JPH0456006A - Porcelain dielectric substance for temperature compensation - Google Patents

Abstract

PURPOSE:To maintain a high Q-value and suppress the absolute value of the temperature coefficient under a certain level by allowing a porcelain dielectric substance as embodiment of the present invention to contain Sr titanate, Ca titanate, La oxide and Ti oxide, and thereby providing a high dielectric constant. CONSTITUTION:A porcelain dielectric substance as embodiment of the present invention contains 57.30-65.50mol% Sr titanate, 33.80-40.90mol% Ca titanate, 0.08-0.62mol% La oxide, and 0.20-2.10mol% Ti oxide, wherein the mol ratio of Ti oxide to La oxide lies within the extent from 2.70 to 3.40. To this compound, 0.15-0.70wt.% Sb oxide is added, and thus a porcelain dielectric substance as object is accomplished.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a temperature-compensating porcelain dielectric material, and in particular, to a method for sufficiently reducing its temperature coefficient while ensuring a high 8-electric constant and a high Q value. Concerning compositional improvements.

[Prior Art] As a conventional temperature compensating porcelain dielectric material, its composition includes M
gO・TIO,, La20,4fO,, 5rTiO,,
There are titanates such as LaTl03, and in order to further reduce the temperature coefficient and increase the telephone call rate, there are various combinations of these titanates, such as Mgo-Tio2-CaTiO3. dielectric,
MgO・TIO2-CaTl05-La2O34i0 as disclosed in Japanese Patent Publication No. 37-11333
2-based dielectrics, as well as 5rTfO, -CaTi0. −
Bi, 0.・There are also TiO and other dielectrics.

[Problems to be Solved by the Invention] However, in the various conventional temperature-compensating porcelain dielectrics as described above, it is necessary to take into account the composition ratio between each component and reduce the temperature change rate of the reading rate. If this is the case, the telephone call rate itself will decrease, and conversely, if you try to increase the telephone call rate, the rate of temperature change will become large and the eight-cell loss will also worsen, which is a trade-off.

In view of this point, the present invention has an octoelectricity of 300 or more and a Q value of 3.
Although both have high values of 1000 or more, the absolute value of the temperature change rate (temperature coefficient) of the dielectric constant does not deteriorate and
It is an object of the present invention to provide a porcelain dielectric material for temperature compensation which can keep ppm/ or less.

[Means for Solving the Problems] In order to solve the above-mentioned problems, as a result of various experiments, the present inventor found that strontium titanate from 57.30 mol% to 65.50 mol% and strontium titanate from 33.80 mol% to 65.50 mol%. 40.90
a composition comprising up to mol % calcium titanate, 0.08 mol % to 0.62 mol % lanthanum oxide, and 0.20 mol % to 2.10 mol % titanium oxide; The molar ratio of titanium to lanthanum oxide is 2
．． We propose a temperature-compensating porcelain dielectric material having a temperature in the range of 70 to 3.40 and further comprising 0.15% to 0.70% by weight of antimony oxide added to the composition.

Of course, all of the numerical range limitations for each component mentioned above are significant; for example, for strontium titanate and calcium titanate, even if their mole percent exceeds the above range specified for each, Even if it exceeds 100, the absolute value of the temperature coefficient is the value that should be achieved.
It exceeds 0 ppII/l:.

Regarding lanthanum oxide, if it falls below the lower limit of 0.08 mol% in the above range, the dielectric constant will not reach the desired value, and if it exceeds the upper limit of 0.62 mol%, the Q value will become extremely low. .

The same goes for titanium oxide; if its mol% is less than 0.20 mol%, which is the lower limit of the above range, the absolute value of the temperature coefficient will exceed 1000 ppm/l, which is the upper limit of 2.
If the content exceeds 10 mol %, the sintered body will significantly fuse during stack firing, which will cause problems in production.

Furthermore, even if all of the components meet the above specified ranges in terms of their mole % or weight %, the molar ratio of titanium oxide to lanthanum oxide should still not fall within the above specified ranges. If the lower limit of the range is less than 2.70, a dielectric constant of 300 or more cannot be obtained, and if the upper limit of 3.40 is exceeded, the dielectric constant of 3.
Q value of 000 or more cannot be obtained, or the absolute value is 1000
It is not possible to obtain temperature coefficient characteristics within ppm/.

Additionally, if antimony oxide is not added, the dielectric constant will be low, and even if antimony oxide is added, if the weight percentage exceeds the above specified range, the dielectric constant will remain at the desired value regardless of whether it is above or below the specified range. This is a little short of 300.

[Function] In the present invention, the range of each mole % of the four main components of strontium titanate, calcium titanate, lanthanum oxide, and titanium oxide is specified, the range of the weight % of antimony oxide as an additive is specified, and the range of the weight % of antimony oxide as an additive is specified. When all these conditions are met, only then can a high dielectric constant of 300 or more and a high Q of 3000 or more be achieved.
While maintaining the value, the absolute value is 1000 ppm/'
A temperature compensating ceramic dielectric material having an excellent temperature coefficient of e or less can be obtained.

[Example] Below, 5rTiOs CaTiOs La2034
Through the examples of the present invention, which are j02-based compositions, the mole % range for each main component limited in the present invention, the weight % range for antimony oxide as an additive, and the molar ratio range of titanium oxide to lanthanum oxide. prove the significance or rationality of

First, prepare SrCO3 and TiO2 as starting materials,
These were weighed so that the molar ratio was 1.0, water was added, and wet mixing was carried out using a ball mill for 18 hours.

The mixture thus obtained was dehydrated and dried at a temperature of 1120°C.
Calcined at ℃, strontium titanate (SrTi03
) was obtained.

In addition, CaC0a and TiO□ were prepared, weighed so that the molar ratio was 1.0, wet-mixed using a ball mill for 18 hours, dehydrated and dried, and then heated to 1120°C. Calcium titanate (Ca
TiOs) was obtained.

Separately, we prepared lanthanum oxide (La203) and titanium oxide (TiOz), and added the powders of strontium titanate and calcium titanate prepared above, and the composition ratios of the four components in total are shown in Table 1 below. By varying the molar ratio of titanium oxide to lanthanum oxide and the weight percent of antimony oxide as an additive, the mixed sample powders of sample numbers 1 to 23 were mixed as shown in . I prepared my body.

After firing each of the sample powders, all sample powders 1 to 23 were heated to find out what kind of characteristics they exhibit in terms of Ut rate, temperature coefficient, and Q value as a ceramic telephone body. After kneading and granulating a binder solution in which 2% by weight of polyvinyl alcohol was dissolved in wood,
000 under a pressure of g7cm' with a diameter of 16mm and a thickness of 0.
Formed into a 6 am disc and heated at 1350°C in an electric furnace.
, and baked for 2 hours.

Silver electrodes are baked on the bidirectional surfaces of the disc-shaped ifl device thus obtained using a conventional method, and then used for measurement! It was extreme.

On top of that, the above-mentioned Nos. 1 to 2 with different compositions respectively.
For each sample porcelain up to No. 3, the reference temperature +20℃, frequency I MH2, measurement voltage I Vras''C-8 electric rate and Q value were measured. Temperature coefficients were also measured within the temperature range from °C to 85 °C.

The results of the 8-electrification rate, temperature coefficient, and Q value thus measured are also listed in Table 1 below.

(Hereinafter referred to as contribution margin) As is clear from Table 1 above, each mol% range or weight% range defined in the present invention, that is, 5rTiO: 57.30 to 65.50 mol%; Ca
TiOs: 33.80-40.90 mol%; La5h
,: 0.08-0.62 mol%; TiO2: 0
．． 20-2.10 mol%; 5bzO3: 0.15-
0.70% by weight; and TiO2 and L
The molar ratio of a2O5 is 2.70 < TiCh/La2
．． Sample numbers 2, 4, 6.1 with s <3.40;
For each sample No. 8, 17, 18, 21, and 22, all of them had a call rate of 300 or more, which is the intended aim of the present invention.
Q value 3000 or more, absolute value of temperature coefficient 1000 ppm
/'e or less, which completely satisfies the excellent characteristics.

On the other hand, samples other than those mentioned above, such as samples with an asterisk "*" on the right side of the sample number in Table 1, do not meet any one of the specific conditions according to the present invention. For samples that do not have the desired value range, the desired value range is not obtained in at least one of the absolute values of the octoelectricity, the Q value, and the temperature coefficient.

For example, in samples No. 1 and No. 7, the composition ratios of the four main components of strontium titanate, calcium titanate, lanthanum oxide, and titanium oxide are within the range specified by the present invention, but additives No antimony oxide is used. As a result, the sample No. 1 had poor absolute values of octocurrency and temperature coefficient, and the sample No. 7 had poor electric call rate.

For samples No. 3, No. 20, and No. 23, both the mol% of the four main components and the weight% of antimony oxide as an additive,
All of them are within the specified range according to the present invention, but the molar ratio of titanium oxide to lanthanum oxide is within the above specified range 2, 7
It is not within the range of 0 to 3.4o, and the sample number 3 is about 3.40, which is above the upper limit.The sample number 20 is about 2.4o, which is below the lower limit.
57, and sample No. 23 again has an upper limit of about 355.
It becomes.

Therefore, the Q value of sample No. 3 is extremely low, the call rate of sample No. 20, and the temperature coefficient and Q value of sample No. 23 are not within the desired value ranges.

In samples No. 5 and No. 15, the weight percent of antimony oxide as an additive was less than the lower limit of the specified range according to the present invention, and as a result, only a low call rate was obtained.
Conversely, in sample No. 9, the weight percent of antimony oxide exceeds the upper limit of the specified range according to the present invention, but the call rate is still low in that case.

Samples No. 8 and 9 have strontium titanate mole%
and the mole % of calcium titanate exceed above or below the specified range according to the present invention, respectively, and the temperature coefficient cannot be kept low in any of such samples.

In samples No. 10 and No. 13, the mole percent of calcium titanate exceeds the upper limit of the specified range according to the present invention, and in addition to such samples having a low call rate, especially in sample No. 10, the temperature coefficient is extremely high. It's getting worse. On the other hand, sample No. 11, which is a sample below the lower limit of the specific mole % range of calcium titanate, has a good call rate but a low Q value and a fairly poor temperature coefficient.

In sample No. 12, the mol% of lanthanum oxide exceeds the specified range in the present invention, and a high Q value was not obtained.

In the last remaining sample No. 14, the mole percent of titanium oxide as well as lanthanum oxide is below the specified range in the present invention,
Desired values for call rate and temperature coefficient are not obtained.

As mentioned above, Table 1 listed in this document not only includes sample groups that meet all of the essential constituent requirements of the present invention, but also includes samples that meet all of the essential constituent requirements of the present invention except for one. Various combinations of sample examples are also shown in which all other conditions are met, and it is clear that such combinations will never give the desired results of the present invention, i.e. even if only one is specified by the present invention. It is clearly shown that the desired effects of the present invention cannot be obtained unless the requirements are met, and paradoxically proves the necessity of satisfying all of the constituent requirements of the present invention.

[Effect] According to the present invention, it has a high fusibility of 300 or more, and
It is possible to obtain a temperature-compensating porcelain telephone body that successfully reduces the absolute value of the temperature coefficient to 1000 ppm/'C or less while maintaining a high Q value of 00 or more.

Furthermore, problems such as fusion during firing do not occur, and manufacturability is not impaired.

Claims (1)

[Claims] Strontium titanate from 57.30 mol% to 65.50 mol%, calcium titanate from 33.80 mol% to 40.90 mol%, and oxidation from 0.08 mol% to 0.62 mol%. Lanthanum and 0.20 mol%
to 2.10 mol % of titanium oxide, wherein the molar ratio of the titanium oxide to the lanthanum oxide is within the range of 2.70 to 3.40, and further comprising: Temperature-compensating porcelain dielectric material with addition of 0.15% to 0.70% by weight of antimony oxide.