JPS6046968A - 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 provides a ceramic composition, particularly a ceramic composition that can be sintered at a low temperature of 1100°C or less, has a high dielectric constant, has high insulation resistance at room temperature and high temperature, and has high mechanical strength. It is related to.

Conventionally, barium titanate (B
It is well known that porcelain containing aTiOx as a main component has been widely put into practical use. However, those whose main component is barium titanate (BaTiO3) have a sintering temperature of usually 1300 to 1400°C. Therefore, when using this material in a multilayer capacitor, a material that can withstand this sintering temperature must be used for the internal electrodes, such as an expensive noble metal such as platinum or palladium, which has the disadvantage of high manufacturing costs. be. In order to manufacture multilayer capacitors at low cost, 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, nickel, etc. can be used for the internal electrodes.

Furthermore, the electrical properties of the ceramic composition are basically required to have a high dielectric constant, low dielectric loss, and high insulation resistance. Furthermore, regarding the value of insulation resistance, it complies with the Military Specification (Mi 11tar7 Specificat), a US Department of Defense standard that requires highly reliable components.
ion) MIL-C-55681B specifies not only the value at room temperature but also the value at 125°C.As you can see, in order to obtain a highly reliable ceramic capacitor, the value at room temperature is specified. In addition, it is necessary to have a high insulation resistance at the maximum operating temperature.

In addition, in the case of multilayer 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. Furthermore, even 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 easier it is to be cranked and damaged, resulting in lower reliability. Therefore, increasing the mechanical strength of porcelain as much as possible is an extremely important problem in practice.

By the way, Pb(PvIg172W1/2)Os PbT
Regarding i0g type porcelain compositions, N.N., Kleinik, and A.

Ai, Maglanovskaya (N, N, Krainik a)
nd A, I.

A, grarovskaya (Fiziko Tver
dogo Te1a+Vo, 2+ No.

1, pp 70-72+ Janvara 1960
)), and (SrxPb 1-, T i
O*)a(PbMgo,sWo,sOs)b
C However, x=θ~0.10. a-0.35 to 0.5.
b-0.5 to 0.65. a+b=1], a monolithic capacitor and its manufacturing method are described in Japanese Patent Application Laid-open No. 5
It is disclosed in Japanese Patent Application Laid-open No. 2-21662, and 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 has not been clarified. However, the inventors have already tested the temperature at 910"50℃.
At a temperature of m-11', Pb (Mg x7zWt7
x) Os and PbTi0. It consists of a two-component system of cpb avb 17xw17J os )X (P
b When expressed as T 10LI, 1, X is 0.6
A composition in the range of 5<X≦1.00 was proposed. This composition has excellent electrical properties such as a high value of the product of dielectric constant and specific resistance and low dielectric loss. However, since all of the above compositions have low mechanical strength, their applications have had to be limited to a narrow range.

Also, Pb(Mg1/2W172)Oa PbT103
For three-component systems including
In Publication No. 1, Pb(Mg1/2W F2)03-P
bTiOs Pb(Mg173Nb27+)Os system is
In JP-A-55-117809, Pb (Mg
,,, W172)Os PbTiOs Pb(Mg
173Ta2/3)Os systems are disclosed respectively. However, none of them discloses the specific resistance or mechanical strength, and the practicality of these porcelain compositions has also not been clarified. 2)Q
3PbTiQ-Pb(InX/□Nb□7□)033 component composition has already been proposed. This composition is 900~
It can be sintered at a low temperature of 1100°C, has excellent properties such as high dielectric constant, low dielectric loss, and high insulation resistance at room temperature and high temperature. However, since this composition has low mechanical strength, its use has to be limited to a narrow range.

In view of the above points, the present invention can be sintered in the low temperature range of 900 to 1100°C, has excellent electrical properties such as high dielectric constant, low dielectric loss, and high insulation resistance at room temperature and high temperature. The purpose is to provide a highly reliable porcelain composition with particularly high mechanical strength, and magnesium lead tungstate (Pb (Mg, 7zWv□)
0. ], lead titanate (PbTiOs) and indium”-lead opate (Pb(I n 17tNb xyx)0
1) to cpb (to) 1. ,w,
□) Ox :] x CPb T i] A [pb (
I n 1. Nb 1,2)Os ], (where x")"z = 1.00), the following composition point (x = 0.796. y = 0.199. z
= 0.005) (x=0.48, 7=0.12
, z=0.40 ) (x=0.21 , )'=0.
09, z=0.70) (x=0.12, y=0
．． 18, Z=0.70) (x=0.398.
y=0.597. z = 0.005) and in the composition range that lies within these five points, manganese lead tantalate [Pb (Mn1/□Ta 1/2)Os- It is characterized by containing 0.05 to 4 mo6% of ' to the main component.

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

Lead (I) oxide with a purity of 99.9% or higher as a starting material
), magnesium oxide (MgO), r? I'l oxidation/gesten (vvOs), titanium oxide (TiO++), indium oxide (InzOi), I'l oxidation=, 1p (Nb
20q), oxidation tank # (Ta205), and manganese carbonate (MnCOx) were used, and each was weighed so as to have the compounding ratio shown in the table. Next, after weighing and drying each month, add an organic binder, size the particles, press, and measure the diameter as a sample! 6 欝i, 4 disks of approximately 2 thicknesses and a diameter of J6π
A cylinder with a thickness of about 10 ynm was created. The samples were then sintered in air at a temperature of 900-1100°C for 1 hour.

Silver electrodes were baked on the top and bottom surfaces of four sintered disks at 600°C, and the dielectric loss was measured using a digital LCR meter at frequency IKI (z), voltage IVr, rn, s, and temperature 20°C.・Next, apply a 50V electric current 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 resistance in terms of bending strength, a rectangular shape with a thickness of 0.5 mm, a width of 2 mm, and a length of about 13 mm was cut from a sintered cylinder. Here, 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 was [Pb(Mg1/2W1.
, )03 ), [PbTiOs )y(Pb(In1/
2Nbl 7B) Os Ez blending ratio X * 7 +
The following table shows the relationship between the amounts of 1 and subcomponents added, dielectric constant, dielectric loss, resistivity at 20° C. and 125° C., and bending strength.

As is clear from the results shown in the table, (Pb (Mg□
7. W17. )Os-PbTiOs-Pb(In,
7tNb1/2)Os Pb (λ Tsumugi, 7tNb1/2)Os
□Ta/2) Those containing Os at the prescribed ratio have a high dielectric constant of 1060 to 3710, a small dielectric loss of 0.2 to 2.9 inches, and a specific resistance at 20°C. 1.8 x 10'2~7.9 x 1013Ω'l
8.2 XlQ10 even at 125℃
It shows a high value of ~1.2 x 1013 Ω・further, and also has a bending strength of 1000~1390 kl? /cffl
It can be seen that this is a highly reliable and highly practical porcelain composition that exhibits a sufficiently high value for practical use. The porcelain composition of the present invention exhibiting such excellent properties has a sintering temperature of 1100°C.
If the temperature is lower than that, it is possible to reduce the cost of the internal electrodes of multilayer capacitors, and it also has the extremely excellent effect of saving energy and furnace materials. 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.

The present invention relates to (:Pb(MgMu1/a)Os:)xCP
bTiOi :)y(Pb(In1/2Nb1/2)
On),! : table t) L k tokini (however,
x+y+z=1. oo), in this three-component composition diagram,
The following composition (X=0.796, y=0.199, z
=o, o05) (X=0.48, y=0.12,
z=0.40) (x=0.21, y=0.09,
z=0.70)(x=0.12,)'=0.18
, z=0.70) (x=0.398, y=0.59
7, z=0. The composition range is limited to the line connecting OQ5) and the composition range surrounded by these five points, and the added content of the subcomponent is limited to 0.05 to 4 mo 1% with respect to the main component.

In the main component composition range, outside the line connecting composition points 2 and 15, the specific resistance at high temperatures becomes small, 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
The amount of (Mn,, Ta17□)o added is 0.05 mo
If it is less than 7%, the effect of improving bending strength is small, and 4mo1%
On the other hand, if it exceeds this, the bending strength decreases, which is not practical.

BRIEF DESCRIPTION OF THE 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 tungstate m CPb (Mg
, /□W engineering, )OS), lead titanate (PbTi03:)
and indium niobium rr'p lead (Pb (In
, 7xNb 1/2) 03 :) CPb (Mg r/, Wl, □) Os ], CP
bT 10s )y CPb (I n1/2Nb 1
/2) When expressed as O3]z (however, X + 7
+ Z = 1.00), in this three-component composition diagram,
The following composition points (x=0.796, y=0.199, z=0.00
5) (x=0.48, y=0.12, z=0.40
) (x=0.21, y=o, oct, z=0.7
0) (x=0.12, 7=0.18, z=0.
70) (x=0.398, 7=0.597, z
= 0.005) and in the composition range surrounded by these five points, manganese and
Lead tantalate [Pb("n1/2" 1/2)Ox:
1.) A porcelain composition characterized in that it contains 0.05 to 4 mol of 0.05 to 4 mol of a main component.