JPH10275523A - Dielectric porcelain composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dielectric constant of 40 or more, Q of 100 or more, an insulation resistance of 4 × 10 ¹³ Ω · cm or more, and a temperature coefficient of relative dielectric constant of −1000 to +100 ppm / ° C. The present invention provides a dielectric porcelain composition according to the present invention. A sPbO · tCaO · uZrO ₂ · vN
b ₂ O ₅ (10.0 ≦ s ≦ 45.0, 5.0 ≦ t ≦ 6
0.0, 1.0 ≦ u ≦ 47.0, 1.0 ≦ v ≦ 33.
A dielectric ceramic composition represented by 0). [Effect] By mixing PbO, CaO, ZrO ₂ and Nb ₂ O ₅ at a predetermined ratio, the relative permittivity, Q and insulation resistance are large, and the temperature coefficient of the relative permittivity is −1000 to +
A dielectric ceramic of 100 ppm / ° C. can be obtained. By itself or in combination with a material having a large relative permittivity and a large positive relative permittivity temperature coefficient such as PbZrO ₃ , the relative permittivity and the Q value are large, and the absolute value of the relative permittivity temperature coefficient is large. A material having a small value can be obtained, which is effective for downsizing electronic devices.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a temperature-compensating dielectric porcelain composition useful as a dielectric material for a multilayer capacitor.

[0002]

2. Description of the Related Art Temperature-compensating dielectric ceramic capacitors are widely used in communication equipment and the like. Dielectric materials used for such applications generally have a large relative dielectric constant, a large Q (that is, a small dielectric loss), and a temperature coefficient of the relative dielectric constant within a range of -750 to +100 ppm / ° C. Some characteristics are required.

Heretofore, CaTiO ₃ —MgTiO ₃ based materials and the like have been known as a temperature compensating dielectric porcelain composition. This material has a large Q (usually about 10,000) with a relative dielectric constant of about 20 to 30. The temperature coefficient of the relative permittivity is about -30 to +30 ppm / ° C.

[0004] In the field of communication devices such as mobile phones, the size of devices has been further reduced in recent years.
Accordingly, the demand for miniaturization of components used in these devices has been further increased. However, with the relative dielectric constant of the conventional dielectric ceramic composition as described above, there is a limit to miniaturization of components, and it is considered that a material having a larger relative dielectric constant is required for miniaturization.

[0005] PbZrO ₃ is known as a material having a large relative dielectric constant of 100 or more, and the temperature coefficient of the relative dielectric constant of this material is a large positive value of +2900 ppm / ° C.

As described above, it is difficult to develop a dielectric material which has a large relative dielectric constant and a high Q value by itself and satisfies all the conditions that the absolute value of the temperature coefficient of the relative dielectric constant is small. Conventionally, attempts have been made to develop a material having the characteristics of each material by mixing two or more dielectric materials.

[0007]

When a material satisfying the required characteristics is realized by combining two or more kinds of dielectric materials, for example, the relative permittivity such as PbZrO ₃ is large and the temperature coefficient of the relative permittivity is positive. By combining with large materials,
In order to obtain a material having a large relative permittivity and a high Q value and a small absolute value of the temperature coefficient of the relative permittivity, the material itself has a large relative permittivity and a high Q value, and has a temperature coefficient of the relative permittivity. It is desired to use a material having characteristics such as a large negative value.

Further, from the viewpoint of expanding the application range of the material by such a combination, a material which can control the temperature coefficient of the relative permittivity arbitrarily by changing the material composition ratio is desired.

Further, in the dielectric ceramic composition, a high insulation resistance is a fundamental required characteristic.

The present invention has been made in view of the above conventional circumstances, and has a relative dielectric constant of 40 or more, a Q of 100 or more,
The insulation resistance is as large as 4 × 10 ¹³ Ω · cm or more, and the temperature coefficient of relative permittivity is −1000 ppm / ° C. to +100 ppm /
It is an object to provide a dielectric porcelain composition in the range of ° C.

[0011]

The dielectric porcelain composition of the present invention is a porcelain composition comprising PbO, CaO, ZrO ₂ and Nb ₂ O ₅ , wherein the composition formula is sPbO.tCaO.uZr.
When expressed as O ₂ · vNb ₂ O ₅ , s, t, u, and v are represented by mol fractions: 10.0 ≦ s ≦ 45.0 5.0 ≦ t ≦ 60.0 1.0 ≦ u ≦ 47. 0 1.0 ≦ v ≦ 33.0 where s + t + u + v = 100.0.

As represented by the above composition formula, PbO, C
By mixing aO, ZrO ₂ and Nb ₂ O ₅ at a predetermined ratio, the relative dielectric constant, Q and insulation resistance are large, and −1
A dielectric ceramic having a relative dielectric constant temperature coefficient in the range of 000 to +100 ppm / ° C. can be obtained.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.

The dielectric ceramic composition for temperature compensation of the present invention comprises:
It consists of PbO, CaO, ZrO ₂ and Nb ₂ O ₅ , and its composition is represented by the formula sPbO.tCaO.uZrO ₂ .vNb ₂
When represented by O ₅ , s, t, u, and v are represented by mole fractions: 10.0 ≦ s ≦ 45.0 5.0 ≦ t ≦ 60.0 1.0 ≦ u ≦ 47.0 1.0 ≦ v ≦ 33.0.

When s, t, u and v are out of the above ranges, Q decreases and the temperature coefficient of relative permittivity becomes + 7000p.
pm / ° C. Alternatively, the sinterability deteriorates.

In the present invention, it is preferable that 19 ≦ s ≦ 455 5 ≦ t ≦ 34 33 ≦ u ≦ 472 2 ≦ v ≦ 12.
Relative dielectric constant is 60 or more, Q is 100 or more, insulation resistance is 8 ×
-1000 to -90 ppm / ° C at 10 ¹³ Ω · cm or more
And a high-performance dielectric having a temperature coefficient of relative permittivity in the range of

In the present invention, it is particularly preferable that 19 ≦ s ≦ 26 27 ≦ t ≦ 34 37 ≦ u ≦ 425 5 ≦ v ≦ 8.5.
Relative permittivity of 60 or more, Q of 2000 or more, insulation resistance of 2
At least × 10 ¹⁴ Ω · cm, -500 to -90 ppm / ° C
, A dielectric material having a higher dielectric constant having a temperature coefficient of relative permittivity in the range of 1 to 3 is provided.

In order to produce such a dielectric ceramic composition of the present invention, for example, lead oxide (PbO, Pb ₂ O, Pb
O ₂ , Pb ₂ O ₃ , Pb ₃ O ₄ ), calcium oxide (C
aO), zinc oxide (ZrO ₂ ), niobium pentoxide (Nb ₂
The powder of O ₅ ) is weighed so as to have a predetermined ratio, and thoroughly mixed using a wet ball mill or the like. Next, after drying this mixture, if necessary, it is calcined for several hours in the range of 1050 to 1100 ° C. The obtained calcined product is pulverized by a wet ball mill or the like. After drying the calcined powder obtained by grinding,
Granules are prepared by adding an appropriate organic binder such as polyvinyl alcohol, and the granules are pressed into a predetermined shape and then fired. This firing is performed in a temperature range of 1200 to 1300 ° C. for about 0.5 to several hours. (Of course, these manufacturing conditions are the most suitable numerical values, and the porcelain composition of the present invention may be manufactured by conditions or methods other than the above.)

[0019]

EXAMPLES The present invention will be described more specifically with reference to examples and comparative examples below, but the present invention is not limited to the following examples unless it exceeds the gist.

Examples 1 to 10, Comparative Examples 1 and ₂ PbO, CaO, ZrO ₂ and Nb ₂ O as starting materials
₅ using, it was weighed so that the mixing ratio shown in Table 1, and mixed for about 20 hours wet with pure water in a ball mill. Then, after dehydrating and drying this mixture, 1050 to 1
The mixture was calcined while being kept at 100 ° C. for 2 hours, again wet-pulverized together with pure water for about 20 hours in a ball mill, then dehydrated and dried.

An ethanol solution of polyvinyl butyral (binder) was added to the obtained powder, and the molding pressure was about 2 t / c.
At m ^3, it was pressed into a disk having a diameter of about 15 mm and a thickness of about 0.7 mm. This molded product was held at about 600 ° C. for 1 hour to remove the binder, and then 1200 magnesia setter.
It was fired at a temperature of １1300 ° C. for 2 hours.

Silver electrodes were placed on both sides of the obtained sintered body at 750.
It was baked at ℃ to make a parallel plate capacitor, and its electrical characteristics were examined. Table 1 shows the measurement results of the electrical characteristics of the obtained sample.

The relative dielectric constant was measured at a measurement frequency of 1 MHz, a measurement voltage of 1.0 Vrms, and a temperature of 25 ° C. using “LF Impedance Analyzer Model 4192A” manufactured by YHP. For Q, use a “Q meter model 4342A” manufactured by YHP, measuring frequency 1 MHz, temperature 25 ° C.
Was measured. The value of the insulation resistance was measured after one minute at a temperature of 25 ° C. and an applied voltage of 100 V using “Analog IR Meter 4329A” manufactured by YHP. The temperature coefficient of the relative dielectric constant was calculated from the following formula based on the capacitor capacitance measured at 25 ° C. and 85 ° C., respectively.

[0024]

(Equation 1)

[0025]

[Table 1]

As apparent from Table 1, the dielectric ceramic composition within the scope of the present invention has a relative dielectric constant as large as 40 or more,
Is 100 or more, the insulation resistance is as large as 4 × 10 ¹³ Ω · cm or more, and it is a high-performance dielectric having a relative dielectric constant temperature coefficient in a range of −1000 to +100 ppm / ° C.

[0027]

As described above, the dielectric ceramic composition of the present invention has a large relative dielectric constant, a large Q, a large insulation resistance, and a temperature coefficient of the relative dielectric constant in the range of -1000 to +100 ppm / ° C. Can be arbitrarily controlled. Therefore, not only the dielectric ceramic composition of the present invention is used alone, but also the PbZr
By combining a material having a large relative permittivity of 100 or more and a temperature coefficient of a large positive relative permittivity such as O ₃ ,
A material having a large relative permittivity and a high Q value and having a small absolute value of the temperature coefficient of the relative permittivity can also be obtained. Then
Parts using the composite material obtained in this way can be much smaller than conventional products, which is effective for miniaturization of various electronic devices.

Claims (1)

[Claims] 1. PbO, CaO, ZrO ₂ and Nb ₂ O
_{5. A} porcelain composition consisting of sPbO.tC
When expressed in _{aO · uZrO 2 · vNb 2 O} 5, s,
t, u, and v are mole fractions: 10.0 ≦ s ≦ 45.0 5.0 ≦ t ≦ 60.0 1.0 ≦ u ≦ 47.0 1.0 ≦ v ≦ 33.0 where s + t + u + v = A dielectric porcelain composition characterized by being in the range of 100.0.