JPH10101406A - Alumina-based sintering material and magnetodielectric resonator using the supporting bed using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an alumina-based firing material which can give a supporting bed having a high non-load Q value and excellent thermal conductivity by setting the contents of the components for alumina base used for a supporting bed of a specific structure. SOLUTION: Two kinds of Al2 O3 powders (of >=99.9% and >=99.99%), MgO as a sintering aid, CaCO3 to be converted to CaO and SiO2 (the purity of both components are >=99.9% are weighed in amounts of <=1.0wt.% of MgO (except 0%), 0.02-1.0wt.% of CaO and 0.1-1.0wt.% of SiO2 based on 100wt.% as the total of Al2 O3 +MgO+CaO+SiO2 (where Al2 O3 is 99.2-99.8wt.% and the case that SiO2 is 40-60wt.% based on 100wt.% of MgO+CaO+SiO2 in total is excluded) and they are formulated. An organic binder and water are added to this mixture, ground and granuled, molded and fired in the air atmosphere at 1,550-1,625 deg.C for 2 hours.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a ceramic dielectric resonator in which an alumina-based sintered material and a resonator main body are fixed to the inner surface of a metal container via a supporting base formed by firing the alumina-based sintered material. About the vessel. More specifically, it has an alumina-based sintered material having a high unloaded Q value (hereinafter simply referred to as " _Qu ") and a high support having excellent thermal conductivity, and a similarly high _Qu . The present invention relates to a porcelain dielectric resonator.

[0002]

2. Description of the Related Art A dielectric having excellent high-frequency characteristics in a microwave region has been developed, and a resonator using the dielectric has been used. However, even in the case of a resonator using a material having excellent dielectric properties, the original excellent performance of the dielectric material may not be sufficient depending on the method of manufacturing a ceramic dielectric resonator using the resonator body or its structure. In some cases, the dielectric properties are degraded.

For example, in a ceramic dielectric resonator in which a resonator body which is widely used at present is fixed in a metal container via a support, the dielectric characteristics of the support and the support of the resonator body Depending on the type and thickness of the glazing material, adhesive and the like for joining to the table, there is a problem that the _{Qu of the} entire porcelain dielectric resonator including the support table, the metal container and the like is reduced. Moreover, sintered materials using alumina of high purity (99.99%) is known to have a particularly high Q _u. However, in order to obtain this high-purity alumina, an expensive high-purity alumina raw material is required, and there is a problem that productivity is low in molding and firing of a sintered material.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an alumina-based sintered material capable of obtaining a support having a high Q _u and further having excellent thermal conductivity, and a Q-alumina. the resonator body is fixed to the inner surface of the metal container via a high support base of _u, and an object thereof is to provide a high porcelain dielectric resonators Similarly Q _u.

[0005]

The alumina-based sintered material according to the first invention has an alumina-based sintered material used for forming a support having one end joined to the resonator body and the other end fixed to the inner surface of the metal container. In the sintering material, the sintered material is Al ₂ O ₃ , M
Assuming that the total amount of gO, CaO and SiO ₂ is 100% by weight, 1.0% by weight or less of MgO, 0.02-1.
0% by weight of CaO and 0.1 to 1.0 wt% of SiO ₂
It is characterized by containing.

In a porcelain dielectric resonator according to a sixth aspect of the present invention, there is provided a porcelain dielectric resonator in which a resonator main body is fixed to an inner surface of a metal container via a supporting base formed by firing an alumina-based sintered material. , The alumina-based sintered material is Al ₂ O ₃ , M
Assuming that the total amount of gO, CaO and SiO ₂ is 100% by weight, 1.0% by weight or less of MgO, 0.02-1.
0% by weight of CaO and 0.1 to 1.0 wt% of SiO ₂
It is characterized by containing. Note that, as described above, in the first and sixth aspects of the present invention, the case where both the ratios of Al ₂ O ₃ and SiO ₂ are within a specific range is excluded.

[0007] "Support" with low dielectric loss and high _Qu
In order to obtain a "porous ceramic dielectric resonator", the above-mentioned "alumina-based sintered material" includes "Al ₂ O ₃ " and a certain amount of "M
gO ", must contain the" CaO "and" SiO ₂ ". When MgO is not contained and Ca
If O is less than 0.02% by weight or SiO ₂ is less than 0.1% by weight, the dielectric loss increases and the _Qu decreases. On the other hand, MgO, CaO, SiO _2, respectively 1.0
When the amount is more than the weight percentage, the dielectric properties are similarly reduced. Further, the content of Al ₂ O ₃ is preferably 98.0% by weight or more. If the amount ratio of Al ₂ O ₃ is so high, the ratio of the auxiliary component becomes relatively low, and Does not decrease in durability.

In the alumina-based sintered material of the present invention, as in the second invention, the content of Al ₂ O ₃ is set to “99.
5 to 99.8% by weight ". Thus it is possible to obtain a large support base and porcelain dielectric resonator Q _u if higher ratio of Al ₂ O _3. Further, as in the third invention, MgO is "0.01 to 0.5% by weight", C
It is preferred aO is "0.02 to 0.5% by weight" and "SiO ₂ is 0.1 to 0.6% by weight". MgO in this range, by the use of alumina-based sintered material containing CaO and SiO _2, more dielectric loss is small, it is possible to obtain a high Q _u support base or the like. Furthermore,
The amount ratio of Al ₂ O ₃ is increased as in the second invention, and
O, also by the weight fraction to be specified in the content of CaO and SiO ₂ fourth invention, it is possible to increase the more Q _u, can also be and improve the thermal conductivity.

Further, since the support has a function of releasing heat generated by the resonator main body from the fixed portion to the metal container, the support must be excellent in heat conductivity. The thermal conductivity of the support tends to increase as the content of Al ₂ O ₃ increases and as the grain growth of the structure progresses. This thermal conductivity is
If the Al ₂ O ₃ content of the support is less than 98.0% by weight, it will be lower than 28 W / mK, and the heat generated by the resonator main body will not be sufficiently dissipated.
The temperature may be as high as 0 ° C. or more.

The amount ratio of Al ₂ O ₃ is increased as in the second invention, MgO, CaO and SiO ₂ are set to the weight fraction specified in the fourth invention, and the porosity is changed as in the fifth invention. to, if "5%", Q _u is not less 5000 or more, the thermal conductivity is not more 30 W / mK or more, it is possible to obtain the support table and the porcelain dielectric resonator with excellent performance. Porosity of the particular 4% or less, more preferably 2% or less, with the above dense sintered body, a Q _u 6000 or more, in particular increased to about 7,000 to 7,500 it can.

The method of joining the resonator body to the support is not particularly limited. For example, a paste-like glazing material is interposed between the resonator body and the support, and heat-treated at a temperature of about 800 ° C. to melt the glass component contained in the glazing material, and then solidify by cooling. And a method of joining the resonator body and the support base. Also, an organic adhesive such as an epoxy-based or cyanoacrylate-based adhesive can be used. However, some of these glazing and the adhesive, some of them reduce the Q _u porcelain dielectric resonator, it is not preferable to the above thickness required of obtaining required bonding strength.

The other end face of the support having the resonator body joined to one end face as described above is fixed to the "inner face" of the "metal container". This fixing may be performed by PTTF, or a method of bonding and fixing with solder or the like. Further, it can be mechanically fixed with screws and nuts. This metal container is usually a cylindrical container whose both end surfaces are sealed, and the support to which the resonator body is joined is fixed to the center of the inner surface of one end surface of the cylindrical container. Thus, a ceramic dielectric resonator in which the resonator main body, the support base, and the metal container are integrated can be obtained.

Many ceramic dielectric resonators made of ceramic have a resonator body fixed to the inner surface of a metal container via a support, as in the present invention. Finished products that are integrated with are provided as products. In such a porcelain dielectric resonator, also have excellent dielectric properties of the resonator body, the dielectric properties of the support, other factors, not necessarily even if high Q _u porcelain dielectric resonator can not be obtained . For this reason, it is necessary to use a ceramic having a high Q _u as the ceramic constituting the support base.
A ceramic dielectric resonator having a high _u can be obtained.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described specifically with reference to examples. (1) Preparation of cylindrical test piece and its evaluation Al ₂ O ₃ powder [Purity: 99.9% or more (Examples and Comparative Examples excluding Comparative Examples 8 and 9) and 99.99% or more (Comparative Examples 8 and 9), and the sintering aids MgO, CaCO ₃ and SiO ₂ (purity: 99.9% or more, both of which become CaO) are shown in Tables 1, 2, and 3. And weighed and blended so as to have the ratios shown in Table 4.

Here, the above-mentioned Al ₂ O having a purity of 99.9% is used.
_{3 As} powders, CaO; 200 ppm, SiO ₂ ;
Those containing impurities of about 800 ppm in total including 00 ppm were used. In addition, when CaCO ₃ becomes an oxide, it is used in an amount as shown in Table 1, Table 2, Table 3 and Table 4, and CaO, Si contained in the Al ₂ O ₃ powder is used.
For impurities such as O ₂ , Table 1, Table 2,
The amounts were adjusted so as to have the ratios shown in Tables 3 and 4.

An appropriate amount of an organic binder and water were added to the mixture of the above powders, and the mixture was ground in a ball mill using 90 mmφ alumina balls at 90 rpm for 16 hours. Then, it granulated by the spray dryer. Using this granulated raw material, a columnar compact of 19 mmφ (diameter) × 11 mmt (thickness) was obtained by isostatic pressing.
The pressing pressure was 1000 kg / cm ² .

Next, the molded body is placed in an air atmosphere for 15 minutes.
It was calcined at a temperature of 50 to 1625 ° C. for 2 hours.
In Comparative Examples 8 and 9, since a dense sintered body was not obtained under the above firing conditions, the temperature was raised from room temperature to 1500 ° C. over 48 hours, and the temperature was maintained at 1500 ° C. for 2 hours. The temperature was lowered to 36 ° C. over 36 hours and calcined.
Thereafter, the peripheral surface and both end surfaces of the obtained sintered body were polished to obtain a columnar shape having a size of about 16 mmφ × 8 mmt.

[0018] The cylindrical sintered body of the above the sample was measured Q _u by the parallel conductive plate type dielectric cylindrical resonator method (TE ₀₁₁ MODE). At the same time, the dielectric constant (ε _r ) was measured. In addition, the resonant frequency at the time of measurement of Q _u was set to 8.7GHz. Further, the thermal conductivity of the same sintered body was measured by a laser flash method. In Examples 12 to 31, the density of the sintered body was measured by the Archimedes method, and the porosity was determined by the following equation. Porosity (%) = 100− (measured density / theoretical density) ×
Tables 1, 2 and 3 show the results of the 100 Examples, and Table 4 shows the results of the Comparative Examples. In Table 4, * indicates that the value is outside the scope of the first invention.

[0019]

[Table 1]

[0020]

[Table 2]

[0021]

[Table 3]

[0022]

[Table 4]

According to the results in Table 1, in Examples 1 to 11 are within the scope of the first invention, it can be seen that high Q _u sintered body is obtained. In particular the sintered bodies of Examples 3-4 and 9-11 within the scope of the third invention has a higher Q _u. As for the thermal conductivity, when the content of Al ₂ O ₃ is 98.79% by weight or more as in these examples, the thermal conductivity becomes 28 W / mK or more. still,
As the amount ratio of Al ₂ O ₃ increases, the thermal conductivity increases. Furthermore, the Al ₂ O ₃ in an amount ratio of 99.75% and higher Example 9, it can be seen that the Q _u becomes large beyond 5000.

Also, according to the results of Tables 2 and 3,
The content of ₂ O ₃ is 99.5 to 99.8% by weight,
The amount ratio of MgO, CaO and SiO ₂ is within the range of the fourth invention, and the porosity is 4% or less, particularly 1.1 to 1.5%
And the sintered body of denseness high embodiment of twelve to twenty-nine, Q _u is from 5010 to 7450, the thermal conductivity of 32~34W / mK
It can be seen that it has very excellent performance. Further, Examples 27, 30, and 31 have the same composition but different porosity, and as the porosity increases, Q
It can be seen that _u and thermal conductivity tend to decrease.
The sintered body of Example 31 has no particular problem as a support or a ceramic dielectric resonator, and can be sufficiently put to practical use.

On the other hand, Q _u is low in general in Comparative Examples 1 to 8 and 10 in Table 4. In particular, sometimes Q _u as in Comparative Examples 6, 7 and 10 is less than 1000, it is seen that below the Q _u of the sintered body of alumina-based sintered material of the present invention greatly. Also, as in Comparative Examples 1 and 10, Al ₂
It can be seen that when the content of O ₃ is less than 98.0% by weight, the thermal conductivity is also greatly reduced.

[0026] In Comparative Example 9 using only high-purity alumina of 99.99% pure, Q _u is very high due to the specimen, is greater than the Q _u of many embodiments. However, in Comparative Example 9, the raw material cost of the high-purity alumina was high, the density of the compact during molding was low, and the press moldability was poor.
Strict temperature control was also required in firing, and a long time was required for firing. Further, while the yield in each of the above examples using 99.9% pure alumina was 80% or more, the yield in Comparative Example 9 was as low as 40% or less. Further, ε _r did not vary so much depending on the composition of the sintered material.

(2) Fabrication and Evaluation of Porcelain Dielectric Resonator A support made of the material shown in Table 5 was fabricated by the same process as in the above (1). Thereafter, a resonator body 1 made of a BaO-TiO ₂ sintered body was joined to one end of the support 2 using an epoxy resin adhesive. Next, the integrated resonator main body 1 and the support table 2 are housed inside a cylindrical metal container 3 whose both end surfaces are sealed, and the other end of the support table 2 is connected to the cylindrical metal container 3. PT at the center of the bottom surface 3a
Bonded and fixed by TF. 4 is a fixed part.

The porcelain dielectric resonator manufactured as described above has a resonance frequency in the TE ₀₁ δ mode of 0.9 G.
1 are set to D = 160 mmφ, L = 130 mm, d = 57 mmφ,
1 is set to 18 mm. Measurement results of the Q _u of the resulting ceramic dielectric resonator shown in Table 5. The material of the metal container is Invar.

[0029]

[Table 5]

According to [0030] Table 5 results, it can be seen that Q _u porcelain dielectric resonator using the support table Q _u by the specimen is made of high sintering material tends to still high. In the case of using a support base made of a sintered material of Example 4 in Table 1, when using high purity alumina of Comparative Example 9 the same very Q _u high porcelain dielectric resonator can be obtained I understand that.

It should be noted that the present invention is not limited to the specific examples described above, but can be variously modified within the scope of the present invention according to the purpose and application. For example, various firing conditions such as a firing temperature can be selected. In addition, as a raw material for forming MgO and CaO, M
In addition to gO and CaCO ₃ , MgCO ₃ or Mg, Ca
Peroxides, hydroxides, nitrates and the like can also be used. Similarly, for other oxides, various compounds that can be converted into oxides by heating can be used.

[0032]

According to the first invention, the alumina-based sintered material has
l certain amount of MgO as auxiliary components ₂ O _3, mixed with CaO and SiO _2, by incorporating, with the porcelain dielectric resonator formed of a fixed to a metal container through the support base of the resonator body A support having a high Q _u can be obtained. Further, the content of Al ₂ O ₃ is set in the range specified in the second invention, and MgO, CaO and SiO ₂
Is within the range specified in the third invention, thereby providing a support having a higher Q _u and a relatively high amount of Al ₂ O ₃ and also having excellent thermal conductivity. be able to. Furthermore, by setting MgO or the like to the range specified in the fourth invention and reducing the porosity as in the fifth invention, a support having particularly excellent performance can be obtained.
In the sixth invention, by using a support base formed by firing the specific alumina-based sintered material, Q _u is high,
In addition, a porcelain dielectric resonator excellent in heat conductivity can be obtained.

[Brief description of the drawings]

FIG. 1 shows MgO, CaO and SiO _{2 according to a} fourth invention.
3 is a graph showing the weight fraction of the sample.

FIG. 2 is a longitudinal sectional view of a porcelain dielectric resonator obtained by fixing a resonator main body on an inner surface of a cylindrical metal container by a support made by firing the alumina-based sintered material of the present invention. is there.

[Explanation of symbols]

1; porcelain dielectric resonator; 2; support base; 3; cylindrical metal container; 31; bottom surface of metal container;

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Kazuhisa Itakura 14-18 Takatsuji-cho, Mizuho-ku, Nagoya-shi, Aichi Japan

Claims (6)

[Claims] 1. An alumina-based sintered material having one end joined to a resonator body and the other end used to form a support fixed to an inner surface of a metal container, wherein the sintered material is Al.
The total amount of ₂ O ₃ , MgO, CaO and SiO ₂ is 100
1.0% by weight or less (not including 0% by weight) of MgO, 0.02 to 1.0% by weight of CaO
And an alumina-based sintered material containing 0.1 to 1.0% by weight of SiO ₂ . (However, the above Al ₂ O
₃ is 99.2 to 99.8% by weight, and the Mg
When the total amount of O, the above CaO and the above SiO ₂ is 100% by weight, the case where the amount of the SiO ₂ is 40 to 60% by weight is excluded. ) 2. The alumina-based sintered material according to claim 1, wherein said Al ₂ O ₃ is 99.5 to 99.8% by weight. 3. The method according to claim 1, wherein the MgO is 0.01 to 0.5% by weight,
The CaO is 0.02 to 0.5% by weight and the SiO ₂
The alumina-based sintered material according to claim 1 or 2, wherein the content is 0.1 to 0.6% by weight. 4. The MgO, the CaO and the SiO
_{2 in} the three-component composition diagram of FIG. 3. The alumina-based sintered material according to claim 1, wherein the alumina-based sintered material is contained at a weight fraction in a region surrounded by. 5. A sintered body obtained by firing has a porosity of 5%.
The alumina-based sintered material according to any one of claims 1 to 4, wherein: 6. A porcelain dielectric resonator in which a resonator main body is fixed to an inner surface of a metal container via a supporting base formed by firing an alumina-based sintered material, wherein the alumina-based sintered material is Al ₂ When the total amount of O ₃ , MgO, CaO and SiO ₂ is 100% by weight, 1.0% by weight or less (0% by weight is not included) of MgO, 0.02 to 1.0% by weight.
Porcelain dielectric resonator, comprising 0.1% to 1.0% by weight of SiO ₂ . (However, the above A
l ₂ O ₃ is 99.2 to 99.8% by weight, and the total amount of MgO, CaO and SiO ₂ is 100
The case where the content of SiO ₂ is 40 to 60% by weight is excluded. )