JPS59116174A - High permittivity 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 Field of Industrial Application The present invention relates to a high dielectric constant ceramic composition that can be used for ceramic capacitors, particularly multilayer ceramic capacitors. As a dielectric constant ceramic composition, titanium 2...
- Barium diacid B a TiOs is the main component, and calcium zirconate CaZr○3. Calcium titanate CaTi○31 Calcium stannate Ca S n031
Products whose properties have been improved by adding an appropriate amount of strontium titanate (S r Ti03, etc.) have been widely put into practical use.The firing temperature of these porcelain compositions is generally 1,300°C to 1,300°C.
The temperature was as high as 400°C. In recent years, with the development of the electronic equipment field, electronic equipment has become significantly smaller and lighter, and even ceramic capacitors that were conventionally used in a disc shape have been replaced with multilayer ceramic capacitors that have a laminated structure to achieve large capacitance in a small size. has been developed and widely used.

As shown in Figure 1, a multilayer ceramic capacitor has a structure in which internal electrodes 2 are placed above and below a ceramic dielectric 1, and many small single-plate capacitors are connected in parallel and stacked. The electrodes 2 are alternately connected to either left or right external electrodes 3.

For such multilayer ceramic capacitors, their manufacturing
1- With the internal electrode embedded in the porcelain dielectric 3.

It is necessary to sinter the material, but since the firing temperature of conventional high-permittivity ceramic compositions mainly composed of barium titanate is as high as 1,300°C or higher, it is difficult to use such high-temperature materials as the material for the internal electrodes. However, it had the disadvantage of having to use expensive precious metals such as stable platinum or palladium.

OBJECTS OF THE INVENTION In view of the above points, the present invention is capable of sintering at a low temperature of 1 Qoo°C or lower, and therefore, inexpensive silver or silver thread alloy can be used as the material t1 of the internal electrode, and the dielectric constant is low. The object of the present invention is to provide a high dielectric constant ceramic composition that has high dielectric loss, low dielectric loss, high insulation resistance, and low capacitance change rate with respect to temperature.

Structure of the Invention The high dielectric constant ceramic composition of the present invention is composed of iron-lead tungstate Pb (Fe3BaQO3, magnesium-lead niobate Pb (Mg3/9Nb%)03.f lead tungstate Pb
When a three-component composition consisting of Tio3 is expressed as P b (Fe Hichi) x (Mg3/9Nb%) yT t 203, the composition ratios x + V and 2 are each 0.01.
<,, x (0, 25, 0, 76 <,, y <:
0,96.

For compositions in the range of 0.01 〈z −”′, o , 10
It is constituted by adding 1.0 to 10.0 parts by weight of Mn, W, and Karasu.

Description of examples Examples of the present invention will be described in detail below.

1 for sintering 21: Pb (Fe, AA) 03. Pb
(Mq, Nb%)03゜P bT IO3 and Pb (
So that the ratio of Mn, W, )03 becomes the displayed value below,
Appropriate amounts of lead oxide, iron oxide, tungsten oxide, magnesium oxide, niobium oxide, titanium oxide, and manganese oxide were weighed and mixed using a ball mill. This mixed raw material was calcined at 700° C. to 85° C., and then finely ground again using a ball mill. This finely pulverized raw material was granulated by adding polyvinyl alcohol, and molded into a disc shape with a diameter of 13 and a thickness of 0.8. After that, it was fired in a magnesia pot at a temperature of 950° C. to 100° C., and then electrodes mainly made of silver were provided on both sides to prepare a dielectric sample. The electrical properties of the samples thus prepared were measured and the results are shown in the following table. Here, dielectric constant ε6 and dielectric loss ta
nδ was measured at 20° C. with a frequency of 1 KHz. Insulation resistance I
R was measured at room temperature by applying 50 V DC. The rate of change in capacity in the table is based on the capacitance at 25°C.
The rate of change in capacitance at -30°C and 85°C is shown.

Samples marked with * in the table are outside the scope of the present invention,
This is shown for comparison.

That is, the molar ratio X of P b (F e3A )03 is o, 2
When X exceeds 6, the dielectric loss tan δ becomes too large to be practical, and when X is less than 0.01, the dielectric constant becomes small. Furthermore, Pb''/5NbX)o3 (7) molar ratio y is 0
．． If the temperature exceeds 96, the firing temperature will be high and the proportion of expensive niobium oxide will be large, making it impractical. y is o, 7
If it is less than 6, the insulation resistance will decrease. ′! ita2 is 0.01
If it is less than 0.10, the dielectric constant is small, and if it exceeds 0.10, the dielectric losses l and lnδ become large. In addition, Pb(Mnzo()03
If it is less than 1.0 fiJL %, the effect of improving the rate of change in capacitance with respect to temperature cannot be obtained, and if it exceeds 10.0 wt %, the insulation resistance decreases and the dielectric constant further decreases, which is not practical.

6 1, 9 ・, - Effects of the Invention As described in detail, the present invention
)03゜Pb(Mq%Nb5i)03+ P bT
Three-component composition Pb consisting of i○3 (F e, w,)
In x(McJy6Nbg)yTll-x-y○3, x, y and 2 are respectively 0.01≦X<0.25゜0.75≦y≦0.96, 0.01≦z<0.1o Pb(MnhX)Oa for compositions within the range of 1. By adding within the range of ○ to 10, ○ weight factor, the dielectric constant ε is as high as 3260 to 6260, the dielectric loss fan δ is small as 0.43 factor to 1.53 factor, and the insulation resistance IR is 1 ．． o×1o shows a high value of 0 or more,
A novel dielectric ceramic composition with high performance and a small rate of change in capacitance with respect to temperature can be obtained. Furthermore, since the firing temperature is as low as 950'C to 1000°C, it is possible to use inexpensive metals such as silver or silver thread alloys as internal electrodes when used in laminated ceramic condensers. This is a very effective value in reducing the cost of the product. In addition, since sintering can be performed at low temperatures, it is easy to maintain the electric furnace used for firing1.
This not only reduces the number of units to zero, but also saves energy in terms of power consumption. Therefore, it is advantageous in terms of manufacturing cost not only when applied to a laminated ceramic capacitor but also when applied to a conventional disc-shaped ceramic capacitor.

[Brief explanation of the drawing]

The drawing is a partially cutaway diagram showing an example of a multilayer ceramic capacitor. 1... Ceramic dielectric, 2... Internal electrode,
3. River...External electrode...

Claims (1)

[Claims] Iron/lead tungstate Pb (F eHVζ) 03. Magnesium lead niobate Pb (MqHNb%)03.
A ternary composition consisting of lead titanate PbTiO3 is
(F eX”X) x (MCI%Nb%) yT
When expressed as I Z○3, the composition ratio X is 0.01≦x
(0,25, y is o, 75≦y≦0.96.2 is 0.
01≦2≦0.10 for the composition. hand,
Manganese lead tungstate pb (MIN, W,)0
1. A high dielectric constant ceramic composition, characterized in that 1.0 to 10.0% by weight of 3 is added.