JPH07176406A - Negative resistance temp. coefficient semiconductor ceramics, rush current-blocking element and motor start delaying element - Google Patents

Abstract

PURPOSE:To provide a semiconductor ceramics having a negative resistance temp. coefficient, low specific resistance and high B constant, allowing a large current to flow in a steady state. CONSTITUTION:A semiconductor ceramics having a negative resistance temp. coefficient is composed by adding, at least, one of Si, Zr, Hf, Ta, Sn, Sb, W, Mo, Te and Ce 0.001-10mol% to a compound contg. a rare earth transition element type oxide (excluding Ce from the rare earth elements but Y) as a main components. This oxide adopts a LaCo oxide.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor porcelain having a negative resistance temperature characteristic, an element for preventing inrush current and an element for delaying motor start-up, which are made of the semiconductor porcelain. In addition, the present invention relates to a composition having a large B constant and capable of passing a large current.

[0002]

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

For example, in a switching power supply, since an overcurrent flows at the moment the switch is turned on, the NTC element is used as an element for absorbing this initial inrush current. As described above, this NTC element has a high resistance value at room temperature and has a function of decreasing the resistance value as the temperature rises. Therefore, when the switch is turned on, the initial inrush current is suppressed, and then self-heating occurs. As a result, the temperature rises to a low resistance, and the power consumption decreases in the steady state.

Further, for example, in a gear device constructed so that the supply of the lubricating oil is started only after the motor is started,
If the drive motor immediately rotates the gear device at a high speed, the supply of the lubricating oil may be insufficient and the gear may be damaged. Further, in a lapping machine used when a grindstone is rotated to polish a porcelain surface, the porcelain may be broken when the drive motor is rotated at a high speed at the moment of starting. In order to avoid such a problem, it is necessary to delay the activation of the drive motor for a certain period of time, and the NTC element is used as an element that delays the activation of the motor. With this NTC element, the motor terminal voltage is lowered at the time of startup, so that the startup of the motor can be delayed. Then, as described above, after that, the temperature rises due to self-heating and the resistance becomes low, and in a steady state, the motor normally rotates.

[0005]

By the way, the above NTC
When the element is used as an element for preventing inrush current and an element for delaying motor start-up, the resistance value must be small in a temperature rising state due to self-heating. However, the NT using the transition metal oxide having the above conventional spinel structure is used.
The C element has a problem that the resistance decrease rate (B constant) due to temperature rise cannot be set to 3200K or more. Therefore, the resistance value of the NTC element in the high temperature state cannot be sufficiently reduced, and the power consumption in the steady state must be increased. In order to sufficiently reduce the resistance value in a high temperature state, for example, when the NTC element has a disc shape, its diameter may be increased or the wall thickness may be reduced. However, such a countermeasure goes against the demand for miniaturization of electronic components, and there is a limit in thinning the strength. In order to improve this point, there is a laminated NTC element in which an internal electrode is interposed between ceramic layers to form a laminated body, and an external electrode to which the internal electrodes are alternately electrically connected is formed on a side surface of the laminated body. . However, this laminated NT
In the C element, the electrodes may be too close to each other and may be destroyed by an initial overcurrent (several A or more).

On the other hand, the inventors of the present invention have made extensive studies on a material exhibiting a negative resistance temperature characteristic, and have paid attention to an oxide composed of a rare earth element system. This rare earth transition element-based oxide has the characteristics that the B constant increases and the resistance value decreases as the temperature rises. This characteristic is
G. Bhide and D. S. Reference by Rajoria (Phys. Rev.
B6 [3] 1021 (1972)) and the like.

However, the above-mentioned rare earth transition element-based oxide has a low resistance value at high temperature as compared with the conventional transition metal oxide having a spinel type structure, but has a small B constant, and a practical value cannot be obtained. There are cases.

The present invention has been made to solve the above-mentioned problems, and in a steady state, a semiconductor having a low specific resistance, a large B constant, and a negative resistance-temperature characteristic capable of flowing a large current. It is an object of the present invention to provide an element for preventing inrush current and an element for delaying motor startup, which is made of a porcelain and a semiconductor porcelain.

[0009]

Therefore, the invention of claim 1 provides a rare earth transition element-based oxide (provided that among rare earth elements, Ce
Except Y, including Y) as the main component, and Si, Zr,
A semiconductor porcelain having a negative resistance-temperature resistance characteristic, characterized in that at least one of Hf, Ta, Sn, Sb, W, Mo, Te, and Ce is added.

According to the invention of claim 2, the additive is 0.00
It is characterized in that it is 1 to 10 mol%. According to the invention of claim 3, the rare earth transition element-based oxide is LaCo.
It is characterized by being a system oxide.

A fourth aspect of the present invention is an inrush current preventing element comprising a rare earth transition element-based oxide and a semiconductor porcelain having a negative resistance temperature characteristic, and a fifth aspect of the invention comprises the semiconductor porcelain. The feature is that it is an element for delaying motor startup.

Here, the rare earth transition element oxide is
LaCoO ₃ system, SmNiO ₃ , or NdCoO ₃
A system or the like can be adopted and is not particularly limited. Among them, when LaCoO ₃ system is adopted, B due to temperature rise
Practical characteristics such as a large increase in the constant and a sufficiently small specific resistance at high temperature can be obtained. Among the above rare earth elements, Ce was excluded because it is difficult to obtain an oxide with a transition metal. Further, Y is included in the group of rare earth elements in the present invention because it has characteristics and effects similar to those of rare earth elements.

In addition, the above rare earth transition element oxide may contain Si,
Zr, Hf, Ta, Sn, Sb, W, Mo, Te, Ce
By adding 0.001 mol% or more, the B constant can be increased while keeping the specific resistance at high temperature low, and a practical value can be obtained. In this case, the addition amount is 10mo
If it exceeds l%, the B constant at high temperature becomes smaller than that of the conventional one. Therefore, the addition amount is preferably in the range of 0.001 to 10 mol%.

Further, the molar ratio of the rare earth element to the transition element is not limited to 1: 1 and may be changed. In this case, when the molar ratio is changed in the range of 0.6 to 1.1, a B constant similar to 1: 1 can be obtained, but the molar ratio becomes less than 0.6 or 1.1. If it exceeds the limit, the resistance value in the temperature rising state does not become small, so the power consumption in the steady state increases, and it may not be usable in a circuit in which a large current flows.

[0015]

According to the semiconductor porcelain having the negative resistance-temperature characteristic according to the present invention, since the above-mentioned subcomponents are added to the rare earth transition element-based oxide, the specific resistance at room temperature while keeping the resistance value at high temperature low. Can be increased, so that an NTC element having a large B constant can be obtained. Therefore,
Even when the NTC element is downsized, the resistance value in the temperature rising state can be made sufficiently small, the power consumption in the steady state can be reduced, and it can be applied to a circuit in which a large current flows. Therefore, by adopting the semiconductor porcelain having the above characteristics as an inrush current prevention element, it can be applied to a device such as a switching power supply through which a large current flows. Further, by adopting the above-mentioned semiconductor porcelain as an element for delaying motor activation, it is possible to deal with a drive motor in which a large current flows.

[0016]

EXAMPLES Examples of the present invention will be described below.

Example 1 In this example, LaCoO was used as a rare earth transition oxide.
_In this example, ₃ is adopted and Zr is added to this.

First, the molar ratio of La to Co is 0.
Each powder of Co ₃ O ₄ and La ₂ O ₃ was weighed so as to be 95.

[0019]

[Table 1]

As shown in Table 1, the weighed powder was
Zr was added in an amount of 0 to 20 mol% and wet-mixed for 16 hours in a ball mill using nylon balls. Then, it was dehydrated, dried, and calcined at 1000 ° C. for 2 hours. The calcined powder was pulverized with a jet mill, a binder was added to the powder, the mixture was wet-mixed again with a ball mill using nylon balls for 5 hours, filtered, dried, and then pressure-molded into a disc shape. The molded body was fired in air at 1400 ° C. for 2 hours to obtain a sintered body. Next, platinum paste was screen-printed on both main surfaces of this sintered body and then baked at 1000 ° C. for 2 hours to form electrodes. This produced each sample of this example.

Each sample thus obtained (Sample No.
Regarding 1-1 to 1-8), the electrical properties of the specific resistance (ρ) and the B constant were measured. In Table 1, the mark * is outside the scope of the claims of the present application. Here, the specific resistance (ρ) is 2
It is a value measured at 5 ° C. Further, the B constant is expressed as B (T) = [Inρ (T ₀ ) −Inρ (T)] / (1 / T ₀ −1 / T) where T is temperature, ρ is specific resistance, and In is natural logarithm. It is a constant that is defined and indicates the resistance change with temperature.
The larger this value, the larger the resistance change with temperature. In the table, the B constant (-10 ° C) and the B constant (140 ° C) are defined as follows. B constant (-10 ° C) = [Inρ (-10 ° C) -Inρ (25
℃)] / [1 / (-10 + 273.15) -1 / (25 +273.5)] B constant (140 ℃) = [Inρ (25 ℃) -Inρ (140
℃)] / [1 / (25 + 273.15) -1 / (140 + 273.5)]

As is clear from Table 1, the main component La
By adding Zr to CoO ₃ in the range of 0.001 to 10 mol%, the specific resistance is 11.1 to 19.8 Ω · c.
As low as m, B constant at -10 ° C is 1220-2620K
It can be seen that the B constant at 140 ° C. is 3020 to 4730K, which is a satisfactory value.

FIG. 1 and FIG. 2 show the results of repeated current-carrying tests of the samples of this example. This test uses a Zr content of 1
A sample (see No. 1-6 in Table 1) having mol% was used. FIG. 1 shows the results of measuring the time change of the switching power supply current when the power supply was turned on by serially connecting the above sample to the switching power supply at 25 ° C. FIG. 2 shows the relationship between the number of repeated energization tests and the resistance value at 25 ° C. In this repeated energization test, one cycle was a step of energizing the sample for 1 minute, then turning off the power for 30 minutes and cooling to 25 ° C.

As is clear from each figure, once to 10 times
No change in properties was observed even after 000 times.
In addition, 100 samples were continuously energized at 20 A for 100 hours to carry out a practical test, but it was confirmed that none of the samples was destroyed and that it could be applied to a large current.

Example 2 This example is the same as Example 1 except that the rare earth transition oxide is used.
The same LaCoO ₃ is adopted, and as shown in Table 2, Si, Mo, Sn, Sb, Te, Hf, Ta, W,
Ce was added in a predetermined amount. Also as shown in Table 3, in the _{LaCoO 3, Zr-Mo, Zr} -Sn, Z
A predetermined amount of each of r-Sn-W and Zr-Mo-Ce was added. Then, each sample of this example was prepared by the same manufacturing method as in Example 1 above, and the electrical properties of the specific resistance (ρ) and B constant of each sample were measured.

[0026]

[Table 2]

[0027]

[Table 3]

As is clear from Tables 2 and 3, in any of the samples (Sample Nos. 1-9 to 1-21), the specific resistance was as low as 16.2 to 20.5 Ω · cm and -10. B of ℃
The constant is 1820 to 2630K, and the B constant at 140 ° C is 4
A satisfactory value of 290 to 4680K is obtained.

Example 3 In this example, LaCrO ₃ was used as a rare earth transition oxide, and the molar ratio of La to Cr was 0.95.
The powders of La ₃ O ₃ and Cr ₂ O ₃ were weighed so that As shown in Table 4, Zr,
Mo, Sb, Hf, Ta, Ce, and Sb-Hf, Zr
-Ta, Sn-Ce, and Si-Mo-W were added in predetermined amounts. Then, each sample of this example was prepared by the same manufacturing method as in Example 1 above, and the electrical properties of the specific resistance (ρ) and B constant of each sample were measured.

[0030]

[Table 4]

As is clear from Table 4, in any of the samples (Sample Nos. 2-1 to 2-10), the specific resistance is 1
It is as low as 6.1 to 20.0 Ω · cm, the B constant at −10 ° C. is 2420 to 2710 K, and the B constant at 140 ° C. is 3870.
A satisfactory value of 4320K is obtained.

Example 4 In this example, SmNiO ₃ was used as a rare earth transition oxide, and the molar ratio of Sm to Ni was 0.95.
Each powder of Sm ₂ O ₃ and NiO was weighed so that As shown in Table 5, Zr, M
o, Sb, Hf, Ta, W and Sb-Ce, Zr-T
A predetermined amount of each of a, Sn-W, and Si-Mo-W was added. Then, each sample of this example was prepared by the same manufacturing method as in Example 1 above, and the electrical properties of the specific resistance (ρ) and B constant of each sample were measured.

[0033]

[Table 5]

As is clear from Table 5, in any of the samples (Sample Nos. 3-1 to 3-10), the specific resistance is 1
It is as low as 2.0 to 15.0 Ω · cm, the B constant at −10 ° C. is 2060 to 2410 K, and the B constant at 140 ° C. is 3620.
A satisfactory value of ~ 3990K is obtained.

Example 5 In this example, NdNiO ₃ was used as the rare earth transition oxide, and the molar ratio of Nd to Ni was 0.95.
Each powder of Nd ₂ O ₃ and NiO was weighed so that As shown in Table 6, Si, Z was added to the weighed powder.
r, Mo, Sn, Sb, Ce and Si-Sn, Zr-
Each of W, Mo-Ta, and Zr-Sn-Ta was added in a predetermined amount. Then, each sample of this example was prepared by the same manufacturing method as in Example 1, and the specific resistance (ρ) and B of each sample were
Each constant electrical property was measured.

[0036]

[Table 6]

As is clear from Table 6, in any of the samples (Sample Nos. 4-1 to 4-10), the specific resistance was 2
It is as low as 2.6 to 25.9 Ω · cm, the B constant at -10 ° C is 1970 to 2240K, and the B constant at 140 ° C is 3710.
A satisfactory value of ~ 3930K is obtained.

Example 6 In this example, PrNiO ₃ was used as a rare earth transition oxide, and the molar ratio of Pr to Ni was 0.95.
Each powder of Pr ₆ O ₁₁ and NiO was weighed so that As shown in Table 7, Zr, M
o, Sb, Te, Ta, W and Zr-Hf, Zr-W,
Mo-Sb and Sb-Hf-W were added in predetermined amounts. Then, each sample of this example was prepared by the same manufacturing method as in Example 1 above, and the electrical properties of the specific resistance (ρ) and B constant of each sample were measured.

[0039]

[Table 7]

As is clear from Table 7, in any of the samples (Sample Nos. 5-1 to 5-10), the specific resistance was as low as 8.9 to 12.0 Ω · cm, and the B of -10 ° C was obtained. The constant is 1960 to 2210K, and the B constant at 140 ° C is 3590.
A satisfactory value of up to 3820K is obtained.

Example 7 In this example, La was used as a rare earth transition oxide._0.9Nd
_0.1CoO₃And the La_0.9Nd_0.1CoO₃Half
La so that conductor porcelain can be obtained₂O₃, Nd₂O ₃as well as
Co₃O_FourEach powder was weighed. To this weighed powder,
As shown in Table 8, Zr, Sb, W and Si-Hf, Z
A predetermined amount of each of r-Mo-Ta was added. And above
Each sample of this example was prepared by the same manufacturing method as in Example 1.
The electrical resistance of each sample (ρ) and B constant
It was measured.

[0042]

[Table 8]

As is clear from Table 8, in any of the samples (Sample Nos. 6-1 to 6-5), the specific resistance was 2
Low as 4.0-26.4 Ω · cm, B constant at -10 ° C is 1720-1910K, and B constant at 140 ° C is 3540.
A satisfactory value of ˜3690K is obtained.

Example 8 In this example, La is used as a rare earth transition oxide._0.9Gd
_0.1CoO₃And the La_0.9Gd_0.1CoO₃Half
La so that conductor porcelain can be obtained₂O₃, Gd₂O ₃as well as
Co₃O_FourEach powder was weighed. To this weighed powder,
As shown in Table 9, Sn, Ta, Ce and Zr-Mo,
Zr-Te-Hf was added in a predetermined amount. And above
Each sample of this example was manufactured by the same manufacturing method as in Example 1.
Electrical characteristics of resistivity (ρ) and B constant of each sample created
Was measured.

[0045]

[Table 9]

As is apparent from Table 9, in any of the samples (Sample Nos. 7-1 to 7-5), the specific resistance was 2
Low as 1.9 to 23.7 Ω · cm, B constant at −10 ° C. is 1840 to 2020K, and B constant at 140 ° C. is 3650.
A satisfactory value of ~ 3860K is obtained.

Example 9 In this example, La _0.99 Y _0.01 was used as a rare earth transition oxide.
MnO ₃ was adopted, and each powder of La ₂ O ₃ , Y ₂ O ₃ and MnO was weighed so that the La _0.99 Y _0.01 MnO ₃ semiconductor ceramic was obtained. As shown in Table 10, Sn, Mo, W and Sb-Ta, Zr-Sb- were added to the weighed powder.
A predetermined amount of Mo was added to each. Then, each sample of this example was prepared by the same manufacturing method as in Example 1 above, and the electrical properties of the specific resistance (ρ) and B constant of each sample were measured.

[0048]

[Table 10]

As is clear from Table 10, in any of the samples (Sample Nos. 8-1 to 8-5), the specific resistance was 1
Low as 9.7 to 21.5 Ω · cm, B constant at -10 ° C is 2190 to 2290K, and B constant at 140 ° C is 3820.
A satisfactory value of -3970K is obtained.

In each of the above Examples 1 to 9, LaCo is used.
O ₃ system, LaCrO ₃ system, SmNiO ₃ system, NdNiO
_{The 3} type and PrNiO ₃ type oxides have been explained.
The present invention is not limited to this, and similar effects can be obtained with other rare earth transition oxides.

[0051]

As described above, according to the semiconductor porcelain having the negative resistance temperature characteristic, the inrush current preventing element including the porcelain, and the motor starting delay element including the same according to the present invention, rare earth element transition element-based oxidation is achieved. For objects, Si, Zr, H
Since at least one of f, Ta, Sn, Sb, W, Mo, Te, and Ce is added, it is possible to reduce the specific resistance near room temperature and obtain a device having a large B constant at high temperature. be able to. Therefore, the resistance value in the temperature rising state can be made sufficiently small, the power consumption in the steady state can be reduced, and the effect can be applied to a circuit in which a large current flows.

[Brief description of drawings]

FIG. 1 is a characteristic diagram showing a result of measuring a time change of a switching power supply current when a power supply is turned on by connecting an NTC element in series to a switching power supply at 25 ° C.

FIG. 2 is a characteristic diagram showing the relationship between the number of repeated normal tests and the resistance value at 25 ° C.

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] February 4, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] Full text

[Correction method] Change

[Correction content]

[Document name] Statement

Title: Semiconductor porcelain having negative resistance temperature characteristics, inrush current prevention element formed of the same, and motor start delay element formed of the same

[Claims]

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor porcelain having a negative resistance temperature characteristic, an element for preventing inrush current and an element for delaying motor start-up, which are made of the semiconductor porcelain. In addition, the present invention relates to a composition having a large B constant and capable of passing a large current.

[0002]

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

For example, in a switching power supply, since an overcurrent flows at the moment the switch is turned on, the NTC element is used as an element for absorbing this initial inrush current. As described above, this NTC element has a high resistance value at room temperature and has a function of decreasing the resistance value as the temperature rises. Therefore, when the switch is turned on, the initial inrush current is suppressed, and then self-heating occurs. As a result, the temperature rises to a low resistance, and the power consumption decreases in the steady state.

Further, for example, in a gear device constructed so that the supply of the lubricating oil is started only after the motor is started,
If the drive motor immediately rotates the gear device at a high speed, the supply of the lubricating oil may be insufficient and the gear may be damaged. Further, in a lapping machine used when a grindstone is rotated to polish a porcelain surface, the porcelain may be broken when the drive motor is rotated at a high speed at the moment of starting. In order to avoid such a problem, it is necessary to delay the activation of the drive motor for a certain period of time, and the NTC element is used as an element that delays the activation of the motor. With this NTC element, the motor terminal voltage is lowered at the time of startup, so that the startup of the motor can be delayed. Then, as described above, after that, the temperature rises due to self-heating and the resistance becomes low, and in a steady state, the motor normally rotates.

[0005]

By the way, the above NTC
When the element is used as an element for preventing inrush current and an element for delaying motor start-up, the resistance value must be small in a temperature rising state due to self-heating. However, the NT using the transition metal oxide having the above conventional spinel structure is used.
The C element has a problem that the resistance decrease rate (B constant) due to temperature rise cannot be set to 3200K or more. Therefore, the resistance value of the NTC element in the high temperature state cannot be sufficiently reduced, and the power consumption in the steady state must be increased. In order to sufficiently reduce the resistance value in a high temperature state, for example, when the NTC element has a disc shape, its diameter may be increased or the wall thickness may be reduced. However, such a countermeasure goes against the demand for miniaturization of electronic components, and there is a limit in thinning the strength. In order to improve this point, there is a laminated NTC element in which an internal electrode is interposed between ceramic layers to form a laminated body, and an external electrode to which the internal electrodes are alternately electrically connected is formed on a side surface of the laminated body. . However, this laminated NT
In the C element, the electrodes may be too close to each other and may be destroyed by an initial overcurrent (several A or more).

On the other hand, the inventors of the present invention have made extensive studies on a material exhibiting a negative resistance temperature characteristic, and have paid attention to an oxide composed of a rare earth element system. This rare earth transition element-based oxide has the characteristics that the B constant increases and the resistance value decreases as the temperature rises. This characteristic is
G. Bhide and D. S. Reference by Rajoria (Phys. Rev.
B6 [3] 1021 (1972)) and the like.

However, the above-mentioned rare earth transition element-based oxide has a low resistance value at high temperature as compared with the conventional transition metal oxide having a spinel type structure, but has a small B constant, and a practical value cannot be obtained. There are cases.

The present invention has been made to solve the above-mentioned problems, and in a steady state, a semiconductor having a low specific resistance, a large B constant, and a negative resistance-temperature characteristic capable of flowing a large current. It is an object of the present invention to provide an element for preventing inrush current and an element for delaying motor startup, which is made of a porcelain and a semiconductor porcelain.

[0009]

Therefore, the invention of claim 1 provides a rare earth transition element-based oxide (provided that among rare earth elements, Ce
Except Y, including Y) as the main component, and Si, Zr,
A semiconductor porcelain having a negative resistance-temperature resistance characteristic, characterized in that at least one of Hf, Ta, Sn, Sb, W, Mo, Te, and Ce is added.

According to the invention of claim 2, the additive is 0.00
It is characterized in that it is 1 to 10 mol%. According to the invention of claim 3, the rare earth transition element-based oxide is LaCo.
It is characterized by being a system oxide.

A fourth aspect of the present invention is an inrush current preventing element comprising a rare earth transition element-based oxide and a semiconductor porcelain having a negative resistance temperature characteristic, and a fifth aspect of the invention comprises the semiconductor porcelain. The feature is that it is an element for delaying motor startup.

Here, the rare earth transition element oxide is
LaCoO ₃ system, SmNiO ₃ , or NdCoO ₃
A system or the like can be adopted and is not particularly limited. Among them, when LaCoO ₃ system is adopted, B due to temperature rise
Practical characteristics such as a large increase in the constant and a sufficiently small specific resistance at high temperature can be obtained. Among the above rare earth elements, Ce was excluded because it is difficult to obtain an oxide with a transition metal. Further, Y is included in the group of rare earth elements in the present invention because it has characteristics and effects similar to those of rare earth elements.

In addition, the above rare earth transition element oxide may contain Si,
Zr, Hf, Ta, Sn, Sb, W, Mo, Te, Ce
By adding 0.001 mol% or more, the B constant can be increased while keeping the specific resistance at high temperature low, and a practical value can be obtained. In this case, the addition amount is 10mo
If it exceeds l%, the B constant at high temperature becomes smaller than that of the conventional one. Therefore, the addition amount is preferably in the range of 0.001 to 10 mol%.

Further, the molar ratio of the rare earth element to the transition element is not limited to 1: 1 and may be changed. In this case, when the molar ratio is changed in the range of 0.6 to 1.1, a B constant similar to 1: 1 can be obtained, but the molar ratio becomes less than 0.6 or 1.1. If it exceeds the limit, the resistance value in the temperature rising state does not become small, so the power consumption in the steady state increases, and it may not be usable in a circuit in which a large current flows.

[0015]

According to the semiconductor porcelain having the negative resistance-temperature characteristic according to the present invention, since the above-mentioned subcomponents are added to the rare earth transition element-based oxide, the specific resistance at room temperature while keeping the resistance value at high temperature low. Can be increased, so that an NTC element having a large B constant can be obtained. Therefore,
Even when the NTC element is downsized, the resistance value in the temperature rising state can be made sufficiently small, the power consumption in the steady state can be reduced, and it can be applied to a circuit in which a large current flows. Therefore, by adopting the semiconductor porcelain having the above characteristics as an inrush current prevention element, it can be applied to a device such as a switching power supply through which a large current flows. Further, by adopting the above-mentioned semiconductor porcelain as an element for delaying motor activation, it is possible to deal with a drive motor in which a large current flows.

[0016]

EXAMPLES Examples of the present invention will be described below.

Example 1 In this example, LaCoO was used as a rare earth transition oxide.
_In this example, ₃ is adopted and Zr is added to this.

First, the molar ratio of La to Co is 0.
Each powder of Co ₃ O ₄ and La ₂ O ₃ was weighed so as to be 95.

[0019]

[Table 1]

As shown in Table 1, the weighed powder was
Zr was added in an amount of 0 to 20 mol% and wet-mixed for 16 hours in a ball mill using nylon balls. Then, it was dehydrated, dried, and calcined at 1000 ° C. for 2 hours. The calcined powder was pulverized with a jet mill, a binder was added to the powder, the mixture was wet-mixed again with a ball mill using nylon balls for 5 hours, filtered, dried, and then pressure-molded into a disc shape. The molded body was fired in air at 1400 ° C. for 2 hours to obtain a sintered body. Next, platinum paste was screen-printed on both main surfaces of this sintered body and then baked at 1000 ° C. for 2 hours to form electrodes. This produced each sample of this example.

Each sample thus obtained (Sample No.
Regarding 1-1 to 1-8), the electrical properties of the specific resistance (ρ) and the B constant were measured. In Table 1, the mark * is outside the scope of the claims of the present application. Here, the specific resistance (ρ) is 2
It is a value measured at 5 ° C. Further, the B constant is expressed as B (T) = [Inρ (T ₀ ) −Inρ (T)] / (1 / T ₀ −1 / T) where T is temperature, ρ is specific resistance, and In is natural logarithm. It is a constant that is defined and indicates the resistance change with temperature.
The larger this value, the larger the resistance change with temperature. In the table, the B constant (-10 ° C) and the B constant (140 ° C) are defined as follows. B constant (-10 ° C) = [Inρ (-10 ° C) -Inρ (25
℃)] / [1 / (-10 + 273.15) -1 / (25 +273.5)] B constant (140 ℃) = [Inρ (25 ℃) -Inρ (140
℃)] / [1 / (25 + 273.15) -1 / (140 + 273.5)]

As is clear from Table 1, the main component La
By adding Zr to CoO ₃ in the range of 0.001 to 10 mol%, the specific resistance is 11.1 to 19.8 Ω · c.
As low as m, B constant at -10 ° C is 1220-2620K
It can be seen that the B constant at 140 ° C. is 3020 to 4730K, which is a satisfactory value.

FIG. 1 and FIG. 2 show the results of repeated current-carrying tests of the samples of this example. This test uses a Zr content of 1
A sample (see No. 1-6 in Table 1) having mol% was used. FIG. 1 shows the results of measuring the time change of the switching power supply current when the power supply was turned on by serially connecting the above sample to the switching power supply at 25 ° C. FIG. 2 shows the relationship between the number of repeated energization tests and the resistance value at 25 ° C. In this repeated energization test, one cycle was a step of energizing the sample for 1 minute, then turning off the power for 30 minutes and cooling to 25 ° C.

As is clear from each figure, once to 10 times
No change in properties was observed even after 000 times.
In addition, 100 samples were continuously energized at 20 A for 100 hours to carry out a practical test, but it was confirmed that none of the samples was destroyed and that it could be applied to a large current.

Example 2 This example is the same as Example 1 except that the rare earth transition oxide is used.
The same LaCoO ₃ is adopted, and as shown in Table 2, Si, Mo, Sn, Sb, Te, Hf, Ta, W,
Ce was added in a predetermined amount. Also as shown in Table 3, in the _{LaCoO 3, Zr-Mo, Zr} -Sn, Z
A predetermined amount of each of r-Sn-W and Zr-Mo-Ce was added. Then, each sample of this example was prepared by the same manufacturing method as in Example 1 above, and the electrical properties of the specific resistance (ρ) and B constant of each sample were measured.

[0026]

[Table 2]

[0027]

[Table 3]

As is clear from Tables 2 and 3, in any of the samples (Sample Nos. 1-9 to 1-21), the specific resistance was as low as 16.2 to 20.5 Ω · cm and -10. B of ℃
The constant is 1820 to 2630K, and the B constant at 140 ° C is 4
A satisfactory value of 290 to 4680K is obtained.

Example 3 In this example, LaCrO ₃ was used as a rare earth transition oxide, and the molar ratio of La to Cr was 0.95.
The powders of La ₃ O ₃ and Cr ₂ O ₃ were weighed so that As shown in Table 4, Zr,
Mo, Sb, Hf, Ta, Ce, and Sb-Hf, Zr
-Ta, Sn-Ce, and Si-Mo-W were added in predetermined amounts. Then, each sample of this example was prepared by the same manufacturing method as in Example 1 above, and the electrical properties of the specific resistance (ρ) and B constant of each sample were measured.

[0030]

[Table 4]

As is clear from Table 4, in any of the samples (Sample Nos. 2-1 to 2-10), the specific resistance is 1
It is as low as 6.1 to 20.0 Ω · cm, the B constant at −10 ° C. is 2420 to 2710 K, and the B constant at 140 ° C. is 3870.
A satisfactory value of 4320K is obtained.

Example 4 In this example, SmNiO ₃ was used as a rare earth transition oxide, and the molar ratio of Sm to Ni was 0.95.
Each powder of Sm ₂ O ₃ and NiO was weighed so that As shown in Table 5, Zr, M
o, Sb, Hf, Ta, W and Sb-Ce, Zr-T
A predetermined amount of each of a, Sn-W, and Si-Mo-W was added. Then, each sample of this example was prepared by the same manufacturing method as in Example 1 above, and the electrical properties of the specific resistance (ρ) and B constant of each sample were measured.

[0033]

[Table 5]

As is clear from Table 5, in any of the samples (Sample Nos. 3-1 to 3-10), the specific resistance is 1
It is as low as 2.0 to 15.0 Ω · cm, the B constant at −10 ° C. is 2060 to 2410 K, and the B constant at 140 ° C. is 3620.
A satisfactory value of ~ 3990K is obtained.

Example 5 In this example, NdNiO ₃ was used as the rare earth transition oxide, and the molar ratio of Nd to Ni was 0.95.
Each powder of Nd ₂ O ₃ and NiO was weighed so that As shown in Table 6, Si, Z was added to the weighed powder.
r, Mo, Sn, Sb, Ce and Si-Sn, Zr-
Each of W, Mo-Ta, and Zr-Sn-Ta was added in a predetermined amount. Then, each sample of this example was prepared by the same manufacturing method as in Example 1, and the specific resistance (ρ) and B of each sample were
Each constant electrical property was measured.

[0036]

[Table 6]

As is clear from Table 6, in any of the samples (Sample Nos. 4-1 to 4-10), the specific resistance was 2
It is as low as 2.6 to 25.9 Ω · cm, the B constant at -10 ° C is 1970 to 2240K, and the B constant at 140 ° C is 3710.
A satisfactory value of ~ 3930K is obtained.

Example 6 In this example, PrNiO ₃ was used as a rare earth transition oxide, and the molar ratio of Pr to Ni was 0.95.
Each powder of Pr ₆ O ₁₁ and NiO was weighed so that As shown in Table 7, Zr, M
o, Sb, Te, Ta, W and Zr-Hf, Zr-W,
Mo-Sb and Sb-Hf-W were added in predetermined amounts. Then, each sample of this example was prepared by the same manufacturing method as in Example 1 above, and the electrical properties of the specific resistance (ρ) and B constant of each sample were measured.

[0039]

[Table 7]

As is clear from Table 7, in any of the samples (Sample Nos. 5-1 to 5-10), the specific resistance was as low as 8.9 to 12.0 Ω · cm, and the B of -10 ° C was obtained. The constant is 1960 to 2210K, and the B constant at 140 ° C is 3590.
A satisfactory value of up to 3820K is obtained.

Example 7 In this example, La was used as a rare earth transition oxide._0.9Nd
_0.1CoO₃And the La_0.9Nd_0.1CoO₃Half
La so that conductor porcelain can be obtained₂O₃, Nd₂O ₃as well as
Co₃O_FourEach powder was weighed. To this weighed powder,
As shown in Table 8, Zr, Sb, W and Si-Hf, Z
A predetermined amount of each of r-Mo-Ta was added. And above
Each sample of this example was prepared by the same manufacturing method as in Example 1.
The electrical resistance of each sample (ρ) and B constant
It was measured.

[0042]

[Table 8]

As is clear from Table 8, in any of the samples (Sample Nos. 6-1 to 6-5), the specific resistance was 2
Low as 4.0-26.4 Ω · cm, B constant at -10 ° C is 1720-1910K, and B constant at 140 ° C is 3540.
A satisfactory value of ˜3690K is obtained.

Example 8 In this example, La is used as a rare earth transition oxide._0.9Gd
_0.1CoO₃And the La_0.9Gd_0.1CoO₃Half
La so that conductor porcelain can be obtained₂O₃, Gd₂O ₃as well as
Co₃O_FourEach powder was weighed. To this weighed powder,
As shown in Table 9, Sn, Ta, Ce and Zr-Mo,
Zr-Te-Hf was added in a predetermined amount. And above
Each sample of this example was manufactured by the same manufacturing method as in Example 1.
Electrical characteristics of resistivity (ρ) and B constant of each sample created
Was measured.

[0045]

[Table 9]

As is apparent from Table 9, in any of the samples (Sample Nos. 7-1 to 7-5), the specific resistance was 2
Low as 1.9 to 23.7 Ω · cm, B constant at −10 ° C. is 1840 to 2020K, and B constant at 140 ° C. is 3650.
A satisfactory value of ~ 3860K is obtained.

Example 9 In this example, La _0.99 Y _0.01 was used as a rare earth transition oxide.
MnO ₃ was adopted, and each powder of La ₂ O ₃ , Y ₂ O ₃ and MnO was weighed so that the La _0.99 Y _0.01 MnO ₃ semiconductor ceramic was obtained. As shown in Table 10, Sn, Mo, W and Sb-Ta, Zr-Sb- were added to the weighed powder.
A predetermined amount of Mo was added to each. Then, each sample of this example was prepared by the same manufacturing method as in Example 1 above, and the electrical properties of the specific resistance (ρ) and B constant of each sample were measured.

[0048]

[Table 10]

As is clear from Table 10, in any of the samples (Sample Nos. 8-1 to 8-5), the specific resistance was 1
Low as 9.7 to 21.5 Ω · cm, B constant at -10 ° C is 2190 to 2290K, and B constant at 140 ° C is 3820.
A satisfactory value of -3970K is obtained.

In each of the above Examples 1 to 9, LaCo is used.
O ₃ system, LaCrO ₃ system, SmNiO ₃ system, NdNiO
_{The 3} type and PrNiO ₃ type oxides have been explained.
The present invention is not limited to this, and similar effects can be obtained with other rare earth transition oxides.

[0051]

As described above, according to the semiconductor porcelain having the negative resistance temperature characteristic, the inrush current preventing element including the porcelain, and the motor start delay element including the same according to the present invention, the rare earth transition element-based oxide is used. For objects, Si, Zr, H
Since at least one of f, Ta, Sn, Sb, W, Mo, Te, and Ce is added, it is possible to reduce the specific resistance near room temperature and obtain a device having a large B constant at high temperature. be able to. Therefore, the resistance value in the temperature rising state can be made sufficiently small, the power consumption in the steady state can be reduced, and the effect can be applied to a circuit in which a large current flows.

[Brief description of drawings]

FIG. 1 is a characteristic diagram showing a result of measuring a time change of a switching power supply current when a power supply is turned on by connecting an NTC element in series to a switching power supply at 25 ° C.

FIG. 2 is a characteristic diagram showing the relationship between the number of repeated normal tests and the resistance value at 25 ° C.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshihiko Tachibana 2 26-10 Tenjin, Nagaokakyo, Kyoto Prefecture Murata Manufacturing Co., Ltd. (72) Inventor Hiroshi Takagi 2 26-10 Tenjin, Nagaokakyo, Kyoto Stock Company Murata Manufacturing Co., Ltd. (72) Inventor, Kunizaburo Banno, 2 26-10 Tenjin Tenjin, Nagaokakyo City, Kyoto Murata Manufacturing Co., Ltd.

Claims (5)

[Claims] 1. A rare earth transition element-based oxide (provided that rare earth is Ce except Y and Y is contained) as a main component, and S is added thereto.
i, Zr, Hf, Ta, Sn, Sb, W, Mo, Te,
A semiconductor porcelain having negative resistance-temperature resistance characteristics, characterized in that at least one of Ce is added. 2. The additive according to claim 1, wherein the additive is 0.0
A semiconductor porcelain having a negative resistance-temperature resistance characteristic, characterized in that the content is 01 to 10 mol%. 3. The semiconductor ceramic according to claim 1, wherein the rare earth transition element-based oxide is a LaCo-based oxide, which has negative resistance-temperature resistance characteristics. 4. An element for preventing inrush current, which is made of a rare earth transition element-based oxide and is made of a semiconductor ceramic exhibiting a negative resistance temperature characteristic. 5. An element for delaying motor start-up, which is made of a rare earth transition element-based oxide and is made of a semiconductor porcelain exhibiting negative resistance-temperature characteristics.