JPS60131856A - Dielectric 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 material for ceramic capacitors that has a low firing temperature and excellent temperature characteristics.

Conventional Structure and Problems Barium titanate-based materials are widely used as high dielectric constant materials for ceramic capacitors. The relative dielectric constant of this type of material is closely related to its temperature characteristics. A material that satisfies the dielectric constant of about 10,000 (within +3o%, -go% as all standards at 20°C), and a material that satisfies Y-class D% (within +20%, -30% under the above conditions). The dielectric constant is about 4000, and for materials that satisfy the Y class B characteristics (within ±10% under the above conditions), it is about 2000 to 3000. Although this barium titanate-based material has a low dielectric loss tan δ and other excellent properties, its firing requires a considerably high temperature of 1300 to 1400°C. Therefore, when this type of material is used in a fully laminated ceramic capacitor, expensive platinum-based electrodes are required as internal electrodes. On the other hand, P b (, Fey2Nb3.
)O3-Pb(FeBWh')o3 yarn and other dielectric materials are known. These have a relative dielectric constant of 100 at room temperature.
It has a large value of 00 to 20,000, but many have large temperature changes.

Most of the capacitors used in consumer electronic devices have characteristics equivalent to Class 7 or Class B characteristics with small temperature changes, so they can be fired at temperatures around 900°C, and the temperature If a capacitor material with excellent characteristics could be obtained, it would have great industrial value.

Purpose of the Invention The present invention has a low firing temperature of 860 to 900°C, and -
It is an object of the present invention to provide a dielectric ceramic composition that satisfies Class Y B characteristics or Class 7 characteristics in a temperature range of 25 to 85°C.

Structure of the Invention The dielectric ceramic composition of the present invention comprises Pb(Zn%Nb5A)
x(Fe5ANb,'), (iVkr, Wi) 20
In the composition of No. 3, X.

It is characterized in that V + z has a composition within the range of polygons A, B, C, and D shown in the figure. Furthermore, the composition is characterized in that it contains the above composition as a main component and 5 to 1% by weight of Mn02f 0-0E as a subcomponent.

Explanation of Examples Chemically high purity PbO, Zn○, Nb2O as raw materials
,.

F' e203. MgO, WO3, Mn02f were weighed according to the composition shown in the table below, and mixed with agate boulder and pure water for 16 hours in a polyethylene pot. After drying, calcined at 750°C for 2 hours, and then crushed in the pot described above for 15 hours. and dried. Thereafter, polyvinyl alcohol aqueous solution was added as a binder, and the cylinder was press-formed with a diameter of 13 myn and a height of 10 m. After the binder was incinerated, it was placed in a magnesia porcelain container and heated at a temperature within the range of 860 to 900°C. It was baked for 2 hours. The obtained fired porcelain product was cut into 1-thick pieces.
Cr-Au1 was deposited on both sides to form all electrodes, and the relative dielectric constant, dielectric loss tangent Lan δ, and temperature change thereof at a temperature of 20° C. were measured at 1 k) h in an electric field of 1 V/mm. The Curie point was defined as the temperature at which the dielectric constant was at its maximum. These results are shown in the table below.

(The following is a blank space) Samples marked with a red mark in the table are samples outside the scope of the present invention. Samples within the scope of the present invention exhibit a relative dielectric constant of 1000 or more at a temperature change rate (Il-satisfied, 20T) as determined by the Y-class B characteristic or the 7th-grade characteristic specified by the JIS standard. Composition formula Pb (Zn%Nb%) (F e3A
Nb%)y (Mq%”M)z03 (Tapz
+y+z=1), 7. Z is 8, B, C, D shown in the figure
Outside the rectangular area with the four points as vertices, the dielectric constant is 1.
000 or less, the temperature change is larger than the rate of change determined by the 7th grade characteristic, or the Curie point is far off to the higher or lower temperature side than room temperature, making it unsuitable as a capacitor material. Therefore, it is excluded from the scope of the present invention. Also tvln02 is 0.055
If the content is 1.0% by weight or less, tan
δ is greatly improved compared to the sample without addition. Mn(-
)2 in a sample containing more than 1.0% by weight of tan
δ increases.

Effects of the Invention As described above, the dielectric ceramic composition according to the present invention has a small temperature change in relative permittivity and a low firing temperature, so it can be used for multilayer ceramic capacitors using inexpensive internal electrode materials. Therefore, the industrial value of the present invention is great3.

[Brief explanation of the drawings] The figure shows Pb (Zn5ANb, q)O3-P b (F
It is a composition diagram of the e5ANb,)o3-Pb(Mqy2W3A)03 ternary system.

Claims (2)

[Claims] (1) Pb(Zn%tqb,)x(Fe3ANby2
), (Mg vortex, )203 solid solution (where z + y
'+ z == 1) in the composition diagram of the ternary system,
,7. The value of Z is the following points A, B, and C. A dielectric ceramic composition characterized by being entirely within a rectangular region with D as the apex. (2) Pb(Zn3ANb, ), (Fe%Nb, maximum (
Mg, W, ), O3 solid bath (x+y+z=1
), in the composition diagram of the ternary system of X, 7. The value of Z is the following points A, B, and C. A dielectric ceramic composition characterized in that the main component is a composition located within a rectangular region with a vertex D, and further contains Mn02i as a subcomponent in a weight ratio of 0.05 to 1.