JP3974723B2 - Dielectric porcelain manufacturing method - Google Patents

Description

【００５４】
【表２】

【００５５】
【表３】

【００５６】
また、上記の製造過程でＸ線回折測定の変化を調べ、その一例として試料Ｎo.１、１０について図２〜図６に示した。
まず、仮焼によって作製した仮焼粉末Ａと、仮焼粉末ＢのＸ線回折チャートを図２、図３に示した。
図２から明らかなように、仮焼粉末Ａは、ＬａＡｌＯ_３を主結晶相とする粉末であり、図３から明らかなように、仮焼粉末Ｂは、ＳｒＴｉＯ_３を主結晶相とする粉末であることがわかる。
【００５７】
次に、上記の仮焼粉末Ａと仮焼粉末Ｂを試料Ｎo.１、Ｎo.１０の組成で混合した混合粉末のＸ線回折チャートを図４と図５にそれぞれ示した。
そして、その混合粉末を用いて焼成した後の誘電体磁器のＸ線回折チャートを図６、図７に示した。
図６、図７の結果から明らかなように、ＬａＡｌＯ_３とＳｒＴｉＯ_３の各ピーク位置の中間に、両者の固溶体によるピークが検出され、（Ｌａ，Ｓｒ）（Ａｌ、Ｔｉ）Ｏ_３のペロブスカイト型結晶相による単一結晶相からなることがわかる。
【００５８】
表１〜表３の結果から明らかなように、各成分の組成比が本発明の範囲内のもの（Ｎo.１〜２８）は、比誘電率εｒが３０以上、１ＧＨｚに換算した時のＱ値が２００００以上、τｆが±３０（ｐｐｍ／℃）以内、かつεｒ、Ｑｆ及び共振周波数の温度係数τｆの標準偏差がそれぞれ０．３以内、３０００以内、０．７ｐｐｍ／℃以内の優れた誘電特性が得られた。
【００５９】
一方、本発明の組成範囲外の誘電体磁器組成（Ｎo.２９〜３９、７６〜８２）は、εｒが低いか又はＱ値が低いか、又はτｆの絶対値が３０を超えていた。
【００６０】
また、同時混合したＮo.４０〜５５、８３〜８７では、εｒ、Ｑ値及びτｆの平均値は上記本発明品と同等であったが、εｒの標準偏差σが１以上、τｆの標準偏差σが２ｐｐｍ／℃以上とばらつきが大きく、一部の比較例ではＱｆの標準偏差σが３０００を越えるものがあり、ばらつきが大きかった。
【００６１】
特に、本発明品の中でも、０．１０６１≦ａ≦０．２１６２、０．１０５０≦ｂ≦０．２０８６、０．３０４０≦ｃ≦０．４１８５、０．２７４７≦ｅ≦０．４３７３、０．７５≦ｂ／ａ≦１．２５、０．７５≦ｅ／ｃ≦１．２５の試料Ｎo.５６〜７５は、１ＧＨｚに換算した時のＱｆ値が４００００以上の優れた誘電特性が得られた。
【００６２】
（実施例２）実施例１の表１、表２に示す磁器組成物の仮焼粉末を表４に示す重量比率で混合した後、実施例１と同様に成形、焼成、研磨し、３０個の試料の誘電特性の測定等を行い、実施例１と同様に実験を３０回行ない、誘電特性の標準偏差σを計算した。
【００６３】

【表４】

【００６４】
その結果、試料Ｎo.８８〜９９のいずれも比誘電率εｒが３０以上、１ＧＨｚに換算した時のＱ値が２００００以上が得られ、表４から明らかなように、εｒ、Ｑｆ及びτｆの標準偏差σが、それぞれ０．２以内、１０００以内、０．２ｐｐｍ／℃以内と、実施例１よりもさらにばらつきを小さくすることができた。
【００６５】
また、これによって得られた誘電体磁器のＸ線回折測定を行ったところ、いずれもペロブスカイト型結晶相による単一結晶相からなるものであった。
【００６６】
【発明の効果】
以上詳述した通り、本発明によれば、ＬｎＡｌＯ_{（ｘ＋３）／２}（Ｌｎ：希土類元素、３≦ｘ≦４）を主結晶相とする仮焼粉末と、ＲＴｉＯ_３（Ｒは、少なくともＳｒを含むアルカリ土類元素）を主結晶相とする仮焼粉末とを混合、粉砕し、成形した後、焼成するとともに、前記金属元素によるモル比による組成式をａＬｎ_２Ｏ_ｘ・ｂＡｌ_２Ｏ_３・ｃＭＯ・ｄＢａＯ・ｅＴｉＯ_２（但し、Ｍは、Ｓｒ、あるいはＳｒとＣａ、３≦ｘ≦４）で表した時、前記ａ、ｂ、ｃ、ｄ、ｅが、０．０５６≦ａ≦０．４５０ ０．０５６≦ｂ≦０．４５０ ０．１００≦ｃ≦０．５００ ０≦ｄ≦０．１００ ０．１００＜ｅ＜０．４７０ ０．７５≦ｂ／ａ≦１．２５ ０．７５≦ｅ／（ｃ＋ｄ）≦１．２５ ａ＋ｂ＋ｃ＋ｄ＋ｅ＝１を満足することにより、高周波領域において高い比誘電率εｒ及び高いＱ値を得ることができ、かつεｒ、Ｑ値、τｆのばらつきを小さくできる。
これにより、マイクロ波やミリ波領域において使用される共振器用材料やＭＩＣ用誘電体基板材料、誘電体導波路、誘電体アンテナ、その他の各種電子部品等に適用することができ、特に、誘電体共振器として用いた場合に無負荷Ｑ及び共振周波数の安定性の向上することができ、信頼性を高めることができる。
【図面の簡単な説明】
【図１】本発明の誘電体磁器の製造方法による誘電体共振器を示す概略図である。
【図２】本発明の実施例におけるＬａＡｌＯ_３仮焼粉末のＸ線回折チャートである。
【図３】本発明の実施例におけるＳｒＴｉＯ_３仮焼粉末のＸ線回折チャートである。
【図４】本発明の実施例（試料Ｎo.１）におけるＬａＡｌＯ_３仮焼粉末とＳｒＴｉＯ_３仮焼粉末との混合粉末のＸ線回折チャートである。
【図５】本発明の実施例（試料Ｎo.１０）におけるＬａＡｌＯ_３仮焼粉末とＳｒＴｉＯ_３仮焼粉末との混合粉末のＸ線回折チャートである。
【図６】本発明の実施例（試料Ｎo.１）における誘電体磁器のＸ線回折チャートである。
【図７】本発明の実施例（試料Ｎo.１０）における誘電体磁器のＸ線回折チャートである。
【符号の説明】
１：金属ケース
２：入力端子
３：出力端子
４：誘電体磁器[0001]
BACKGROUND OF THE INVENTION
The present invention stably controls the relative permittivity εr, the sharpness Q value of the resonator, and the temperature coefficient τf in a high frequency region such as a microwave and a millimeter wave, and a dielectric ceramic composition having a small variation in manufacturing characteristics. With respect to dielectric resonators, for example, various resonator materials used in the high frequency region, dielectric substrate materials for MIC (Monolithic IC), dielectric waveguide materials, dielectric ceramics used for multilayer ceramic capacitors, etc. The present invention relates to a composition, a method for manufacturing a dielectric ceramic, and a dielectric resonator.
[0002]
[Prior art]
Dielectric ceramics are widely used in dielectric resonators, dielectric substrates for MICs, waveguides, and the like in high frequency regions such as microwaves and millimeter waves.
The required characteristics are as follows: (1) The wavelength of the electromagnetic wave propagating in the dielectric is shortened to 1 / εr 1/2, so that the relative permittivity is large for the demand for miniaturization, (2) The dielectric loss in the high frequency region is small, that is, the Q value is high, (3) the change of the resonance frequency with respect to the temperature is small, that is, the temperature dependence of the relative dielectric constant εr is small and stable. Three characteristics are mainly mentioned.
[0003]
In order to satisfy these requirements, the present applicant has previously described a dielectric having a high relative dielectric constant of 34 to 46 made of a complex oxide containing rare earth elements (Ln), Al, Ca and Ti, and a Q value of 20000 or more. A porcelain composition was proposed (see JP-A-6-76633).
[0004]
[Problems to be solved by the invention]
However, although the LnAlCaTi dielectric ceramic composition has a high relative dielectric constant and a high Q value, the values of the relative dielectric constant εr, the Q value, and the temperature coefficient τf of the resonance frequency vary in the manufacturing process, and these are stabilized. However, there is a problem that it is difficult to control.
[0005]
The present invention has been completed in view of the above circumstances, and its purpose is that the relative permittivity εr is large, the Q value is high, and the relative permittivity εr, the Q value, and the variation of the temperature coefficient τf of the resonance frequency are varied. It is an object of the present invention to provide a dielectric ceramic composition, a dielectric ceramic manufacturing method, and a dielectric resonator that can be stably controlled.
[0006]
[Means for Solving the Problems]
The dielectric ceramic manufacturing method of the present invention includes a calcined powder having a main crystal phase of LnAlO _{(x + 3) / 2} (Ln: rare earth element, 3 ≦ x ≦ 4), and RTiO ₃ (R contains at least Sr). The calcined powder having an alkaline earth element) as the main crystal phase is mixed, pulverized , molded, fired, and the composition formula based on the molar ratio of the metal elements is aLn ₂ O _x · bAl ₂ O ₃ · cMO・ DBaO.eTiO _{2 (} where M is Sr, or Sr and Ca, 3 ≦ x ≦ 4), a, b, c, d, e are 0.056 ≦ a ≦ 0.450 0.056 ≦ b ≦ 0.450 0.100 ≦ c ≦ 0.500 0 ≦ d ≦ 0.100 0.100 <e <0.470 0.75 ≦ b / a ≦ 1.25 0.75 ≦ e /(C+d)≦1.25 satisfying a + b + c + d + e = 1 That.
[0007]
[Action]
According to the method for manufacturing a dielectric ceramic of the present invention, the relative dielectric constant εr is large, the Q value is high, the relative dielectric constant εr, the Q value, and the temperature coefficient τf of the resonance frequency are small and stable. Ru can be obtained ceramics can be controlled.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
The dielectric ceramic manufacturing method of the present invention is based on the viewpoint that it is important to control the main crystal phase in the dielectric ceramic composition in order to reduce the variation in dielectric characteristics. is there.
The porcelain composition of the present invention may be a powder or a bulk body (porcelain) that is fired after being molded into a specific shape.
[0009]
That is, the method for manufacturing a dielectric ceramic according to the present invention includes a calcined powder having LnAlO _{(x + 3) / 2} (Ln: rare earth element, 3 ≦ x ≦ 4) as a main crystal phase, and RTiO ₃ (R is at least Sr And calcining powder having a main crystal phase as a main crystal phase is mixed, pulverized, molded, fired, and the composition formula by molar ratio of the metal elements is aLn ₂ O _x · bAl ₂ O ₃ CMO · dBaO · eTiO ₂ (where M is Sr, or Sr and Ca, 3 ≦ x ≦ 4), a, b, c, d, e are 0.056 ≦ a ≦ 0 .450 0.056 ≦ b ≦ 0.450
0.100 ≦ c ≦ 0.500 0 ≦ d ≦ 0.100 0.100 <e <0.470 0.75 ≦ b / a ≦ 1.25 0.75 ≦ e / (c + d) ≦ 1.25 a + b + c + d + e = 1 is satisfied.
[0010]
The main crystal phase can be measured by analyzing the porcelain composition by X-ray diffraction.
In the present invention, the term “perovskite-type crystal phase as a main crystal phase” means that the main peak of the crystal phase composed of the solid solution by X-ray diffraction is higher than the main peaks of other crystal phases, In addition, it is desirable to consist only of the perovskite crystal phase.
In particular, the perovskite crystal phase is made of a solid solution of at least LnAlO _{(x + 3) / 2} (3 ≦ x ≦ 4) and RTiO ₃ (R is an alkaline earth element containing at least Sr) (Ln, R). It is desirable that it is represented by (Al, Ti) O ₃ .
[0011]
The reason why the amount of each metal element is limited to the above range is as follows.
That is, 0.056 ≦ a ≦ 0.450 is set because τf increases positively or Q value decreases when a <0.056, and when a> 0.450. This is because the relative dielectric constant εr decreases, the Q value decreases, and τf increases negatively.
In particular, 0.078 ≦ a ≦ 0.325 is preferable.
[0012]
The reason why 0.056 ≦ b ≦ 0.450 is set is that when b <0.056, the Q value decreases or τf increases positively, and when b> 0.450, the Q value decreases. It is because it falls.
In particular, 0.078 ≦ b ≦ 0.325 is preferable.
[0013]
The reason for setting 0.100 ≦ c ≦ 0.500 is that when c <0.100, the Q value decreases or τf increases negatively, and when c> 0.500, τf This is because the value of Q becomes larger or the Q value decreases.
In particular, 0.250 ≦ c ≦ 0.47 is preferable.
[0014]
The reason why 0 ≦ d ≦ 0.100 is set is that the Q value decreases when d> 0.100.
[0015]
The reason for setting 0.100 <e <0.470 is that when e ≦ 0.100, τf increases negatively or the Q value decreases, and when e ≧ 0.470, τf This is because the value of Q becomes larger or the Q value decreases.
In particular, 0.250 ≦ e ≦ 0.422 is preferable.
[0016]
The reason why 0.75 ≦ b / a ≦ 1.25 is set is that the Q value decreases when b / a <0.75, and the Q value decreases when b / a> 1.25. Because.
In particular, 0.80 ≦ b / a ≦ 1.20 is desirable.
[0017]
The reason why 0.75 ≦ e / (c + d) ≦ 1.25 is set is that when e / (c + d) <0.75, the Q value decreases, and e / (c + d)> 1.25. This is because the Q value decreases.
In particular, 0.80 ≦ e / (c + d) ≦ 1.20 is desirable.
[0018]
According to the present invention, in the above method for manufacturing a dielectric ceramic, it is composed of a complex oxide containing at least La, Al, Sr, and Ti as metal elements, and the composition formula by molar ratio is expressed as aLa ₂ O ₃ .bAl ₂ O. _When represented by ₃ · cSrO · eTiO ₂ , the a, b, c and e are 0.1061 ≦ a ≦ 0.2162 0.1050 ≦ b ≦ 0.2086 0.3040 ≦ c ≦ 0.4185. 2747 ≦ e ≦ 0.4373 0.75 ≦ b / a ≦ 1.25 0.75 ≦ e / c ≦ 1.25 a + b + c + e = 1 is satisfied, and a solid solution of LaAlO ₃ and SrTiO ₃ is used as the main crystal phase. In this case, a higher Q value can be achieved.
[0019]
Thus, the dielectric ceramic manufacturing method of the present invention has a large relative dielectric constant εr, a high Q value, a small variation in the relative dielectric constant εr, the Q value, and the temperature coefficient τf of the resonance frequency, and is stable. This has the effect of being controllable.
[0020]
As a method for producing a dielectric ceramic according to the present invention, a mixture obtained by combining and mixing oxide powders of a plurality of metal elements forming a dielectric ceramic is temporarily calcined and pulverized, then mixed again, and molded and fired. This method is desirable in order to promote solid solution of the metal oxide in the dielectric ceramic and to unitize the crystal phase.
[0021]
That is, a calcined powder having a main crystal phase of LnAlO _{(x + 3) / 2} (3 ≦ x ≦ 4) containing a rare earth element and Al, and RTiO ₃ (R is an alkaline earth element containing at least Sr). The calcined powder as the main crystal phase is mixed, molded, and fired.
That is, a calcined powder obtained by calcining and pulverizing a mixture of a rare earth element oxide and an Al oxide, and a calcined powder obtained by calcining and crushing a mixture of an alkaline earth metal oxide containing at least SrO and TiO _2. Are mixed, formed into a predetermined shape, and then fired.
[0022]
By such a manufacturing method, a solid solution of the above LnAlO _{(x + 3) / 2} and RTiO ₃ (R is an alkaline earth element containing at least Sr), that is, (Ln, R) (Al, Ti) O ₃ It is possible to obtain a dielectric ceramic having a characteristic value of εr, Q value, and τf with a perovskite type crystal as a main crystal phase.
In addition to Sr, examples of alkaline earth elements include Ca and Ba.
[0023]
The reason why the variation in the characteristic value can be reduced by the manufacturing method of the present invention is considered as follows.
[0024]
In general, the raw material of the dielectric ceramic composition contains impurities, water, and the like.
In addition, the composition changes due to elution as ions in the solvent during the production process, sedimentation in the slurry, and discharge of heavy elements during spray drying.
For this reason, it is difficult to accurately control the ratio of each component of Ln, Al, Sr, Ca, Ba, and Ti, regardless of how highly accurate they are prepared. This causes variations in characteristic values.
[0025]
On the other hand, the dielectric ceramic manufacturing method of the present invention can control the ratio of each component with high accuracy by mixing the calcined powder produced by the above combination. It is inferred that the variation in the size can be reduced.
[0026]
More specifically, the method for manufacturing a dielectric ceramic according to the present invention includes the following steps (1) to (6).
[0027]
(1) As a starting material, high-purity, at least one kind of rare earth element (Ln) oxide (Ln ₂ O ₃ ) and aluminum oxide (Al ₂ O ₃ ) powders are used in a predetermined ratio, In particular, after weighing so that 0.75 ≦ Al ₂ O ₃ / Ln ₂ O ₃ ≦ 1.25, pure water is added, and 1 to 100 hours until the average particle size of the mixed raw material becomes 2.0 μm or less, Wet mixing and pulverization are performed by a ball mill using zirconia balls.
[0028]
(2) This mixture is dried, calcined at 1000 to 1300 ° C. for 1 to 10 hours, and then pulverized to make LnAlO _{(x + 3) / 2} (Ln: rare earth element, 3 ≦ x ≦ 4) as the main crystal phase. A calcined powder is obtained.
[0029]
(3) Similarly, an alkaline earth metal carbonate capable of producing an alkaline earth (R) oxide (RO) by heat treatment such as calcium carbonate, strontium carbonate, barium carbonate, and titanium oxide (TiO ₂ ). Using each powder, after weighing so that the desired ratio as described above, in particular, 0.75 ≦ TiO ₂ /RO≦1.25, pure water is added, and the average particle size of the mixed raw material is 2.0 μm. Wet mixing and pulverization are performed by a ball mill using zirconia balls or the like for 1 to 100 hours until the following.
[0030]
(4) The mixture is dried, calcined at 1000 to 1300 ° C. for 1 to 10 hours, pulverized, and calcined with RTiO ₃ (R is an alkaline earth element containing at least Sr) as a main crystal phase. Obtain a powder.
[0031]
(5) Next, the calcined powder having LnAlO _{(x + 3) / 2} as the main crystal phase and the calcined powder having RTiO ₃ as the main crystal phase are mixed at a predetermined ratio, and the average of the mixed raw materials Wet mixing and pulverization are performed by a ball mill using zirconia balls or the like for 1 to 100 hours until the particle size becomes 2.0 μm or less.
[0032]
(6) Further, 3 to 10% by weight of an organic binder for molding is added and then dehydrated, and then granulated or sized by a known method such as spray drying, and the obtained granulated product or sized powder. The body is molded into an arbitrary shape by a known method such as a die pressing method, a cold isostatic pressing method, an extrusion molding method, or the like.
[0033]
(7) By firing the molded body produced as described above in the atmosphere at a temperature of 1400 to 1700 ° C. for 1 to 10 hours, LnAlO _{(x + 3) / 2} , RTiO ₃ (R contains at least Sr) Dielectric porcelain having a main crystal phase of a solid solution with an alkaline earth element) can be produced.
[0034]
In particular, according to the method for manufacturing a dielectric ceramic of the present invention, the crystal phase is substantially composed of a solid solution of LnAlO _{(x + 3) / 2} and RTiO ₃ (R is an alkaline earth metal containing at least Sr) ( By being composed of a single phase of a perovskite type crystal phase composed of Ln, R) (Al, Ti) O ₃ , a dielectric ceramic excellent in stability of relative permittivity εr, Q value, and τf can be manufactured.
[0035]
In the present invention, rare earth elements (Ln) used are Y, La, Ce, Pr, Sm, Eu, Gd, Dy, Er, Yb, Nd, and the like.
Examples of the oxide form of these rare earth elements (Ln) include Ln ₂ O _x (3 ≦ x ≦ 4).
As the rare earth element, Y, La, Sm, Gd, Dy, Er, Yb, and Nd are particularly preferable, and La and Nd are particularly desirable.
[0036]
Furthermore, according to the method for producing a dielectric ceramic of the present invention, the above-mentioned dielectric ceramic composition is used as a main component, ZnO, NiO, SnO ₂ , Co ₃ O ₄ , ZrO ₂ , WO ₃ , LiCO ₃ , Rb ₂ CO ₃ , Sc ₂ O ₃ , V ₂ O ₅ , CuO, SiO ₂ , MgCO ₃ , Cr ₂ O ₃ , B ₂ O ₃ , GeO ₂ , Sb ₂ O ₅ , Nb ₂ O ₅ , Ta ₂ O ₅ or the like may be added.
These may be added at a ratio of 6 parts by weight or less with respect to 100 parts by weight of the main component, although depending on the additive component.
[0037]
The method for manufacturing a dielectric ceramic according to the present invention is most preferably used particularly as a dielectric ceramic for a dielectric resonator.
FIG. 1 shows a schematic diagram of a TE mode type dielectric resonator.
The dielectric resonator shown in FIG. 1 is provided with an input terminal 2 and an output terminal 3 on opposite sides of an inner wall of a metal case 1, and a dielectric ceramic made of the above dielectric ceramic composition between the input / output terminals 2 and 3. 4 is arranged.
In such a TE mode type dielectric resonator, a microwave is input from the input terminal 2, and the microwave is confined in the dielectric ceramic 4 by reflection at the boundary between the dielectric ceramic 4 and the free space, and has a specific frequency. Causes resonance.
This signal is electromagnetically coupled to the output terminal 3 and output.
[0038]
Although not shown, the dielectric ceramic composition according to the method for manufacturing a dielectric ceramic according to the present invention includes a coaxial resonator using a TEM mode, a stripline resonator, a TM mode dielectric ceramic resonator, Of course, it may be applied to other resonators.
Furthermore, a dielectric resonator can also be configured by providing the input terminal 2 and the output terminal 3 directly on the dielectric ceramic 4.
[0039]
The dielectric ceramic 4 is a resonance medium having a predetermined shape made of a dielectric ceramic composition according to the method of manufacturing a dielectric ceramic of the present invention. The shape of the dielectric ceramic 4 is a rectangular parallelepiped, a cube, a plate, a disk, a cylinder, A rectangular column or any other solid shape that can resonate may be used.
The frequency of the input high frequency signal is about 100 MHz to 300 GHz, and the resonance frequency is preferably about 200 MHz to 100 GHz in practice.
[0040]
Thus, by using the dielectric ceramic manufacturing method of the present invention, the no-load Q, the resonance frequency stability, and the resonance frequency temperature stability can be improved.
[0041]
【Example】
Example 1 A dielectric ceramic was produced in the following steps (1) to (7) based on the second manufacturing method described above.
[0042]
(1) Rare earth element (Ln) oxide Ln ₂ O _x (3 ≦ x ≦ 4) having a purity of 99% or more as a starting material, specifically Y ₂ O ₃ , La ₂ O ₃ , CeO ₂ , Pr ₆ O ₁₁ , each powder of Sm ₂ O ₃ , Eu ₂ O ₃ , Gd ₂ O ₃ , Dy ₂ O ₃ , Er ₂ O ₃ , Yb ₂ O ₃ , Nd ₂ O ₃ , and aluminum oxide (Al ₂ O ₃ ) After using powders and weighing them so as to have the molar ratio shown in Table 1, pure water was added and mixed, and about 20 hours by a ball mill until the average particle size of the mixed raw material became 2.0 μm or less. Wet mixed and pulverized.
[0043]
(2) This mixture was dried, calcined at 1200 ° C. for 2 hours, and then pulverized to produce LnAlO _{(x + 3) / 2} (3 ≦ x ≦ 4) having an average particle size of 0.4 to 1.5 μm as the main crystal A calcined powder A as a phase was obtained.
[0044]
(3) Similarly, calcium carbonate (CaCO ₃ ), strontium carbonate (SrCO ₃ ), barium carbonate (BaCO ₃ ), and titanium oxide (TiO ₂ ) powders are used, and the molar ratios in Table 1 are used. After weighing, pure water was added and mixed, and the mixture was wet-mixed by a ball mill for about 20 hours until the average particle size of the mixed raw material became 2.0 μm or less, and pulverized.
[0045]
(4) This mixture is dried, calcined at 1200 ° C. for 2 hours, pulverized, and mainly RTiO ₃ having an average particle diameter of 2.5 to 10 μm (R is an alkaline earth element containing at least Sr). A calcined powder B as a crystal phase was obtained.
[0046]
(5) The calcined powder A of (2) and the calcined powder B of (4) above are mixed with pure water and mixed until the average particle size of the mixed raw material is 2.0 μm or less. The mixture was wet-mixed for about 20 hours by a ball mill and pulverized.
[0047]
(6) Further, 5% by weight of an organic binder for molding was added to the obtained slurry, and the particle size was adjusted by spray drying.
[0048]
(7) The obtained granulated powder was shaped into a disk shape at a pressure of about 1 ton / cm ² and fired in the atmosphere at a temperature of 1400-1700 ° C. for 2 hours to produce a dielectric ceramic.
As a result of performing X-ray diffraction measurement on the obtained porcelain, the main crystal phase was a perovskite crystal phase composed of a solid solution of LnAlO _{(x + 3) / 2} and RTiO ₃ .
[0049]
And the disk part (main surface) of the obtained porcelain was surface-polished, ultrasonically cleaned in acetone, dried at 150 ° C. for 1 hour, and then measured at a frequency of 3.5 to 4.5 GHz by a cylindrical resonator method. The relative dielectric constant εr, the Q value, and the temperature coefficient τf of the resonance frequency were each measured 30 times, and the average value was calculated.
The Q value was converted to a Q value at 1 GHz from the relationship (Q value) × (measurement frequency f) = (constant) that is generally established in microwave dielectrics.
The temperature coefficient τf of the resonance frequency was measured in the range of −40 to 85 ° C.
[0050]
The same experiment as above was performed 30 times using the same starting materials as described above, and the relative dielectric constant εr, Q of 30 lots using the relative dielectric constant εr, Q value of each lot and the average value of the temperature coefficient τf of the resonance frequency. The standard deviation σ of each value and the temperature coefficient τf of the resonance frequency was calculated by σ = {Σ (w−y) 2 / (n−1)} 1/2.
[0051]
Here, w is an average value of εr of 30 samples of each lot, or an average value of Qf, or an average value of τf, y is a value obtained by dividing the sum of the average values of εr of each lot by 30, or A value obtained by dividing the sum of the average values of Qf of the lots by 30 or a value obtained by dividing the sum of the average values of τf of each lot by 30, and n = 30.
The results are shown in Tables 1 to 3.
[0052]
On the other hand, as comparative examples, rare earth element oxides Ln ₂ O _x (3 ≦ x ≦ 4), aluminum oxide (Al ₂ O ₃ ), calcium carbonate (CaCO ₃ ), strontium carbonate (SrCO ₃ ), barium carbonate (BaCO ₃ ). ), Titanium oxide (TiO ₂ ) powders are mixed at the same time, pulverized, dried, calcined, sized, fired and polished to produce dielectric porcelain, and the same test is performed on the obtained dielectric porcelain. Went.
The results are shown in Sample Nos. 40 to 55 in Table 2 and Sample Nos. 83 to 87 in Table 3.
[0053]
[Table 1]

[0054]
[Table 2]

[0055]
[Table 3]

[0056]
Further, changes in the X-ray diffraction measurement were examined in the above manufacturing process, and as an example, Sample Nos. 1 and 10 are shown in FIGS.
First, X-ray diffraction charts of calcined powder A and calcined powder B produced by calcining are shown in FIGS.
As is apparent from FIG. 2, the calcined powder A is a powder having LaAlO ₃ as a main crystal phase, and as is clear from FIG. 3, the calcined powder B is a powder having SrTiO ₃ as a main crystal phase. I know that there is.
[0057]
Next, X-ray diffraction charts of the mixed powder obtained by mixing the calcined powder A and the calcined powder B with the compositions of samples No. 1 and No. 10 are shown in FIG. 4 and FIG. 5, respectively.
And the X-ray-diffraction chart of the dielectric ceramic after baking using the mixed powder was shown in FIG. 6, FIG.
As is apparent from the results of FIGS. 6 and 7, a peak due to the solid solution of LaAlO ₃ and SrTiO ₃ is detected between the peaks of LaAlO ₃ and SrTiO ₃ , and a perovskite type of (La, Sr) (Al, Ti) O ₃ is detected. It turns out that it consists of a single crystal phase by a crystal phase.
[0058]
As is apparent from the results of Tables 1 to 3, when the composition ratio of each component is within the range of the present invention (No. 1 to 28), the relative dielectric constant εr is 30 or more and 1 Q when converted to 1 GHz. Excellent dielectric properties with values of 20000 or more, τf within ± 30 (ppm / ° C), and standard deviations of εr, Qf, and resonance frequency temperature coefficient τf within 0.3, 3000, and 0.7 ppm / ° C, respectively. Characteristics were obtained.
[0059]
On the other hand, the dielectric ceramic composition (No. 29-39, 76-82) outside the composition range of the present invention had a low εr, a low Q value, or an absolute value of τf exceeding 30.
[0060]
In Nos. 40 to 55 and 83 to 87 mixed simultaneously, the average values of εr, Q value and τf were the same as those of the present invention, but the standard deviation σ of εr was 1 or more and the standard deviation of τf The σ was 2 ppm / ° C. or more and the variation was large. In some comparative examples, the Qf standard deviation σ exceeded 3000, and the variation was large.
[0061]
Particularly, among the products of the present invention, 0.1061 ≦ a ≦ 0.2162, 0.1050 ≦ b ≦ 0.2086, 0.3040 ≦ c ≦ 0.4185, 0.2747 ≦ e ≦ 0.4373,. Samples Nos. 56 to 75 with 75 ≦ b / a ≦ 1.25 and 0.75 ≦ e / c ≦ 1.25 obtained excellent dielectric characteristics with a Qf value of 40000 or more when converted to 1 GHz. .
[0062]
(Example 2) After calcining the calcined powder of the porcelain composition shown in Tables 1 and 2 of Example 1 at a weight ratio shown in Table 4, it was molded, fired and polished in the same manner as in Example 1, and 30 pieces. The dielectric properties of the samples were measured and the experiment was performed 30 times in the same manner as in Example 1 to calculate the standard deviation σ of the dielectric properties.
[0063]

[Table 4]

[0064]
As a result, each of samples No. 88 to 99 had a relative dielectric constant εr of 30 or more and a Q value of 20000 or more when converted to 1 GHz. As is clear from Table 4, the standard of εr, Qf and τf The deviations σ were within 0.2, within 1000, and within 0.2 ppm / ° C., respectively, and the variation could be further reduced as compared with Example 1.
[0065]
Further, when X-ray diffraction measurement was performed on the dielectric ceramics thus obtained, all of them were composed of a single crystal phase of a perovskite crystal phase.
[0066]
【The invention's effect】
As described in detail above, according to the present invention, calcined powder having LnAlO _{(x + 3) / 2} (Ln: rare earth element, 3 ≦ x ≦ 4) as a main crystal phase, and RTiO ₃ (R is at least Sr). And calcining powder having a main crystal phase as a main crystal phase is mixed, pulverized, molded, fired, and the composition formula by molar ratio of the metal element is aLn ₂ O _x · bAl ₂ O ₃ · cMO · dBaO · eTiO ₂ (where M is Sr, or Sr and Ca, 3 ≦ x ≦ 4), a, b, c, d, and e are 0.056 ≦ a ≦ 0. 450 0.056 ≦ b ≦ 0.450 0.100 ≦ c ≦ 0.500 0 ≦ d ≦ 0.100 0.100 <e <0.470 0.75 ≦ b / a ≦ 1.25 0.75 ≦ e / (c + d) ≦ 1.25 By satisfying a + b + c + d + e = 1 In the high frequency region, a high relative dielectric constant εr and a high Q value can be obtained, and variations in εr, Q value, and τf can be reduced.
As a result, it can be applied to resonator materials, MIC dielectric substrate materials, dielectric waveguides, dielectric antennas, and other various electronic components used in the microwave and millimeter wave regions. When used as a resonator, the stability of the no-load Q and the resonance frequency can be improved, and the reliability can be improved.
[Brief description of the drawings]
FIG. 1 is a schematic view showing a dielectric resonator according to a method of manufacturing a dielectric ceramic according to the present invention.
FIG. 2 is an X-ray diffraction chart of LaAlO ₃ calcined powder in an example of the present invention.
FIG. 3 is an X-ray diffraction chart of SrTiO ₃ calcined powder in an example of the present invention.
FIG. 4 is an X-ray diffraction chart of a mixed powder of LaAlO ₃ calcined powder and SrTiO ₃ calcined powder in an example of the present invention (sample No. 1).
FIG. 5 is an X-ray diffraction chart of a mixed powder of LaAlO ₃ calcined powder and SrTiO ₃ calcined powder in an example of the present invention (Sample No. 10).
FIG. 6 is an X-ray diffraction chart of a dielectric ceramic in an example of the present invention (Sample No. 1).
7 is an X-ray diffraction chart of a dielectric ceramic in an example (sample No. 10) of the present invention. FIG.
[Explanation of symbols]
1: Metal case 2: Input terminal 3: Output terminal 4: Dielectric porcelain

Claims (1)

LnAlO _{(X + 3) / 2} A calcined powder having a main crystal phase of (Ln: rare earth element, 3 ≦ x ≦ 4), and RTiO ₃ (R is an alkaline earth element containing at least Sr) and a calcined powder having a main crystal phase as a main crystal phase, mixed, pulverized, molded, fired, and a composition formula by a molar ratio of the metal element is aLn ₂ O _x ・ BAl ₂ O ₃ ・ CMO ・ dBaO ・ eTiO ₂ (However, when M is Sr, or Sr and Ca, 3 ≦ x ≦ 4), a, b, c, d, e are
0.056 ≦ a ≦ 0.450
0.056 ≦ b ≦ 0.450
0.100 ≦ c ≦ 0.500
0 ≦ d ≦ 0.100
0.100 <e <0.470
0.75 ≦ b / a ≦ 1.25
0.75 ≦ e / (c + d) ≦ 1.25
a + b + c + d + e = 1
A method of manufacturing a dielectric ceramic characterized by satisfying

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