JP3179121B2 - Dielectric porcelain composition - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dielectric porcelain composition, and more particularly to a dielectric material having a small rate of change in capacitance with respect to temperature, a high non-dielectric constant, and a dielectric loss. Is small for a dielectric porcelain composition. 2. Description of the Related Art A method for manufacturing a laminated ceramic capacitor widely used for an IC circuit element or the like used for a communication device, an electronic computer, a television receiver or the like is roughly classified into a printing method and a sheet method.
There are seeds. In the printing method, a dielectric slurry is printed in a predetermined shape, and after drying, an electrode paste is printed thereon and dried.
On this, a method of printing a dielectric slurry again is repeated to laminate. [0004] In the sheet method, a dielectric sheet is formed, an electrode paste is printed thereon, a plurality of the sheets are stacked and laminated by thermocompression bonding, and the laminate is fired in a natural atmosphere.
A sintered body is made, and an external lead-out electrode which is electrically connected to the internal electrode is baked thereon. In this case, since the electrode paste and the dielectric which are to be the internal electrodes of the capacitor are fired simultaneously, the material of the internal electrodes is that the electrodes can be formed within the temperature at which the dielectric sinters. It is essential that they also do not oxidize or react with the dielectric. Conventionally, precious metals such as platinum and palladium have been mainly used to satisfy these conditions. However, these noble metals are very stable, but expensive, and have been the biggest cause of the increase in the cost of the laminated ceramic capacitor. For this reason, attempts have been made to use inexpensive base metals such as nickel as internal electrodes. However, nickel is oxidized when heated in an oxidizing atmosphere and reacts with a dielectric to make electrode formation impossible. Therefore, when firing in a neutral or reducing atmosphere, the dielectric material is reduced this time, resulting in a very low specific resistance, and cannot be used as a dielectric material for capacitors. In order to improve such disadvantages, BaTiO ₃ , CaTiO ₃ , and the like have conventionally been used as dielectric ceramic compositions.
BaZrO _3, MnO, SiO _2, various dielectric ceramic composition containing MgO and the like have been proposed (e.g., JP 61-155255, JP-Sho 63-10386
No. 1). However, these materials have short lifespan characteristics and are not well-balanced. Accordingly, an object of the present invention is to provide a long life characteristic,
It is fired in a neutral or reducing atmosphere so that a laminated ceramic capacitor using a base metal such as nickel as an internal electrode can be formed while having a small rate of change in capacitance with respect to temperature and having a base metal such as nickel. The present invention also provides a dielectric ceramic composition having good temperature characteristics and good dielectric characteristics. [0011] To achieve the above object Means for Solving the Problems], MnO 0.10 mol% relative to BaTiO ₃ 100 mol% in the present invention 2.00 mol% Y ₂ O ₃ 0.01 mole% to 1.00 mole% {Baα, Ca (1-α)} SiO ₃ (where 0.43 ≦ α ≦ 0.62) The present invention provides a dielectric ceramic composition having a composition in the range of 0.5 to 10.00 mol%. The dielectric ceramic composition of the present invention has a sufficiently high specific resistance even when fired in a reducing atmosphere, has a small rate of change in capacitance with respect to temperature, and has a low relative dielectric constant. Is high,
The dielectric loss is small. Thus, it is possible to obtain a dielectric ceramic composition particularly useful for forming a laminated ceramic capacitor having nickel as an internal electrode. An embodiment of the present invention will be described with reference to FIG. FIG. 1 is an explanatory view of a manufacturing process according to one embodiment of the present invention. FIG. 1 (a) is an explanatory view of a material manufacturing process of a dielectric ceramic composition, and FIG. 1 (b) is a dielectric ceramic of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory view of a process for forming a laminated ceramic capacitor using a composition. As a starting material, BaTiO ₃ obtained by roasting titanyl barium oxalate synthesized by a liquid phase method was used. However, BaTiO ₃ prepared by the solid phase method may be used. CaCO ₃ , BaC
Using O ₃ and SiO ₂ , (BaOα, CaO (1-
α)) Synthesize SiO ₂ and pulverize it. BaTiO ₃ is finely pulverized, and MnO, Y ₂ O ₃ , {BaOα, CaO (1
-Α)｝ We weigh and mix powders such as SiO _{2 so} that the compositions after final firing are as shown in Tables 1 to 3 (see 1 in FIG. 1A). Next, these fine powders are wet-mixed and pulverized together with a dispersant, and dehydrated and dried (see 2, 3 in FIG. 1A). The dehydrated and dried composition is crushed into powder (see 4 in FIG. 1 (a)). The thus obtained fine powder is mixed with a dispersant and the like to prepare a raw material slurry. Next, an organic binder is added to this raw material slurry together with a plasticizer, mixed well, and enameled (see 1 in FIG. 1B). The enameled raw material is formed into a sheet by a doctor blade method to obtain a dielectric sheet (see 2 in FIG. 1 (b)). A nickel paste as an internal electrode material is printed on the obtained dielectric sheet (see 3 in FIG. 1 (b)).
A plurality of these are stacked and thermocompression bonded to form a laminate (see 4 in FIG. 1B). The formed laminate is cut with a cutter to a size of, for example, 4 × 2 millimeters (5 in FIG. 1B).
reference). Next, this sample was heated at 250 ° C. to 400 ° C. for 15 minutes.
After destabilizing for a time, the binder is removed (see 6 in FIG. 1B). Thereafter, the oxygen partial pressure is from 7 × 10 ^{-9 to} 9 × 10
^-13 a.t.m., firing temperature 1200 ° C-1300
Firing is performed at a temperature of 2 ° C. for 2 hours (see 7 in FIG. 1B). The obtained fired body is further treated in a neutral atmosphere at 7
Reoxidation is performed at 00 ° C. to 1100 ° C. for a stabilization time of 9 hours (see 8 in FIG. 1B). A terminal electrode made of an indium-gallium alloy is applied and formed on both upper and lower surfaces of the finally formed sintered body.
A multilayer capacitor type measurement sample is completed (see 9 in FIG. 1B). This test sample was subjected to a frequency of 1 KHz and a room temperature of 20
Various electrical characteristics as shown in Tables 1 to 3 are measured under the condition of ° C. (see 10 in FIG. 1B). The life test conditions were an applied voltage of 200 V,
It is an evaluation result at a measurement temperature of 200 ° C. The insulation resistance is a value after a measurement voltage of 50 V, a room temperature of 20 ° C. and 30 seconds. Table 1 shows the measurement results obtained in this manner.
It is shown in Table 3. Samples marked with * in Tables 1 to 3 are out of the scope of the present invention, and are provided for comparison with those of Examples of the present invention. [Table 1] [Table 2] [Table 3] Tables 4, 5 and 6 show the oxide-converted values of the compositions shown in Tables 1, 2 and 3, respectively. [Table 4] [Table 5] [Table 6] As is clear from Tables 1 to 3, the composition according to the present invention has a high relative dielectric constant of 2,000 or more,
The rate of change of capacitance in a wide temperature range of 125 ° C. has a relatively small value, other dielectric properties are good, and the average life is long. Next, the reasons for limiting the composition range of the dielectric ceramic composition of the present invention will be described. With respect to 100 mol% of BaTiO ₃ , Mn
Addition of O content of 0.10 mol% or more improves the temperature characteristics and insulation resistance. However, if not added, the dielectric composition is reduced, and both the insulation resistance and the life characteristics are deteriorated. (For example, see Sample No. 1 in Table 1). On the other hand, when the content of MnO is more than 2.00 mol%, the relative dielectric constant becomes 2000 or less, and practical dielectric properties cannot be obtained (for example, see Sample No. 25 in Table 2). When the content of Y ₂ O ₃ is 0.01 mol% to 1.00 mol%, the life characteristics are improved. However, the life characteristics are extremely deteriorated when no Y ₂ O ₃ is added (for example, the sample shown in Table 1). No. 4). When the content of Y ₂ O ₃ exceeds 1.00 mol%, the insulation resistance is 1 × 10 ¹⁰ Ω or less, the life characteristic is less than 1 hour, and practical dielectric characteristics cannot be obtained (for example, see Table 2). Sample No. 27). Next, {Baα, Ca (1-α)} SiO ₃
By adding 0.5 to 10.00 mol%, balanced characteristics having excellent life characteristics and a small capacitance change rate with respect to temperature can be obtained (for example, sample No. 17 in Table 1).
Sample No. 23) in Table 2 shows that the addition of 0.5 mol% or less
The life characteristics are extremely deteriorated (for example, sample Nos. 4 and 4 in Table 1).
5). However, {Baα, Ca (1-α)} Si
If more than 10.00 mol% of O ₃ is added, the relative dielectric constant becomes 2
000 or less, and practical dielectric properties cannot be obtained (for example, see Sample No. 24 in Table 2). Further, {Baα, Ca (1-α)} SiO
_{Even if} the addition amount of ₃ is 10.00 mol% or less, if α is less than 0.43 or if α is more than 0.62, sintering becomes difficult and it cannot be put into practical use (for example, sample Nos. 4 and 6 in Table 3).
reference). The dielectric ceramic composition of the present invention has a relatively high relative dielectric constant, a small dielectric loss, and a relatively small change rate of the capacitance with respect to temperature. Thus, a balanced, highly reliable dielectric ceramic composition having good life characteristics can be obtained. Such a dielectric ceramic composition has excellent characteristics particularly for a laminated ceramic capacitor having nickel as an internal electrode.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory view of a production process of a dielectric ceramic composition of the present invention.

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Izumi Soma 1-13-1, Nihombashi, Chuo-ku, Tokyo Inside TDK Corporation (56) References JP-A-2-83256 (JP, A) JP-A-63 −221505 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01B 3/12 303 C04B 35/46 H01G 4/12 358

Claims (1)

(57) All Claims BaTiO ₃ to MnO 0.10 mol% relative to 100 mol% to 2.00 mol% Y ₂ O ₃ 0.01 mole% to 1.00 mole% {Baα, Ca (1- α)} SiO 3 ( (0.43 ≦ α ≦ 0.62) A dielectric ceramic composition having a composition in the range of 0.5 to 10.00 mol%.