JPS5866205A - Porcelain composition - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a porcelain composition, and particularly to a porcelain composition that can be sintered at a low temperature of 1000°C or less, has a high product of dielectric constant and specific resistance, and has high mechanical strength. .

Conventionally, barium titanate (B
It is well known that porcelain compositions containing a TiOs as a main component have been widely put into practical use.

However, for those whose main component is barium titanate (BaTiO), the sintering temperature is usually 1300 to 1400.
The temperature is ℃. Therefore, if this is used in a laminated capacitor, a material that can withstand this sintering temperature must be used as the internal electrode, such as an expensive noble metal such as platinum or palladium, which increases the manufacturing cost. There are drawbacks. In order to make laminated type F/densors at low cost, it is necessary to have a porcelain composition that can be sintered at as low a temperature as possible, especially below 1000°C, so that inexpensive metals mainly composed of silver and nickel can be used for the internal electrodes. be.

For this reason, Pb(FI&A%/s)Os-Pb(Few/1Nb
t/2) 0, system (refer to Special Committee Publication No. 55-34962)
(8 r -P b )
T i On pb (Mg 7z Wt) 0.
systems (see Japanese Patent Laid-Open No. 52-21699) have been proposed.

By the way, when producing a practical multilayer capacitor using a ceramic composition, many items must be evaluated as the electrical properties of the ceramic composition.

Generally, it is required that the dielectric constant be as large as possible, the dielectric loss as small as possible, the resistivity as large as possible, and the temperature change in the dielectric constant as small as possible.

However, for practical purposes, in multilayer capacitors, values such as the capacitance 9, the temperature change rate of the capacitance, the dielectric loss, etc. are required, rather than the dielectric constant. In multilayer capacitors,
Capacity is proportional to the dielectric constant of the porcelain composition, but it is inversely proportional to its thickness, and proportional to the electrode area and the number of laminated layers, so it is not necessarily necessary that the dielectric constant of the porcelain composition be large in order to obtain a constant capacitance. It is not a factor. Furthermore, the temperature change rate of capacitance (temperature change rate of dielectric constant) has various allowable ranges depending on the application, and the humidity change (tJ) of the dielectric constant of a ceramic composition is not an absolute factor when manufacturing a multilayer capacitor. .

On the other hand, there is a regulation that the dielectric loss must be below a certain value depending on the application, and the maximum is below ■I at room temperature. Furthermore, regarding specific resistance, for example, as stated in the P:IAJ standard [Japan Electronics Industry Co., Ltd.'s multilayer ceramic capacitors for electronic equipment (chip type → RC-3698B), the insulation resistance of multilayer capacitors is 1100 OOΩ or more or the capacitance resistance is It is specified that the product is 500μF-MΩ or more, whichever is smaller. In other words, if the product of the permittivity and resistivity of the porcelain composition is not greater than a certain absolute value, it is an arbitrary capacitance.

In particular, capacitors with large capacitances cannot be made to meet practical standards, so their uses are extremely limited and they have no practical meaning. This point will be explained in detail as follows. A multilayer capacitor has a structure in which single-layer capacitors are stacked, generally consisting of n layers of the same thickness and forming n+1 internal electrodes. In this case, if the capacitance per single layer is C (1e and the insulation resistance is R, then the capacitance C of the multilayer capacitor is C00n times, and the insulation resistance B is 1 of B.
It becomes /n. Here, if the permittivity of the ceramic composition is C1, the permittivity of vacuum is I・, the specific resistance of the ceramic composition is ρ, and the thickness of the ceramic of the single layer capacitor is 61, the area of the overlapping electrodes is S,
The C0 of a single layer capacitor is (#.(S)/d, and the bird is (ρa)/8. Therefore, the product C×R of the capacitance 0 and the insulation resistance ■ of a multilayer capacitor consisting of n layers is [(ρd)/ (
ns ) ] X [(neo as)/d )=to
It becomes tρ. In other words, the capacitance/resistance product (CxR) of any capacitance of the laminated layers is determined by
It is normalized to a constant value (t6gρ) obtained by multiplying the product of C· by C·. The capacitance/resistance product CxR is 500μF・MΩ, or 50
0F・Ω or more means s'0=8.855 x
From 10''' F/cIn, CxR=t@gl=8.8
55 x 10-14 (P/erR) xg xρ≧5
00F-Ω.

Therefore, there is a requirement that Cρ≧5.65×10 Ω0 country.

For example, when t=10000, ρ≧5.65×10”Ω.

When ξ=3000, ρ≧1.88X10.9-equipment, g=5
00 requires ρ≧1.13×10 90 countries.

Any large capacitance multilayer capacitor will have a capacitance or
The resistance product satisfies 500 μF and MΩ.

If ε is 3000 and ρ is 1.88x, which is one order of magnitude lower than the required value
1 () If 11Ω・α, then ε. Cρ=50μF, M
Ω does not satisfy 500aF*MtJ, and in order to satisfy the standard value of insulation resistance of 10000147G, that is, BLO''Ω or more, the capacitance C must be limited to 0.005JP or less.
Resistance @ (Cx R) is always K 50 aF-MJ? As shown, when R is 1100OO#, C is 0.0
05#r, and if C is larger than this, R is 1000
This is because the capacitance is smaller than 0 Mg, and 0.005 μF is the highest capacitance that satisfies the standard. Therefore, if the specific resistance of the porcelain composition is low, the practicality of the material, especially the small size and large capacity that is a feature of laminated capacitors, cannot be taken advantage of, and it is completely meaningless. Therefore, it is extremely important in practice that the product of the dielectric constant and specific resistance of the porcelain composition has a certain value or more.

In addition, in the case of multilayer chip capacitors, when the chip capacitor is mounted on a board, due to the difference in thermal expansion coefficient between the board and the ceramic composition that makes up the chip capacitor,
Mechanical strain is applied to the chip capacitor, which may cause cracks or damage to the chip capacitor. Furthermore, in the case of a dip capacitor coated with epoxy resin or the like, cracks may occur in the dip capacitor due to the stress of the coat resin. In either case, the lower the mechanical strength of the porcelain forming the capacitor, the more likely it is to crack and break, resulting in lower reliability.

Therefore, it is of practical importance to increase the mechanical strength of porcelain as much as possible.

By the way, Pb(Mgt/zWx/z)Os-PbTi
Regarding the porcelain composition of the 03 series, N.
ainikand A, 1. Agranovska
ya (F!ziko Tverdog.

Te1a, v,, 2. ) ml, pp70-72
．． Janvara (1960)), but among the characteristics to be evaluated when manufacturing a multilayer capacitor, only the dielectric constant and its temperature characteristics were described, and its practicality was not clear. Also (8rzPl)1-a:T
i2B)a(PbMga,sWe,!50.)b
C * ” ” O~0.10, a is 0.35
-0.5. b is 0.5-0.65 and a+b
=1] is disclosed in JP-A-52-21662 as a monolithic capacitor and its manufacturing method, and as a dielectric powder composition in JP-A-52-216'1.
It is disclosed in G9 publication. Here again, the characteristics of the composition are that the dielectric constant is about 2000 to 8000 and the dielectric loss is 0.
．． Although there is a description of 5% to 5.0%, there is no description of specific resistance or capacitance-resistance product, and its practicality was unclear. Furthermore, Pb(Mgl/z W1/2) Os
and PbTfO, and Pb (M
gx/2%/z) 0. is 20.0 to 70.0 mol%
, pb'rio, a composition in the range of 30.0 to 80.0 mol %, and a high dielectric constant porcelain composition characterized in that the amount of S MgO is added to be 30% or less of the calculated value. It is disclosed as No. 55-144609.

However, in this patent, the dielectric constant is about 2300~
In addition to the description that the dielectric loss is 0.3% to 2.1% in 7100, there is also a description of the temperature characteristics of the dielectric constant, but there is no description of specific resistance or capacitance-resistance product, and the practicality of this composition is unclear. .

Next, we have already shown that P b (Mg 1/2 Wx/z ) O, and Pb'l'i0. The system consists of two components, which are [:Pb(
Mgx/lWx/z ) Os NL-[P b T
s 03 ] 1-x, when X is 0.6
A composition in the range of 5<X≦1.00 is proposed.

This composition has a product of dielectric constant and specific resistance of 5.65X101
It has a high value of Ω・Taku or higher and has excellent electrical properties with low dielectric loss.However, the above composition has
Since both have low mechanical strength, their uses have had to be limited to a narrow range.

In view of the above points, the present invention can be sintered in a low temperature range of 900 to 1000°C, and has a product of dielectric constant and specific resistance of 5.65.
X 1015Ω・m (that is, the capacitance-resistance product is 500
The purpose is to provide a porcelain composition that has a high value of μF - Mg) or higher, has low dielectric loss, has good electrical properties, and also has high mechanical strength. (Pb(Mgx/z Wl/2)
P l) (Mg x/z Ws/z )
01)x(PbTie, ]l-,y, 2 is within the range of 0.50≦X≦LOG, and niobium (Nb) and tanta # (T&) are added as subcomponents to the main component composition.
and antimony (8b), and the element is added in an amount of 0.02 to 1 atomic % based on the main component.

The present invention will be explained in detail below with reference to Examples.

Lead oxide (PbO) with a purity of 99.9% or more as a starting material
.

Magnesium oxide (MgO), tungsten oxide (Wa)
S), titanium oxide (Tie, ), niobium oxide (Nb.

Os), tantalum oxide (Tag's), and antimony oxide (8btOm) were weighed so that the mixing ratio shown in Table 1 was obtained. Next, the weighed materials were wet-mixed in a ball mill, and then pre-baked at 750-80°C.
This powder is crushed in a ball mill, dried, and then mixed with an organic binder, sized, and then pressed.
Four disks with a diameter of 16 mm and a cylinder with a thickness of about 10 mm were prepared. Next, it was sintered in air at a temperature of 900 to 1000°C for 1 hour.

Silver at 600℃ on the top and bottom surfaces of four sintered disks! Burn the apple and measure the frequency IKHz with a digital LCR meter.

The capacitance and dielectric loss were measured at a voltage I Vr of −8 and a temperature of 20° C., and the dielectric loss 1 & i was calculated. Next, use a super insulation resistance tester to
A voltage of 0 V was applied for 1 minute, insulation resistance was measured at a temperature of 20° C., and specific resistance was calculated. In order to evaluate the mechanical properties in terms of bending strength, 10 rectangular plates each having a thickness of 0.5 days, 9 widths of 2 ga, and a length of approximately 13 ga were cut out from the sintered cylinder. Using the distance between the fulcrums as 9III, the bending strength τ [
[exposure] was determined. however! is the distance between the supporting points, t is the thickness of the sample, and W is the width of the sample. Electrical characteristics are average values of four disk samples.

The bending strength was determined from the average value of 10 rectangular plate samples.

The main component (P b (M
g1/zWl/2 ) 03 lr (P b T t
03) Combination ratio X of tz and additive amount of subcomponents, bending strength, dielectric constant, dielectric loss, and capacitance-resistance product (ε in the table).

The relationship between Cρ and Cρ is shown in the table.

□ As is clear from the results shown in the table, s as a kll component
By adding at least one of Nb, Ta, and sb, it is highly reliable and highly practical, increasing both the transverse flexural strength and the capacitance-resistance product while maintaining a low dielectric loss value. It can be seen that a dielectric constant ceramic composition is obtained. The ceramic composition of the present invention exhibiting these excellent properties has a low sintering temperature of 1000°C or less, so it can reduce the cost of internal electrodes of multilayer capacitors, and
It also has the extremely excellent effect of saving energy and saving furnace materials.

Note that if the main component blending ratio X is less than 0.5, the capacitance-resistance product will be smaller than the standard value and the dielectric loss will also exceed &O%, which is not practical. Also, Nb is a subcomponent.

For Ta and sb, the amount of one or more elements added.

If it is less than 0.02 atomic %, the effect of improving bending strength is small;
If it exceeds 1 atomic %, the bending strength decreases, which is not practical.

Procedural amendment (Self-control, Indication of incident, 1981 Patent Application No. 1458)
No. 64 2° Invention 0 Title Porcelain, Composition 3, Relationship with the amended person case Applicant 5-33-1 Shiba, Minato-ku, Tokyo (423) NEC Corporation Representative Tadahiro Sekimoto 4, Agent Sumitomo Sanda Building, 37-8 Shiba 5-chome, Minato-ku, Tokyo 108 Telephone Tokyo (03) 456-3111 (Main) 5,
Detailed inducement column on the original side of the specification subject to amendment.

6. Contents of amendment (1) Specification-2 Sada/His lines 15 to 20 [ko0
), it can be sintered at below 1000°C, and Pb (Fe 273VV l, /, ) 03Pb can be used as a 611a vessel composition.
(Fe 1.,, Nb η) 03 series (Special Publication 1984-
34962) and at temperatures above 1050°C6 (5r-P b ) TtOa -pb (Mg
t72w+7. )03 thread (special υi4 jLi52 2
1699) have been proposed. ” will be deleted.

(2) Ming-i1! '-A 5 mm r [(
, f'd) / (ns))x [(ngots) /
d) J is 1 [(J) d) / (ns)
') x [(nε.εS)/d) J.

Claims (1)

[Claims] Magnesium tungsten fullEt (Pb(Mg
When expressed as t/z, X is in the range of 0.50≦5≦1.00, and as a subcomponent, from among niobium alpha tantalum (Ta) and antimoy (8b) Select at least one type or more, and make Q for 4 with that element as the main component.
A porcelain composition characterized by containing an additive amount of 02 to 1%.