JPS6386319A - 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 [Field of Industrial Application] The present invention relates to a dielectric ceramic composition suitable as a dielectric for a temperature-compensating multilayer ceramic capacitor having internal electrodes made of a base metal such as nickel.

[Prior art] Japanese Patent Application Laid-Open No. 59-227769 describes ((Sr C
a) Basic components consisting of 1-x x O)kTio2, Li2O and 5i0
2 and MO (however, MO is BaO, CaO and SrO
Disclosed is a dielectric ceramic composition containing an additive component consisting of at least one metal oxide of the following. Since this ceramic composition can be sintered in a non-oxidizing atmosphere, it can be used to provide a temperature-compensating multilayer ceramic capacitor in which 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. In the case of materials, the Q is 4400 or less in the range where the temperature coefficient (TC) of the dielectric constant is +350 to -1000 (pI)l/'C), and a sufficient Q cannot necessarily be obtained. Therefore, the applicant of this case filed the patent application No. 60-29800.
In the specification No. 3, ((Sr Ca M
) Ol y (” 1-zl-x-y X
V Zr2)02 where M is the basic component consisting of M (l or Zn) and Li
O and 5i02 and MO (Ba O, Ma O1Zn
At least one of O, Sr O and CaO? A new dielectric porcelain composition is disclosed, which comprises: According to this new dielectric ceramic composition, the temperature coefficient (T
C) is within and outside the range of +350 to -1ooo <pp1/'C), Q of 4500 or more and 1.
A resistivity ρ of OX107MΩ·C1 or more can be obtained.

[Problems to be Solved by the Invention] The dielectric ceramic composition disclosed in the above specification can be used as a dielectric substrate of a capacitor used under normal environmental conditions (for example, -25°C to +85°C). Although fully usable, it has been found to be insufficient 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-mentioned book 11tlI, the resistivity ρ at high temperature (for example, 125° C.) is set to 1.
(It is impossible or difficult to make l x 1Q 5MΩ·cm or more.

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. OX105MΩ
・An object of the present invention is to provide a dielectric ceramic composition having a diameter of cm or more.

[Means for Solving the Problems] The present invention for solving the above problems and achieving the above objects consists of 100 parts by weight of the basic component and 0.2 to 15.0 parts by weight of additional components. and the basic component is ((M a
1-y-z M b M n ) 0 ) k(
T i 12wz Zr) 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)). The metals, y, z, k, w are
0.005≦y≦0.100.0.001≦2≦0゜1
00.1.00≦≦1.200.0.005≦W≦0
．． 100), and the additive component is 40
A dielectric ceramic composition comprising ~80 mol% of 5102 and 20-60 mol% of MO (MO is at least one metal oxide among BaO1MgO, Zn01SrO1, and CaO). This is related to.

[Operations and Effects of the Invention] The dielectric ceramic composition of the invention described above is provided in a non-oxidizing atmosphere, 12
Since it can be obtained by firing at 00°C or lower, it is suitable as a dielectric for temperature-compensating multilayer 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 153 to 323, and the Q is 500.
0 or more, temperature coefficient of dielectric constant TC is -600 to -3400
pIll /'C1 resistivity ρ is lx10MΩ at 20°C
・C1 or higher, 1. at 125℃. A temperature-compensating ceramic capacitor of OX105MΩ・C11 or more can be obtained. The major difference between the dielectric ceramic composition disclosed in the above-mentioned Japanese Patent Application No. 60-298003 and the dielectric ceramic composition of the present invention is that it maintains a Q of 5000 or more and has a resistivity of 125°C. Let ρ be 1. It is possible to make Ox 105 MΩ·cm or more. Such a high Qt! The reason why it is possible to suppress the decrease in resistivity ρ at high temperatures while maintaining - is due to the inclusion of Mn (manganese) in the basic components. 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 decreases,
Desired characteristics cannot be obtained. By using the dielectric ceramic composition having a large resistivity ρ at high temperatures according to the present invention, the distance between the electrodes of the container can be shortened, so that the temperature compensation porcelain container used under high temperature conditions can be miniaturized. Can be done. Also, despite the large resistivity ρ,
Since it is possible to provide a ceramic capacitor with a high Q, it is possible to improve the performance of electronic circuits using the ceramic capacitor.

[Example] Next, Examples (including comparative examples) of the present invention will be described. Sample Nα1 in Table 1 = 1. oo, x-〇, 28
, y=O, (11, z=0.02, w=(1,05)
)0 0.05 2 More specifically, Ma = Sr CaO,97
0,690,28゛Mb = Zn, so 0.01 0.01 (Sr Ca Zn MnO,690,2
In order to obtain the basic components consisting of 80,010,02)0('r”i Zr O,950,05)02, SrCO3 (strontium carbonate), CaCO3 (calcium carbonate), and Zn0( 1Sr Co 475.62 (1
(equivalent to 0.69 mole part) Ca CO130.75g
(equivalent to 0.28 mol parts) Zn O3,80(] (0
,01 mole part) MnO6,62(+ (0,0
equivalent to 2 molar parts) T”i 02354.44a (0,
(equivalent to 95 mole parts) ZrO228,77(J (0,0
(equivalent to 5 mole parts) were weighed out, and 2.51 parts of water was added to these raw materials and mixed 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 the sample flkl shown in Table 2, 67.96 g of SiO (80 mol%) BaCo
11.16(+ (4 mol%) M(IQ
2.2h (4 mol%) Zn O4,60 (]
(4 mol%) Sr Co 8.35 g (
4 mol%) Ca Co 5.65 (1 (4 mol%
) was weighed, 300cc of alcohol was added thereto, stirred for 10 hours using an alumina ball in a polyethylene pot, and then pre-calcined in the air at 1000°C for 2 hours, and then put into an alumina pot with 300cc of water. Grind with an alumina ball for 15 hours, then dry at 150°C for 4 hours. SiO□ is 80 mol% and MO is 20 mol%.
, (Ba 04 mol% + Ma 04 mol% + Zn 04
A powder of additive components having a composition of mol % + 4 mol % Sr + 4 mol % CaO was obtained.

Next, 30 g (3 parts by weight) of the above additive component powder was added to 1000 (1 (100 parts by weight)) of the basic component powder,
Furthermore, an organic binder consisting of an aqueous solution of acrylic acid ester polymer, glycerin, and condensed phosphate was added in an amount of 15% by weight based on the total weight of the basic components and additive components, and further,
50% by weight of water was added, and the mixture was placed in a ball mill and ground and mixed to prepare a slurry of porcelain raw materials.

Next, the above slurry is put into a vacuum defoaming machine to defoam, and this slurry is put into 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 applied onto 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 long and is used by punching it into a 10 cm 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 0.99g 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 14 nn and a width of 7 nn, 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 by applying a pressure of approximately 40 tons in the thickness direction at a temperature of approximately 50°C. Ta. Thereafter, this mi product was cut into a grid shape to obtain 50 laminated 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.

After that, the atmosphere of the furnace is changed from the atmosphere to H22 volume % + N29.
The atmosphere was changed to 8% by volume. Then, while maintaining the reducing atmosphere in the furnace as described above, the heating temperature of the stacked chips was increased from 600°C to the sintering temperature of 1190°C for 100 minutes.
After raising the temperature at a rate of C/h and holding it at 1190°C (maximum temperature) for 3 hours, lowering the temperature to 600'C at a rate of 100°C/h, changing the atmosphere to atmospheric atmosphere (oxidizing atmosphere), Oxidation treatment was performed by maintaining the temperature at 600° C. for 30 minutes, and then cooling 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 to form a zinc electrode layer. Copper is deposited on top of this by electroless plating, and then Pb is deposited on top of this by electroplating.
A -3n solder layer was provided to form a pair of external electrodes.

As a result, as shown in the drawing, dielectric porcelain ff1(1)
, (2), (3), internal electrodes (4), (5), and external electrodes (6), (7), a multilayer ceramic capacitor (10) was obtained. In addition, this capacitor <10)
The thickness of the dielectric ceramic layer (2) is 0.02 In+, the opposing area of the internal electrodes (4) and (5) is 5nn x 5IIn
There are =25nn2te. In addition, the porcelain layer (1) (2) after sintering
) (3) is substantially the same as the mixed composition of the basic component and the additive component before sintering, and is composed of composite provskite (p
Basic component of type structure (8'0.69°aO, 28Z00.01M00.02
)0(0,950,05)02 Between the crystal grains of TiZr, Si0280 mol%, Ba04 mol%, M(104 mol%, Zn04 mol%, and 5rO4
A homogeneous distribution of the additive components consisting of mol % is obtained.

Next, we measured the dielectric constant ε, temperature coefficient TC, Q, and resistivity ρ of the completed multilayer ceramic capacitor. As shown in sample No. 1 in Table 3, ε was 279 and TC was -140.
01) +111/”C1Q is 8800, ρ is 3.2 at 20℃, 1.9X at 107MΩ・C1, 125℃
It was 105MΩ・C1. Note that the above electrical characteristics were measured using the following capacity.

(A) The relative permittivity ε is at a temperature of 20°C and a frequency of IHt.
lz, the capacitance was measured under the condition of AC voltage (effective value) 0.5V, and this measured value and the thickness of porcelain R (2) 0.051
Calculated from 1.

(B) The temperature coefficient (TC) is the capacitance (C
85) Measure the n capacitance (C20) at 20°C, and (
C) Q is the frequency I HN3 at a temperature of 20°C,
Voltage [actual value] Measured with a Q meter at 0.5 V AC.

(D) Resistivity ρ (MΩ・cn) is calculated by measuring the resistance value between the pair of external electrodes (6) (71) after applying DC 50V for 1 minute at temperatures of 20°C and 125°C, respectively. It was calculated based on the dimensions.

The preparation method of sample Nα1 and its characteristics have been described above, but the compositions of basic components and additive components, their ratios, and firing in a reducing atmosphere (non-oxidizing atmosphere) have also been described for other samples Nα2 to Nα78. A multilayer ceramic capacitor was manufactured in exactly the same manner as Sample Nα1, except that the temperature was changed as shown in Tables 1, 2, and 3, and the electrical characteristics were measured in the same manner. Table 1 shows that for each numerical value for determining the compositional formula (% formula %) of the basic components of each sample, indicating the contents;
Table 2 shows the amount (parts by weight) of the additive components relative to 100 parts by weight of the basic components of each sample and the composition of the additive components. In the MO content column of Table 2, BaOlMgO, Zn
The proportions of o, Sro, and caO are shown in mol%. Table 3 shows the firing temperature for sintering in a reducing atmosphere (A high temperature) and 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 permittivity ε is 153 to 323, the Q is 5000 or more, and the temperature coefficient of the permittivity is TC from -eoo to -34001) pI/℃
The range is . Also, the resistivity ρ is 1.0×10 at 20℃
Mo-C1 or more, 1. at 125°C. OXl05Mn・
It becomes C1 or higher.

On the other hand, sample group 14.15.16.17.18.24.2
8.2933.38.43.44.48.49.53.
58.59.64.65.71.72.78, the object of the present invention cannot be achieved. Therefore, these 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, as is clear from sample Nα72, a dense sintered body cannot be obtained even if the firing temperature is 1300°C, but as shown in sample No. 73, when the amount added is 100
11 in the case of 0.2 parts by weight based on the basic component of parts by weight
A sintered body having desired electrical properties can be obtained by firing at 90°C. Therefore, the lower limit of the additive component is 0.2 part by weight.

On the other hand, when the amount added is 18 parts by weight as shown in sample 111Q78, Q becomes less than 5000, which is worse than the desired characteristics, but when the amount added is 15 parts by weight as shown in sample Nα77, the desired characteristics are obtained. can be obtained. Therefore,
The upper limit of the amount added is 15 parts by weight.

The value of X is, for example, 19.20.21.22.23 for the sample.
As shown, 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 NQ23, x+y+z=1, and Sr is zero after all. Therefore, the contents of Ma in the general formula according to the present invention are S', Ca,
One of Sr + Ca.

If the value of y is < 0.002 as shown in sample Nc24.29, no effect of adding Mb (Mb and/or Zn) is seen;
When the value of is 0, <1 (15), desired electrical characteristics are obtained.

Therefore, the lower limit of the value of y is o, oos. On the other hand, when the value of y is <0.12 as shown in sample No. 1128.33.38, a dense sintered body cannot be obtained;
．． As shown in 32.37, when the value of y is 0.10, desired electrical characteristics can be obtained. Therefore, the upper limit of the value of y is 0
．． It is 01.

If the value of 2 for the sample is < 0.0005 as shown in 44.49, then ρ at 125°C is 1. OX105Ma・C1l
However, as shown in samples No. 39, 45, 50, and 54, 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, if the value of 2 is 0.12, sample N043.48.53.5
As shown in 8, even if ρ is a satisfactory value, Q is 500.
However, sample N (142, 47, 52
, 57, when the value of z is 0.10, desired electrical characteristics can be obtained.

Therefore, the upper limit of the value of 2 is 0.10. In addition, for example,
As shown in Sample No. 50.51.52, when the value of z is gradually increased, ρ at 125° C. also gradually increases, indicating that Mn contributes to increasing the resistivity ρ at high temperatures.

When the value of W is <0.002 as shown in sample Nα59, ρ at 125°C is 1. It fell below OXIO3zr
Although the effect of adding 0.02 was not observed, when the value of W was 0.005 as shown in sample No. 60, desired electrical characteristics were obtained. Therefore, the lower limit of the value of W is o, oos. On the other hand, when the value of W is 0.12 as shown in sample Nα64, a dense sintered body cannot be obtained;
As shown in the figure, 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.

As shown in sample Nα65, the value of k is 0.99,
ρ is 3.8 x 103.1 at 20℃ and 125℃, respectively.
．． Ox101MΩ・CI, and Q is also significantly lower at 50, but as shown in sample No. 6f3, the value of k is 1.0.
In the case of 0, desired electrical characteristics can be obtained. Therefore, the lower limit of the value of k is 1.00. On the other hand, the value of k is sample NQ7
As shown in sample No. 1.25, a dense sintered body cannot be obtained, but as shown in sample No. 70, when the value of k is 1°20
In this case, desired electrical characteristics can be obtained. Therefore, the upper limit of the value of k is 1.20.

As is clear from samples Nα1.2.3.9, etc., the preferred composition of the additive components is 5102-Mo (however, MO is B
aOlMbO, ZnO, SrO, at least one type of gold m oxide) binary component system diteS
i O2 is 40-80 mol%, MO is 20-60 mol%
The composition is within the range of If the composition is within this range, desired electrical characteristics can be obtained.

On the other hand, like sample Nα14.15.1617.18,
If the composition of the additive components falls outside the range specified in the present invention, a dense sintered body cannot be obtained.

[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) A part of MnO, which is a starting material for obtaining the basic component, can be replaced with MnO2 or M port 304, etc., within a range that does not impede the purpose of the present invention.

Further, other substances may be added to the basic components and additive components as necessary.

(b) The starting materials for obtaining the basic components may be other than those shown in the examples, for example, oxides or hydroxides such as S 0, CaO, etc., or the starting materials for the additive components. Other compounds such as oxides and hydroxides may be used as the raw materials.

(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]

The drawing is a sectional view showing a multilayer ceramic capacitor according to an embodiment of the present invention. (1) (2) (3)...Dielectric ceramic layer, (4) (5)
...Internal electrode, (su(7)...External electrode.

Claims (1)

[Claims] (1) Consists of 100 parts by weight of a basic component and 0.2 to 15.0 parts by weight of additional components, and the basic component is {(Ma_1_-_y_-_zMb_yMn_z)O}
_k(Ti_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 40 to 80 mol% of SiO_2 and 20 to 6
0 mol% MO (however, MO is BaO, MgO, ZnO
, SrO, and at least one metal oxide of CaO).