JP3206517B2 - Semiconductor porcelain composition and semiconductor porcelain device using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor porcelain composition having a negative resistance temperature characteristic, and a semiconductor porcelain element using the same, particularly useful for preventing inrush current and delaying motor start-up.

[0002]

2. Description of the Related Art Conventionally, as an element for preventing an initial overcurrent, a semiconductor ceramic element (NTC thermistor element) having a negative resistance temperature characteristic in which a resistance value decreases with a rise in temperature has been used. Since this semiconductor ceramic element has a high resistance value at room temperature, the initial overcurrent is suppressed, and then the temperature rises to a low resistance due to self-heating, and the power consumption decreases in a steady state.

For example, in a switching power supply, an overcurrent flows at the moment when the switch is turned on. Therefore, such a semiconductor ceramic element is used as an element for suppressing the initial rush current. This semiconductor porcelain element has a high resistance value at room temperature and has a function of decreasing the resistance value as the temperature rises, so the initial rush current is suppressed, and then the temperature rises due to self-heating and the resistance becomes low. In a steady state, power consumption can be reduced.

[0004] In this type of semiconductor porcelain element, a semiconductor porcelain composition comprising a transition metal composite oxide having a spinel structure has been conventionally used.

[0005]

By the way, in order to use a semiconductor ceramic element (NTC thermistor element) for preventing an inrush current, the resistance value must be sufficiently reduced in a state where the temperature rises due to self-heating. However, in the conventional semiconductor porcelain element having a spinel structure, the B constant does not increase to 3250 K or more, so that the resistance value in the temperature rising state cannot be sufficiently reduced from the state where the rush current is prevented, and the power consumption in the steady state is not increased. There was a problem that the amount became large.

In addition, the conventional semiconductor porcelain element has a problem that the resistance value is largely increased under a change in the outside air temperature, particularly in a low-temperature environment of 0 ° C. or lower, and the rise of the device is delayed due to a voltage drop. In order to improve these problems, it is necessary to have a property that the B constant is small near normal temperature (−10 to 60 ° C.) and large at a high temperature (140 to 200 ° C.).

However, the lanthanum-cobalt-based oxide ceramic has a temperature dependence of the B constant, a small B constant near room temperature, and a negative resistance temperature characteristic such that the B constant increases as the temperature increases. buoy. Gee. Buheide (V.
G. Bhide) and Dee. S. La Jolia (DSRajori)
a) (Phys. Rev. B6, [3] 1021 (1972)).

The present inventors have found that a main component comprising a lanthanum-cobalt-based oxide is Si, Zr, Hf, Ta, S
By adding at least one selected from the group consisting of n, Sb, W, Mo, Te, and Ce, the B constant around room temperature can be reduced to 3000K or less (conventionally 3250K or more).
In addition, the high-temperature B constant is set to 4000K or more (conventionally, 3250K
In the following, it has been found that the inrush current prevention characteristic can be further enhanced (Japanese Patent Laid-Open No. 7-176406).
issue).

The main components of the lanthanum cobalt-based oxide include Si, Zr, Hf, Ta, Sn, Sb, W, M
When at least one selected from the group consisting of o, Te, and Ce is added, the resistivity at room temperature and the B constant increase as the amount of addition increases. These additives are
It acts as a donor in the lanthanum cobalt-based oxide, and contains impurities (Ni, Ca) contained in the lanthanum cobalt-based oxide.
This is for compensating the charge of the acceptor group.
Therefore, when the addition amount of the donor group is larger than the impurity amount of the acceptor group, the room temperature resistivity and the B constant decrease as the addition amount of the donor group increases.

The specific resistance and the B constant of the lanthanum cobalt-based oxide at room temperature become maximum when the amount of the donor group added becomes equal to the amount of the impurities of the acceptor group. About 4700 K is obtained as (25 to 140 ° C.).

By the way, the magnitude of the rush current and the suppression level thereof differ depending on the circuit. For example, in a circuit having a large rush current or a circuit requiring a large suppression level,
It is necessary to increase the resistance of the semiconductor porcelain used. In order to increase the resistance value without changing the shape of the semiconductor porcelain, a semiconductor porcelain composition having a high specific resistance at room temperature is required. However, since the specific resistance at room temperature of the conventional lanthanum cobalt-based oxide composition did not become higher than 20 Ω · cm as described above, there was a problem that these circuits could not be accommodated without changing the shape of the semiconductor porcelain. Was.

Accordingly, an object of the present invention is to reduce the power consumption by reducing the resistance value in a temperature rising state, and to reduce the rise in the resistance value near room temperature to achieve a good start-up and to cope with a large current. With respect to a semiconductor ceramic composition having a negative resistance-temperature characteristic that can be obtained, the B constant is kept constant and about 10Ω
An object of the present invention is to provide a semiconductor porcelain composition capable of obtaining an arbitrary room-temperature specific resistance in a range of from 1 cm to 100 Ωcm, and a semiconductor porcelain element using the same.

[0013]

In order to achieve the above object, a semiconductor ceramic composition having a negative resistance temperature characteristic according to the present invention comprises a lanthanum cobalt-based oxide as a main component and Fe and Al as subcomponents as subcomponents. At least one oxide of the elements, Si, Zr, Hf, Ta, Sn, Sb, W, M
It is characterized by containing at least one oxide among the elements of o, Te, Ce, Nb, Mn, Th and P.

Further, according to the present invention, there is provided a semiconductor ceramic device comprising a semiconductor ceramic having a negative resistance temperature characteristic and an electrode formed on the semiconductor ceramic, wherein the semiconductor ceramic is made of a lanthanum-cobalt-based oxide. At least one oxide of the elements Fe and Al as subcomponents, and Si, Zr, Hf, Ta, Sn, Sb, W, M
It is characterized by containing at least one oxide among the elements of o, Te, Ce, Nb, Mn, Th and P.

The content of at least one oxide of the above-mentioned Fe and Al elements is 0.001 to 30 mol% in total in terms of the above-mentioned elements.
r, Hf, Ta, Sn, Sb, W, Mo, Te, Ce,
The content of at least one oxide among the elements of Nb, Mn, Th and P is 0.000 in total in terms of the above elements.
1 to 10 mol%.

The content of at least one oxide of the above-mentioned Fe and Al elements is 0.1 to 10 mol% in total in terms of the above-mentioned elements, and the above-mentioned Si, Zr, Hf,
Ta, Sn, Sb, W, Mo, Te, Ce, Nb, M
The content of at least one oxide of the elements n, Th and P is 0.1 to 5 mol in total in terms of the above elements.
%.

Further, the lanthanum cobalt-based oxide is L
a _x CoO ₃ (where 0.60 ≦ x ≦ 0.99).

A part of La in the La _x CoO ₃ is P
It is characterized by being substituted by any one of r, Nd and Sm.

Further, the semiconductor porcelain element is for preventing inrush current or delaying motor starting.

With such a composition, the resistivity at room temperature can be increased to about 10 Ω · cm to 100 · cm while the B constant is kept at a constant value.
Therefore, a semiconductor porcelain element having a negative resistance temperature characteristic that can cope with a circuit having a large rush current or a circuit requiring a large suppression level without changing the porcelain shape can be obtained.

The content of at least one of Fe and Al is 0.001 to 30 mol in terms of element.
1% is preferred. That is, when the amount is less than 0.001 mol%, the effect of addition is too small to increase the specific resistance at room temperature, and when it exceeds 30 mol%, the specific resistance at room temperature becomes 10%.
Since the resistance becomes larger than 0 Ω · cm and the high-temperature B constant decreases, the resistance value in the temperature rising state cannot be sufficiently reduced.

A lanthanum-cobalt-based oxide is represented by the general formula L
When represented by a _x CoO ₃ , x is 0.60 ≦ x ≦ 0.99
Is preferable. This means that x is less than 0.60 or 0.
If it exceeds 99, the B constant at a high temperature becomes 3000K or less, and the resistance value in a heated state cannot be sufficiently reduced.

The semiconductor porcelain element having a negative resistance temperature characteristic according to the present invention is preferably used for preventing inrush current and for delaying motor start-up, but is not limited to these uses.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below based on examples.

(Embodiment 1) In this embodiment, the lanthanum cobalt-based oxide is La _0.94 CoO ₃ .

First, the molar ratio of La to Co is 0.94.
The powders of La ₂ O ₃ and Co ₃ O ₄ were weighed so that
Thereafter, a predetermined amount of the additive elements shown in Tables 1 and 2 was weighed and added to the weighed powder in the form of a compound such as an oxide.
In addition, the amounts of the additional elements in Tables 1 and 2 are the amounts converted into each element.

Next, pure water was added to the obtained powder, wet-mixed in a ball mill using nylon balls for 16 hours, dried, and calcined at 1000 ° C. for 2 hours. After pulverizing the calcined powder, 3 wt% of a vinyl acetate binder is added,
Pure water was added and wet-mixed again in a ball mill using nylon balls for 16 hours. Thereafter, the resultant was dried, granulated, pressure-formed into a disk shape, and fired at 1350 ° C. for 2 hours in the air to obtain a semiconductor porcelain. Thereafter, a platinum paste is screen-printed and applied to both main surfaces of the semiconductor porcelain.
The electrodes were formed by baking in the air at 00 ° C. for 2 hours to obtain a semiconductor ceramic device.

With respect to the thus-obtained semiconductor ceramic element having a negative resistance temperature characteristic, the electrical characteristics of the specific resistance ρ and the B constant were measured. The results are shown in Tables 1 and 2. In Tables 1 and 2, those marked with * are out of the scope of the present invention, and others are within the scope of the present invention.

The specific resistance ρ is a value measured at 25 ° C. The B constant is a constant indicating a resistance change due to a temperature change, and the specific resistance at the temperatures T and T ₀ is ρ
Assuming that (T), ρ (T ₀ ), and natural logarithm are ln, they are defined as follows.

B constant = [lnρ (T ₀ ) −lnρ (T)] / (1 / T ₀ −1 / T) As the value of the B constant increases, the resistance change due to temperature increases. Based on this equation, the B constant (−10 ° C.) and the B constant (140 ° C.) obtained this time are respectively defined as follows.

B (−10 ° C.) = [Lnρ (−10 ° C.) − Lnρ (25 ° C.)] / [1 /
(-10 + 273.15) −1 / (25 + 273.15)] B (140 ° C) = [lnρ (140 ° C) −lnρ (25 ° C)] / [1 / (140 + 273.15)
−1 / (25 + 273.15)] The smaller the B constant (−10 ° C.), the smaller the variation in resistance change due to outside air temperature, and the smaller the resistance rise in low-temperature environments. It is possible to suppress a delay in starting up the device.

Further, the larger the B constant (140 ° C.), the smaller the power consumption in the temperature rising state, so that it is excellent as an initial rush current suppressing element such as a circuit in which a large current flows or a switching power supply.

[0033]

[Table 1]

[0034]

[Table 2]

As is clear from Tables 1 and 2, at least one oxide of the elements Fe and Al was added to La _0.94 CoO _{3 as the} main component and Si, Zr, Hf,
By containing at least one oxide among the elements of Ta, Sn, Sb, W, Mo, Te and Ce,-
It is possible to obtain a semiconductor ceramic composition having a negative resistance temperature characteristic in which the specific resistance ρ at room temperature is changed while suppressing the fluctuation of the B constant at 10 ° C. and 140 ° C.

In addition, the content of at least one oxide of the elements of Fe and Al is equal to 0.
001 to 30 mol%, Si, Zr, Hf, T
When the content of at least one oxide of the elements a, Sn, Sb, W, Mo, Te and Ce is 0.001 to 10 mol% in total in terms of the element, B (−10
C) is 1820-2850K and B (140C) is 4
120-4730 K, and ρ (25 ° C.) is 15.4
A value of about 99.4 Ω · cm is preferable.

The total content of at least one element of Fe and Al is 0.1 to 10 mol%, and Si, Zr, Hf, Ta, Sn, Sb, W, Mo,
When the total content of at least one element of Te and Ce is 0.1 to 5 mol%, B (-1
0 ° C) is 1970 to 2810K, B (140 ° C) is 4310 to 4730K, and ρ (25 ° C) is 18.
A value of 9 to 50.3 Ω · cm is obtained, and a semiconductor ceramic composition is obtained in which the change in the specific resistance ρ is narrowed but the change in the B constant is further suppressed.

In the above embodiment, the case where the lanthanum cobalt-based oxide is La _0.94 CoO ₃ has been described, but the general formula La _x CoO ₃ (where 0.60 ≦ x ≦ 0.
The same effect can be obtained for the composition in the range represented by 99).

In the above embodiment, Si, Zr,
Similar effects can be obtained by using Nb, Mn, Th or P instead of Hf, Ta, Sn, Sb, W, Mo, Te, and Ce.

(Embodiment 2) In this embodiment, the lanthanum cobalt-based oxide is La _0.85 Pr _0.09 CoO ₃ .

First, La ₂ O ₃ , P ₂ were added such that the molar ratios of La and Pr to Co were 0.85 and 0.09, respectively.
The r ₆ O ₁₁ and Co ₃ O ₄ powders were weighed. Thereafter, a predetermined amount of an additive element shown in Table 3 was weighed and added to the weighed powder in the form of a compound such as an oxide. In addition, the amount of the additional element in Table 3 is the amount converted into each element.

Next, pure water was added to the obtained powder, wet-mixed in a ball mill using nylon balls for 16 hours, dried, and calcined at 1000 ° C. for 2 hours. The calcined powder was treated in the same manner as in Example 1 to obtain a semiconductor porcelain element having a negative resistance temperature characteristic.

With respect to the semiconductor ceramic device thus obtained, the specific resistance ρ and the B constant were determined in the same manner as in Example 1. Table 3 shows the results.

[0044]

[Table 3]

As is clear from Table 3, when the lanthanum cobalt-based oxide is La _0.85 Pr _0.09 CoO ₃ , similarly to the case of La _0.94 CoO ₃ shown in Example 1, −10 is used.
It is possible to obtain a semiconductor ceramic composition having a negative resistance temperature characteristic in which the specific resistance ρ at room temperature is changed while suppressing the fluctuations of the B constant at 140 ° C. and 140 ° C.

(Embodiment 3) In this embodiment, the lanthanum cobalt-based oxide is La _0.85 Nd _0.09 CoO ₃ .

First, La ₂ O ₃ and N ₂ were mixed such that the molar ratios of La and Nd to Co were 0.85 and 0.09, respectively.
The d ₂ O ₃ and Co ₃ O ₄ powders were weighed. Thereafter, a predetermined amount of an additive element shown in Table 4 was weighed and added to the weighed powder in the form of a compound such as an oxide. In addition, the amount of the additional element in Table 4 is the amount converted into each element.

Next, pure water was added to the obtained powder, wet-mixed in a ball mill using nylon balls for 16 hours, dried, and calcined at 1000 ° C. for 2 hours. The calcined powder was treated in the same manner as in Example 1 to obtain a semiconductor porcelain element having a negative resistance temperature characteristic.

With respect to the semiconductor ceramic device thus obtained, the specific resistance ρ and the B constant were obtained in the same manner as in Example 1. Table 4 shows the results.

[0050]

[Table 4]

As is clear from Table 4, when the lanthanum-cobalt-based oxide is La _0.85 Nd _0.09 CoO ₃ , similarly to the case of La _0.94 CoO ₃ shown in Example 1, it is −10.
It is possible to obtain a semiconductor ceramic composition having a negative resistance temperature characteristic in which the specific resistance ρ at room temperature is changed while suppressing the fluctuations of the B constant at 140 ° C. and 140 ° C.

(Embodiment 4) In this embodiment, the lanthanum cobalt-based oxide is La _0.85 Sm _0.09 CoO ₃ .

First, La ₂ O ₃ and S ₂ are so adjusted that the molar ratios of La and Sm to Co are 0.85 and 0.09, respectively.
The powders of m ₂ O ₃ and Co ₃ O ₄ were weighed. Thereafter, predetermined amounts of the additional elements shown in Table 5 in the form of compounds such as oxides were weighed and added to the weighed powder. In addition, the amount of the additional element in Table 5 is the amount converted into each element.

Next, pure water was added to the obtained powder, wet-mixed in a ball mill using nylon balls for 16 hours, dried, and calcined at 1000 ° C. for 2 hours. The calcined powder was treated in the same manner as in Example 1 to obtain a semiconductor porcelain element having a negative resistance temperature characteristic.

With respect to the semiconductor ceramic device thus obtained, the specific resistance ρ and the B constant were determined in the same manner as in Example 1. Table 5 shows the results.

[0056]

[Table 5]

As is clear from Table 5, when the lanthanum-cobalt-based oxide is La _0.85 Sm _0.09 CoO ₃ , similarly to the case of La _0.94 CoO ₃ shown in Example 1, it is −10.
It is possible to obtain a semiconductor ceramic composition having a negative resistance temperature characteristic in which the specific resistance ρ at room temperature is changed while suppressing the fluctuations of the B constant at 140 ° C. and 140 ° C.

In Examples 1-4, the lanthanum cobalt-based oxide was La _0.94 CoO ₃ , La _0.85 Pr _0.09
CoO ₃ , La _0.85 Nd _0.09 CoO ₃ and La _0.85 Sm
_Although the case of _0.09 CoO ₃ has been described, the present invention is not limited to this. The replacement amount of La is 0.0
The same effect can be obtained also in the case of a lanthanum cobalt-based oxide in which La is partially substituted with Eu, Y, or the like, without being limited to 9.

[0059]

As is apparent from the above description, the main component consisting of a lanthanum-cobalt-based oxide and the secondary component Fe
And at least one oxide of the elements Al and Si,
Zr, Hf, Ta, Sn, Sb, W, Mo, Te, C
at least one of the elements e, Nb, Mn, Th and P
By containing the seed oxide, a semiconductor ceramic composition having a negative resistance-temperature characteristic having an arbitrary room temperature specific resistance of about 10 Ω · cm to 100 Ω · cm is obtained while keeping the B constant constant. be able to.

Therefore, by using this semiconductor ceramic composition, a semiconductor ceramic element (NTC thermistor element) having a negative resistance temperature characteristic capable of coping with a circuit having a large inrush current or a circuit requiring high current suppression is manufactured. be able to.

That is, the obtained semiconductor porcelain element is used not only for preventing inrush current of the switching power supply, but also at the beginning of voltage application, such as a general circuit for starting a motor, protection of a drum of a laser printer, protection of a halogen lamp, and a bulb. As an element for preventing inrush current of equipment where excessive current flows,
It can be used widely.

[0062]

──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Yukio Sakabe 2-26-10 Tenjin, Nagaokakyo-shi, Kyoto, Japan Examiner, Murata Manufacturing Co., Ltd. Tatsuo Takeshige (56) References JP-A-9-208310 (JP, A JP-A-7-37706 (JP, A) JP-A-7-37705 (JP, A) JP-A-1-290549 (JP, A) JP-A-55-71667 (JP, A) 265803 (JP, A) JP-A-7-176406 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C04B 35/495 C04B 35/50 CA (STN) REGISTRY (STN)

Claims (11)

(57) [Claims] 1. A main component comprising a lanthanum-cobalt-based oxide, at least one oxide of Fe and Al as sub-components, and Si, Zr, Hf, Ta, Sn, S
A semiconductor ceramic composition having negative resistance temperature characteristics, characterized by containing at least one oxide among the elements b, W, Mo, Te, Ce, Nb, Mn, Th and P. 2. The content of at least one oxide of the Fe and Al elements is 0.001 to 30 mol% in total in terms of the elements, and the Si, Zr, H
f, Ta, Sn, Sb, W, Mo, Te, Ce, Nb,
The content of at least one oxide of the elements of Mn, Th and P is 0.001 to 1 in total in terms of the above elements.
The semiconductor ceramic composition having a negative resistance temperature characteristic according to claim 1, wherein the composition is 0 mol%. 3. The content of at least one oxide of the Fe and Al elements is 0.1 to 10 mol% in total in terms of the elements, and the Si, Zr, Hf,
Ta, Sn, Sb, W, Mo, Te, Ce, Nb, M
The content of at least one oxide of the elements n, Th and P is 0.1 to 5 mol in total in terms of the above elements.
%. The semiconductor ceramic composition having a negative resistance temperature characteristic according to claim 1. 4. The lanthanum cobalt-based oxide is La
_The semiconductor ceramic composition having a negative resistance temperature characteristic according to claim 1, wherein _x CoO ₃ (where 0.60 ≦ x ≦ 0.99). 5. 5. A method according to claim 5, wherein a part of La in said La _x CoO ₃ is Pr,
The semiconductor ceramic composition having a negative resistance temperature characteristic according to claim 4, wherein the semiconductor ceramic composition is substituted with any one of Nd and Sm. 6. A semiconductor porcelain device comprising a semiconductor porcelain having a negative resistance temperature characteristic and an electrode formed on said semiconductor porcelain, wherein said semiconductor porcelain is composed mainly of a lanthanum-cobalt-based oxide and as a sub-component. At least one oxide of the elements Fe and Al, and Si, Zr, Hf, T
a, Sn, Sb, W, Mo, Te, Ce, Nb, Mn,
A semiconductor porcelain element comprising at least one oxide of Th and P elements. 7. The content of at least one oxide of the Fe and Al elements is 0.001 to 30 mol% in total in terms of the elements, and the Si, Zr, H
f, Ta, Sn, Sb, W, Mo, Te, Ce, Nb,
The content of at least one oxide of the elements of Mn, Th and P is 0.001 to 1 in total in terms of the above elements.
The semiconductor ceramic device according to claim 6, wherein the content is 0 mol%. 8. The content of at least one oxide of the Fe and Al elements is 0.1 to 10 mol% in total in terms of the elements, and the Si, Zr, Hf,
Ta, Sn, Sb, W, Mo, Te, Ce, Nb, M
The content of at least one oxide of the elements n, Th and P is 0.1 to 5 mol in total in terms of the above elements.
%. The semiconductor porcelain element according to claim 6, wherein 9. The lanthanum cobalt-based oxide is La
The semiconductor ceramic device according to claim 6, wherein _x CoO ₃ (where 0.60 ≦ x ≦ 0.99). 10. A part of La of the La _x CoO ₃ is P
The semiconductor ceramic device according to claim 9, wherein the semiconductor ceramic device is substituted with any one of r, Nd, and Sm. 11. The semiconductor porcelain element according to claim 6, wherein said semiconductor porcelain element is for preventing inrush current or delaying motor start.