DD299220A7 - METHOD FOR THE PRODUCTION OF CLASS 2 CERAMIC DIELECTRICS IN ACCORDANCE WITH IEC - Google Patents

Abstract

The invention relates to a process for the production of dielectrics for capacitors. According to the invention, the dielectric constant of dielectrics is based on separately preformed components of and / or K 1BamTiO3 {ceramic; Dielectric; Production method; BaTiO3; complex lead piperines; Bismuth layer compounds; Glaszusaetze; oxidic eutectics}

Description

Field of application of the invention

The invention relates to the field of electrical engineering / electronics and relates to a method for producing ceramic dielectrics for capacitors, in particular for multilayer and disk capacitors, and for active substances for printed capacitors.

Characteristic of the known state of the art

Miniaturization of capacitors and improvement of material economy and labor productivity in the manufacture of these capacitors require an increase de; Dielectric constant ε, the effective dielectric while maintaining the lowest possible temperature dependence thereof, z. B. of max. ± 15% deviation in the temperature range from -55T to + 125 ° C for class 2R1 according to IEC or X7R according to EIA standard.

The fulfillment of these requirements is generally sought by finding ever new compositions based on BaTiO ₃ and other components.

Thus, the following solutions are known which make progress in this respect:

According to DD-PS 258915 are achieved with active ingredients of preformed BaTiO ₃ and mixtures of bismuth layer compounds and other supplements only ε, values around 2000.

According to EP 205137 dielectrics of very fine and pure BaTiO ₃ , which is mixed with Nb ₂ O ₆ OdOrTa ₂ O ₆ and Sm ₂ O ₃ or other oxides of SE elements, these dielectrics contain further separately supplied dopants, ε, values achieved to 3 205, but at sintering temperatures not lower than 123o C. However, because of ⁰ Riesenkomwachstums they are unsuitable for multilayer capacitors having thin dielectric layers. A mixture of at least 0.5 parts by mass of BaTiO ₃ , preferably in the particle size range of 0.8 to 2.0 pm with a complex lead piperite kit gives only max. ε, values of 2,920, the minimum sintering temperatures of 1200 ⁰ C, however, are still too high for ceramic multilayer capacitors, if the proportion of expensive precious metals such as Pd is to be kept low in the inner electrode layers. (EP 257 653).

The production of the dielectrics of these solutions always takes place via the separate preforming of the individual components, such as BaTiO ₃ , other perovskites or layer compounds, or this route is at least indicated as being advantageous.

Object of the invention

The object of the invention is to find a manufacturing method for ceramic dielectrics of class 2 according to IEC on the basis of industrially produced BaTiO ₃ and various complex Blelperowskiton and / or bismuth layer compounds, especially in the production of ceramic multilayer capacitors economic advantages over the said known solutions allows.

Explanation of the essence of the invention

The invention has for its object to find a manufacturing method with which the dielectric constant ε, ceramic dielectrics of class 2 according to IEC on the basis of industrially produced BaTiO ₃ and various complex Bleiperowskiten and / or bismuth layer compounds compared to those known when using

Manufacturing process can be obtained, is increased at the same gross composition and the usual technical requirements for the material, such as dielectric losses tan5 and insulation resistance Ri ₁ , when using sintering temperatures T ₁ S 1200 ⁰ C are met. The effectiveness of the method shall be demonstrated on class 2 R1 dielectrics according to IEC.

According to the invention, this object is achieved by initially preforming or providing the following components in a known manner:

K1 = Ba _1n TiO ₃ or Ba _n JiO ₃ with dopants, where m = 0.97 to 1.00,

K2 = (Pb _x Sr ₁ -X) _n I (MFI ₇₃ Nb ₂₇₃₎ Ji ₁ _ _V] O ₃

with x = 0.75 ... 0.98 y = 0.70 ... 0.95

and η = 0.98 ... 1.06, the sintered at a sintering temperature between 115O ⁰ C and 1250 ° C and at 25 ⁰ C a

Dielectric constant ε,> 4000 has, K3 = (Pb ₁ Ai-, Mv ₁ B ₁ ... ViBiIO ₃ , of which at least 0.6, but not more than 0.95 mole fractions PbI [Fe ₁₇₂ Nb ₁₇₂ ] O ₃ ,

with A £ Sr, Ba, Ca

B ₁ ... Bi ²⁺ Mg ²⁺ , Ni ²⁺ , Zn ²⁺ , Fe ²⁺ , Co ²⁺ , Mn ²⁺ , Fe ³⁺ , Co ³⁺ , Mn ³⁺ , Sc ³⁺ , Ti ⁴⁺ , Zr ⁴⁺ , Sn ⁴⁺ , Hf ⁴⁺ , Nb ⁶⁺ , Ta ⁶⁺ , Sb ⁶⁺ , W ⁸⁺ , where V) ... V | the corresponding mole fractions of B ₁ ... Bj and

W ₁ ... W | the valences of B ₁ ... Bi mean the Smolensky conditions for perovskites

i i

£ Vi = 1 and £ WM = 4,

1 1

ζ = 0.80 ... 1.00 and

I = 0.98 ... 1.06, the sintered sintered at a sintering temperature between 93O ⁰ C and 1060 ⁰ C, and thereby in the temperature range

from -20 ° C to + 6O ⁰ C in a maximum has a dielectric constant ε,> 8000, K4 = (Pb ₁ D ₁ -, UU ₁ ZMu ₁ C ₁ ... UjCj), - _q _.] O ₃

with DASr, Ba, Ca, SE or Didym,

C ₁ ... C, & Mg ²⁺ , Ni ²⁺ , Zn ²⁺ , Fe ²⁺ , Co ²⁺ , Mn ²⁺ , Fe ³⁺ , Co ³ \ Mn ³⁺ , Sc ³ *, Ti ⁴⁺ , Zr ⁴⁺ , Sn ⁴⁺ , Hf ⁴⁺ , Nb ⁶⁺ , Ta ⁶⁺ , Sb ⁶⁺ , W ⁸⁺ , where U ₁ ... Uj are the corresponding mole fractions of C ₁ ... C j and W ₁ . .. Wj mean the valences of C ₁ ... Cj, which are the

j j

Smolensky conditions for Perowskiteq + s + £ uj = 1 and4 (q + s) + £ wjUj = 4,

1 1

mitq = 0.40 ... 0.60 s = 0.30 ... 0.55

and q + s> 0.80,

t = 0.80 ... 1.00 for DSSr, Ba, Ca or

t = 0.93 ... 1.00 for D ύ, SE or Didym and

ρ = 0.98 ... 1.06, the sintered at a sintering temperature> 115O ⁰ C, Doren dielectric constant ε, at 25 ⁰ C 2 300

is, has a maximum at> 150 ° C and little drops to negative temperatures, K5 = SrBi ₄ Ti ₄ Oi ₆ or another bismuth layer compound of the forms

Bi ₄ Ti ₃ O ₁₂

MBi ₄ Q ₄ O ₁₆ and

N ₂ Bi ₄ R ₆ O ₁₈

with M, NA Sr, Ba, Ca and optionally or simultaneously replaced by 0.01 to 0.30 molar proportions Pb and Q, R £ Ti and optionally or simultaneously by up to 0.5 mole fraction Sn and / or up to 0.2 Substance quantity Zr replaceable,

G, a low-melting glass with a hemisphere point up to max. 700 ⁰ C, which consists of at least three or six oxides PbO,

B ₂ O ₃ , ZnO, SiO ₂ , Al ₂ O ₃ and Bi ₂ O ₃ , these as fritted glasses or mixtures thereof with further of the

oxides may be present,

and E, an eutectic mixture of lead oxide and the oxides of W, Sb, Nb, Ta, Cu, Cr, Mg, Mn, Zn, Fe, Sn, Co, La, Pr, Ce, Didym or Bi or from the oxides of Co and Mn or Bi and Zn, which have a max. eutectic point <980 ° C have.

Thereafter, the components become K1 and K2, K1 and K3, and K1 and K5

mixed in the following proportions by weight, calcined at a temperature in the range of 1000 to 1100 ⁰ C, thereby forming materials, which are referred to here as intermediate components Z1 / 2, Z1 / 3 and Z1 / 5, milled and have the following properties as sintered specimens :

Between component Output component Possible mass shares Wesentl. Properties with increasing proportion of the respective second component Z1 / 2 K1 K2 0.40 ... 0.70 0.60 ... 0.30 High insulation resistance Rj, low dielectric. Losses tan δ E, decreasing Z1 / 3 K1 K3 0.35 ... 0.60 0.65 ... 0.40 very high ε, values Ri, decreasing, especially in the upper temperature range of the class Z1 / 5 K1 K5 0.75 ... 0.97 0.25 ... 0.03 very low temperature dependence of ε, ε, decreasing

At least two of these three intermediate components Z1 / 2, Z1 / 3 and Z1 / 6 are used together with the preformed and

comminuted component K4 in the following limits of mass proportions mixed, the material combinations W1 to

W4, which in the case that Z1 / 3 and Z1 / 5 at least a mass fraction of 0.5 of the total mass of the respective Material combination is, at about 1160-118O ⁰ C internal density: For mass fractions Z1 / 3 + Z1 / 5 <0.5 of the total mass, the sintering temperatures T ₁ can be increased by adding up to

0.05 parts by mass of the low-melting glass G or up to 0.03 parts by mass of oxidic eutectics E based on

Z1 / 2 + Z1 / 3 + Z1 / 5 h K4 = 1.0to max. 1200 ⁰ C are set.

Limits of mass shares in Wi .0,70 Z1 / 3 .0,20 Z1 / 5 .0,70 K4 Z1 / 2 - .0,20 0.10 .. .0,75 0.20 ... 0.40 W1 0.10 .. .0,75 0.05 .. .0,20 0.40 .. 0.20 ... 0.40 W2 - .0,55 0.05 .. - .0,55 0.20 ... 0.40 W3 0.40 .. 0.05 .. 0.10 .. 0.20 ... 0.40 W4 0.10 ..

In this case, the constraint that contains in the intermediate components Z1 / 2, Z1 / 3 and Z1 / 5.) Output component K1 in 0.30 ... 0.67 parts by mass must be included in the total offset, the scope. When exceeding the proportion of the intermediate component Z1 / 3, the insulation resistance values deteriorate and the dielectric losses increase.

If the proportion of K4 falls short of ε, words <3000 for materials of class X7 R or 2 R1. Exceeding the proportion of K4 diminishes the effect of this process due to the necessarily associated reduction of the necessary proportion of K1.

embodiments The invention will be described below with reference to an example of the formation of the intermediate components Z1 / 2, Z1 / 3 and Z1 / 5

the preformed in a known manner components

K1 = BaTiO ₃

K2 = (Pb ₀₁₈₈ Sr ₀₁₁₂ ) I (Mg ₁₇₃ Nb ₂₇₃ ) O ₁₈ TiC ₂ IO ₃ K3 = 0,86Pb [Fe, _7, Nb, _{/ 2]} O _3; 0.06Pb [Fe ₂₇₃ W ₁₇₃ ) O ₃ ; 0.05Pb [Ni ₁₇₃ Nb ₂₇₃ IO ₃ ; 0.03SrSnO ₃ and

K5 = SrBi ₄ Ti ₄ O ₁₆

and one each of the material combinations W1 to W4 of these and also preformed in a known manner

Component K4 = PbtZro.wTio ^ eiNii ^ Sb ^ lo.oelOs explained in more detail and won the disc-shaped specimens Results from the intermediate components and materials produced according to the invention. First, the finely divided components present K1 and K2 in the mass ratios 60:40, K1 and K3 in mass ratios 40:60 and K1 and K5 in the mass ratios 85:15

separately mixed for 2 h in a Agatpulverisette and calcined at a temperature of 1000 ... 1050 ° C and then finely ground (d ₆₀ <5 pm).

After plasticizing and shaping in a known manner, specimens of these intermediate components were obtained

the following technical data, to which the ε, values of the same compositions, not according to the invention, are produced ε, *

to be contrasted:

Between req'd. insulation resistance dielectric losses tan +25 ⁰ C + 125 ° C _P U2I ε · "· ²¹ component Sintertem- stood R ;, (ΙΟ " ³ )" 12 1 peraturT, (Q) ¹¹ 25 80 -55 ⁰ C 12 1 Z1 / 2 1250 ° C > 10 ¹³ 30 2200 1740 Z1 / 3 117O ⁰ C = 10 ⁹ 15 4400 3500 Z1 / 5 112O ⁰ C 5 · 10 " 60 2500 2050

1) measured at 25 ⁰ C.

2) Measuring frequency 1 kHz

From the burned and finely ground, unplasticized intermediate components and the component K4 and a glass additive G or an addition of oxidic eutectics E were prepared by mixing the specified in Table 1 Masseanteüe for 3 h in a planetary ball mill each one of the material combinations W1 to W4 according to the invention as embodiments and processed in a known manner into disc-shaped specimens on which the technical data given in Table 2 were determined.

Table 1: Compositions

execution Plant- req'd. mass fractions Z1 / 3 Z1 / 5 the comp. Ri. additional glass - (F). " additive - rungsbeisp. stoffkomb. Sintertem the intermediate components - 0.50 K4 G - e - temperature T ₁ Z1 / 2 0.20 0.60 0.30 +0.03 - 1 W1 Hold time / h 0.20 0.10 - 0.20 - - 2 W2 - 0.20 0.30 0.40 - +0.008 3 W3 1160 ° C / 2h 0.50 0.20 0.30 0.30 3 · 10 ¹² 4 W4 1160 ° C / 2h 0.20 0.30 5 · 10 " Max. deviation 5 W4 0.20 ε, ¹¹ · » tan δ ae Table 2: Technical data 1200 ° C / 2h (ΙΟ " ³ ) ¹ » · ²¹ > 1 , 0 " - in% execution In the range of rungsbeisp. 1180 ° C / 2h 3 · 10 ¹² -55 to + 125 ^° C ± 10 1170 ° C / 2h 3200 15 3 · 10 ¹² + 10 3350 16 -15 1 + 10 2 3150 12 -15 + 10 3 3260 15 -14 + 10 4 3400 15 -14 5

1) measured at 25 ° C

2) Measuring frequency 1 kHz

The glass additive G used was a solder glass, which had the following constituents:

0.85 parts by weight PbO 0.07 parts by mass B ₂ O ₃ 0.06 parts by mass ZnO 0.01 parts by mass Al ₂ O _{3 and} 0.01 parts by mass SiO ₂

As the dectectic mixture E, 5PbO Cr ₂ O _{3 was} used. This method is also applicable to the production of other class 2 dielectrics not under subclass 2Fi 1

correspond, but z. B. class 2 D1 and have increased ε, - values, if a corresponding selection of

Components and intermediate components and their mass fractions takes place.

Claims (1)

-1- 29 * 220 claims: Process for the production of ceramic dielectrics of class 2 according to IEC, in particular those of class 2 R1 according to IEC on the basis of preformed components of Ba _m TiO ₃ or Ba _m TiO ₃ with customary dopings, where m = 0.97 to 1.00 is referred to herein for abbreviation K1, with which
the complex lead piper kite
(Pb _x Sr ₁ -X) _n I (Mg ₁ Z ₂ Z ₃ Nb ₃₎ VTi ₁ _ _y] O ₃
with x = 0.75 ... 0.98
y = 0.70 ... 0.95 and η = 0.98 ... 1.06, which is abbreviated herein
referred to as K2, (PbIA ₁ -Z) I [V ₁ B ₁₁₁₁ VjBj] O ₃ , of which between 0.6 and 0.95 mole fractions PbI (Fe ₁ Z ₂ Nb ₁ Z ₂ ] O ₃ , with A ^ Sr, Ba, Ca, B ₁ ... Bi & Mg ²⁺ , Ni ²⁺ , Zn ²⁺ , Fe ²⁺ , Co ²⁺ , Mn ²⁺ , Fe ³⁺ , Co ³⁺ , Mn ³⁺ , Sc ³⁺ , Ti ⁴⁺ , Zr ⁴⁺ , Sn ⁴⁺ , Hf ⁴⁺ , Nb ⁶⁺ , Ta ⁶⁺ , Sb ⁶⁺ , W ⁶⁺ , i i where Y ₁ Vj = 1 and Σ W ₁ V ₁ = 4 1 1 if V ₁ ... v, the corresponding proportions of B ₁ ... Bj and W ₁ ... Wj are the respective valences of B ₁ ,
ζ = 0.80 ... 1.00 and I = 0.98 ... 1.06, which will be referred to herein for brevity as K3, (Pb ₁ D ₁ _, Jp [TIqZr ₈ (U ₁ C ₁ ... UjCj) ₁ _ _q _ _S ] O ₃
with D & Sr, Ba, Ca, SE or Didym, C ₁ ... C j δ Mg ²⁺ , Ni ²⁺ , Zn ²⁺ , Fe ²⁺ , Co ²⁺ , Mn ²⁺ , Fe ³⁺ , Co ³⁺ , Mn ³⁺ , Sc ³⁺ , Ti ⁴⁺ , Zr ⁴⁺ , Sn ⁴⁺ , Hf ⁴⁺ , Nb ⁵⁺ , Ta ⁵⁺ , Sb ⁵⁺ , W ⁶⁺ , where q + s + £ ui = 1 and 4 (q + s) + £ WjUj = 4, if U ₁ ... Ui the 1 1 corresponding molar fractions of C ₁ ... C, - and W ₁ ... Wj denote the respective valences of Cj,
q = 0.40 ... 0.60
s = 0.30 ... 0.55
q + s> 0.80 t = 0.80 ... 1.0OfUrD ^ Sr, Ba, Ca or
t = 0.93 ... 1.00 for D & SE or Didym and ρ = 0.98 ... 1.06, herein abbreviated as K4, and / or the bismuth layer compounds of the forms
Bi ₄ Ti ₃ O ₁₂ ,
MBi ₄ Q ₄ O ₁₅ and
N ₂ Bi ₄ R ₅ O ₁₈ with M, N = Sr, Ba, Ca and optionally or simultaneously replaced by 0.01 to 0.30 mole fractions Pb and Q, R ^ y; and optionally or simultaneously replaced by up to 0.5 molar proportions Sn and / or up to 0.2 molar fractions Zr, herein abbreviated as K5, and up to 0.05 mass fractions of low melting glass additions G and / or eutectic mixtures of lead oxide and the oxides of W, Sb, Nb, Ta, Cu, Cr, Mg, Mn, Zn, Fe, Sn, Co, La, Pr, Ce, Didyrn or Bi or from the oxides of Co and Mn or Bi and Zn, the a max. eutectic point 98O ⁰ C and are referred to herein as oxidic eutectics E, characterized in that from K1 and K2, the intermediate component Z1 / 2,
from K1 and K3 the intermediate component Z1 / 3 and
from K1 and K5 the intermediate component Z1 / 5 is formed by mixing the respective components K1, K2, K3 and K5 and calcination at a temperature in the range of 1000 to 1100 ⁰ C and subsequent fine grinding, wherein the mass fractions in Z1 / 2 0.40 ... 0.70 of component K1 and 0.60 ... 0.30 represent component K2, the mass fractions in Z1 / 3 0.35 ... 0.60 of component K1 and 0.65 ... 0.40 of the component K3 and the mass fractions in Z1 / 5 0.75 ... 0.97 of the component K1 and 0.25 ... 0.03 of the component K5 can be that at least two of these three intermediate components Z 1/2, Z 1/3 and Z 1/5 together with the preformed and comminuted component K4 and optionally the further sintering temperature-reducing glass additives of up to 0.05 parts by weight or the additions of oxidic eutectics of up to 0.03 Mass components to the respective dielectrics forming combinations W1 to W4 is mixed together, wherein the mass fractions in W1 0.10 ... 0.70 of the intermediate component Z 1/2, 0, 0..., 0.70 of the intermediate component Z 1/5 and 0.20 ... 0.40 of the component K4, which Mass proportions in W2 0.05... 0.20 of the intermediate component Z 1 /0.40, 0.75, 0.75 of the intermediate component Z1 / 5 and 0.20-0.40 of the component K4, the mass fractions in W3 0.40 ... 0.75 of the intermediate component Z 1/2 0.05 ... 0.20 of the intermediate component Z 1/3 and 0.20 ... 0.40 of the component K4 and the mass fractions in W4 0.10 to 0.55 of the intermediate component Z 1/2, 0, 0 to 0, 0 of the intermediate component Z 1/3, 0, 0, 0 to 0.55 of the intermediate component Z 1/5 and 0, 20 ... 0.40 of the component K4 and at the same time the component K1 contained in Z 1/2, Z 1/3 and Z 1/5 in the total offset between 0.30 and 0.67 parts by weight.