JPS6036367A - Ceramic 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, particularly a porcelain composition that can be sintered at a low temperature of 1100°C or less, has a high dielectric constant, has a high insulation resistance at room temperature and high temperature, and has high mechanical strength. It is something.

Conventionally, barium titanate (B
It is well known that porcelain containing aTi(h) as a main component has been widely put into practical use. However, those whose main component is barium titanate (BaTiOs) have a sintering temperature of usually 1300 to 1400°C. Therefore, when using this in a multilayer capacitor, a material that can withstand this sintering temperature must be used for the internal electrode, such as an expensive noble metal such as platinum or palladium.
The disadvantage is that manufacturing costs are high. In order to make multilayer capacitors cheaply, it is necessary to use porcelain that can be sintered at as low a temperature as possible, especially below 1100°C, so that inexpensive metals mainly composed of silver and nickel can be used for the internal electrodes.

Furthermore, the electrical properties of a ceramic composition are basically high dielectric constant, low dielectric loss, and high insulation resistance. Furthermore, the value of insulation resistance is based on Military Specification (ML1i-tary 5peci), which is a US Department of Defense standard that requires highly reliable components.
In the MIL-C-55681B of fication), not only the value at room temperature but also the value at 125°C is defined. As can be seen from this, in order to obtain a highly reliable ceramic capacitor, it is necessary not only to have a high value of insulation resistance at room temperature, but also to have a high value of insulation resistance at the highest expected temperature.

In addition, in the case of BJa type chip capacitors, when the chip capacitor is mounted on a board, mechanical strain is applied to the chip capacitor due to the difference in thermal expansion coefficient between the board and the porcelain that makes up the chip capacitor. Cracks may occur or damage may occur.

In addition, in the case of dip capacitors coated with epoxy resin, etc., cracks may occur in the dip capacitor due to the stress of the coat resin.In either case, the mechanical strength of the porcelain that forms the capacitor is low. The more likely it is that cracks will occur, the more easily it will be damaged, and the reliability will be lower. Therefore, it is of practical importance to increase the mechanical strength of porcelain as much as possible.

By the way, Pb (Mg Yu/2W1/2) 0. - PbTi
0. Regarding porcelain compositions, N0. N., Krajnik, A.

Ai, 7 Granovskaya N, N, Krainik an
d A, I.

Agrarovskaya (Fiziko Tverd
ogo Te1apVo, 2. No, 1°pp 70~
72* Janvara 1960) has a proposal.
Also, (S rxPb 1-XTIO++ ) B (
PbMg O,5W+1,sO++)b [where x=
0-0.10. a=0.35-0.5. bm, 5~
0.65. a + bm1: ], a monolithic capacitor and its manufacturing method are disclosed in Japanese Patent Application Laid-Open No. 52-
It is disclosed in Japanese Patent Application Laid-Open No. 21662, and also disclosed as a dielectric powder composition in Japanese Patent Application Laid-Open No. 52-21699.

However, none of them discloses any specific resistance, and the practicality of these ceramic compositions is unknown.

On the other hand, the present inventors have already been able to sinter at a temperature of 910-950℃, and Pb(Mgyo/2W□/2)03 and PbTi0
It consists of a two-component system with a, which is converted into [Pb(MgF2W172)Os)a(Pb'riOs)
When expressed as 1-e.

We are proposing a composition in which ing.

However, since all of the above compositions have low mechanical strength, their applications have had to be limited to a narrow range.

In addition, Pb(Mgt/zWl/z)Os PbTi(%
For three-component systems including
In No. 1 pb(Mg□/2W□/z')Os Pb
Ti0a Pb (Mg□/+1Nb 2/3)0.
The system has the odor "CPb" described in JP-A No. 55-117809.
(Mg 1/2Wl/2)Os PbTie, -Pb
(8Ig□/5TfL273)Os systems are each disclosed. However, none of them discloses specific resistance or mechanical strength, and the practicality of these ceramic compositions is unclear.

Mata, the inventors have already developed Pb (MjKx72Ws/2)
Os PbTiQ3Pb(In1/zNb1/z)Oi
A three-component composition is proposed.

This composition can be sintered in a low temperature range of 900 to 1100°C, and has excellent properties such as high dielectric constant, low dielectric loss, and high insulation resistance at room temperature and high temperature.

However, this composition has low mechanical strength;
Its use 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 1100°C, has a high dielectric constant, low dielectric loss, high insulation resistance at room temperature and high temperature, and has excellent electrical properties. The purpose is to provide a highly reliable porcelain composition with particularly high mechanical strength.
2) Oa l), lead titanate CPbTiO3] and indium lead niobate [Pb (I n vzNb 1
/2) A three-component composition from Os'l [Pb (Mg
, /2W□/2)03]yu(PbTi0a)a[Pb
When expressed as (Inl/lNb+7z)On':lz (however, x"7+z=1.oO:), the following composition points in this three-component composition diagram, (x=0.796, y=0.191 ), z=0.0
05 ) (x=0.48, Y=0.12, z=
0.40) (x=0.21, y=o, oct,
z=0.70) (x=0-12, y=o, is
, z=0.70) (x=0.398, r 0.
597, z-0,005) and in the composition range surrounded by these five points, as a subcomponent, manganese lead niobate CPb (Mn□/2Nb
□/z) Oa) 0.05 to 5 mol1 to the main component
%.

The present invention will be explained in detail below using examples.

Lead oxide (PbO) with a purity of 99.9 or higher as a starting material
, magnesium oxide (MgO), tungsten oxide C
WO, ), titanium oxide (TiOz-containing indium oxide n = os), niobium oxide (Nb20s), and manganese carbonate (MnCO*) are used, and each is weighed so as to have the compounding ratio shown in the table. Next, the weighed materials were wet-mixed in a ball mill, pre-baked at 750-800°C, and this powder was ground in a ball mill, dried, and then mixed with an organic powder (inder), sized, and then pressed. , four disks with a diameter of 16 mm and a thickness of approximately 2 mm were used as samples;
v+rn, a cylinder with a thickness of about 10 dragons was created. Next, the sample was sintered in air at a temperature of 900 to 1100°C for 1 hour, and silver electrodes were baked at 600°C on the top and bottom surfaces of the four sintered disks. ,
Frequency IKHz, voltage IV with digital LCR meter
r, m, s, measured the capacity and dielectric loss at a temperature of 20°C,
The dielectric constant was calculated.

Next, a voltage of 50 V was applied for 1 minute using a super insulation resistance meter, insulation resistance was measured at temperatures of 20° C. and 125° C., and specific resistance was calculated.

In order to evaluate the mechanical properties by the bending strength, the bending strength τ [p pieces] was calculated from the sintered cylinder according to the formula of a rectangle with a thickness of 65 mm, a width of 2 vax, and a length of about 13 dragons. However, l
is the distance between the supporting points, t is the thickness of the sample, and W is the width of the sample.

The electrical properties were determined from the average value of 4 disk samples, and the bending strength was determined from the average value of 10 rectangular plate samples.

The main component of the porcelain thus obtained (Pb (R/I
g1/2Wx/z)On )X [PbT i Os
)y (Pb (Inx/zNb 1/2)03:)
Z (7) Pb ( Mg+/2W1/z)OsPb
Ti0m Pb(In1/2Nbt/z)On Pb (Mu 172Nb/
2) Those containing 01 in a specific proportion have a high dielectric constant of 1000 to 3520, and a dielectric loss of 0.2
The resistivity is as small as -2 and 6 inches, and the resistivity is 2. I
XIQ'L8.2
It shows a high value of 1013 Ω・α, and also has a bending strength of 980 to 1240 kg/a! It can be seen that this is a highly reliable and extremely practical ceramic composition that exhibits a sufficiently high value for practical use.

The porcelain composition of the present invention, which exhibits such excellent properties, has a low sintering temperature of 1,100°C or less, which makes it possible to reduce the cost of the internal electrodes of multilayer capacitors, and also to save energy and furnace materials. An extremely excellent effect also occurs. The figure shows the main component composition range of the present invention. The numbers shown in the figure correspond to the numbers of the main component blending ratios shown in the table.

In the present invention, the main component composition is (Pb (Mg s/2W□
/2)On')[PbTiOs:)y[:Pb(
In1/2Nbt/z)Os :] When expressed as z (where X"y"z=1.OO), the following composition point (x=0.796, y=0. 199, z=0.0
05 ) (x=0.48, y=0.12, z=0
．． 40 ) (X=0.21, y=o, o9. z=
0.70) (x=0.12, 3'=0.18,
z=0.70) (X=0.398, y=0.597
, z=0.005) and the composition range surrounded by these five points, and the added content of the subcomponent is limited to 0.05 to 5 mol relative to the main component. In addition, in the main component composition range, the resistivity at high temperatures becomes small outside the line connecting composition points 2 and 15, making it impractical. Outside the line connecting composition points 15, 16, 7, and 3.2, the dielectric constant becomes small and is not practical. In addition, the subcomponent Pb
(Mn17xNb □72) The amount of Os added is Q-05
If the mol is less than 1, the effect of improving the bending strength is small, and the
If it exceeds 1%, the bending strength will decrease, which is not practical.

[Brief explanation of drawings]

The figure is a diagram showing the main component composition range of the present invention and the composition points shown in Examples.

Claims (1)

[Claims] (1) Magnesium lead tungstate (Pb(Mg□
/2Wl/2)Os), lead titanate (PbTiOa) and lead indium niobate (Pb(Inl/zNbt
/z)On :) A three-component composition consisting of (Pb(Mg
t/zWi/z)Ox)z(PbTiOs)y(P
b(Int/zNb 1/2)08) When expressed as z (however, X + 7 + z ==1.00)
, in this ternary composition diagram, the following composition points, (X=0.
796, 7=0.199, z=0.005) (
x=0.48, y-0,12, z=0.40) (
x=0.21, y=0.09, z=0.70
) (x=0.12, y=o, is, z=0.7
0-)(x=0.398, )'=0.597,
z=0.005) and in the composition range surrounded by these five points, manganese lead niobate CPb (Mnl/zNbt/z)Os is added as a subcomponent to the main component composition in the composition range surrounded by these five points.
) in an amount of 0.05 to 5 mol % based on the main component.