0.
7, 0.40 ≦ x ≦ 0.55, 0.15 ≦ y ≦ 0.3
We filed a dielectric porcelain composition satisfying 0, 0.20 ≦ z ≦ 0.30, and x + y + z = 1. With this dielectric porcelain composition, a high porcelain density and a high Q value can be obtained,
In recent years, higher Q values and higher strengths have been required.

The dielectric ceramic composition of the present invention is disclosed in
Provided is a dielectric porcelain composition capable of further improving the Q value and improving porcelain density (bulk density) than the dielectric porcelain composition disclosed in Japanese Patent No. 270366.

[0007]

The inventor of the present invention has made various studies on the above problems, and as a result, has found that x ｛(1-a) BaO.
・ ASrO｝ ・ y ｛(1-b) MgO ・ bAO｝ ・ zW
O ₃ (A is at least one of iron group metals and Zn)
By adding a predetermined amount of at least one of boron (B), phosphorus (P), silicon (Si), and an alkali metal to the composition represented by the formula, the Q value is improved,
The present inventors have found that the porcelain density (bulk density) can be improved, and have reached the present invention.

That is, the dielectric porcelain composition of the present invention contains at least Mg and W as metal elements, and the composition formula based on the molar ratio of these metal element oxides is represented by x ｛(1-
a) BaO.aSrO {.y} (1-b) MgO.bA
When expressed as O｝ · zWO ₃ (A is at least one of iron group metals and Zn), the above a, b, x, y and z
Is 0 ≦ a ≦ 1, 0.01 ≦ b ≦ 0.7, 0.40 ≦ x
≦ 0.55, 0.15 ≦ y ≦ 0.30, 0.20 ≦ z ≦
0.30, x + y + z = 1.

The dielectric porcelain composition of the present invention comprises the above-mentioned main component and (1) a boric acid compound in an amount of 0.005 to 0.2 parts by weight in terms of B ₂ O _{3 based on} 100 parts by weight of the main component. Parts, (2) a phosphorus compound in an amount of 0.005 to 1 part by weight in terms of P, and (3) a silicon compound in an amount of 0.005 to _{1 in} terms of SiO _2.
Parts by weight of (4) alkali metal compound in terms of carbonate in an amount of 0.1 parts by weight.
005 to 1 part by weight, containing at least one selected from the above (1) to (4).

[0010]

In the dielectric ceramic composition of the present invention, x ｛(1-
a) BaO.aSrO {.y} (1-b) MgO.bA
With respect to a composition represented by O｝ · zWO ₃ (A is at least one of iron group metals and Zn), boron (B),
By including at least one of phosphorus (P), silicon (Si), and alkali metal in a predetermined amount, sinterability is improved, thereby increasing porcelain density (bulk density) and realizing high strength. And x ｛(1-a) BaO · aS
The crystallinity of rO｝ · y ｛(1-b) MgO · bAO｝ · zWO ₃ can be improved, and the Q value can be improved.

That is, by containing a predetermined amount of a boric acid compound, a phosphorus compound, a silicon compound, and an alkali metal compound with respect to the main component, sintering is promoted, and a high porcelain strength and a high Q value can be obtained. .

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The dielectric porcelain composition of the present invention has a composition formula based on a molar ratio of x {(1-a) BaO.aSrO}.
Y ｛(1-b) MgO · bAO｝ · zWO ₃ (A is at least one of iron group metals and Zn)
A, b, x, y and z are 0 ≦ a ≦ 1, 0.01
≦ b ≦ 0.7, 0.40 ≦ x ≦ 0.55, 0.15 ≦ y
≦ 0.30, 0.20 ≦ z ≦ 0.30, x + y + z = 1
Satisfying the following conditions.

The reason why the substitution amount b of MgO with the iron group metal and Zn is set to 0.01 ≦ b ≦ 0.7 is that if b is less than 0.01, the effect of lowering the firing temperature and improving the porcelain density is obtained. Is hardly obtained, and when it is more than 0.7, the Q value is significantly reduced. It is desirable that b satisfies 0.01 ≦ b ≦ 0.65 from the viewpoint of obtaining a higher porcelain density and a higher Q value. As iron group metals, Fe, Ni,
Although there is Co, Ni and Co are desirable among them.

Further, the reason why the composition ratio of the above composition formula is limited to the above range is that if the composition ratio is outside the above range, the effect of solid solution is insufficient, or there is a problem that the sinterability is lowered and the Q value is lowered. Because.

That is, when the molar ratio x is 0.40 ≦ x ≦ 0.55
The reason for this is that if the value is smaller than 0.40 or larger than 0.55, the Q value decreases or sintering becomes poor. x is 0.49 ≦ for the reason of improving the Q value.
x ≦ 0.52 is desirable.

Further, the molar ratio of MgO is set to 0.15 ≦ y ≦
The reason for setting the value to 0.30 is that when y is smaller than 0.15, the Q value decreases, and when y is larger than 0.30, the Q value decreases or sintering becomes poor. The molar ratio y of MgO is 0.20 ≦ M from the reason of improvement of Q value and sinterability.
It is desirable that y ≦ 0.27.

Further, the molar ratio of WO ₃ is set to 0.20 ≦ z ≦
The reason for setting the value to 0.30 is that when z is smaller than 0.20, sintering becomes defective, and when z is larger than 0.30, the Q value decreases. The molar ratio z of WO ₃ is preferably 0.22 ≦ z ≦ 0.28 from the viewpoint of improving the Q value and sinterability.

In the dielectric porcelain composition of the present invention, the composition formula is expressed as x {(1-a) BaO.aSrO} .y} (1-
b) When expressed as MgO · bAO｝ · zWO ₃ , a, b,
x, y, and z are 0 ≦ a ≦ 1, 0.01 ≦ b ≦ 0.65,
0.49 ≦ x ≦ 0.52, 0.20 ≦ y ≦ 0.27,
It is desirable that 0.22 ≦ z ≦ 0.28 and x + y + z = 1 be satisfied.

In the dielectric ceramic composition of the present invention, (1) 0.005 to 0.20 parts by weight of boric acid compound in terms of B ₂ O ₃ , and (2) 0.005 to 1 part by weight of a phosphorus compound in terms of P, (3) 0.005 to 1 part by weight of a silicon compound in terms of SiO ₂ , (4)
It contains 0.005 to 1 part by weight of an alkali metal compound in terms of carbonate, and one selected from the above (1) to (4).

When the content of the boric acid compound is 0.005 to 0.20 parts by weight in terms of B ₂ O ₃ with respect to 100 parts by weight of the main component, the porcelain density (bulk) is less than 0.005 part by weight. Density) and almost no Q value improvement effect, 0.20
If the amount exceeds the weight part, the Q value will decrease. The content of the boric acid compound is desirably 0.01 to 0.1 part by weight in terms of B ₂ O ₃ from the viewpoint of obtaining a high porcelain density and a high Q value.

Further, the content of the phosphorus compound is set to 0.005 to 1 part by weight in terms of P with respect to 100 parts by weight of the main component. When the content is less than 0.005 part by weight, the porcelain density (bulk density)
This is because there is almost no effect on the improvement of Q and the Q value, and when it exceeds 1 part by weight, the Q value decreases. The content of the phosphorus compound can be increased from the point that a higher porcelain density and a higher Q value are obtained.
Desirably, it is 0.005 to 0.5 parts by weight in conversion.

Furthermore, the reason that the silicon compound is 0.005 to 1 part by weight in terms of SiO ₂ with respect to 100 parts by weight of the main component is that the porcelain density (bulk density) is less than 0.005 part by weight.
This is because there is almost no effect on the improvement of Q and the Q value, and when it exceeds 1 part by weight, the Q value decreases. The silicon compound is SiO ₂ because of obtaining a higher porcelain density and a higher Q value.
Desirably, it is 0.005 to 0.50 parts by weight in conversion.

The reason why the alkali metal-containing compound is added in an amount of 0.005 to 1 part by weight in terms of carbonate with respect to 100 parts by weight of the main component is that when the amount is less than 0.005 part by weight, the porcelain density (bulk density) is reduced. This is because there is almost no effect on improvement and improvement of the Q value, and when it exceeds 1 part by weight, the Q value decreases. The alkali metal compound is desirably 0.01 to 1.0 part by weight in terms of carbonate in terms of obtaining a high porcelain density and a high Q value.

Here, B ₂ O ₃ ,
There are colemanite, CaB ₂ O ₄ , ZnB ₂ O _{4 and the} like.
Examples of the phosphorus compound include H ₃ PO ₄ , P ₂ O ₅ , and P. As the alkali metal, Li, Na, K,
There are Rb and Cs, and examples of the compounds include alkali metal carbonates and fluorides.

As a method of manufacturing a porcelain based on the present invention, for example, in addition to oxides of Ba, Sr, Mg, and W or metal salts such as carbonates and nitrates that generate oxides by firing, CoO such as CoO A cobalt compound, a nickel compound such as NiO, a zinc compound such as ZnO, etc. are prepared as main raw materials, and these are weighed so that the sintered body falls within the above-described range, and then sufficiently mixed. Thereafter, the mixture is added to 9
A calcination treatment is performed at 00 to 1200 ° C. In the obtained calcined material,
For example, boric acid compounds such as B ₂ O ₃ , phosphorus compounds such as P ₂ O ₅ , silicon compounds such as SiO ₂ , Li ₂
Each compound of an alkali metal compound such as CO ₃ is weighed and added to a predetermined amount, and mixed and pulverized. Then, this is molded into a predetermined shape by a molding method such as press molding or a doctor blade method. Next, the molded body is fired at 1300 ° C. to 1600 ° C. in an oxidizing atmosphere such as the air to obtain a dielectric ceramic.

In the dielectric porcelain composition of the present invention, Cl, Al, and Na are used as inevitable impurities (Na as an alkali metal).
Is not added), Zr, Y and the like may be mixed. Even if these are mixed in about 0.1% by weight in the total amount, there is no problem in characteristics. In addition, metal or the like may be mixed in the crushed balls during crushing.

[0027] In the dielectric ceramic composition of the present invention, the general formula _{(Ba 1-a Sr a)} {(Mg 1-b A b) 1/2 W 1/2} O
₃ (0 ≦ a ≦ 1, 0.
01 ≦ b ≦ 0.7) as the main crystal. That is,
The A site is composed of Ba and Sr, and the B site is (Mg _1-b
Ab ) and W have a crystal composed of 1: 1. The material having such a crystal may be in any form of a polycrystal such as a sintered body or a single crystal.

In the dielectric porcelain composition of the present invention, (B
As _{a 1-a Sr a) {} (Mg 1-b A b) 1/2 W 1/2} O 3 other than crystalline phase, but sometimes BaWO _4, SrWO _4, etc. is present, if a minor There is no problem in characteristics.

[0029]

EXAMPLES Example 1 As raw materials, BaCO ₃ , SrCO ₃ ,
MgCO ₃ , CoO (or NiO, or Zn
O) and WO ₃ powders, and
Was placed in a rubber-lined ball mill together with isopropyl alcohol (IPA) and mixed with ZrO ₂ balls for 18 hours. Then
After drying this mixture, it was calcined at 1000 ° C. for 2 hours. B ₂ O ₃ in the calcined _{product, H 3 PO 4, SiO 2} , L
i ₂ CO ₃ , Na ₂ CO ₃ , and K ₂ CO ₃ were weighed so as to have the ratios shown in Tables 1 and 2, and the calcined product was placed in a ball mill using ZrO ₂ balls together with IPA and wet-pulverized for 18 hours. .

[0030] Thereafter, the pulverized product was dried, after addition of organic binder, 40th granulated through mesh of the mesh, the size of the resulting powder 3000 kg / pressure cm ² diameter 10 mm × thickness 5mm cylinder Molded. Furthermore,
The cylinder was fired at 1450 ° C. for 2 hours to obtain a porcelain sample having a diameter of 8.5 mm and a thickness of 4.3 mm.

The bulk density of the obtained porcelain sample was determined by JI.
It measured based on S standard C2141-1992 (test method of ceramic material for electrical insulation). The frequency is about 10G
The relative dielectric constant (εr) and Q value at Hz were measured by the dielectric resonator method, and the Q value was converted to a Q value at 10 GHz on the assumption that the general formula Qf = constant. Further, the temperature coefficient (τf) of the TE011 mode resonance frequency at each temperature from 25 ° C. to 85 ° C. is given by τf = [(f ₈₅ −
f ₂₅ ) / f ₂₅ ] / 60 × 10 ⁶ [ppm / ° C.] Here, f ₈₅ is the resonance frequency at 85 ° C., and f ₂₅ is the resonance frequency at 25 ° C. The results are shown in Tables 1 and 2.

[0032]

[Table 1]

[0033]

[Table 2]

According to Tables 1 and 2, BaO, Sr
Samples having a composition of O, MgO, WO ₃ , and CoO (NiO, ZnO) outside the range of the present invention have a Q value of 2000.
The following or poor sintering occurred. On the other hand, the sample of the present invention obtained a high Q value of 4000 or more. Further, B,
It can be seen that the bulk density is improved and the Q value is improved as compared with a sample containing no P, Si or an alkali metal element.

Example 2 Sample No. 1 shown in Table 1 in Example 1 was used. B, P, Si and an alkali metal element were added in the amounts shown in Table 3 to the main components of No. 5 and molded and fired in the same manner as in Example 1.

Then, in the same manner as in Example 1, the bulk density,
The relative permittivity, the Q value, and the temperature coefficient (τf) of the resonance frequency were determined. Table 3 shows the results.

[0037]

[Table 3]

According to Table 3, the content of the boric acid compound was 0.005 to 0.2 in terms of B ₂ O ₃ with respect to 100 parts by weight of the main component.
0 parts by weight, 0.005 to 1 parts by weight of a phosphorus compound in terms of P, 0.005 to 1 parts by weight of a silicon compound in terms of SiO ₂ , and 0.005 to 1 parts by weight of an alkali metal compound in terms of carbonate.
By adding these parts by weight, sample N to which these were not added was used.
It can be seen that the bulk density is higher than that of o.5 and the Q value is higher. In addition, the kind of the additive of Tables 1-3 showed the converted compound or metal.

[0039]

As described in detail above, BaO, SrO, M
Sinterability is improved by containing a predetermined amount of boron, phosphorus, silicon, and alkali metal with respect to a main component composed of gO, WO ₃ , and AO (A is at least one of iron group metal and Zn). Therefore, the bulk density can be improved and the strength can be increased, and the crystallinity can be improved and the Q value can be increased. The resulting porcelain is a resonator material used in microwave and millimeter wave regions, MI
It can be sufficiently applied to a dielectric substrate material for C, a capacitor material, a dielectric antenna material, a dielectric waveguide material, and the like.

Claims (2)

[Claims] 1. A composition formula containing at least Mg and W as metal elements, and the molar ratio of these metal element oxides is expressed as x {(1-a) BaO.aSrO} .y {(1-b) M
When expressed as gO · bAO｝ · zWO ₃ (A is at least one of iron group metals and Zn), a, b, x, y and z are 0 ≦ a ≦ 1 0.01 ≦ b ≦ 0.7 0.40 ≦ x ≦ 0.55 0.15 ≦ y ≦ 0.30 0.20 ≦ z ≦ 0.30 x + y + z = 1 and a boric acid compound with respect to 100 parts by weight of the main component. A dielectric ceramic composition containing 0.005 to 0.2 parts by weight in terms of ₂ O ₃ . 2. At least Mg and W are contained as metal elements, and the composition formula based on the molar ratio of these metal element oxides is expressed as x {(1-a) BaO.aSrO} .y {(1-b) M
When expressed as gO · bAO｝ · zWO ₃ (A is at least one of iron group metals and Zn), a, b, x, y and z are 0 ≦ a ≦ 1 0.01 ≦ b ≦ 0.7 With respect to a main component satisfying 0.40 ≦ x ≦ 0.55 0.15 ≦ y ≦ 0.30 0.20 ≦ z ≦ 0.30 x + y + z = 1 and 100 parts by weight of the main component,
A dielectric ceramic composition comprising 0.005 to 1 part by weight of at least one of a phosphorus compound, a silicon compound, and an alkali metal compound in terms of P, SiO ₂ , and carbonate.