JPH0465101A - Manufacture of barium titanium oxide ceramic semiconductor - Google Patents

Abstract

PURPOSE:To ensure a positive resistance temperature coefficient at the Curie temperature or higher and make very small a room temperature resistance coefficient by adding the predetermined quantity of PbTiO3, Sb2O3 and La2O3 to a BaTiO3 base material. CONSTITUTION:As a semiconductor producing agent, lead compounds, PbTiO3 of 0.1 to 50mol%, Sb2O3 of 0.080 to 0.145mol% and La2O3 of 0.01 to 0.06mol% are added to basic compound, barium titanium oxide and then mixed compound is baked. With the added semiconductor producing agent, a semiconductor may easily be manufactured and moreover resistivity at the room temperature may be set to a smaller value and rising of resistivity at the temperature of Curie point or higher may be set to a large value. Therefore, a low resistance PCT element having excellent flexibility may be manufactured for use in the circuit having a small current capacity. In addition, a barium site may partially be replaced with Pb with addition of a lead compound, PbTiO3. Thereby, element density becomes very large and it may be applied to a circuit having a large current capacity.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention provides titanic acid which has a positive temperature coefficient of resistance at temperatures above the Curie point and has excellent PTC properties due to very low room temperature resistivity. The present invention relates to a method for manufacturing a barium ceramic semiconductor.

[Conventional technology]

By adding oxides such as lanthanum, tantalum, cerium, yttrium, bismuth, tungsten, silver, samarium, and dysprosium to barium titanate-based porcelain, a positive temperature coefficient of resistance (PTC property) can be achieved. ) has been widely known for a long time. In addition, rare earth elements, tantalum,
It has also been proposed to improve the electrical properties of a barium titanate ceramic semiconductor composition containing niobium or antimony by adding silicon dioxide to it and firing it in the presence of oxygen (Japanese Patent Application Laid-Open No. Showa 53-5
(See Publication No. 9888).

[Problem to be solved by the invention]

However, in the conventional method for manufacturing barium titanate porcelain semiconductors, the rise in resistivity at temperatures above the Curie point is large, the resistivity is very small at room temperature, and the barium titanate porcelain semiconductor has a high density element. The problem is that it is difficult to obtain.

[Means for Solving the Problems] In order to solve the above problems, the method for manufacturing a barium titanate ceramic semiconductor according to the present invention includes adding a semiconducting agent to a barium titanate base composition containing a Curie point transfer substance. A method for producing a barium titanate ceramic semiconductor by firing, the method comprising: 0.1 mol% to 50 mol% of P, which is a lead compound, based on a barium titanate base composition as a semiconducting agent;
b T x O3o, oso mol% to 0.145 mol% 5bzO8, and 0.01 mol% to 0.06 mol% La2O3.

[Function] According to the above structure, semiconductor formation can be easily performed by the added semiconductor formation agent, and the resistivity at room temperature can be set lower, and the rise of resistivity at temperatures above the Curie point can be made smaller. A versatile low resistance PCT that can be used in circuits with small current capacity because the width can be increased.
devices can be manufactured. In addition, P, which is a lead compound,
By adding bTiO3, some of the barium sites can be replaced with Pb, so the density of the element becomes very high, and it can be applied to circuits with large current capacity. It should be noted that the compatibility between Pb and La is good when the semiconducting agent is added.

〔Example〕

An embodiment of the present invention will be described below based on FIGS. 1 and 2.

In this example, strontium titanate (Sr”hOs)
In a method for manufacturing a barium titanate ceramic semiconductor, which comprises adding a semiconducting agent to a barium titanate base composition containing a Curie point transfer substance such as , 0.0
80 mol% to 0.145 mol% antimony oxide (5b
20ff ), 0.01 mol % to 0.06 mol % of lanthanum oxide (La20.) is used, and some of the barium sites are added with lead i! When tA(0,] mol% to 50.0 mol% PbTiO3) was removed, lanthanum oxide (La2
The authors disclose how the resistivity at room temperature changes depending on the amount of 03) added, and as a result, the preferred range of the amount of the semiconductor-forming agent added for the production of barium titanate ceramic semiconductors.

In this example, 0.080 mol % to 0
．． 145 mol% antimony oxide (5bzO:+) and 0.01 mol% to 0.06 mol% lanthanum oxide (
La, 0. ), and in this case, manganese carbonate (MnC0, ) is blended as a mineralizer, and silicon dioxide (5iOz) and the like are blended as a voltage-dependent stabilizer. Further, in this base composition, lead titanate (Pb
By adding Ti0:+) and replacing some of the barium sites with Pb, the density of the element body is increased.

In the above configuration, the compatibility between pb and La is good.

In addition to the above additives, 0.1 mol% to 30 mol% of strontium titanate (5rTi03) may be added. As a result, the lead titanate (PbTi)
Oz) shifts the Curie point to a higher temperature side, while strontium titanate (5rTiO+) shifts the Curie point to a lower temperature side, so the Curie point can be set to a desired temperature.

This formulation is wet mixed in an automatic mortar for 1 to 24 hours in the presence of ethanol (special grade reagent), dried, and then calcined at 1000°C to 1400°C for 1 to 3 hours. The calcined compound is crushed and mixed with PVA (polyvinyl alcohol) 2wt% to 8wt% in an automatic mortar.
Add an aqueous solution of , mix for 1 to 6 hours, dry, and then thoroughly pulverize. After molding the powder obtained in this way in a disc molding machine, the molded product is heated to 1300°C
The barium titanate ceramic semiconductor is obtained by holding and firing at 1400°C for 0 to 10 hours.

The present invention will be described below as [Comparative Example] and [Example 1].
This will be explained in more detail based on [Example 3].

[Comparative example] Anhydrous barium carbonate (BaCO3, BK-KL manufactured by Sakai Chemical Co., Ltd.)
) 680.52g, high purity titanium dioxide (TiO2,
(manufactured by Toho Titanium Co., Ltd.) 90.02 g, - anhydrous strontium carbonate (SrCO3, manufactured by Honjo Chemical Co., Ltd.) 26.7
9g, manganese carbonate (MnCO3, manufactured by Wako Pure Chemical Industries, Ltd., 99
．． 9% reagent) 0.2087 g, silicon dioxide (SiO
□, Rare Metallic Co., Ltd., 99.9% reagent) 1.090
4 g, antimony oxide (Sb203, manufactured by Rare Metallic Co., Ltd., 99.9% reagent), 1.0581 g, and tantalum oxide (TazOs, manufactured by Rare Metallic Co., Ltd., 99.9% reagent).
Put 0.3209 g of 9% reagent) into a 5i capacity ball mill, add 3.51 g of water, and wet-mill for 24 hours.
After mixing, it was filtered and the mixture was dried at 130"C. The dry mixture was placed in a mold (6.5mm
(diameter) x 451ml + (height)], 150 kg
The molded product was placed in an electric furnace and heated at a temperature increase rate of 180°C/hour to a temperature of 115° C./C1fi.
Calcination was performed at 0°C for 2 hours.

The calcined product was placed in a vibrating ball mill, and water was added at 0.71%
was added and wet-milled for 16 hours, and 15% (iy
/w) Polyvinyl alcohol (PVA) aqueous solution 15
After adding 0 g and stirring for 2 hours, the slurry was spray-dried with a spray dryer to form granules with a diameter of about 50 μm. The granules are molded into a mold [12.5 mm (diameter)].
X35mo+ (height)] and molded under a pressure of 1 ton/ad, and the molded product was fired under the following conditions.

Temperature range: Temperature rising or falling conditions room temperature to 80°C
0℃ 145℃/hour Temperature increase 800℃ Hold for 2 hours 800℃~1360℃ 150℃/hour Temperature increase 1360℃
Holding for 15 minutes 360°C ~ 1000°C
°C360℃/hour temperature drop 1000'C~550''C2
45°C/hour temperature drop 550'C End of temperature control After cooling to room temperature, an ohmic silver electrode (manufactured by Degussa) was applied to the disk surface of the tablet-shaped molded product and baked at 580°C for 5 minutes. A cover electrode (manufactured by Degussa) was applied on the electrode, and the electrode was heated at 560"C for 50 minutes.
Baking was further performed for a minute to obtain a barium titanate porcelain semiconductor sample.

The composition of the raw materials for this barium titanate ceramic semiconductor is as follows.

(Bao, qsSro, os) TiOs+0.0
005MnOz+0.005SiOz+0.001Sb
z03+O,0O02TazOsAs a result of measuring the temperature change in the resistance of this sample, the temperature at which a region exhibiting a positive temperature coefficient of resistance occurs (Curie point) was 107°C, and the rise width of the resistance was approximately 3.5 orders of magnitude. . At this time, the resistivity at room temperature was 5.50 Ω·Cll1, and the density of the element body was 5.54 g/cm'.

[Example 1] 61.15 g of anhydrous barium carbonate (BaCO3, high-purity product manufactured by Nihon Kagaku Kogyo), high-purity titanium dioxide (Tie,
Toho Titanium > 29.16g, anhydrous strontium carbonate (SrCO3, Honjo Chemical) 5.38g
, lead oxide (PbO1 high purity product manufactured by Nippon Chemical Industry) 4.07
g, manganese carbonate (MnC0, manufactured by Wako Pure Chemical Industries, Ltd. 99.
9%) 0.0209 g, silicon dioxide (SiO□,
Manufactured by Toshiba Ceramics, US-85) 0.1095g,
Antimony oxide (5bzOz, manufactured by Rare Metallic Co., Ltd., 9
9.9% reagent) 0.1063g, lanthanum oxide (La2
O3, manufactured by Rare Metalink, 99.9% reagent) 0.01
19 g was placed in an alumina mortar with an inner diameter of 200 ann, and after wet mixing in an automatic mortar in the presence of 3 o'clock ethanol (special grade reagent), the mixture was dried at 130'C. The dry mixture was poured into a 90III11 x 90 area aluminum crucible (Mitsubishi Mining Cement, DFA-PS99).
), this was placed in an electric furnace, heated at a temperature increase rate of 180''C/hour, and calcined at 1150°C for 2 hours.

After pulverizing the calcined product in a mortar, about 10 mW of polyvinyl alcohol (PVA) 2wt% water was added in an automatic mortar.
Mixed with 0 cc for 3 hours and dried at 130°C.

Thoroughly crush the dried product thus obtained in a mortar, and
A molding machine (12.5am (diameter)) for molding VA blended powder
x35 mm (height)] and molded under a pressure of 1 ton/cl, and the molded product was fired under the following conditions.

Temperature range: Conditions for heating or cooling Room temperature ~80
0°C 145°C/h temperature increase 800°C 2 hours hold 800°C to 1360°C 150°c/h temperature increase 136
Hold 0°C for 15 minutes 1360°C to 1000°C 360°c/h temperature drop 10
00°C to 550°C 245°C/h temperature drop 55
End of 0°C temperature control After cooling to room temperature, an ohmic silver electrode (manufactured by Degussa) was applied to the disk surface of the tablet-shaped molded product and baked at 580°C for 5 minutes to form an electrode. A cover electrode (manufactured by Degussa) was applied thereon and baked at 560''C for 5 minutes to obtain a barium titanate ceramic semiconductor sample.

The composition of the raw materials for this barium titanate ceramic semiconductor was as follows.

(Bao, essro, +oPbo, os)Ti
03+0.0005MnOz+0.005SiOz+
O,0O075SbzOz +〇,0001LazOs
As a result of measuring the temperature change in the resistance of this sample, the temperature at which a region exhibiting a positive temperature coefficient of resistance occurs (Curie point) is 107
°C, and the rise width of the resistance was 4.6 digits.

At this time, the resistivity at room temperature was 39.48 Ω·l, and the density of the element was 5.85 g/cm''.

[Example 2] Anhydrous barium carbonate (BaCO5) 61.14 g, high purity titanium dioxide (TiO□) 29.16 g, anhydrous strontium carbonate (5rC(h) 5.38 g, lead oxide (PbO) 4.067 g, carbonic acid Manganese (MnC0:+
) 0.0210 g, silicon dioxide (SiO□) 0.
1095g, antimony oxide (5bzOs) 0.106
2g, lanthanum oxide (LazOz) 0.0238g
A barium titanate ceramic semiconductor sample was obtained in the same manner as in Example 1 above, except that .

The composition of the raw materials for this barium titanate ceramic semiconductor is as follows.

(Bao, 5ssro, I 0pbQ, os)T
i03+0. OO05MnOz〇、005SiOz
+0. oo1osb2o3 +O,0O02Laz
O + As a result of measuring the temperature change in the resistance of this sample, the temperature at which a region exhibiting a positive temperature coefficient of resistance occurs (Curie point) is 1
The temperature was 14°C, and the rise width of the resistance was 3.4 orders of magnitude. At this time, the resistivity at room temperature is 5.52Ω・mark,
The density of the element body was 5.79 g/cm3.

[Example 3] Anhydrous barium carbonate (BaC0:+) 61.13 g, high purity titanium dioxide (TiO□) 29.15 g, anhydrous strontium carbonate (5rC(h) 5.38 g, lead oxide (PbO) 4.07 g, Manganese carbonate (MnC0:
+) 0.0210 g, silicon dioxide (SiO□) 0
．． 1095 g, antimony oxide (5bz03) 0.1
062 g, lanthanum oxide (La2O5) 0.035
A sample of barium titanate porcelain was obtained in the same manner as in Example 1 above, except that 6 g was used.

The composition of the raw materials for this barium titanate porcelain is as follows.

(Baa, 5sSro, IoPbo, as)T
iO:+ +0.0005Mn02+0.005SiO
z +0.0010SbzO:+ +0.0003La
zO.

As a result of measuring temperature changes in the resistance of this sample, the temperature at which a region exhibiting a positive temperature coefficient of resistance occurs (Curie point) is 109
°C, and the rise width of the resistance was 4°0 digits.

At this time, the resistivity at room temperature was 44.72 Ω·1, and the density of the element body was 5.88 g/cm 3 .

From the above, the results of [Comparative Example] and [Example 1] to [Example 3] are summarized as shown in Table 1. As is clear from Table 1, a barium titanate ceramic semiconductor having a positive temperature coefficient of resistance at temperatures above the Curie point and a very low resistivity at room temperature can be obtained as a semiconducting agent. In addition, [Example 1] or [
Example 3] contains PbTiOs, so PbT
The density of the element body is much larger than that of the comparative example that does not contain i0+.

Further, the dependence of the resistivity of the barium titanate ceramic semiconductor of this example at room temperature on the amount of lanthanum oxide (LazO=) added is as shown in FIG. As shown in Figure 1, the amount of lanthanum oxide (LazO:+) added is 0.01
If it is less than mol%, it is difficult to control the compounding concentration, etc., and it is not practical for manufacturing. In addition, the amount of lanthanum oxide (LazO3) added was 0.
It can be seen that when the amount exceeds 0.06 mol %, the resistivity increases significantly. In addition, in the above comparative example, lanthanum oxide (La
zOi) was not added.

The temperature dependence of the resistivity of the barium titanate ceramic semiconductor of this example is 62 as shown in FIG. As shown in FIG. 2, when the Curie point is exceeded, the resistivity becomes large in each of the examples, and the rise width thereof is also very large. On the other hand, below the Curie point, the respective resistivities are kept approximately constant and low. Note that (1) to (3) in FIG. 3) respectively.

Here, methods for measuring various physical properties of samples of the above-mentioned barium titanate ceramic semiconductors having different compositions of raw materials will be explained below.

(1) Measurement of Curie point Attach the sample of barium titanate porcelain semiconductor to the sample holder for measurement, and place it in the measurement tank (MINI-5UBZEROM
C-810P (manufactured by Tahai Nispec ■) and measured the change in electrical resistance of the sample against temperature changes from -50°C to 190°C using a DC resistance meter (multimeter 3).
478A (manufactured by HP).

From the electrical resistance-temperature plot obtained by measurement, the temperature at which the resistance value becomes twice the resistance value at room temperature was defined as the Curie point.

(2) Room temperature resistivity A sample of barium titanate porcelain semiconductor was measured with a DC resistance meter (multimeter 3478AYH) in a 25°C measurement tank.
The electrical resistance value was measured using a commercially available product (manufactured by P.P.).

In preparing a barium titanate porcelain semiconductor sample, the size (diameter and thickness) of the sample was measured before applying the electrode, and the specific resistance (ρ) was calculated using the following formula, and this was taken as the resistivity.

ρ-R-S/l ρ: Specific resistance (resistivity) [Ω・C] R: Measured value of electrical resistance (Ω) S: Area of electrode 3cJ:1 t: Thickness of sample (cm) (3 ) Rising width of resistivity Temperature change in Curie point measurement (-50°C to 190°C
), the change in electrical resistance of the sample was measured for an additional 20
Continue until the temperature exceeds 0°C, and compare the resistivity at the time of the sudden rise in electrical resistance at the Curie point with the resistivity at 200°C using the resistivity-temperature plot ↓ to find the value of that order. The number was defined as the rise width of resistivity.

As described above, the present invention provides a barium titanate base composition containing a Curie point transfer substance, in which o, oso mol% to 0 mol % to the barium titanate base composition is added as a semiconducting agent to the barium titanate base composition.
．． 145 mol% antimony oxide (Sb20.) and 0.01-0.06 mol% lanthanum oxide (La2'
s) can be added to the base composition, and lead titanate (PbTi) in an amount of 0.1 mol% to 50.0 mol%
Since the barium sites can be replaced by adding O3), a barium titanate ceramic semiconductor having a very high element density, low resistivity at room temperature, and a positive temperature coefficient can be obtained. Since the system of the present invention contains lead titanate having a low melting point, the density of the element is very high, making it easier to prevent the formation of bores during the sintering process.

Therefore, a device that is delicate and has a high withstand voltage can be obtained.

Further, when 0.1 mol % to 30 mol % of strontium titanate (5rTi03) is added, the Curie point of the barium titanate ceramic semiconductor is shifted to the lower temperature side, so the Curie point can be set to a desired temperature.

In addition, since the barium titanate ceramic semiconductor according to the present invention has a low resistivity at room temperature, it can be used as a low resistance PTC element in a circuit with a small current capacity.
For example, it can also be used as a comparator for a temperature fuse switching power supply. In addition to the above, the barium titanate ceramic semiconductor according to the present invention can be applied to electrolytic capacitor protection circuits, color TV automatic degaussing devices, motor starting devices for automobiles, overheat prevention devices for electronic equipment, delay elements, timers, liquid level gauges, etc. It can be used for non-contact switches, relay contact protection devices, etc.

(Margins below) Table 1 C below) [Effects of the Invention] As described above, the method for producing a barium titanate ceramic semiconductor according to the present invention uses a barium titanate base composition as a semiconducting agent. .1 mol% to 50 mol% PbT
i0. +, 0.080 mol% to 0.145 mol% S
b z O'r , and 0.01 mol % to 0.06 mol % La20. This is a configuration that uses .

Therefore, a barium titanate ceramic semiconductor having a positive temperature coefficient of resistance at temperatures above the Curie point and a very low resistivity at room temperature can be reliably obtained. In addition, since the barium titanate porcelain semiconductor according to the present invention contains a lead compound, an element body with extremely high density can be obtained, and the formation of bores in the sintering process can be prevented, so that it is dense and withstand voltage. As an element with high current capacity, it also has the effect of being compatible with a wide range of applications with large current capacity.

[Brief explanation of drawings]

1 and 2 show an embodiment of the present invention. FIG. 1 is an explanatory diagram showing the dependence of the resistivity at room temperature of the barium titanate ceramic semiconductor obtained by the manufacturing method of the present invention on the amount of lanthanum oxide (LazO=) added. FIG. 2 is an explanatory diagram showing the temperature dependence of resistivity of a barium titanate ceramic semiconductor obtained by the manufacturing method of the present invention. Figure Patent applicant Sekisui Plastics Co., Ltd. La, zo
3 (moQ'10)

Claims (1)

[Claims] 1. In a method for producing a barium titanate ceramic semiconductor by adding a semiconducting agent to a barium titanate base composition containing a Curie point transfer substance and firing the mixture, as the semiconducting agent,
0.1 mol% to 5 based on barium titanate base composition
0 mol% PbTiO_3, 0.080 mol% to 0.1
45 mol% Sb_2O_3, and 0.01 mol% ~
A method for producing a barium titanate ceramic semiconductor, characterized in that 0.06 mol% of La_2O_3 is used.