JP3384043B2 - Piezoelectric ceramic - Google Patents
Piezoelectric ceramicInfo
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- JP3384043B2 JP3384043B2 JP20043893A JP20043893A JP3384043B2 JP 3384043 B2 JP3384043 B2 JP 3384043B2 JP 20043893 A JP20043893 A JP 20043893A JP 20043893 A JP20043893 A JP 20043893A JP 3384043 B2 JP3384043 B2 JP 3384043B2
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Description
【０００１】[0001]
【産業上の利用分野】この発明は、セラミック発振子、
セラミックフィルタ、セラミックディスクリミネータな
どの圧電素子、特に、耐熱性が要求される表面実装型の
圧電部品に使用される圧電磁器に関する。BACKGROUND OF THE INVENTION The present invention relates to a ceramic oscillator,
The present invention relates to a piezoelectric element such as a ceramic filter or a ceramic discriminator, and particularly to a piezoelectric ceramic used for a surface-mounted piezoelectric component that is required to have heat resistance.
【０００２】[0002]
【従来の技術】セラミックフィルタなどに用いられる圧
電磁器（圧電磁器組成物）として、従来より、チタン酸
ジルコン酸鉛（Ｐｂ（ＴｉXＺｒ1-X）Ｏ3）を主成分と
する圧電磁器が広く用いられており、その圧電特性を改
善するために種々の微量添加物を添加した圧電磁器が用
いられている。2. Description of the Related Art As a piezoelectric ceramic (piezoelectric composition) used for a ceramic filter or the like, a piezoelectric ceramic mainly containing lead zirconate titanate (Pb (Ti x Zr 1-x ) O 3 ) has been conventionally used. It is widely used, and in order to improve its piezoelectric characteristics, piezoelectric ceramics to which various trace additives are added are used.
【０００３】そして、これらの圧電磁器の中でも、特
に、群遅延時間（ＧＤＴ）特性が平坦で、位相歪が小さ
いセラミックフィルタ（圧電フィルタ）用の圧電磁器に
は、機械的品質係数Ｑｍ値の小さいことが要求される。Among these piezoelectric ceramics, a piezoelectric ceramic for a ceramic filter (piezoelectric filter) having a flat group delay time (GDT) characteristic and a small phase distortion has a small mechanical quality factor Qm. Is required.
【０００４】ところで、この機械的品質係数Ｑｍ値の小
さい圧電磁器としては、チタン酸ジルコン酸鉛（Ｐｂ
（ＴｉXＺｒ1-X）Ｏ3）に添加物として、酸化ニオブ、
酸化アンチモン、酸化タンタルなどを添加した圧電磁器
や、チタン酸ジルコン酸鉛（Ｐｂ（ＴｉXＺｒ1-X）
Ｏ3）のＰｂ原子の一部をＬａなどの希土類元素で置換
した圧電磁器などが知られている。By the way, as a piezoelectric ceramic having a small mechanical quality factor Qm value, lead zirconate titanate (Pb) is used.
(Ti x Zr 1-x ) O 3 ) as an additive, niobium oxide,
Piezoelectric ceramics containing antimony oxide, tantalum oxide, etc., and lead zirconate titanate (Pb (Ti X Zr 1-X )
There is known a piezoelectric ceramic in which a part of Pb atoms of O 3 ) is replaced with a rare earth element such as La.
【０００５】また、上記の圧電磁器の他にも、圧電磁器
に微量成分を拡散させた材料として、Ｐｂ（Ｚｒ0.52Ｔ
ｉ0.48）Ｏ3にＭｎを拡散させた材料が報告されている
（M.Takahashi and S.Takahashi ; Japan. J. Appl. ph
ys. Vol.9, No.8, pp.1006 (1970) ）。In addition to the above-mentioned piezoelectric ceramic, Pb (Zr 0.52 T
i 0.48 ) A material in which Mn is diffused in O 3 has been reported (M. Takahashi and S. Takahashi; Japan. J. Appl. ph.
ys. Vol.9, No.8, pp.1006 (1970)).
【０００６】[0006]
【発明が解決しようとする課題】しかし、上記従来の機
械的品質係数Ｑｍ値の小さい圧電磁器は、アクチュエー
タ用として圧電ｄ定数を増大させたものや、広帯域フィ
ルタ用として電気機械結合係数Ｋを増大させることを主
たる目的とするものが多く、キュリー温度が低く、耐熱
性が不十分なものが多い。However, the above-mentioned conventional piezoelectric ceramics having a small mechanical quality factor Qm have an increased piezoelectric d constant for actuators and an electromechanical coupling factor K for broadband filters. In many cases, the main purpose is to do so, the Curie temperature is low, and the heat resistance is insufficient.
【０００７】また、上記従来の機械的品質係数Ｑｍ値が
小さい圧電磁器は、キュリー温度が高いものであって
も、半田付け工程などで温度上昇を伴う場合において
は、圧電磁器の両端に形成した電極間を短絡させたとき
はよいが、開放したときには、電気機械結合係数Ｋが低
下し、共振・***振周波数が大きくずれてしまうという
欠点がある。Further, the conventional piezoelectric ceramic having a small mechanical quality factor Qm value is formed at both ends of the piezoelectric ceramic even if the Curie temperature is high, even if the temperature rises in the soldering process or the like. When the electrodes are short-circuited, it is good, but when they are opened, the electromechanical coupling coefficient K is lowered, and the resonance / anti-resonance frequencies are greatly deviated.
【０００８】このため、上記従来のＱｍ値が小さい圧電
磁器は、表面実装型のフィルタ素子として使用した場
合、リフロー半田付けの工程で高温（約２５０℃）にさ
らされると、フィルタ特性が大きく劣化するという問題
点がある。Therefore, when the conventional piezoelectric ceramic having a small Qm value is used as a surface-mounting type filter element, when it is exposed to a high temperature (about 250 ° C.) in the reflow soldering process, the filter characteristic is largely deteriorated. There is a problem of doing.
【０００９】また、Ｐｂ（Ｚｒ0.52Ｔｉ0.48）Ｏ3にＭ
ｎを拡散させた材料（M.Takahashi and S.Takahashi ;
Japan. J. Appl. phys. Vol.9, No.8, pp.1006 (1970)
）では、共振・***振周波数の温度特性が悪いという
問題点があり、フィルタ素子用の材料として用いるには
不適当である。In addition, Pb (Zr 0.52 Ti 0.48 ) O 3 contains M
n-diffused material (M.Takahashi and S.Takahashi;
Japan. J. Appl. Phys. Vol. 9, No. 8, pp. 1006 (1970)
(1) has a problem that the temperature characteristics of the resonance / anti-resonance frequency are poor, and is unsuitable for use as a material for a filter element.
【００１０】さらに、Ｍｎをチタン酸ジルコン酸鉛系の
圧電磁器の粒界部分に拡散させる場合に、その拡散温度
が高すぎるとＭｎが粒内に侵入し、バルク特性を劣化さ
せる（すなわち、Ｑｍ値が上昇する）という問題点があ
る。Further, when diffusing Mn in the grain boundary part of a lead zirconate titanate-based piezoelectric ceramic, if the diffusion temperature is too high, Mn penetrates into the grain and deteriorates bulk characteristics (that is, Qm). The value rises).
【００１１】この発明は、上記の問題点を解決するもの
であり、機械的品質係数Ｑｍ値が小さく、かつ、耐熱性
に優れた圧電磁器であって、特に、群遅延時間特性が平
坦で位相歪が小さく、かつ、表面実装に対応することが
可能なフィルタ素子用の圧電磁器を提供することを目的
とする。The present invention solves the above problems and is a piezoelectric ceramic having a small mechanical quality factor Qm value and excellent heat resistance, and in particular, has a flat group delay time characteristic and a phase. An object of the present invention is to provide a piezoelectric ceramic for a filter element, which has a small distortion and is compatible with surface mounting.
【００１２】[0012]
【課題を解決するための手段】上記問題点を解決するた
めに、この発明の圧電磁器は、一般式：ＰｂＺｒ1-xＴ
ｉxＯ3（但し、ｘ＝０．４６〜０．５４）で表されるチ
タン酸ジルコン酸鉛のＰｂ原子の８．０モル％までをＣ
ａ，Ｓｒ，及びＢａからなる群より選ばれる少なくとも
１種で置換し、また、Ｓｂ，Ｎｂ，Ｗ，及びＴａからな
る群より選ばれる少なくとも１種を、Ｓｂ2Ｏ3，Ｎｂ2
Ｏ5，ＷＯ3，及びＴａ2Ｏ5に換算して０．１〜２．９重
量％添加し、さらに、Ｓｉ及びＧｅの少なくとも１種を
ＳｉＯ2及びＧｅＯ2に換算して０．００１〜０．５重量
％添加した組成を有する圧電磁器に対して、Ｍｎを拡散
による方法により、ＭｎＯ2に換算して０．００５〜
０．９重量％含有させたことを特徴とする。In order to solve the above problems, the piezoelectric ceramic of the present invention has a general formula: PbZr 1-x T
i x O 3 (where, x = 0.46~0.54) up to 8.0 mol% of Pb atoms of lead titanate zirconate represented by C
at least one selected from the group consisting of a, Sr, and Ba, and at least one selected from the group consisting of Sb, Nb, W, and Ta is replaced with Sb 2 O 3 , Nb 2
O 5, WO 3, and in terms of Ta 2 O 5 was added 0.1 to 2.9 wt%, further, 0.001 in terms of at least one of Si and Ge in the SiO 2 and GeO 2 Diffusion of Mn to a piezoelectric ceramic having a composition with 0.5% by weight added
Is converted to MnO 2 by the method
It is characterized by containing 0.9% by weight.
【００１３】また、この発明の圧電磁器は、前記Ｍｎ
が、圧電磁器の粒内部より、粒界層に高濃度で存在して
いることを特徴とする。Further, the piezoelectric ceramic of the present invention is the above Mn.
Is present in the grain boundary layer at a higher concentration than inside the grains of the piezoelectric ceramic.
【００１４】上記のように、この発明の圧電磁器は、機
械的品質係数Ｑｍ値が小さく、キュリー温度が高い圧電
磁器に対してＭｎを含有させることにより抵抗率を低下
させることを特徴とするものであり、特に、圧電磁器中
にＳｉＯ2及びＧｅＯ2の少なくとも１種をあらかじめ添
加しておくことにより、粒界部分（ＰｂＯ−ＳｉＯ
2系，及びＰｂＯ−ＧｅＯ2系の２次相成分）の液相化温
度を低下させ、従来より低い温度でＭｎを拡散させるこ
とを可能にして、その抵抗率を低下させるようにしたも
のである。As described above, the piezoelectric ceramic of the present invention is characterized by including Mn in a piezoelectric ceramic having a small mechanical quality factor Qm value and a high Curie temperature to reduce the resistivity. In particular, by adding at least one of SiO 2 and GeO 2 to the piezoelectric ceramic in advance, the grain boundary portion (PbO-SiO 2
2 system and PbO—GeO 2 system secondary phase component), the liquidus temperature of the system is lowered, Mn can be diffused at a lower temperature than before, and its resistivity is lowered. is there.
【００１５】[0015]
【作用】例えば、分極処理済みの圧電磁器を加熱し、こ
れを室温に戻したときには焦電電荷が発生する。この焦
電電荷による電場は、圧電磁器の分極方向と反対方向に
発生し、圧電磁器の分極の大きさを減少させる。For example, when the polarized piezoelectric ceramic is heated and returned to room temperature, pyroelectric charge is generated. An electric field due to this pyroelectric charge is generated in a direction opposite to the polarization direction of the piezoelectric ceramic, and reduces the magnitude of polarization of the piezoelectric ceramic.
【００１６】これに対して、Ｍｎを熱拡散などの方法に
より含有させることにより、圧電磁器の抵抗率を低下さ
せ、焦電電荷を速やかに放電させて消滅させることによ
り、分極方向と反対方向の電場が長時間印加されること
を防止することが可能になる。その結果、残留分極の大
きさが減少することを抑制し、共振・***振周波数の変
化量を減少させることができるようになる。On the other hand, by incorporating Mn by a method such as thermal diffusion, the resistivity of the piezoelectric ceramic is reduced, and the pyroelectric charge is quickly discharged and eliminated, whereby the direction opposite to the polarization direction is obtained. It becomes possible to prevent the electric field from being applied for a long time. As a result, it is possible to suppress the reduction of the magnitude of the remanent polarization and reduce the amount of change in the resonance / anti-resonance frequency.
【００１７】また、通常、圧電磁器の粒界部分の主成分
は、ＰｂＯ（融点約８９０℃）であるが、この圧電磁器
にあらかじめＳｉＯ2，及びＧｅＯ2を添加しておくこと
により、Ｓｉ，Ｇｅが粒界部分に偏析し、粒界成分はＰ
ｂＯ−ＳｉＯ2系及びＰｂＯ−ＧｅＯ2系の２次相成分と
なる。そして、この成分系の融点は、例えば、ＰｂＯ−
ＳｉＯ2系の場合、ＰｂＯ単体に比べ１５０℃程度低下
する。このことは、「Geller,R.& Bunting,E.; J.Res.N
at.Bur.Stand.31(11),255-270,(1943)」にも明示されて
いるところである。したがって、Ｍｎの拡散を低温で行
うことが可能になり、Ｍｎの粒内への侵入による特性の
劣化（Ｑｍ値の増大）を防止し、安定して粒界部分のみ
にＭｎを拡散させることができる。Usually, the main component of the grain boundary portion of the piezoelectric ceramic is PbO (melting point of about 890 ° C.), but by adding SiO 2 and GeO 2 to this piezoelectric ceramic in advance, Si, Ge segregates at the grain boundary portion, and the grain boundary component is P
a quadratic phase component of bO-SiO 2 system and PbO-GeO 2 system. The melting point of this component system is, for example, PbO-
In the case of SiO 2 system, it is about 150 ° C lower than that of PbO alone. This is `` Geller, R. & Bunting, E .; J. Res. N.
at.Bur.Stand.31 (11), 255-270, (1943) ”. Therefore, it becomes possible to diffuse Mn at a low temperature, prevent deterioration of characteristics (increase in Qm value) due to invasion of Mn into grains, and stably diffuse Mn only at grain boundary portions. it can.
【００１８】[0018]
【実施例】以下、この発明の実施例を示して、発明をさ
らに具体的に説明する。まず、圧電磁器の構成材料であ
るＰｂＯ，ＳｒＣＯ3，ＴｉＯ2，ＺｒＯ2，Ｓｂ2Ｏ3，
Ｎｂ2Ｏ5，ＷＯ3，Ｔａ2Ｏ5，ＳｉＯ2及びＧｅＯ2の各
原料を表１に示すような組成となるように秤取し、これ
に水を加え、ボールミルを用いて湿式混合する。そし
て、湿式混合により得られた混合物を乾燥した後、８０
０〜９００℃で２時間仮焼し、この仮焼材料をボールミ
ルを用いて湿式粉砕することにより調整粉末を得た。The present invention will be described in more detail below by showing examples of the present invention. First, PbO, SrCO 3 , TiO 2 , ZrO 2 , Sb 2 O 3 , which are the constituent materials of the piezoelectric ceramic,
Raw materials of Nb 2 O 5 , WO 3 , Ta 2 O 5 , SiO 2 and GeO 2 are weighed so as to have the composition shown in Table 1, water is added thereto, and wet-mixed using a ball mill. . Then, after the mixture obtained by the wet mixing is dried,
The powder was calcined at 0 to 900 ° C. for 2 hours, and the calcined material was wet pulverized using a ball mill to obtain an adjusted powder.
【００１９】そして、この調整粉末に水またはポリビニ
ルアルコールなどの粘結材を添加し、プレス成形を行な
った後、１１５０〜１２５０℃の温度で２時間焼成を行
ない、直径１０mm、厚さ１mmの円板状の磁器を得た。こ
の磁器の表面に、ＭｎＣＯ3をワニスで練って作製した
ペーストを筆で塗布し、乾燥させた後、これを８５０〜
１１００℃の温度で２時間加熱して熱拡散処理を施し
た。その後、この磁器を厚さ０．５mmに研磨し、両端面
（両主面）に銀電極を焼き付けした後、８０℃の絶縁オ
イル中で３０分間、２〜３ｋＶ／mmの電界で分極処理を
行ない圧電磁器（振動子試料）を得た。なお、比較のた
め、上記実施例と同様の方法でこの発明の範囲外の組成
を有する圧電磁器（振動子試料）を作製した。Then, after adding a binder such as water or polyvinyl alcohol to the adjusted powder and press-molding the mixture, it is fired at a temperature of 1150 to 1250 ° C. for 2 hours to give a circle having a diameter of 10 mm and a thickness of 1 mm. A plate-shaped porcelain was obtained. On the surface of this porcelain, a paste prepared by kneading MnCO 3 with a varnish was applied with a brush and dried, and then 850-500
Heat diffusion treatment was performed by heating at a temperature of 1100 ° C. for 2 hours. After that, this porcelain was polished to a thickness of 0.5 mm, silver electrodes were baked on both end surfaces (both main surfaces), and then polarized in an insulating oil at 80 ° C. for 30 minutes in an electric field of 2 to 3 kV / mm. A piezoelectric ceramic (vibrator sample) was obtained. For comparison, a piezoelectric ceramic (vibrator sample) having a composition outside the scope of the present invention was produced by the same method as in the above-described examples.
【００２０】そして、これらの試料について、比抵抗
ρ，径方向の振動における電気機械結合係数Ｋｐ，機械
的品質係数Ｑｍｐ，及び共振周波数Ｆｒの温度変化率
（Ｆｒ−ＴＣ（温度係数）と表記）を測定した。その結
果を表１に示す。With respect to these samples, the resistivity ρ, the electromechanical coupling coefficient Kp in radial vibration, the mechanical quality coefficient Qmp, and the temperature change rate of the resonance frequency Fr (expressed as Fr-TC (temperature coefficient)). Was measured. The results are shown in Table 1.
【００２１】[0021]
【表１】 [Table 1]
【００２２】また、振動子試料を２５０℃の恒温槽に３
分間入れて加熱処理を施し、両端電極間を開放させたま
ま取り出した後、約１時間放置し、共振周波数Ｆｒ及び
***振周波数Ｆａの変化量ΔＦｒ，ΔＦａを測定した。
その結果も併せて表１に示す。The vibrator sample was placed in a constant temperature bath at 250 ° C.
After being put in the heat treatment for 1 minute and taken out with the electrodes between both ends opened, it was left for about 1 hour, and the changes ΔFr and ΔFa of the resonance frequency Fr and the anti-resonance frequency Fa were measured.
The results are also shown in Table 1.
【００２３】なお、表１において、ＡＡ，ＢＢ，ＣＣ，
ｘ，ｙ，ｚ，α，βは、下記の式(1)：
Ｐｂ1-zＡＡzＺｒ1-xＴｉxＯ3
＋ β（wt%）ＢＢ ＋ ｙ(wt%)ＣＣ ＋ α(wt%)ＭｎＯ2 ……(1)
（但し、ＡＡ：Ｃａ，Ｓｒ，Ｂａの少なくとも１種
ＢＢ：Ｓｂ2Ｏ3，Ｎｂ2Ｏ5，ＷＯ3，Ｔａ2Ｏ5の少なく
とも１種
ＣＣ：ＳｉＯ2，ＧｅＯ2の少なくとも１種）
で表される圧電磁器の組成を示している。In Table 1, AA, BB, CC,
x, y, z, alpha, beta, the following equation (1): Pb 1-z AA z Zr 1-x Ti x O 3 + β (wt%) BB + y (wt%) CC + α (wt %) MnO 2 (1) (However, at least one kind of AA: Ca, Sr, Ba BB: Sb 2 O 3 , Nb 2 O 5 , at least one kind of WO 3 , Ta 2 O 5 CC: SiO 2 , GeO 2 ).
【００２４】表１において、試料No.に*印を付したもの
はこの発明の範囲外の圧電磁器（比較例）を示してい
る。In Table 1, the sample numbers marked with * indicate piezoelectric ceramics (comparative examples) outside the scope of the present invention.
【００２５】なお、表１に示した試料以外の他の試料を
も含めて検討した結果、ＡＡ（Ｃａ，Ｓｒ，Ｂａ）の置
換量ｚが０．０８（８．０モル％）を越えるとキュリー
温度が低下するとともに、加熱後の共振・***振周波数
の変化量ΔＦｒ，ΔＦａが大きくなり、耐熱性が悪化す
ることがわかった。したがって、ＡＡ（Ｃａ，Ｓｒ，Ｂ
ａ）の置換量ｚは０．０８（８．０モル％）以内である
ことが好ましい。As a result of examination including samples other than the samples shown in Table 1, when the substitution amount z of AA (Ca, Sr, Ba) exceeds 0.08 (8.0 mol%). It was found that as the Curie temperature decreases, the changes ΔFr and ΔFa in the resonance / anti-resonance frequency after heating increase, and the heat resistance deteriorates. Therefore, AA (Ca, Sr, B
The substitution amount z of a) is preferably within 0.08 (8.0 mol%).
【００２６】また、ＢＢ（Ｓｂ2Ｏ3，Ｎｂ2Ｏ5，Ｗ
Ｏ3，Ｔａ2Ｏ5の少なくとも１種）の添加量βが０．１
重量％未満の場合、Ｆｒの温度変化率Ｆｒ−ＴＣが大き
くなるなどの問題があり、また添加量βが２．９重量％
を越えるとキュリー温度が低下し、耐熱性が悪化するた
め、ＢＢ（Ｓｂ2Ｏ3，Ｎｂ2Ｏ5，ＷＯ3，Ｔａ2Ｏ5の少
なくとも１種）の添加量βは、０．１〜２．９重量％の
範囲にあることが好ましい。BB (Sb 2 O 3 , Nb 2 O 5 , W
The addition amount β of at least one of O 3 and Ta 2 O 5 is 0.1
If it is less than 10% by weight, there is a problem that the temperature change rate Fr-TC of Fr becomes large, and the addition amount β is 2.9% by weight.
If it exceeds 1.0, the Curie temperature is lowered and the heat resistance is deteriorated. Therefore, the addition amount β of BB (at least one of Sb 2 O 3 , Nb 2 O 5 , WO 3 and Ta 2 O 5 ) is 0.1 to 0.1%. It is preferably in the range of 2.9% by weight.
【００２７】さらに、Ｔｉの割合（モル比）ｘが０．５
４（５４モル％）を越えると電気機械結合係数Ｋｐが低
下し、また、ｘが０．４６（４６モル％）未満になると
キュリー温度が低下し、耐熱性が悪化するため、Ｔｉの
割合（モル比）ｘは０．４６〜０．５４の範囲にあるこ
とが好ましい。Further, the Ti ratio (molar ratio) x is 0.5.
When it exceeds 4 (54 mol%), the electromechanical coupling coefficient Kp decreases, and when x is less than 0.46 (46 mol%), the Curie temperature decreases and heat resistance deteriorates. The molar ratio x is preferably in the range of 0.46 to 0.54.
【００２８】さらに、ＣＣの添加量ｙが０．００１重量
％未満の場合、拡散温度の低下の効果が認められず、ま
た、添加量が０．５重量％を越えるとＫｐが低下するた
め、ＣＣの添加量ｙは、０．００１〜０．５重量％の範
囲にあることが好ましい。Further, when the added amount y of CC is less than 0.001% by weight, the effect of lowering the diffusion temperature is not recognized, and when the added amount exceeds 0.5% by weight, Kp is lowered. The CC addition amount y is preferably in the range of 0.001 to 0.5% by weight.
【００２９】また、表１より、Ｍｎを含有していない比
較例の試料（試料No.１）と、Ｍｎを含有するこの発明
の実施例の試料（例えば、試料No.２）を比較すると、
実施例の試料（試料No.２）は、比較例の試料（試料No.
１）に比べて比抵抗（抵抗率）ρが１桁以上小さくなっ
ていることがわかる。Further, from Table 1, comparing the sample of the comparative example containing no Mn (Sample No. 1) with the sample of the example of the present invention containing Mn (eg Sample No. 2),
The sample of the example (Sample No. 2) is the sample of the comparative example (Sample No. 2).
It can be seen that the specific resistance (resistivity) ρ is smaller than that of 1) by one digit or more.
【００３０】そして、比抵抗ρが低下した結果、この発
明の実施例の圧電磁器においては、表１に示すように、
加熱後の共振周波数及び***振周波数の周波数変化量Δ
Ｆｒ，ΔＦａが大幅に小さくなっている。しかもこの場
合、機械的品質係数ＱｍｐはＭｎを含有しない試料No.
１とほとんど変らず、電気機械結合係数Ｋｐの値は、試
料No.１よりもかなり大きくなっており、この点におい
ても、実施例の圧電磁器はその特性が向上していること
がわかる。As a result of the decrease in the specific resistance ρ, in the piezoelectric ceramic of the embodiment of the present invention, as shown in Table 1,
Frequency change Δ of the resonance frequency and anti-resonance frequency after heating
Fr and ΔFa are greatly reduced. Moreover, in this case, the mechanical quality factor Qmp is the sample No. containing no Mn.
The value of the electromechanical coupling coefficient Kp is substantially the same as that of Sample No. 1, and it can be seen that the characteristics of the piezoelectric ceramics of the example are also improved in this respect.
【００３１】なお、これらの効果は、主として、拡散に
より磁器中に含有させたＭｎＯ2（粒界層に偏在してい
る）によるものであると考えられる。It is considered that these effects are mainly due to MnO 2 (distributed unevenly in the grain boundary layer) contained in the porcelain by diffusion.
【００３２】また、試料No.２（ＳｉＯ2を添加した実施
例）と同じ組成を有し、ＣＣ（ＳｉＯ2，ＧｅＯ2）のみ
を添加しない試料（比較例）を作成し、これと試料No.
２（実施例）の試料について、拡散温度と抵抗率（log
ρ）の関係を比較した。その結果を図１に示す。図１よ
り、シリカを添加した実施例（試料No.２）の圧電磁器
は、ＣＣ（ＳｉＯ2，ＧｅＯ2）を添加しない比較例の圧
電磁器に比べて同じ拡散温度における抵抗率（logρ）
が低くなっており、比較例の場合に比べて１００℃以上
低い温度でＭｎを拡散させることが可能になっているこ
とがわかる。Further, a sample (comparative example) having the same composition as sample No. 2 (example in which SiO 2 was added) but not containing only CC (SiO 2 , GeO 2 ) was prepared. .
The diffusion temperature and the resistivity (log
ρ) was compared. The result is shown in FIG. From FIG. 1, the piezoelectric ceramic of the example (Sample No. 2) to which silica is added has a resistivity (log ρ) at the same diffusion temperature as compared with the piezoelectric ceramic of the comparative example to which CC (SiO 2 , GeO 2 ) is not added.
It is understood that Mn can be diffused at a temperature lower by 100 ° C. or more than in the case of the comparative example.
【００３３】なお、Ｍｎの含有量αがＭｎＯ2に換算し
て０．００５重量％未満の場合、比抵抗（抵抗率）ρや
周波数変化量ΔＦｒ，ΔＦａなどの特性改善の効果が不
十分になり、また、０．９重量％を越えると機械的品質
係数Ｑｍｐが大きくなったり、周波数変化量ΔＦｒ，Δ
Ｆａが大きくなったりする傾向があるため、Ｍｎの含有
量αは、ＭｎＯ2に換算して０．００５〜０．９重量％
の範囲にあることが好ましい。When the Mn content α is less than 0.005 wt% in terms of MnO 2 , the effect of improving the characteristics such as the specific resistance (resistivity) ρ and the frequency changes ΔFr and ΔFa becomes insufficient. Further, if it exceeds 0.9% by weight, the mechanical quality factor Qmp becomes large, and the frequency variation ΔFr, Δ
Since Fa tends to be large, the Mn content α is 0.005 to 0.9% by weight in terms of MnO 2.
It is preferably in the range of.
【００３４】[0034]
【発明の効果】上述のように、この発明の圧電磁器は、
チタン酸ジルコン酸鉛のＰｂ原子の一部をＣａ，Ｓｒ，
及びＢａの少なくとも１種で置換するとともに、Ｓｂ，
Ｎｂ，Ｗ，及びＴａの少なくとも１種を所定量添加し、
さらに、Ｓｉ及びＧｅの少なくとも１種ををＳｉＯ2及
びＧｅＯ2に換算して０．００１〜０．５重量％添加し
た組成を有する圧電磁器に対して、Ｍｎを拡散による方
法により、ＭｎＯ2に換算して０．００５〜０．９重量
％含有させるようにしているので、電気機械結合係数Ｋ
ｐが大きく、かつ、共振周波数及び***振周波数の温度
変化率、及び機械的品質係数Ｑｍの値が小さい圧電磁器
を得ることができる。As described above, the piezoelectric ceramic of the present invention is
Some of the Pb atoms of lead zirconate titanate are Ca, Sr,
And at least one of Ba and Sb,
Adding at least one of Nb, W, and Ta in a predetermined amount,
Further, in a piezoelectric ceramic having a composition in which at least one of Si and Ge is converted into SiO 2 and GeO 2 by 0.001 to 0.5% by weight, Mn is diffused.
By the method, 0.005 to 0.9 wt% of MnO 2 is contained, so that the electromechanical coupling coefficient K
It is possible to obtain a piezoelectric ceramic having a large p, a temperature change rate of the resonance frequency and the anti-resonance frequency, and a small mechanical quality coefficient Qm.
【００３５】そして、この発明の圧電磁器をセラミック
フィルタ（圧電フィルタ）素子に用いた場合、広い周波
数帯域において、群遅延時間（ＧＤＴ）特性を平坦にす
るとともに、位相歪を小さくすることが可能になり、デ
ジタル信号に対してビット誤りを生じにくくさせること
ができる。したがって、この発明の圧電磁器は、デジタ
ル対応の圧電フィルタ素子用の材料として特に有意義で
ある。When the piezoelectric ceramic of the present invention is used for a ceramic filter (piezoelectric filter) element, it is possible to flatten the group delay time (GDT) characteristic and reduce the phase distortion in a wide frequency band. Therefore, it is possible to prevent a bit error from occurring in the digital signal. Therefore, the piezoelectric ceramic of the present invention is particularly significant as a material for a digital-compatible piezoelectric filter element.
【００３６】また、この発明の圧電磁器は、加熱及び加
熱後の冷却に対する共振周波数及び***振周波数の変化
量が小さいという特徴を有している。Further, the piezoelectric ceramic of the present invention is characterized in that the amount of change in the resonance frequency and the anti-resonance frequency with respect to heating and cooling after heating is small.
【００３７】したがって、この発明にかかる圧電磁器
は、リフロー半田などにより表面実装されるフィルタ素
子材料として用いた場合にも、高温（〜２５０℃）によ
る特性劣化、特にフィルタの通過帯域のずれ、及び通過
帯域幅の減少割合が小さく、表面実装に十分に対応する
ことができる。Therefore, when the piezoelectric ceramic according to the present invention is used as a filter element material which is surface-mounted by reflow soldering or the like, characteristic deterioration due to high temperature (up to 250 ° C.), especially deviation of the pass band of the filter, and The reduction rate of the pass band width is small, and it is possible to sufficiently cope with surface mounting.
【００３８】さらに、この発明の圧電磁器においては、
製造工程におけるＭｎの拡散温度を低下させることが可
能になり、特性の安定化を図ることができる。Further, in the piezoelectric ceramic of the present invention,
The diffusion temperature of Mn in the manufacturing process can be lowered, and the characteristics can be stabilized.
【図１】ＳｉＯ2を添加した実施例の圧電磁器と、Ｓｉ
Ｏ2を添加しない比較例の圧電磁器の、拡散温度と抵抗
率（logρ）との関係を示す図である。FIG. 1 is a piezoelectric ceramic of an embodiment to which SiO 2 is added, and Si
O 2 without the addition of the piezoelectric ceramic of the comparative example, is a graph showing the relationship between the diffusion temperature and the resistivity (log .rho).
───────────────────────────────────────────────────── フロントページの続き (72)発明者 橘高 敏彦 京都府長岡京市天神二丁目26番10号 株 式会社 村田製作所内 (56)参考文献 特開 平５−139829（ＪＰ，Ａ) 特開 平７−33522（ＪＰ，Ａ) 特開 平６−1656（ＪＰ，Ａ) 特公 昭39−6277（ＪＰ，Ｂ１) (58)調査した分野(Int.Cl.7，ＤＢ名) C04B 35/42 - 35/49 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshihiko Tachibana Toshihiko Tachibana 2-10-10 Tenjin, Nagaokakyo, Kyoto Murata Manufacturing Co., Ltd. (56) Reference JP-A-5-139829 (JP, A) JP-A 7-33522 (JP, A) JP-A-6-1656 (JP, A) JP-B 39-6277 (JP, B1) (58) Fields investigated (Int.Cl. 7 , DB name) C04B 35/42 -35/49
Claims (2)
ｘ＝０．４６〜０．５４）で表されるチタン酸ジルコン
酸鉛のＰｂ原子の８．０モル％までをＣａ，Ｓｒ，及び
Ｂａからなる群より選ばれる少なくとも１種で置換し、
また、Ｓｂ，Ｎｂ，Ｗ，及びＴａからなる群より選ばれ
る少なくとも１種を、Ｓｂ2Ｏ3，Ｎｂ2Ｏ5，ＷＯ3，及
びＴａ2Ｏ5に換算して０．１〜２．９重量％添加し、さ
らに、Ｓｉ及びＧｅの少なくとも１種をＳｉＯ2及びＧ
ｅＯ2に換算して０．００１〜０．５重量％添加した組
成を有する圧電磁器に対して、Ｍｎを拡散による方法に
より、ＭｎＯ2に換算して０．００５〜０．９重量％含
有させたことを特徴とする圧電磁器。1. A general formula: PbZr 1-x Ti x O 3 (however,
x = 0.46 to 0.54), and replaces up to 8.0 mol% of Pb atoms of lead zirconate titanate represented by at least one selected from the group consisting of Ca, Sr, and Ba,
In addition, at least one selected from the group consisting of Sb, Nb, W, and Ta is converted into Sb 2 O 3 , Nb 2 O 5 , WO 3 , and Ta 2 O 5 and the amount is 0.1 to 2.9. % By weight, and at least one of Si and Ge is added to SiO 2 and G
For a piezoelectric ceramic having a composition of 0.001 to 0.5 wt% converted to eO 2 , a method of diffusing Mn
More, the piezoelectric ceramic, characterized in that which contains 0.005 to 0.9 wt% in terms of MnO 2.
界層に高濃度で存在していることを特徴とする請求項１
記載の圧電磁器。2. The Mn is present at a higher concentration in the grain boundary layer than in the grains of the piezoelectric ceramic.
The described piezoelectric ceramic.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20043893A JP3384043B2 (en) | 1993-07-19 | 1993-07-19 | Piezoelectric ceramic |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20043893A JP3384043B2 (en) | 1993-07-19 | 1993-07-19 | Piezoelectric ceramic |
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| Publication Number | Publication Date |
|---|---|
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| JP3384043B2 true JP3384043B2 (en) | 2003-03-10 |
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ID=16424297
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|---|---|---|---|---|
| JP2757121B2 (en) * | 1994-07-15 | 1998-05-25 | 日本航空電子工業株式会社 | Socket connector |
| JP3204056B2 (en) * | 1995-11-08 | 2001-09-04 | 株式会社村田製作所 | Piezoelectric ceramic |
| JP2001080956A (en) * | 1999-09-07 | 2001-03-27 | Murata Mfg Co Ltd | Piezoelectric ceramic and laminated piezoelectric vibrator using the same |
| JP2001089237A (en) * | 1999-09-20 | 2001-04-03 | Tdk Corp | Piezoelectric porcelain composition |
| JP3562402B2 (en) * | 1999-09-29 | 2004-09-08 | 株式会社村田製作所 | Piezoelectric ceramic material and surface wave device using the same |
| KR100693385B1 (en) * | 2005-07-07 | 2007-03-09 | 한양대학교 산학협력단 | Low Temperature Sintered Piezoelectric Ceramic Composite |
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1993
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