JPS6386316A - Dielectric ceramic composition - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a dielectric ceramic composition suitable as a dielectric of a temperature-compensating multilayer ceramic capacitor having an internal pole made of a base metal such as nickel.

[Prior art] Japanese Patent Application Laid-Open No. 59-227769 describes ((Sr C
a) 1-xx 0) Basic component consisting of TiO2 and Li 20 and 5
in2 and MO (however, MO is BaO, CaO and S
A dielectric ceramic composition containing an additive component consisting of at least one metal oxide of rO is disclosed. Since this porcelain composition can be sintered in a non-oxidizing atmosphere,
Using this, it is possible to provide a temperature-compensating multilayer ceramic capacitor whose internal electrodes are made of a base metal such as nickel.

By the way, in order to improve the performance and reduce the size of temperature-compensating ceramic capacitors, a dielectric ceramic composition having a high Q and a high resistivity ρ is required, and the dielectric ceramic composition disclosed in the above-mentioned publication is required. For materials, the temperature coefficient of dielectric constant (TC
) is +350 to -1000 (DpI!/”C), Q is 4400 or less, and there is not necessarily sufficient Q.
Therefore, the applicant filed a patent application 1986-29.
In the specification of No. 8003, ((Sr Ca
M) Ofk(Ti1゜1-x-y x y Li 20 and SiO2 and MO(BaO, M90, Z
A new dielectric ceramic composition comprising an additive component consisting of at least one of n O, Sr O, and CaO has been disclosed. According to this new dielectric ceramic composition, the temperature coefficient (TC) is +350 to -1000 (pt11/"C)
Q above 4500 and 1 at 20°C within and outside the range of . A resistivity ρ of OX107Ma·C1 or higher can be obtained.

[Problems to be Solved by the Invention] The dielectric ceramic composition disclosed in the above specification is sufficient as a dielectric substrate for capacitors used under normal environmental conditions (for example, -25°C to +85°C). Although usable, it has been found to be unsatisfactory as a dielectric substrate for capacitors that may be used in harsh environmental conditions (eg, 125° C.). That is, in the dielectric ceramic composition disclosed in the above specification, the resistivity ρ at high temperature (for example, 125°C) is set to 1. OXl05M
It is impossible or difficult to rub more than a cm. Therefore, the object of the present invention is to obtain a material that can be obtained by firing in a non-oxidizing atmosphere at 1200°C or less, and has a Q of 5000.
As mentioned above, the resistivity ρ at 125°C is 1. OXl05Ma
- cm or more [Means for solving the problems] The present invention, which solves the above problems and achieves the above objects, consists of 100 parts by weight of the basic components. and 0.2 to 1° and 0 parts by weight of additional components, and the basic component is ((Ma
Mb Mn )0)k (Ti1-Wl-y-z
y z Z" )02 (However, Ma is at least one metal selected from Sr (strontium) and Ca (calcium), and Mb is at least one selected from M(+ (magnesium) and zn (zinc). metal, y, z, k%w are 0.005≦y≦0.100, 0.001≦2≦0
゜100.1.00≦k≦1.200.0.005≦W
≦0.100), and the additive component is
Li 20, 5102 and MO (however, MO is BaOlM
f) In the triangular diagram showing the composition of at least 61 types of metal oxides among ZnO, SrOl, and CaO, the LiO is 1 mol%, the 5in2 is 80 mol%, and the MO is 19 mol. % point (A) and the L i
Point (B) where Ofi' 1 mol%, the Sio2 is 491 nyl%, the MO is 50 mol%, and the Li2O
is 25 mol%, the SiO2 is 35 mol%, the MO is 40 mol%, and the Li 20 is 50 mol%.
, a point (D) where the 5in2 is 50 mol% and the MO is 0 mol%, and the Li 20 is 20 mol% and the Si
This relates to a dielectric ceramic composition that is within a region surrounded by five straight lines connecting in order the point (E) where O2 is 80 mol % and the MO is 0 mol %.

[Operations and Effects of the Invention] The dielectric ceramic composition of the above invention is prepared in a non-oxidizing atmosphere, 12
Since it can be obtained by firing at temperatures below 00°C, it is suitable as a dielectric for temperature repair laminated ceramic capacitors whose internal electrodes are made of base metals such as nickel. According to this dielectric ceramic composition, the relative dielectric constant ε is 160 to 325, and the Q is 5000.
Above, the temperature coefficient TC of dielectric constant is -630 to -3400E
IE) Im/'C1 resistivity ρ is 1x10MΩ at 20℃
・1 or more, 1 at 125℃. A temperature-compensating ceramic capacitor with a temperature of OX10" Ma・C1 or more can be obtained. By combining the dielectric ceramic composition disclosed in the above-mentioned Japanese Patent Application No. 60-298003 and the dielectric ceramic composition of the present invention. The major difference is that it is possible to maintain a Q of 5000 or more and increase the resistivity ρ at 125°C to 1.0 × 105 MΩ・C1 or more.While maintaining a high Q, the resistivity at high temperatures can be increased. The reason why the decrease in ρ can be suppressed is because Mn (manganese) is included in the basic component.As the amount of manganese in the basic component increases, the resistivity ρ at high temperatures increases, but if it increases too much, the Q If the dielectric ceramic composition according to the present invention has a large resistivity ρ at high temperatures is used, the alternating layers between the electrodes of the capacitor can be shortened, making it impossible to obtain the desired characteristics under high temperature conditions. It is possible to miniaturize the temperature compensation ceramic capacitor used in the electronic circuit using the ceramic capacitor. It becomes possible to improve the performance of

[Examples] Next, examples (including comparative examples) of the present invention will be described. k of sample Nα1 in Table 1 = 1.00, X = 0.
28, composition formula % determined according to y=0.01, z=0.02, w=0.05 More specifically, Ma = Sr Ca0.97
0.69 0.28-Mb = Zn
Therefore, 0.01 0.01 (Sr Ca Zn MnO,690,2
In order to obtain the basic component consisting of 80,010,02)0(TiZrO,950,05)02, 5rC03 (strontium carbonate) with a purity of 99.0% or more, cac.

3 (calcium carbonate), Zn0 (zinc oxide), Mno
(manganese oxide), T i 02 (titanium oxide)
nZrO2 (zirconium oxide) is prepared as a starting material, and without adding impurities, SrCo4
75.62+1 (equivalent to 0,139 mole parts) Ca C
o 130.75g (equivalent to 0.28 mole part)
Zn O3,80G (equivalent to 0.01%) Mn
O6.62g (equivalent to 0.02 mole part) T i O235
4,44Q (equivalent to 0.95 mole part) Zr 0228
．． 77 (equivalent to 0.05 mole part), add 2.54! of water to the raw materials for this hat, and mix for 15 hours.

Next, this raw material mixture was dried at 150°C for 4 hours, and then ground. Next, this ground material was dried at 1100°C for 2 hours.
The powder was calcined in the atmosphere for a period of time to obtain a powder having the basic components of the above composition formula. On the other hand, in order to obtain the additive components of sample Nα1 in Table 2, 10.12 g (25 mok%) of S i O
28,48!11 (35 mol%) BaCo
21.38 (1 (8 mol%) MgO4, 37g (8 mol%) ZnO8, 82g (8 mol%) Sr C01G, OOg (8 mol%) Ca Co
10.84 (J (8 mol%)) was weighed, 300 cc of alcohol was added thereto, and the mixture was stirred for 10 hours using an alumina ball in a polyethylene pot. was placed in an alumina pot with 300cc of water, crushed with an alumina ball for 15 hours, and then dried at 150°C for 4 hours to form L.
I20 is 25 mol%, S i O2 is 35 mol%, M
O is 40 mol% (Ba 08 mol% + M908 mol% +
A powder of additive components having a composition of 3 mol % ZnO + 5 mol % CaO + 3 mol % CaO was obtained.

Next, 30!7 (3 parts by weight) of the above-mentioned additive component powder was added to 1000 (] (1100 parts by weight) of the basic component powder, and an aqueous solution of acrylic acid ester polymer, glycerin, and condensed phosphate was added. Organic binder was added 15 times over the total weight of basic components and additive components, and 50% by weight of water was added, and these were crushed and mixed in a ball mill to create a slurry of porcelain raw materials. Shina.

Next, the above slurry is placed in a vacuum foaming machine to degas it, and this slurry is placed in a reverse roll coater, which is used to form a thin film based on the slurry on a polyester film, and this thin film is coated on the film. The mixture was heated to 100° C. and dried to obtain a green sheet (unsintered porcelain sheet) with a thickness of about 25 μm. This sheet is a long sheet, and is used by punching out a 10 CI square.

On the other hand, the conductive paste for internal electrodes has an average particle size of 1.5 μm.
10g of nickel powder and 0.9g of ethyl cellulose
was dissolved in 9.1 g of butylcarpitol and placed in a stirrer and stirred for 10 hours. This conductive paste was printed on one side of the green sheet through a screen having 50 patterns each having a length of 14111 mm and a width of 71111 mm, and then dried.

Next, two green sheets were laminated with the printed side facing up. At this time, the adjacent upper and lower sheets were arranged so that their printed surfaces were shifted by about half in the longitudinal direction of the pattern. Furthermore, four green sheets each having a thickness of 60 μl were laminated on the upper and lower surfaces of this laminate. Next, this laminate was compressed at a temperature of about 50° C. by applying a pressure of about 40 tons in the thickness direction. Thereafter, this laminate was cut into a grid shape to obtain about 50 laminate chips.

Next, this laminate chip was placed in a furnace capable of firing in an atmosphere, and the temperature was raised to 600° C. at a rate of 100° C./h in an air atmosphere to burn the organic binder.

However, after 4 hours, the atmosphere in the furnace was changed from the atmosphere to H22 volume % + N29.
The atmosphere was changed to 8% by volume. Then, while keeping the furnace in a reducing atmosphere as described above, the heating temperature of the stacked chips was increased from 600°C to the sintering temperature of 1150°C.
After raising the temperature at a rate of 1150°C (A high temperature) for 3 hours, the temperature was lowered to 600°C at a rate of 100°C/h, and the atmosphere was changed to air (oxidizing atmosphere). , 600°C was maintained for 30 minutes for oxidation treatment, and then cooled to room temperature to obtain sintered chips.

Next, a conductive paste consisting of zinc, glass frit, and vehicle is applied to the side surface of the sintered chip where the electrodes are exposed, dried, and baked in the air at a temperature of 550°C for 15 minutes. A J layer is formed, copper is deposited on top of this by electroless plating, and p is further deposited on top of this by electroplating.
A b-9n solder layer was provided to form a pair of external electrodes.

As a result, as shown in Fig. 1, the dielectric ceramic layer (1)
, (2), (3), and internal electrodes (4), (5),
A multilayer ceramic capacitor (10) consisting of external electrodes (6) and (7) was obtained. The thickness of the dielectric ceramic N (2) of this capacitor (10) is 0.02 nn, and the opposing area of the internal electrodes (4) and (5) is 5 nm x 5 ni = 25
II112 Theal.

Also, porcelain 7 after sintering! The compositions of (1), (2), and (3) are substantially the same as the mixed composition of the basic components and additive components before sintering, and are composed of composite perovskite (perovskite).
e) Basic components of type structure (Sr Ca Zn MnO, 690, 2
80,010,02)0(TiZrO,950,05)02 25 mol% of Li 20 and S i O
235 mol%, BaO 3 mol%, M2O 8 mol%, and Zn
A uniform distribution of the additive components consisting of O3 mol%, 5r08 mol% and Ca08 mol% is obtained.

Next, we measured the relative dielectric constant ε3, temperature coefficient TC, Q, and resistivity ρ of the completed multilayer ceramic capacitor. As shown in Table 3, ε is 281 and TC is -1400.
1) 1111/”C2Q is 10300, ρ is 3 at 20℃, OX10MΩ-CI, 1.4 at 125℃ X105
It was MΩ・C11. Note that the above electrical characteristics were measured in the following manner.

(A) The relative permittivity ε is at a temperature of 20°C and a frequency of 1MH.
z, the capacitance was measured under the condition of AC voltage (effective value) 0.5 V, and this measured value and the thickness of porcelain N (2) 0.05
It was calculated from 11.

(B) The temperature coefficient (TC) is the capacitance (C
) and the capacitance (C2o) at 20°C, and (C)
Q is the frequency IHH2 and the voltage [
Actual Value] Measured with a Q meter at 0.5 V AC.

(D) Resistivity ρ (MΩ・cn+) is measured at a temperature of 20°C.
After applying DC 50V for 1 minute at 125° C. and 125° C., the resistance value between the pair of external electrodes (6) and (7) was measured and calculated based on this measured value and the dimensions.

Above, we have described the preparation method for sample amount 1 and its characteristics, but for other samples No. 002 to No. 82, we also discussed the composition of basic components and additive components, their ratios, and the characteristics in a reducing atmosphere (non-oxidizing atmosphere). Except for changing the firing temperature as shown in Tables 1, 2, and 3, multilayer ceramic capacitors were produced in exactly the same manner as Sample NQ 1, and the electrical characteristics were measured in the same manner.

Table 1 shows the compositional formulas of the basic components of each sample.

Ca　Mb　Mn　　　O).

((Sri-x-y-z x y z(T
In each numerical value for determining iZr)021-ww, x, y, z, w, that is, a numerical value indicating the ratio of the number of atoms of each element, and the content of Mb are shown.
Table 2 shows the amount (parts by weight) of additive components added to 100 parts by weight of the basic component of each sample and the composition of the additive components. ，
The proportions of Zn 2 O, Sr 2 O, and CaO are shown in mol%. Table 3 shows the firing temperature (maximum temperature) for sintering in a reducing atmosphere and the electrical properties of each sample.

As is clear from Tables 1 to 3, in the samples according to the present invention, when fired in a non-oxidizing atmosphere at 1200°C or lower, the relative dielectric constant ε is 160 to 325, the Q is 5000 or more, and the temperature coefficient of the dielectric constant is TC ranges from -630 to -3400 ppn/°C. Also, the resistivity ρ is 1.0×1 at 20°C
07MΩ・C1 or more, 1 at 125℃. OXl05Ma・
It becomes C1 or higher.

On the other hand, sample Nα6.7.8.9.10.11.29.3
3.34.38.43.48.49.53.54.58
．． 63, 64, 69, 70, 76, 77, 82 cannot achieve the purpose of the present invention, and therefore they are outside the scope of the present invention.

Next, the reasons for limiting the composition will be described.

When the amount of additive components added is zero, a dense sintered body cannot be obtained even if the firing temperature is 1300°C, as is clear from sample Nα77, but when the amount added is 10 as shown in sample Nα78, a dense sintered body cannot be obtained.
1 in the case of 0.2 parts by weight for 0 parts by weight of the basic component
A sintered body having desired electrical properties can be obtained by firing at 190°C. Therefore, the lower limit of the additive component is 0.2 part by weight. On the other hand, when the amount added is 12 parts by weight as shown in sample NQ82, Q becomes less than 5000, which is worse than the desired characteristics, but when the amount added is 10 parts by weight as shown in sample Nα81, the desired characteristics are obtained. can be obtained. Therefore, the upper limit of the amount added is 10 parts by weight.

The value of X is, for example, sample No. 24.25.26.27.
As shown in 28, desired electrical characteristics can be obtained with any value from 0 to 0.994. Therefore, the value of X includes all values from 0 to 0.994.

Note that when x is 0.994 as shown in sample No. 28, x+y+z=1, and S'' is zero after all. Therefore, the content of Ma in the general formula according to the present invention is S'', Ca
, Sr +Ca.

When the value of y is < 0.002 as shown in the sample amount 29.34, no effect of adding Mb (Mb and/or Zn) is observed, but the value of y as shown in the sample Nα30.35.3g When is 0,005, desired electrical characteristics can be obtained.

Therefore, the lower limit of the value of y is o, oos. On the other hand, as shown in sample Na33.38.43 (0,12), a dense sintered body cannot be obtained, but sample N (132,
As shown in Figs. 37 and 42, desired electrical characteristics can be obtained when the value of y is 0.10. Therefore, the upper limit of the value of y is 0.
It is 10.

As shown in sample Nα49.54, the value of 2 is < 0.0005
In the case of , ρ at 125°C is 1. OX105Ma・Cra
However, as shown in sample Na44.50.55.59, when the value of 2 is o or ooi, desired electrical characteristics can be obtained.

Therefore, the lower limit of 2 is 0.001. On the other hand, the value of 2 is 0
．． In the case of 12, as shown in sample 11Q48.53.58.63, even if ρ is a satisfactory value, Q will be less than 5000, but as shown in sample amount 47.52.57.62. When the value of z is 0.10, desired electrical characteristics can be obtained.

Therefore, the upper limit of the value of 2 is 0610. In addition, for example,
As shown in the sample amount, 55, 56, 57, when the value of 2 is gradually increased, ρ at 125° C. also gradually increases, indicating that Mn contributes to increasing the resistivity ρ at high temperatures.

As shown in sample Nα64 (0,002), when the value of W is 0,002, ρ at 125°C is less than 1.OXl05Ma CI, and the effect of adding Z'02 is not seen, but as shown in sample N65. If the value of W is 0.005, the desired electrical characteristics can be obtained. Therefore, the lower limit of the value of W is 0.005.
It is. On the other hand, as shown in sample Nα69, the value of w is 0.1
In the case of 2, a dense sintered body cannot be obtained, but in the case of sample flN1
As shown in 168, when the value of W is 0.10, desired electrical characteristics can be obtained. Therefore, the upper limit of the value of W is 0.10.

When the value of k is 0°99 as shown in test FINα70, ρ is 3.8×103. at 20°C and 125°C, respectively.
1. Ox101MΩ·C1, and Q is also significantly lowered to 60, but as shown in sample No. 71, when the value of k is 1.00, desired electrical characteristics can be obtained. Therefore, the lower limit of the value of k is 1.00. On the other hand, when the value of k is <: 1.25 as shown in sample No. 76, a dense sintered body cannot be obtained, but when the value of k is 1.20 as shown in sample No. 75, the desired sintered body cannot be obtained. The electrical characteristics of Therefore, the upper limit of the value of k is 1.20.

The preferred composition of the additive components is Li20-3i 0 in Figure 2.
It can be determined based on a triangular diagram showing the composition ratio of 2-Mo. Point (A) in the triangular diagram is Li of sample No. 3.
01 mol%, S i 0280 mol%, MO 19 mol%
The point (B) shows the composition of Li 01 of sample Nα2.
Point (C) shows the composition of Li 025 mol%, Si 0235 mol%, MO 40 mol% of sample flN0.1, and point (D) shows the composition of sample flN0.1. Li2o 50 mol% of Nα4,
It shows the composition of 500 mol% SiO, 0 mol% M○, and the point (
E) shows the composition of sample No. 5 of 20 mol% Li, 80 mol% SiO2, and mol% MOO.

The composition of the additive components of the sample that falls within the scope of the present invention is within the area surrounded by five straight lines connecting the first to fifth points (A) to (E) of the triangular diagram in order. . If the composition is within this range, desired electrical characteristics can be obtained. As is clear from Samples 4 and 5 in the triangular diagram, the characteristics targeted by the present invention can be obtained even if Mo is omitted.

On the other hand, if the composition of the additive components falls outside the range specified in the present invention, as in sample NQ6.7.8.9.10.11, a dense sintered body cannot be obtained. ,
For example, as shown in sample NQ12.13.14.15.16 (it may be any one of Ba 05 Mg 01 ZnO 1 Sr O, Ca 2 O), or it may be in an appropriate ratio as shown in other samples.

[Modifications] Although the embodiments of the present invention have been described above, the present invention is not limited thereto, and, for example, the following modifications are possible.

(a) MnO, which is the starting material for obtaining the basic component, can be partially replaced with MnO or Mn3O4, etc., within a range that does not impede the purpose of the present invention. Appropriate amounts of substances may be added as needed.

(b) The starting materials for obtaining the basic components may be oxides or hydroxides other than those shown in the examples, such as 5rO1CaO, or other compounds. Further, the starting materials for the additive components may be other compounds such as oxides and hydroxides.

(c) The oxidation temperature may be set to a temperature other than 600°C lower than the sintering temperature (preferably 1000°C or less).

That is, various changes can be made in consideration of the electrode made of nickel or the like and the oxidation of the ceramic.

(d) The firing temperature in a non-oxidizing atmosphere can be varied depending on the electrode material.

(e) Sintering may be performed in a neutral atmosphere.

(f) It is of course applicable to general ceramic capacitors other than laminated ceramic capacitors.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a multilayer ceramic capacitor according to an embodiment of the present invention. FIG. 2 is a triangular diagram showing the composition range of additive components. (1)(2)(3)...Dielectric ceramic layer, (4)(5)
...Internal electrode, (6) (7)...External electrode.

Claims (1)

[Claims] (1) Consists of 100 parts by weight of the basic component and 0.2 to 10.0 parts by weight of additional components, and the basic component is {(Ma
_1_-_y_-_zMb_yMn_z)O}_k(T
i_1_-_wZr_w)O_2 (However, Ma is at least one metal among Sr and Ca, Mb is at least one metal among Mg and Zn,
y, z, k, w are 0.005≦y≦0.100, 0.
001≦z≦0.100, 1.00≦k≦1.20, 0
．． 005≦w≦0.100), and the additive components are Li_2, OSiO_2, and MO (however, M
O is a metal oxide of at least one of BaO, MgO, ZnO, SrO, and CaO. Point (A) of mol% and the Li_2
O is 1 mol%, the SiO_2 is 49 mol%, the MO
is 5 mol% point (B), and the Li_2O is 25 mol%
, the SiO_2 is 35 mol%, the MO is 40 mol%
point (C), the Li_2O is 50 mol%, the Si
Point (D) where O_2 is 50 mol% and the MO is 0 mol%, and the Li_2O is 20 mol% and the SiO_2 is 80 mol%.
The dielectric ceramic composition is within a region surrounded by five straight lines sequentially connecting points (E) with 0 mol % of MO.