DD218087A1 - DIELECTRIC CERAMIC MATERIAL - Google Patents

Abstract

The invention relates to the field of electrical engineering / electronics and relates to low-sintering dielectric ceramic materials for multilayer capacitors and thick-film pastes. The aim of the invention is the production of low-sintering ceramics with DK values of 400 to 1500, which exceed the so-called semi-stable ceramics based on BaTiO3 with sintering temperatures of 1 400 C in the stability values. The invention has for its object to develop dielectric materials with low sintering temperatures, which at DK values of about 400-1 500 have high stability with respect to temperature dependence, Feldstaerkeabhaengigkeit and aging of the DK, beyond favorable dissipation factors (250 10 4) and a high Insulation resistance (1010) have. This object is achieved according to the invention with a dielectric material whose basic composition corresponds to a ternary system with the following individual components: III perovskite type III ferroelectric III perovskite type III BiFeO3 antigroelectric, the following coordinates being in the three-coordinate system for ABCDE (data in mol%) : I Ferroelectric II Antiferroelectric III BiFeO3A501040B105040C107020D3067 3E8710 3

Description

Dielectric ceramic material Field of application of the invention

The invention relates to the field of electrical engineering / electronics and relates to a dielectric ceramic material, which is applicable as a dielectric for ceramic capacitors, preferably for ceramic multilayer capacitors and also as active substance for thick film pastes, which are used for printing of Kodensatoren ·

Characteristic of the known technical solutions

Dielectric ceramic materials with low sintering temperatures are increasingly required for the realization of capacitors in the context of microelectronics. The low sintering temperature is important for thick film technology stoving pastes but also for multilayer or lunar lithium capacitors. In the latter case, especially for a Pd substitution in the electrode material and for a simplified manufacturing technology · Low-sintering dielectric materials are currently produced so that ceramic powders of different composition are embedded in a glass substance with a low melting point · With these glass ceramics, DK values are achieved from 20 to 1200, in the best case of 2500, whereby with increasing DK quality deductions with respect to liability among other things must be done. Glass ceramics can not be used to realize very high DK values for large volume capacities. Dielectric materials with low sintering »

temperature and DK values up to 30,000 can be built up from combined ferroelectrics that crystallize in the perovskite type. Partly antiferroelectrics are also used. The number of possible material systems with high DK is severely limited by the requirement for a low sintering temperature. A special role is played by the so-called semi-stable materials. They do not achieve the stability of Type I materials (e.g., NPO), but are of type II materials in terms of temperature history of the DK, field strength dependence, aging, and the like. Far superior to stability parameters. In addition there is the relatively large DK in the range of about 700 - 1200, which, in combination with the stability values, represents a very favorable compromise. The technical status of high-sintering ceramics includes the following values:

DK value Change in the DK from -55 ⁰ C to + 125 ° C

400 +. 3%

700 '. '+ 7.SJ 1200 £ 10%

2000 £ 15 %

The development of analogous materials on a low sintering basis, which exceed the mentioned temperature dependencies in this broad temperature range, has not yet been achieved. Thus, the thick film pastes offered at a DK around 1200 have a DK change of _ + 12 % in a restricted temperature range and age 2-3 % per decade. In a known material of this type, changes of + 20% occur at DK values around 1100 in the temperature range from 0 to 100 ° (US Pat. No. 3,852,077). The DK is changing very much with the sinterertaperatur.

In summary, low-sintering semi-stable ceramics have poorer dielectric data than their high-sintering precursors.

Object of the invention

The aim of the invention is to produce low-sintering ceramics with OK values of 400 to 1500, which exceed the so-called semi-stable ceramics based on BaTiO, with sintering temperatures around 1400 C in the stability values.

Explanation of the essence of the invention

The invention has for its object to develop dielectric materials with low sintering temperatures, which have high stability with respect to temperature dependence, Feldsterkeabhängigkeit and aging of the DK at DK values of about 400 - 1500, in addition favorable loss factors (<250 10) and a high insulation resistance (> 10). This object is achieved according to the invention with a dielectric ceramic material whose ürundzusammensetzung corresponds to a ternary system with the following individual components:

I Perovskite-type ferroelectric. II perovskite type III BiFeO ₃ antiferroelectric,

where the following coordinates are defined in the three-coordinate system for ABCDE (data in mol%):

I Ferroelectric II Antiferroelectric III BiFeO,

10 40

50 40

70 20

67 3

10 3

The invention can be advantageously designed in the following way:

There are PbTiO for the individual component I. and for II ^Pb L ^M 9y2 ^W / 2J ° 3, where in the three- ^coordinate system

following coordinates BKLH are fixed (in%):

A 50 B 10 C 10 D 30 Ü 87

PbTiO ₃ B 10 κ 10 L 30 M 30

- 4 Pb] Mg ₁ , "VW I 0, BiFeO

50 40

62 28

62 8

50 20

For the individual component I Pb J Fe _O y, W _v , I 0, and for PbZrO, the following coordinates are specified in the three-coordinate system (details in FIG

Pb | .Fe «/, Wi" IO ₃ PbZrO ₃ BiFeO ₃

F 70 10 20

G 35 45 20

H 50 45 5

E 85 10 5

For the single component I Pb [^ 9] / χ ^ 2 / ζ1 ° 3 ^unc * ^for II Pb [Mg ^ ₂ VVw ₂ Jo ₃ , the following coordinates NOPQR being specified in the three-coordinate system (data in mol%):

Pb [Mg _{/ 3} Nb _2/3] O ₃ Pb [Mg _{/ 2} W _{/ 2]} O ₃ BiFeO ₃

30 40

35 35

35 ^l0

12 10

12 25

the individual component I Pb ^[Fe 2/3 ^V V3 J ^unci ° 3 * ^ÜR 1 ° 3 ^used> wobei'im ternary coordinate system the following coordinates Andst are fixed (in mol%):

Pb [Fe ₂₇₃ W ₇₃ ] O ₃ Pb [Mg _{/ 2} W _{/ 2} ] O ₃ BiFeO ₃

10 40

30 40

67 3

37 3

10 30

N - 30 O 30 P 55 Q 78 R become 63 It Pb [Mg, For 'Λ

A 50 N 30 D 30 3 60 T 60

For the individual component I Pb [Fey ₂ Nby ₂ ] 0_ and for II ^p b [Mg ^ ₂ Wy ₂ ] 0_, the following coordinates UBVWXY are specified in the three-coordinate system (data in mol% ·)

PB / rOl / «HUWn

U 40 B 10 V io W 37 X 50 Y 50

Yz y 2 y O, BiFeO- ^ / '"£ ⁴⁰ 4 40 20 30 50 3 60 3 60 30 47 20

According to the invention, the material may additionally contain 0.2 to 2 mass MnO 2 and / or 0.1 to 4 mass% SiO ₉ . The material is expediently incorporated into a glass phase, preferably PbSiO ,, the proportion of which amounts to 5 to 35% by volume.

embodiment

The invention is explained below with reference to several embodiments:

I.

Example 1 .

System: PbTiO ₃ - Pb ^[M _9/2 ^W y2 ^ ° 3 ^"BiFe0 3

component

PbTiO ₃ (ferroelectric) ^Pb [ ^M 9/2 ^W / 2] °

3 BiFeO

MnCO 05 wt% 05 wt %

Addition MnCO ₃ 0.5% by 05 weight%.

mol% Offset 2 Offset 1 15 25 58 58 27 17 % 0.5 wt. 0.5 wt

Pb ₃ O _4, TiO _2, MgCO _3, WO _3, Bi ₂ O ₃₁ Fe ₂ O ₃ and MnCO ₃ were weighed as starting materials in accordance with the above displacement information, wet-mixed in a Pulverisette and burns up after drying at 850 ^p / 2 h. The resulting powder is finely ground again and pressed into tablets of 12 mm 0 and 1 mm thickness. The sintering

the discs are at 900 ⁰ C / lh. After contact with polishing silver, the following data were measured:

^{RiS TK} B o ^TK c O

-25 -. + 85 ⁰ C -5% - + 125 ° C

Offset 1 offset 2

1200 900

200.10 "* ⁴ 1O ¹² Tl -1 / - 2% -2 / -4% 150.1O" ⁴ 1O ¹² Zl -2 / -1% -4 / -2%

Field strength dependence 1 kV / mm Gleichsp.

Offset 1  -1.5% - PbZrO ₃ - BiFeO ₃ Offset 2 -1.5 % ₅ ] o ₃ Example 2 System: Pb j_ Ca \ U Ι Ο ^ ^θ 2/3 / 3 J ^U 3 64 mol% Pb / Fe W < 24 mol% PbZrO ₃

12 mol% BiFeO ₃ + 0.5 mass% MnCO ₃

Pb ₃ O _4, Fe ₃ O _3, VVO _3, ZrO _2, Bi ₃ O ₃ and MnCO ₃ were weighed as starting raw materials according to the above Versatzeinwaage and wet-mixed in a Pulverisette and burns up after drying at 850 2 / 2h. The resulting powder is finely ground again and pressed into tablets of 12 mm 0 and 1 mm thickness. The sintering of the discs takes place at 870 ^° C. (1 hour holding time). The contact is made with polishing silver, whereby the following data were obtained:

Tan egg Ris

2000 < 180> 10

" ⁴

¹¹ Jl

Range -25 ° C- + 125 C ⁰ i 15

Example 3 System: Pb

O ₃ - Pb [

] O ₃ - BiFeO

50 mole% Pb [Mgy ₃ ^Nb 2 / 3-] ° 3 23 mole% Pb lMg _{i / 2} Wy ₂ JO3 27 mole% BiFeO ₃ + 0.5 Massed MnCO ₃

The treatment from the raw materials takes place accordingly

Example 2.

The following values were obtained:

£ 900

tan egg <150. 1O ^-4

Ris> 5. 1O ¹¹ - ^

ΤΚ, τ range -25 ° t- +125 ⁰ C +2 &

Example 4

System: Pb [Fe ₂ ^ ₃ Vy ₃ ] O ₃ - Pb [^ 9y ^ y ₂ Jo ₃ - BiFeO ₃ 39 Μ0Ι & Pb [Fe _2/3 W _y3 ] ° 3 31 mol% Pb [Mgy ₂ Wy | 0 ₃ 30 mol% BiFeO ₃ + 0.5 mass MnCO ₃

The preparation was carried out from the oxides or carbonates corresponding to Examples 1 and the following values were obtained:

tan<f <200. 10 _.

Ris> 10 Xl

TK £ in the range of O - 125 ⁰ C + _ 2 % Example 5

^v r ~. r ~ r

System: Pb Fe Nb_{1 / O} | 0_ - Pb Mg_VoW_{I / o} 0_ - BiFeO, · - y 2 / <- - <3* - 7 c- 7 <t- * ο ο

40 mole% Pb [Fey ₂ Nby ₂ "] O ₃

30 MoI ^ Pb [MQy ₂ Wy ₂ ] ° 3. 30 mol% BiFeO ₃ + 0.5 mass% MnCO ₃

The treatment was carried out from the oxides or carbonates according to Examples 1 and

The following values were obtained:

^ l kHz ¹²⁵ °

tan cT <160. Erase "*

Ris> 3. 10 ¹¹ £ 1

TK _e in the range of -25 ⁰ C- + 125 ⁰ C +2

Claims (10)

      , g. , Erfihdungsanspruch 1. Dielectric ceramic material, characterized in that its basic composition corresponds to a ternary system with the following individual components: I perovskite type II ferroelectric, perovskite type III BiFeO ₃ antiferroelectric, where ABCOE has the following coordinates in the three-coordinate system (in%): I Ferroelectric II Antiferroelectric 111 BiFeO ₃ 10 40 50 40 70 20 67 3 10 3 2. Material according to item 1, characterized in that the following components are used for I and II I PbTiO ₃ Ii Pb [M where for BKLM the following coordinates are defined in the three-coordinate system (data in mol%): [ ₃ ι BiFeO ₃ 40
28
8th
20 3. Material according to item 1, characterized in that the following components are used for I and II: I Pb [Fe _2/3 W _{/ 3} ] 0 ₃ II PbZrO ₃ , -. ". ' ''; '.. - ίο - · whereby for FGI-IE the following coordinates are defined in the three-coordinate system (data in mol%): Pb I F 70 G. '·, ·. 35 H 50 E 85 4. Material according to item 1, characterized in that the following components are used for I and II: I PbίMg ^ ₃ Nb ₂ Z ₃ ] O ₃ II Pb [Mg ₂ O ₃ ] where for NÖPQR the following coordinates are defined in the three-coordinate system (data in mol%): 5. Material according to item 1, characterized in that the following components are used for I and II: I Pb! wherein * Andst for the following coordinates in the D _r eistoffkoordinatensystem are fixed (in mol%): PI? [Fe ₂₇₃ W ^ ₃ ] O ₃ Pb [Mg 6. Material according to item 1, characterized in that the following components are used for I and II: I Pb [Fe _{/ 2} Nb _{/ 2} ] 0 ₃
II P [ where for UBVWXY the following coordinates are defined in the three-coordinate system (data in mol%): Pb [Fe _y2 Nb _{/ 2} ] 0 ₃ Pb [Mg _{/ 2} W _y2 j O ₃ BiFeO ₃ U 40 20 40 B 10 50 40 V 10 60 30 W 37 60 3 X 50 47 3 Y 50 20 30 7. Material according to item 1 to 6, characterized in that it additionally contains 0.2 to 2% by mass of MnO ₂ . 8. Material according to item 1 to 7, characterized in that it additionally contains 0.1 to 4 mass SiO ₂ . 9. material according to item 1 to 7, characterized in that it is incorporated in a glass phase, wherein the glass phase 5 to 35 vol.% Share makes up. 10. Material according to item 9, characterized in that PbSiO _{3 is} used as glass phase.