KR20160042402A - Ptc element and heat-generating module - Google Patents

Abstract

Wherein the nonmagnetic electrode is a PTC element formed by baking a nonmetal based electrode in a semiconductor ceramic composition and the semiconductor ceramic composition has a perovskite structure of BaTiO ₃ type oxide, A low resistance layer having at least B and a resistance lower than that of the parent semiconductor composition is formed on the nonmetal-based electrode side of the semiconductor ceramic composition while a main component is a main component.

Description

[0001] PTC ELEMENT AND HEAT GENERATING MODULE [0002]

The present invention relates to a PTC element and a heat generating module in which electrodes are formed in a semiconductor ceramic composition having a positive temperature coefficient.

2. Description of the Related Art Semiconductor magnetic compositions having various semiconducting elements added to the composition of a perovskite system represented by BaTiO ₃ as a material exhibiting a PTC characteristic (positive temperature coefficient of resistivity) have been proposed. The PTC characteristic is a characteristic in which the resistance value abruptly increases when the temperature exceeds a Curie Point. A semiconductor ceramic composition having PTC characteristics is used as a PTC element by forming an electrode.

Patent Document 1 discloses a PTC device using a lead-free semiconductor ceramic composition and an electrode, wherein 50 to 85% of BaTiO ₃ , 3 to 15% of CaTiO ₃ , ₃ to 50% of SrTiO 3 and 1 to 2% of SiO ₂ are preferable as the semiconductor ceramic composition (See paragraph 0006). Further, as a method of forming the electrode, the electrode or the partial layer of the electrode is preferably manufactured by a metal precipitation method. Examples of the metal precipitation method include sputtering, vapor deposition, electrolytic precipitation, and chemical precipitation. However, it is described that the electrode may be manufactured by baking a metal paste (see paragraph 0007).

Patent Document 2 discloses that a Ba _m TiO ₃ composition having a perovskite-type structure represented by the general formula A _m BO ₃ as a main component and at least a part of Ba constituting the A site contains at least an alkali metal element, Bi, And the molar ratio m of the A site and the B site is 0.990? M? 0.999, and has a good rise characteristic (see paragraph 0026). Further, there is a substrate in which an external electrode is formed by plating, sputtering, electrode baking or the like, whereby a PTC thermistor is obtained (see paragraph 0069). In the embodiment, dry plating is performed to form an external electrode having a three-layer structure of NiCr / NiCu / Ag (see paragraph 0079).

The PTC element occupies a very large proportion of the cost of manufacturing the electrode for forming the electrode and the material cost for the entire production cost.

The metal deposition method, which is one of the electrode formation methods, is advantageous in that the adhesion between the semiconductor ceramic composition and the electrode can easily be enhanced, and the interface resistance between the semiconductor porcelain composition and the electrode (hereinafter referred to as "interface resistance") can be easily reduced. When the interfacial resistance is reduced, the resistance of the PTC element (hereinafter referred to as "element resistance") is also reduced, and the current efficiency of the PTC element can be improved. On the other hand, however, the metal deposition method has a problem of high manufacturing cost.

A baking method may be employed as a means for forming an electrode at low cost. Baking is a method of preparing an electrode paste in which a metal powder is dispersed in a glass component or an organic component, applying the paste to a semiconductor ceramic composition by printing or the like, and heating it to evaporate a glass component or an organic component from the electrode paste, .

Patent Document 3 discloses a PTC device comprising at least two ohmic electrodes and a semiconductor ceramic composition in which a part of Ba of BaTiO ₃ disposed between the electrodes is substituted with Bi-Na, and the semiconductor ceramic composition has a composition formula of [Bi _{-Na) x (Ba 1-y} -θ RyA θ) 1-x] Ti 1-z M z O 3 ( however, R is at least one kinds of rare earth elements, A is at least one kinds of Ca, Sr, M is Nb, Ta, and Sb), and the x, y, z, and θ satisfy 0 <x? 0.30, 0? Y? 0.020, 0? Z? 0.010, and 0? A ratio of an area in which the ohmic component of the electrode does not contact the semiconductor magnetic composition at the interface of the semiconductor ceramic composition to 25% or less is disclosed. In this embodiment, it is described that the electrode contains Ag as a main component as a metal component.

However, the electrode uses a noble metal-based electrode paste mainly composed of elements such as Ag, Au and Pt as a metal component and a base metal electrode paste mainly composed of elements such as Al and Ni . If a noble metal-based electrode paste is used, the electrode can be baked in air because it is difficult to oxidize. However, since the noble metal element is expensive, it hinders cost reduction of the PTC element.

On the other hand, the non-metal based electrode paste is very cheap because it contains Al or Ni as a main component as a metal component. However, since it is easily oxidized, it becomes a hindrance to lowering resistance.

Patent Document 4 discloses an electrode of an electronic component made of metal aluminum, 0.1 to 10% by weight of boron nitride, and 0.01 to 5% by weight of glass frit (borosilicate glass). It is said that this electrode material can be formed into an electrode having an ohmic property to a ceramic element by firing at 850 to 900 DEG C in the air.

Published Japanese Patent Publication No. 2010-501988 International Publication WO2010 / 067866 Japanese Unexamined Patent Application Publication No. 2012-169515 Japanese Patent Application Laid-Open No. H03-233805

However, when a non-metallic electrode (hereinafter simply referred to as "electrode") using Al or Ni is baked in a BaTiO ₃ semiconductor ceramic composition, a gap is formed at the interface between the semiconductor ceramic composition and the electrode, Is not brought into ohmic contact. For this reason, a problem has arisen that the interface resistance per unit area (1 cm 2) of the interface between the semiconductor ceramic composition and the electrode becomes, for example, larger than 10 Ω. When the interfacial resistance is increased, the current efficiency of the PTC element is lowered. Hereinafter, the description of "per unit area (1 cm 2)" is omitted and simply referred to as interface resistance.

An object of the present invention is to provide a PTC element and a heat generating module having a sufficiently low interfacial resistance when a non-metallic electrode is formed by baking in a semiconductor ceramic composition having a perovskite structure of BaTiO ₃ type oxide.

The present invention is a PTC device in which a non-metallic electrode is formed on a semiconductor ceramic composition by baking, and the semiconductor ceramic composition has a perovskite structure of BaTiO ₃ type oxide, And Ni, and at least B, and a low-resistance layer having resistance lower than that of the semiconductor ceramic composition is formed on the nonmetal-based electrode side of the semiconductor ceramic composition.

In the PTC element of the present invention, the thickness of the low-resistance layer is preferably 0.1 mu m or more.

The present invention can be a PTC device in which the thickness of the low-resistance layer is 0.4 占 퐉 or more and the interface resistance of the device per unit area (1 cm2) is 5? Or less.

In the present invention, a PTC device having an element resistance of 10 Ω or less per unit area (1 cm 2) can be used.

The present invention can provide a PTC device having a surface resistance of 10 m? Cm or less.

In the PTC element of the present invention, it is preferable that a reaction phase mainly containing Ba oxide is present on the side of the semiconductor ceramic composition of the non-metallic electrode.

The non-metallic electrode of the present invention may contain B in an amount of 3% by mass or more and 25% by mass or less, the total amount of Al, Ni and B being 100% by mass.

The non-metallic electrode according to the present invention comprises Si as a metal component, wherein the total amount of Al, Ni, B and Si is 100 mass%, B is at least 3 mass% and at most 25 mass%, Si is at most 0 mass% By mass or more and 26% by mass or less.

The non-metallic electrode of the present invention may contain Al in an amount of 100 mass% or more, and Al in an amount of 50 mass% or more.

The non-metallic electrode of the present invention may contain not less than 5 mass% and not more than 40 mass% of Ni, with the total of Al, Ni, B and Si being 100 mass%.

The non-metallic electrode of the present invention may be such that Al particles having an average particle diameter of 1.2 占 퐉 or more and 10 占 퐉 or less are dispersed.

The semiconductor ceramic composition of the present invention, the composition formula is _{[(BiA) x (Ba 1} -y R y) 1-x] [Ti 1-z Mz] O 3 (A is Na, Li, at least one kinds of K, R And at least one of rare earth elements including Y and at least one of M, Nb, Ta and Sb, wherein x, y and z satisfy 0 < x? 0.25, 0? Y? 0.052, 0? Z? (However, y + z > 0).

The non-metallic electrode of the present invention can be baked at a temperature of 720 DEG C or higher and 850 DEG C or lower in an air atmosphere.

The present invention is a heat generating module comprising any one of the above-described PTC devices, wherein the semiconductor ceramic composition generates heat.

According to the present invention, even when the nonmetal-based electrode is formed by baking, a PTC element having a small interface resistance can be provided. Further, the PTC element can be a small PTC element at the same time as the element resistance. By using this PTC element, it is possible to provide a heat generating module excellent in current efficiency.

1 is a SEM photograph of a cross section of a PTC device according to an embodiment of the present invention.
2 is a schematic diagram of Fig.
Fig. 3 is an Al mapping screen by EDX analysis in the same field of view as Fig.
4 is a schematic diagram of Fig.
5 is a Ba mapping screen by EDX analysis in the same field of view as Fig.
Fig. 6 is a schematic diagram of Fig. 5. Fig.
7 is a cross-sectional SSRM observation image of a PTC device according to another embodiment of the present invention.
8 is a schematic diagram of Fig.
9 is a schematic diagram showing an example of a heat generating module according to an embodiment of the present invention.
10 is a diagram for explaining a method of measuring the interfacial resistance.

The inventors of the present invention have found that a low resistance layer having a low resistance against the parent phase is formed on the non-metallic electrode side of the semiconductor ceramic composition by incorporating a low resistance auxiliary such as B (boron) as a metal component of a non- And it is believed that this improves the ohmic contact, thereby reducing the interface resistance and the like. Hereinafter, the resistance reduction of the PTC element of the present invention will be described.

1 is a SEM photograph of a cross section of a PTC device showing an example of the present invention, and Fig. 2 is a schematic view thereof. Fig. 7 is a photograph of the cross section of the PTC device observed by a scanning type diffusion resistance microscope (SSRM), and Fig. 8 is a schematic diagram thereof.

In Figs. 1 and 2, reference numeral 1 denotes a semiconductor ceramic composition having a perovskite structure composed of a nonmetal-based electrode and 2, a BaTiO ₃ type oxide. The interface between the nonmetal electrode 1 and the semiconductor ceramic composition 2 is a broken line portion 7 drawn to the left and right in the figure and the low resistance layer 3 is formed on the nonmetal based electrode side of the semiconductor ceramic composition 2 . According to the resistance value distribution in FIGS. 7 and 8, the color tone of the low-resistance layer 3 is thicker than the other, and it is found that the resistance is lower than that of the mother layer. That is, in the present specification, the low-resistance layer refers to a layer that forms a portion having a small resistance as compared with the parent semiconductor ceramic composition, and the resistance value thereof is, for example, 1 Ω · cm or less. Details will be described later.

Since the low resistance layer 3 has a low electrical resistance and a large number of carriers as a semiconductor, the Schottky barrier between the low resistance layer 3 and the nonmetal electrode 1 is lowered and the ohmic contact is caused to decrease the interface resistance. The low resistance layer 3 does not necessarily have to be a continuous layer, but it is preferably formed to diffuse over the entire interface, and the thickness is preferably 0.1 m or more. More preferably 0.2 mu m or more, more preferably 0.4 mu m or more, and most preferably 0.5 mu m or more since the resistance is promoted. The upper limit of the thickness is affected by the amount of B and the baking temperature, but if the thickness exceeds 3 탆, the effect of reducing the interfacial resistance can not be expected. This is because the low-resistance auxiliary itself such as B has a high resistance, and therefore, if the added amount is excessive, there is a problem such as deterioration of insulation resistance and thermal conductivity.

When the low resistance layer 3 is formed, the reaction phase 4 in which Ba is diffused to the electrode side is formed in the non-metal based electrode 1 to be thicker than the conventional one. This reaction phase (4) is composed of an oxide containing Ba as a main component. Since the reaction phase 4 is formed so as to fill the gap between the low-resistance layer 3 and the electrode 1 and the gap between the Al particles, the contact area between the low-resistance layer 3 and the electrode 1 is increased and the interface resistance is reduced . Furthermore, if the reaction phase 4 is thickened, the adhesion strength between the semiconductor ceramic composition and the electrode is increased. On the other hand, the presence or absence of the reaction phase can be discriminated from the SEM observation photograph, but it is not specified quantitatively because the shape is irregular and the size is difficult to specify. However, if a low resistance layer is formed, a reaction phase is formed. The thicker the low resistance layer, the more the reaction phase tends to thicken.

The mechanism by which the low-resistance layer is formed is not clear, but is considered as follows. When an element susceptible to oxidation of B or the like is introduced into the nonmetal-based electrode, B or the like at the time of baking deprives oxygen from the semiconductor porcelain composition to make oxygen defects in the crystal structure. It is considered that the emitted electrons are generated in the vicinity of the interface, and that this becomes the root and the low resistance layer is formed. In addition, the oxygen defects generated at this time do not emit electrons, and some of them migrate from the semiconductor ceramic composition along with cations such as Ba to the electrode side and try to maintain the electrical neutrality. It is considered that the Ba moved at this time reacts with the electrode side to form a reaction phase. As the low-resistance auxiliary having such an action, B is the most preferable. However, at least one kind of Zn, Ca, Sb and Sn may be used alone or in combination with B, .

In the present invention, the non-metal-based electrode refers to at least one of Al and Ni as a main component as the entire metal component. Means that the content of Al or Ni is 50 mass% or more, or that the total content of Al and Ni is 50 mass% or more, but Al has a cost lower than Ni It is preferable that the electrode is made of Al rather than Ni because it is inexpensive. Further, since the vicinity of the metal surface is covered with the oxide layer, Al is chemically stable and excellent in reliability and oxidation hardly progresses to the inside. Baking is easy. In this regard, the cost can be reduced.

The B contained in the nonmetal based electrode is preferably 3 mass% or more and 25 mass% or less based on 100 mass% of the total of Al, Ni and B. B is included, a low resistance layer having a thickness of 0.1 mu m or more can be formed. The thickness of the low-resistance layer is 0.4 占 퐉 or more when the content is 3% by mass or more, and a reaction phase with the low-resistance layer is sufficiently formed, whereby a PTC device having an interface resistance of 5? Or less can be obtained. On the other hand, Si may be contained as follows.

When B exceeds 25 mass%, B penetrates to the surface layer of the electrode, and an oxide layer starts to be formed on the surface, so that the surface resistance of the electrode tends to increase. Further, since the device resistance also tends to increase, the upper limit is preferably 25 mass% or less. More preferably not less than 5 mass% and not more than 17 mass%. At this time, a PTC device having an element resistance of not more than about 5? And a surface resistance of not more than 10 m? If it is more than 5 mass% and less than 10 mass%, a PTC device having a surface resistance of 2 m? Cm or less can be obtained. Here, the surface resistance is a value obtained by measuring the resistance of the non-metallic electrode itself. By reducing the surface resistance, an electric field can be uniformly applied to the PTC element.

The non-metal based electrode contains Si as a metal component and contains 3 mass% or more and 25 mass% or less of B, 0 mass% or more of Si % Or less by mass. By including Si in the above-described range, it is possible to improve the humidity resistance and to reduce the change with time of the element resistance, particularly the change with time of the PTC element in a high temperature and high humidity environment. In addition, the inclusion of Si makes it easy for Al particles, which are difficult to be melted, to be melted, thereby increasing the ratio of the contact area of the interface between the Al particles and reducing the interfacial resistance. The Si content is preferably 5.0 mass% or more and 20.0 mass% or less, and more preferably 5.0 mass% or more and 15.0 mass% or less.

B is preferably added in the form of a single metal rather than an oxide. If B is a stable compound such as an oxide or a nitride, the ability to deprive oxygen from the semiconductor ceramic composition can not be exhibited, or the force to deprive oxygen is weak, so that it is difficult to form a low resistance layer. In addition, if the low-resistance layer is not formed, Ba of the semiconductor ceramic composition becomes difficult to move to the electrode side, so that most of the reaction phase is not formed.

Further, the non-metal based electrode preferably contains Si and the total amount of Al, Ni, B, and Si is 100 mass%, and Al is preferably 50 mass% or more. The cost of the electrode can be further reduced.

The non-metallic electrode may contain Ni in an amount of 5% by mass or more and 40% by mass or less, the total amount of Al, Ni, B and Si being 100% by mass. Preferably, Al is contained in an amount of 50% by mass or more. When Ni is contained in the above range, the Ni particles are removed at low temperature in the oxide layer on the surface of Al particles to easily alloy the Al particles with the Ni particles. . However, it is preferable to adjust the baking time to such an extent that excessive sintering reaction does not occur. When the amount of Ni is 5 mass% or more, the above-mentioned effect can be sufficiently obtained. When the amount of Ni is not more than 40% by mass, it is easy to avoid the increase of the resistance of the electrode itself, and the cost of the material of the electrode can be further suppressed. When the amount of Ni is 20 mass% or more, the baking temperature can be further lowered, and more specifically baking at 700 캜 is possible.

A non-metallic electrode having Ni of 20 mass% or less, B of 5 mass% or more and 10 mass% or less, Si of 5.0 mass% or more and 15.0 mass% or less and the remainder being Al, , And a PTC element having a surface resistance of 2.0 m? Cm or less can be obtained.

The Al powder used for the non-metallic electrode preferably has an average particle diameter of 1.2 mu m or more and 10 mu m or less. Further, it is more preferable to use a material having a particle size distribution of a median diameter d30 of 0.1 m or more and less than 1.2 m.

The Al particles in the nonmetal based electrode are hardly melted due to the presence of the oxide film on the surface, and remain almost the same size as that at the time when they were contained in the electrode paste before firing as shown in Fig. As a result, the gap 6 easily occurs between the Al particles and the contact area between the semiconductor ceramic composition and the electrode becomes small, and the interface resistance tends to become large. In this case, it is preferable to use Al particles having an average particle diameter of not less than 1.2 탆 and not more than 10 탆, and furthermore, with an electrode structure having a particle size distribution in which small particles of less than 1.2 탆 are contained in an amount of about 20 to 40% Or less of the Al particles are filled between the Al particles smaller than 0.1 mu m and less than 1.2 mu m so as to reduce the gap between the interfaces. Further, since the ratio of the contact area of the semiconductor ceramic composition to the electrode is increased by the presence of the reaction phase 4 which is relatively thickly formed, the interface resistance of the PTC element can be reduced even if an electrode in which relatively large Al particles are dispersed is formed It is easy. At the same time, the adhesion strength of the electrode is increased.

When the non-metallic electrode is made such that both the Al particles and the Ni particles are dispersed, it is preferable to use Ni particles having a smaller average particle diameter than the Al particles. The gap between the Al particles and the semiconductor ceramic composition is easily filled with the Ni particles and contributes to reducing the interface resistance. For example, when the average particle diameter of the Al particles is 1.2 μm or more and 10 μm or less, the average particle diameter of the Ni particles is preferably 0.1 μm or more and 5 μm or less.

On the other hand, the smaller the particle diameter of the Al particles, the higher the risk of dust explosion and the like, and the handling becomes difficult. On the other hand, if it exceeds 10 mu m, the ratio of the contact area tends to be small, so that it is difficult to reduce the interfacial resistance.

Next, a preferable manufacturing method for obtaining the PTC device of the present invention will be described.

First, a semiconductor ceramic composition having a perovskite structure made of BaTiO ₃ type oxide is prepared, and a nonmetal-based electrode containing at least B, at least one of Al and Ni as main components, The paste may be applied by printing or the like to a target thickness and heated at a temperature of 720 DEG C to 850 DEG C in an air atmosphere to bake the nonmetal electrode.

Even if the bake temperature is as low as about 720 deg. C, the bonding of the semiconductor ceramic composition and the electrode becomes insufficient, and at the same time, the increase in interfacial resistance can be suppressed.

Since B also has an effect as an oxidation inhibitor, oxidation of the semiconductor ceramic composition and the non-metallic electrode can be suppressed even if the baking temperature is as high as about 850 DEG C by using the non-metal based electrode paste to which B is added, A PTC element having a small resistance can be easily obtained.

The baking temperature is preferably 750 DEG C or more and 830 DEG C or less, and a PTC device having an interface resistance of 5 or less and a device resistance of 10 or less can be obtained. By reducing the device resistance, a PTC device having excellent current efficiency can be obtained. More preferably not lower than 750 ° C but not higher than 800 ° C.

The time for which the non-metallic electrode is exposed to the temperature of 720 DEG C or more and 850 DEG C or less is preferably 10 minutes or more and 5 hours or less. If the baking time is longer than 10 minutes, bonding of the semiconductor ceramic composition and the electrode becomes insufficient and it is easy to suppress increase of the interface resistance. If the baking time exceeds 5 hours, the oxidation inhibiting effect tends to become insignificant. If the baking time is shorter than 5 hours, oxidation of the semiconductor ceramic composition is suppressed and a PTC element having a small device resistance is easily obtained. The baking time is preferably from 15 minutes to 1 hour, more preferably from 20 minutes to 50 minutes.

The thickness of the electrode is preferably 5 占 퐉 to 50 占 퐉. If it is 5 mu m or more, occurrence of coating unevenness and peeling of the electrode can be suppressed easily. When the thickness is 50 mu m or less, the cost of the electrode can be reduced. Preferably 10 mu m or more and 35 mu m or less, more preferably 12 mu m or more and 30 mu m or less.

On the other hand, the non-metal based electrode paste can lower the baking temperature to 700 캜 by setting Ni to 20% by mass or more.

In order to prevent the oxidation of the nonmetal-based electrode or improve the wettability of the solder, a noble metal electrode such as an Ag-based electrode may be formed on the nonmetal-based electrode as the second-layer electrode. It is also possible to use an electrode structure having three or more layers for forming another electrode on the noble metal-based electrode.

Next, a preferred embodiment of the semiconductor magnetic composition will be described.

The semiconductor ceramic composition may have a perovskite structure composed of a BaTiO ₃ type oxide, and among these, a non-ferromagnetic semiconductor ceramic composition is preferable. For example, the formula contains _{[(BiA) x (Ba 1} -y R y) 1-x] [Ti 1-z Mz] O 3 (A is at least one kinds of Na, Li, K, R is Y X, y, and z are 0 <x? 0.25, 0? Y? 0.052, and 0? Z? 0.01 (where y + z is at least one kind of rare earth element, M is at least one of Nb, Ta, z > 0).

By using the above-described semiconductor ceramic composition, it is easier to obtain a PTC element having a higher resistance temperature coefficient? Than a semiconductor ceramic composition containing Pb as a dopant. Specifically, even if the PTC element has a small element resistance (10 Ω or less), the resistance temperature coefficient α is 2.5% / ° C. or more, preferably 3.5% / ° C. or more.

The semiconductor ceramic composition containing Pb as a dopant tends to have a small resistance temperature coefficient alpha. This is presumably because the nonmetal based electrode paste at the time of baking deprives oxygen in the mouth layer of the semiconductor ceramic composition, thereby causing the Schottky barrier formed inside the composition to be easily lost and the resistance temperature coefficient? do. On the other hand, since the semiconductor ceramic composition of the above composition is only deprived of oxygen in the surface layer in contact with the electrode in the semiconductor ceramic composition and oxygen in the grain boundary phase inside the composition that exhibits the jump characteristic is hard to be taken away, The high resistance temperature coefficient? Can be maintained. Therefore, it is more preferable to use the semiconductor ceramic composition of the above composition, and this is one of the new findings obtained in the review process of the present invention.

The reason for limiting each element in the composition formula of the semiconductor ceramic composition will be described below.

The addition amount x of Bi or A is more than 0 and not more than 0.25. Curie temperature can be increased to 130 ° C or higher by setting x to be greater than zero.

If x exceeds 0.25, the device resistance becomes large. In addition, the elements of Bi and A are likely to evaporate during sintering, so that the number of moles of Ba sites is smaller than that of Ti sites. As a result, since the semiconductor ceramic composition becomes a Ti rich phase, the Ti rich phase becomes abnormal phase and is precipitated. A part of the Ti rich phase melts during sintering, resulting in poor yield or in some cases a semiconductor ceramic composition of a desired shape can not be obtained.

At least one of the addition amount y of R and the addition amount z of M is essential, that is, y + z > 0. By adding the R element and the M element, the resistance temperature coefficient? Can be increased. However, it is not necessary to set both R and M as essential, and at least one of them may be used.

The range of the addition amount y of R is 0 or more and 0.052 or less (y + z> 0). When y exceeds 0.052, the resistance temperature coefficient of the PTC characteristic is small and the semiconductor ceramic composition having good heat resistance is not available. In addition, the temperature required for sintering is increased, and this temperature may exceed the heat resistance of the sintering furnace, which is not desirable from the viewpoint of production. R is at least one element selected from rare earths (La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu) La is preferable because excellent PTC characteristics can be obtained.

The addition amount z of M is 0 or more and 0.01 or less (y + z> 0). If z exceeds 0.01, the device resistance becomes large. Further, since the mechanical strength of the semiconductor ceramic composition is lowered, cracks tend to occur when the PTC element is used as the PTC element, which is not desirable from the viewpoint of production. M is particularly preferable because Nb can obtain excellent PTC characteristics.

The ratio of Bi to A may be 1: 1. However, even if the ratio of Bi and A is 1: 1, Bi may be volatilized by calcination or sintering, resulting in a difference in the ratio of Bi to A, 1: 1 is not included. In other words, it is acceptable in the range of Bi: A = 0.78 to 1.55: 1, and if it is within this range, it is possible to suppress the increase in the above range, and the increase in room temperature resistivity and change with the passage of time can be suppressed. A more preferred range is Bi: A = 0.90 to 1.2: 1. In this range, an effect of improving the Curie temperature is obtained.

On the other hand, in the present specification, the evaluation method of each characteristic value is as follows.

(Element resistance per unit area)

A nonmetal-based electrode was formed on both main surfaces of the semiconductor ceramic composition to make a PTC device. The nonmetal-based electrodes on both sides were brought into contact with a probe of an ammeter / voltmeter and the device resistance was measured at room temperature (25 캜) by a four-terminal method.

This element resistance is the element resistance of the entire PTC element, and the element resistance per unit area (1 cm 2) can be calculated by dividing the area (cm 2) of the range covered by the electrode.

On the other hand, in the following examples, since the thickness of the semiconductor ceramic composition is 1 mm and the area is 1 cm 2, the resistivity can be converted into room temperature resistivity (Ωcm) by setting the value of the device resistance to 10 times.

(Interface resistance per unit area)

First, a non-metallic electrode is provided in the semiconductor magnetic composition to measure the element resistance. Thereafter, the electrodes are once peeled off, the thickness of the semiconductor porcelain composition is adjusted to a thickness of 3/4 of the initial thickness, and a non-metallic electrode is further provided to measure the element resistance. Likewise, the thickness of the semiconductor ceramic composition is set to 2/4 and 1/4 of the initial thickness, and the device resistance is measured each time. As shown in Fig. 10, the horizontal axis represents the thickness of the semiconductor porcelain composition, and the vertical axis represents the device resistance. From this data, the approximate straight line of the thickness of the semiconductor porcelain composition and the device resistance is obtained. Indicates the approximate line as _{R = a · Δt + R 0} (Δt: thickness, R: device resistance, a: the resistivity of the semiconductor ceramic composition) and the thickness Δt on the graph to conveniently calculated by the resistance value R ₀ at 0 . In the present invention, this resistance value R ₀ is regarded as an interface resistance. This interfacial resistance is the total interfacial resistance of the PTC device, and the interfacial resistance per unit area (1 cm 2) can be calculated by dividing the area (cm 2) of the range covered by the electrode.

(Thickness of the low-resistance layer)

The thickness of the low resistance layer was measured from an SEM observation image (magnification: 3000 times) as shown in Fig. 1 and an EDX analysis mapping (Al) of the same visual field as shown in Fig. In the EDX analysis mapping (Al), the boundary portion at which Al was not detected was set at the interface between the semiconductor ceramic composition and the electrode (indicated by the dotted line 7 in Fig. 2). On the SEM observation photograph, A width different in color tone was arbitrarily measured at 10 points and the average value was determined as the thickness of the low resistance layer. On the other hand, in the SEM observation photograph, the low resistance layer is darker than the parent layer, and the color tone is different. Also, the reaction phase can be discriminated by the same tone and different color tone. Since the low-resistance layer and the reaction phase are formed almost at the same time, if the layer that is darker than the parent phase can be seen on the electrode side of the semiconductor porcelain composition in the SEM observation photograph, existence of both the low-resistance layer and the reaction phase can be confirmed.

(Means for checking resistance reduction)

The means for confirming that the low-resistance layer is low-resistance was evaluated using SSRM (scanning spreading resistance microscopy) (NanoScope IVa AFM Dimension 3100, manufactured by Bruker AXS). According to this method, by scanning the interface between the semiconductor magnetic composition and the electrode with a conductive probe, the distribution of the resistance value can be measured two-dimensionally and the resistance can be visualized. More specifically, a mapping image in which the height of the electric resistance value is represented by the density of the color is obtained, and the dark color portion is in the low resistance. Therefore, the shape of the parent phase (depth in the thickness direction of at least 5 탆) It can be recognized by the difference in color tone (shade) of the resistive layer.

(Surface resistance)

The surface resistance is a value obtained by measuring the resistance of the non-metallic electrode itself. The resistance Rw in the plane direction of the formed electrode was measured by a four-terminal method and converted into a resistivity (= Rw x (W x T) / L) from the length L, the width W of the electrode, and the electrode thickness T measured by SEM observation . On the other hand, in the present embodiment, W was set to 1 cm, L was set to 1 cm, and T was set to 0.0025 cm. However, since the thickness T of the electrode is difficult to set to a constant value, it is measured every time. On the other hand, the initial m of a unit of m [Omega] cm represents the milli ( ^10-3 ).

(Curie temperature)

The temperature at which the resistance twice the room temperature resistivity at room temperature is indicated as the Curie temperature.

(Resistance temperature coefficient?)

The resistance temperature coefficient? Was calculated by measuring the resistance-temperature characteristic while raising the temperature to 260 占 폚.

On the other hand, the resistance temperature coefficient? Is defined by the following equation.

α = (lnR ₁ -lnR _c ) × 100 / (T ₁ -T _c )

R ₁ is the room temperature resistivity at 260 ° C, T ₁ is the temperature at which R ₁ is represented, T _c is the Curie temperature, and R _c is the room temperature resistivity at T _c .

The change over time is preferably 15% or less, more preferably 10% or less.

(Change over time)

The reliability of the electrode was evaluated by a high temperature and high humidity test. The change in the device resistance before and after being left for 1000 hours under the conditions of 80 DEG C and 95% RH was measured.

(Metal component ratio of electrode)

The total amount of Al, Ni, B, and Si was set to 100 mass%, and the ratio of each element was obtained. An electron beam microanalyzer (manufactured by Shimadzu Corporation: EPMA1610) was used for measurement. As the measurement conditions, an average value of five points was obtained with an acceleration voltage of 15 kV, a current of 100 nA, and a beam diameter of 10 mu m.

<Examples>

Next, the present invention will be described in more detail with reference to Examples. However, the present invention is not limited to the following embodiments.

(Example 1: No. 1-1)

10 parts by mass of glass frit and 10 parts by mass of B were added to 100 parts by mass of spherical Al particles having an average particle diameter of 5 占 퐉, and an organic binder and an organic solvent were added thereto to obtain a non-metallic electrode paste.

B was a single metal B particle rather than an oxide. B particles having an average particle diameter of 1 탆 or less were used.

The ratio of Al and B in the non-metal based electrode paste were as shown in Table 1. 1-1.

A semiconductor ceramic composition serving as a substrate was processed into a plate having a size of 10 mm x 10 mm (plate surface dimension) x 1.00 mm (thickness dimension).

The non-metallic electrode paste was coated on both sides of the semiconductor ceramic composition by screen printing. After the applied electrode paste was dried at 150 캜, the temperature was maintained at 30 캜 / min and at 775 캜 for 10 minutes in the air, and the temperature was increased to 30 캜 / min to obtain a PTC element having a baking electrode formed thereon. The area covered by the electrode was 1 cm 2, and the thickness of the electrode was about 25 μm.

The semiconductor ceramic composition used in the examples was prepared as follows.

BaCO ₃ , TiO ₂ and La ₂ O ₃ were prepared and mixed so as to be (Ba _0.994 La _0.006 ) TiO ₃ and mixed with pure water. The obtained mixed raw material powder was calcined at 900 DEG C for 4 hours in the air to prepare a first calcined powder.

Raw material powders of Na ₂ CO ₃ , Bi ₂ O ₃ and TiO ₂ were prepared, metered to be Bi _0.5 Na _0.5 TiO ₃ , and mixed in ethanol. The obtained mixed raw material powder was calcined at 800 캜 for 2 hours in the air to prepare a second calcined powder.

The prepared first calcined powder (Ba _0.994 La _0.006 ) TiO ₃ and the second calcined powder Bi _0.5 Na _0.5 TiO ₃ were mixed in a molar ratio of 73: 7 to obtain [(Bi _0.5 Na _0.5 ) _0.0875 (Ba _0.994 La _0.006 ) _0.9125 ] TiO ₃ , and mixed and pulverized with pure water as a medium until the average particle diameter of the mixed potash powder became 1.0 탆 to 2.0 탆 by a pot mill, followed by drying. And then heat-treated at 1150 ° C for 4 hours to obtain a third calcined powder. 1.0 mol% of Y ₂ O ₃ was added to the obtained calcined powder, and mixed and pulverized with pure water as a medium until the average particle diameter became 1.0 탆 to 2.0 탆 using a pot mill, followed by drying to obtain a mixed calcined powder . 10% by mass of PVA was added to the pulverized powder of the mixed potash powder, mixed and assembled by a granulating apparatus. The obtained powder of the coarse powder was molded with a uniaxial pressing apparatus to obtain a molded article. The formed body was debinded at 700 占 폚 and held at 1400 占 폚 for 4 hours in a nitrogen atmosphere with an oxygen concentration of 0.01% (100 ppm), and then slowly cooled to obtain a sintered body of 50 mm 占 25 mm 占 4 mm.

On the other hand, the above-described manufacturing method is merely an example, and the present invention is not limited thereto. For example, the raw powder is mixed in a batch without obtaining the first and second firing powders, followed by pulverization, drying and heat treatment to obtain a firing powder (corresponding to the third firing powder), and Y ₂ O ₃ May be added, and thereafter the same process as described above may be carried out.

In order to measure the interfacial resistance, the sintered body was processed to prepare sintered bodies of semiconductor ceramic compositions which were processed into plate shapes having a plate surface size of 10 mm x 10 mm and thickness dimensions of 1.00 mm, 0.75 mm, 0.50 mm, and 0.25 mm, In the same manner, PTC devices were fabricated.

Fig. 1 shows the result of observing the boundary between the semiconductor ceramic composition of the PTC device and the electrode by SEM. 2 is a schematic diagram thereof. 3 is a schematic view of FIG. 3, FIG. 5 is a diagram of an EDX mapping of Ba in the same view as FIG. 1, FIG. 6 5 is a schematic diagram of Fig.

The portion where Al is not detected is made to be at the interface (indicated by a dotted line 7 in Figs. 2 and 4) between the base metal electrode 1 and the semiconductor ceramic composition 2, and from this interface, It can be seen that the low resistance layer 3 is formed with the reaction phase 4 in which the irregular Ba having different color tone penetrates into the nonmetal electrode 1 side. The degree of penetration of Ba is not clear, but is thought to occur to the extent shown in Fig. 6.

From the mapping of Al in Fig. 3, it can be seen that the portion (5 in Fig. 2) which is mainly spherical in the non-metal electrode 1 of Fig. 1 is Al. Al particles retain almost the shape at the time when they are contained in the electrode paste in the electrodes after firing, but relatively small particles are contained between large particles, and particle particles are present in the vicinity of the interface. On the other hand, in FIG. 1, a black portion (portion 6 in FIG. 2) between the Al particles is a void inside the electrode.

Figure 7 is a resistance mapping of SSRM. And a portion with a dark color has a low resistance and a portion with a light color has a high resistance. It can be clearly seen from FIG. 7 that a colored layer is formed on the semiconductor ceramic composition 2 side from the interface 7 between the base metal electrode 1 and the semiconductor ceramic composition 2. That is, this layer can be said to be a low-resistance layer 3 which has a darker color tone than the inside of the inner layer and has a low resistance. On the other hand, it was confirmed that the low-resistance layer 3 coincided with the low-resistance layer 3 shown in the SEM observation of Fig.

Next, the Al ratio (mass%), the Ni ratio (mass%), the B ratio (mass%), the Si ratio (mass%), the thickness (占 퐉) , The surface resistance (Ω), the surface resistance (mΩ · cm), the Curie temperature (° C.), the resistance temperature coefficient α (% / ℃) and the change with time (%). On the other hand, characteristics other than the interface resistance were measured using a semiconductor ceramic composition having a thickness of 1.00 mm. The evaluation results are shown in Table 1.

In this embodiment, the thickness of the low-resistance layer is 0.5 占 퐉 in the form of a reactive phase, the interface resistance is 1.1?, The element resistance is 4.9?, The surface resistance is 0.9?? Cm, the Curie temperature is 160 占 폚, Was 4.1% / ℃, and the change with time was 12.5%. Therefore, both the interface resistance and the device resistance show an effect of lowering the resistance, and the PTC characteristics are also satisfied.

On the other hand, the composition of the non-metallic electrode was measured by EPMA, and the ratio (mass%) of Al, Ni, B and Si shown in Table 1 was obtained. Also in the following examples and comparative examples, the ratios of Al, Ni, B, and Si in the table show measured values by EPMA. This value was the same as that of each of the electrode pastes.

(Example 2: Nos. 1-2 to 1-9)

No. 1-2 to 1-9, no. 1-1, a part of Al was replaced with Si, and an electrode in which the amount of addition of B was changed was formed.

Spherical Al particles having an average particle diameter of 5 占 퐉 and Si particles having an average particle diameter of 5 占 퐉 were mixed so as to have a mass ratio of 92: 8, and the total amount thereof was changed to 100 parts by mass, 10 parts by mass of glass frit, 5 parts by mass, 7.5 parts by mass, 10 parts by mass, 12.5 parts by mass, 15 parts by mass, 20 parts by mass and 25 parts by mass, respectively.

As a result of measuring the metal component after the formation of the nonmetal-based electrode, the Al ratio, the B ratio, and the Si ratio were as shown in Table 1. 1-2 to 1-9. On the other hand, as described above, the Al ratio, the B ratio, and the Si ratio in the non-metal based electrode paste were the same as those shown in Table 1.

Other methods of manufacturing and evaluating the PTC device were carried out in the same manner as in Example 1. The evaluation results are shown in Table 1.

It was confirmed that all the PTC devices had a low-resistance layer having a resistance lower than that of the parent phase. Also, the presence of a reaction phase corresponding to the thickness of the low-resistance layer was confirmed.

According to Table 1, when the B ratio is not less than 3% by mass. In the PTC devices 1-3 to 1-9, the low resistance layer had a thickness of 0.4 탆 or more and the interface resistance was 5 Ω or less.

Further, No. 5 having a B ratio of 5 mass% or more and 17 mass% or less. PTC devices 1-4 to 1-8 had an interface resistance of 1.5Ω or less and an element resistance of 5Ω or less. The PTC element has a surface resistance of 10 m? Cm or less. Further, in the case where the B ratio is 5 mass% or more and 10 mass% or less. The PTC devices 1-4 to 1-5 had a surface resistance of 2 m? Cm or less.

(Comparative Example 1: No. 1-10)

A nonmetal based electrode to which B was not added was formed.

8 parts by mass of Si particles were added to 92 parts by mass of the same Al particles as in Example 1 to make 100 parts by mass, and 10 parts by mass of glass frit was added thereto to obtain a non-metallic electrode paste.

Other methods of manufacturing and evaluating the PTC device were carried out in the same manner as in Example 1. The evaluation results are shown in Table 1.

In this example, the low resistance layer could not be confirmed. The reaction phase was confirmed, but the thickness of the reaction phase was almost 1/5 or less as compared with the case where B was added. The interface resistance was as large as 12 OMEGA, and the device resistance was large as 15.5 OMEGA.

(Comparative Example 2: No. 1-11, 1-12)

B ₂ O ₃ , and H ₃ BO ₃ were used as additives of B to form a non-metallic electrode.

10 parts by mass of B ₂ O ₃ or H ₃ BO ₃ and 10 parts by mass of glass frit were added to 92 parts by mass of the same Al particles as in Example 1 in the amount of 8 parts by mass of Si in a ratio of 100 parts by mass Made into a paste.

Other methods of manufacturing and evaluating the PTC device were carried out in the same manner as in Example 1. The obtained results are shown in Table 1.

In this example, no. 1-11, No. 1-12 All low resistance layers could not be identified. However, the reaction phase was confirmed. However, the interfacial resistances were very large, 23.4? And 13.7?, Respectively, and the device resistances were as large as 26.2? And 16.9 ?.

(Example 3: No. 2-1 to 2-5) The non-metallic electrode was formed by changing the baking temperature.

Spherical Al particles having an average particle diameter of 5 占 퐉 and Si particles having an average particle diameter of 5 占 퐉 were mixed so as to have a mass ratio of 92: 8, and the total amount thereof was changed to 100 parts by mass, 10 parts by mass of glass frit, Was added in an amount of 10 parts by mass.

As the semiconductor magnetic composition, a plate processed into a plate having a size of 10 mm x 10 mm (plate surface dimension) x 1.00 mm (thickness dimension) was used. In order to measure the interfacial resistance, semiconductor ceramic compositions were also prepared which were processed into plates of 10 mm x 10 mm x 0.75 mm, 10 mm x 10 mm x 0.50 mm, and 10 mm x 10 mm x 0.25 mm.

The non-metallic electrode paste described above was applied to both sides of the semiconductor ceramic composition by screen printing. After the coated non-metallic electrode paste was dried at 150 캜, the temperature was raised to 30 캜 / min in the air, the holding temperatures were changed to 725 캜, 750 캜, 775 캜, 800 캜, 825 캜 and 850 캜, , The temperature was lowered at 30 DEG C / min and baked to obtain a PTC device having electrodes formed thereon. The area covered by the electrode was 1 cm 2, and the thickness of the electrode was about 25 μm. Each of the semiconductor ceramic compositions having the above-mentioned thicknesses was similarly formed into a PTC device.

Other methods of manufacturing and evaluating the PTC device were carried out in the same manner as in Example 1. The evaluation results are shown in Table 2.

It was confirmed that all the PTC devices had a low-resistance layer having a resistance lower than that of the parent phase. Also, the presence of a reaction phase corresponding to the thickness of the low-resistance layer was confirmed.

According to Table 2, the baking temperature was set to 725 占 폚. In 2-1, the low resistance layer is thin as 0.2 m and the interface resistance is 6.8?. No. 7 having a baking temperature of 750 캜 or higher. 2-2 to 2-5, the thickness of the low-resistance layer was 0.4 μm or more, and the interface resistance was 5Ω or less. Further, when the baking temperature is lower than 830 캜, In 2-2 to 2-4, the device resistance was 10Ω or less.

From the above, it can be said that the baking temperature is more preferably 750 ° C or more and 830 ° C or less. On the other hand, if the baking temperature exceeds 850 deg. C, the semiconductor ceramic composition itself is oxidized and becomes high resistance, which is not preferable.

(Example 4: No. 3-1 to 3-8)

As a non-metal-based electrode, the Si content was changed.

The same Al and Si particles as those of the above example were used and the mass ratio of Al and Si was 98: 2, 96: 4, 94: 6, 88:12, 84:16, 80:20, 76:24 , 72:28. 10 parts by mass of glass frit and 10 parts by mass of B were added thereto.

Other methods of manufacturing and evaluating the PTC device were carried out in the same manner as in Example 1. The evaluation results are shown in Table 3.

It was confirmed that all the PTC devices had a low-resistance layer having a resistance lower than that of the parent phase. Also, the presence of a reaction phase corresponding to the thickness of the low-resistance layer was confirmed.

According to Table 3, when the Si ratio is 1.8 to 21.8 mass% 3-1 to 3-7, an interfacial resistance of 5? Or less, an element resistance of 10? Or less, and a surface resistance of 10 m? Cm or less were obtained. Further, in the case where the Si ratio is 5.5 mass% to 21.8 mass% 3-3 to 3-7 show a change over time of 10% or less, and even with a small amount of Si, the effect of reducing the change over time is shown.

On the other hand, when the Si ratio was 25.5% by mass, In 3-8, a PTC device having a surface resistance exceeding 10 m? Cm but a small device resistance and interface resistance was obtained.

From the above, it can be said that Si has an effect of suppressing change with time, and more preferably 5.0 mass% or more and 15.0 mass% or less in consideration of low resistance.

(Example 5: No. 4-1 to 4-6)

And a nonmetal-based electrode to which Ni was added.

Spherical Al particles having an average particle diameter of 5 탆, Si particles having an average particle diameter of 5 탆 and Ni particles having an average particle diameter of 0.2 탆 were dispersed in a mass ratio of 82.8: 7.2: 10, 73.6: 6.4: 20, 64.4: 5.6: 30, 55.2: 4.8: 40, 27.6: 2.4: 70, and 9.2: 0.8: 90, and the total amount thereof was changed to 100 parts by mass and 10 parts by mass of B was added thereto. The glass frit was made 0 parts by mass.

Other methods of manufacturing and evaluating the PTC device were carried out in the same manner as in Example 1. Table 4 shows the evaluation results.

It was confirmed that all the PTC devices had a low-resistance layer having a resistance lower than that of the parent phase. Also, the presence of a reaction phase corresponding to the thickness of the low-resistance layer was confirmed.

According to Table 4, all the PTC devices had a small value of the interface resistance of 2.5? Or less. No. 4-1 showed the lowest resistance value. Particularly, when the Ni content is not less than 5 mass% and not more than 20 mass%. 4-1 and 4-2, a PTC device having an interface resistance of 1? Or less, an element resistance of 5? Or less, and a surface resistance of 2.0 m? Cm or less was obtained.

From the above, it can be said that the Ni ratio is more preferably 20 mass% or less since the effect of lowering the resistance of the interface resistance is increased by adding a small amount of Ni.

From the present example, it is considered that addition of the glass frit is not absolutely necessary, and that it is preferable to add the glass frit when the baking temperature exceeds 800 ° C.

(No. 4-7 ~ 4-9)

Ni was added as a nonmetal-based electrode, and the amount of B was changed.

No. 4-7 to 4-12 show that spherical Al particles having an average particle diameter of 5 탆, Si particles having an average particle diameter of 5 탆 and Ni particles having an average particle diameter of 0.2 탆 were mixed at a mass ratio of 55.2: 4.8: 40 And the total amount thereof was adjusted to 100 parts by mass, and B was added thereto in amounts of 5.0, 7.5 and 12.5 parts by mass, respectively. The glass frit was made 0 parts by mass.

Other methods of manufacturing and evaluating the PTC device were carried out in the same manner as in Example 1. The obtained evaluation results are shown in Table 4.

It was confirmed that all the PTC devices had a low-resistance layer having a resistance lower than that of the parent phase. Also, the presence of a reaction phase corresponding to the thickness of the low-resistance layer was confirmed.

According to Table 4, all of the PTC devices had a PTC device having a small value of an interface resistance of 1.0? Or less and an element resistance of 5? Or less.

(No. 4-10 to 4-12)

No. The non-metallic electrode paste prepared in 4-9 was used to change the baking temperature. The obtained evaluation results are shown in Table 4.

It was confirmed that all the PTC devices had a low-resistance layer having a resistance lower than that of the parent phase. Also, the presence of a reaction phase corresponding to the thickness of the low-resistance layer was confirmed.

According to Table 4, all of the PTC devices had a PTC device having a small value of an interface resistance of 1.0? Or less and an element resistance of 5? Or less. The baking temperature was lowered to 700 占 폚. It is equivalent to the interface resistance and the device resistance in the PTC device of 4-12.

(Example 6: No. 5-1 to 5-8)

And the ratio of x and y was changed with respect to the composition of the semiconductor magnetic composition.

No. 5-1 to 5-4, y = 0.006 and z = 0; The values of x for 1-5 are 0.02, 0.14, 0.18, and 0.2, respectively. 5-5 to 5-7, x = 0.0875 and z = 0, and the values of y were 0.003, 0.048, and 0.05, respectively. The electrodes are No. 1-5. The same goes for the following examples. Other methods of manufacturing and evaluating the PTC device were carried out in the same manner as in Example 1. The evaluation results are shown in Table 5.

In addition, 5-8, No. 1-5, a rare earth element was not used as a semiconducting element (y = 0), a portion of the Ti site was Ta, and the value of z in the composition formula was 0.009.

In this example, BaCO ₃ , TiO ₂ , and Ta ₂ O ₅ raw material powders were prepared and mixed so as to be Ba (Ti _0.991 Ta _0.009 ) O ₃ and mixed with pure water. The obtained mixed raw material powder was calcined at 900 DEG C for 4 hours in the air to prepare a first calcined powder.

The second preliminary firing powder was produced in the same manner as in Example 1. The following methods of manufacturing and evaluating the PTC element by mixing, molding, sintering, and electrode formation of the first and second preliminary firing powders were carried out in the same manner as in Example 1. The evaluation results are shown in Table 5.

It was confirmed that all the PTC devices had a low-resistance layer having a resistance lower than that of the parent phase. Also, the presence of a reaction phase corresponding to the thickness of the low-resistance layer was confirmed.

From the results shown in Table 5, all the PTC devices had an interface resistance of 5? Or less. A surface resistance of 2.0 m? Cm or less, and a resistance temperature coefficient? Of 2.5% / ° C or more.

(Example 7: No. 6-1 to 6-4)

A particle size of Al particles used in a nonmetal-based electrode was changed.

No. 6-1, Al particles having an average particle diameter of 3.8 占 퐉 were used. In Fig. 6-2, Al particles having an average particle diameter of 2.5 占 퐉 were observed. 6-3 and 6-4, Al particles having an average particle diameter of 1.5 mu m were used, respectively. These Al particles and Si particles were mixed in a mass ratio of 92: 8, and the total amount of the Al particles and the Si particles was 100 parts by mass, to which 10 parts by mass of glass frit and 10 parts by mass of B were added. In addition, 6-4 changed the baking temperature to 750 ° C.

Other methods of manufacturing and evaluating the PTC device were carried out in the same manner as in Example 1. Table 6 shows the evaluation results.

It was confirmed that all the PTC devices had a low-resistance layer having a resistance lower than that of the parent phase. Also, the presence of a reaction phase corresponding to the thickness of the low-resistance layer was confirmed.

According to Table 6, a PTC device having an interface resistance of 1? Or less, an element resistance of 5? Or less, and a surface resistance of 10.0 m? Cm or less was obtained in both cases.

By reducing Al particles, surface resistance tends to increase.

(Example 8: No. 7-1)

A semiconductor ceramic composition containing Pb as a semiconductor ceramic composition was used.

(Ba _0.83 Pb _0.17 ) TiO ₃ as a semiconductor ceramic composition containing Pb. Other manufacturing methods and evaluation methods of the PTC element are as follows. 1-5. Table 7 shows the evaluation results.

It was confirmed that there is a low resistance layer having a resistance lower than that of the parent layer. Also, the presence of a reaction phase corresponding to the thickness of the low-resistance layer was confirmed. Although the resistance temperature coefficient is small, the device resistance, interface resistance, and surface resistance all have low values.

(Heat generating module)

9 is a schematic diagram of a heat generating module (PTC heater) according to an embodiment of the present invention.

The heat generating module 20 can be constructed by fixing the PTC element described above to the heat dissipation fins 21a, 21b, and 21c made of metal as shown in Fig. The PTC element 11 is composed of the base 1a of the semiconductor ceramic composition and the nonmetallic electrodes 2a, 2b and 2c and the electrodes 2a and 2c are arranged on the anode side of the power supply electrodes 20a and 20c, And the electrode 2b formed on the other surface is brought into thermal and electrical contact with the power supply electrode 20b on the cathode side. The power supply electrodes 20a, 20b, and 20c are thermally connected to the radiating fins 21a, 21b, and 21c, respectively. On the other hand, the insulating layer 2d is provided between the power supply electrode 20a and the power supply electrode 20c to electrically insulate them. Heat generated in the PTC element 11 is transmitted in the order of the electrodes 2a, 2b and 2c, the power supply electrodes 20a, 20b and 20c and the radiating fins 21a and 21b and 21c, 21c.

When the power supply 30c is connected between the power supply electrode 20a and the power supply electrode 20b or between the power supply electrode 20c and the power supply electrode 20b, the power consumption becomes small, and the power supply electrode 20a And the power supply electrode 20c and the power supply electrode 20b, power consumption is increased. That is, the power consumption can be changed to two levels. In this manner, the heat generating module 20 can change the heating ability in accordance with the load condition of the power source 30c and the degree of the desired degree of heating. The heating device 30 can be configured by connecting the heat generating module 20 capable of switching the heating ability to the power source 30c. On the other hand, the power source 30c is a DC power source. The power supply electrode 20a and the power supply electrode 20c of the heat generating module 20 are connected in parallel to one electrode of the power supply 30c through separate switches 30a and 30b, Is connected to the other electrode of the power source 30c as a common terminal. When only one of the switches 30a and 30b is turned on, the heating capacity can be reduced and the load on the power source 30c can be lightened.

According to this heating device 30, the PTC element 11 can be maintained at a constant temperature without providing a special mechanism in the power source 30c. That is, when the base 1a having a large resistance temperature coefficient is heated to the vicinity of the Curie temperature, the resistance value of the base 1a is abruptly increased and the current flowing in the PTC element 11 is reduced, . When the temperature of the PTC element 11 is lowered near the Curie temperature, a current flows to the element again, and the PTC element 11 is heated. This cycle is repeated so that the temperature of the PTC device 11 and hence the temperature of the entire heat generating module 20 can be made constant. Therefore, a circuit for adjusting the phase and amplitude of the power source 30c, A mechanism for comparing with the target temperature, a heating power adjusting circuit, and the like are unnecessary.

The heating device 30 can warm the air by flowing air between the radiating fins 21a to 21c or by connecting a metal pipe for passing a liquid such as water between the radiating fins 21a to 21c to warm the liquid . At this time, since the PTC element 11 is maintained at a constant temperature, a safe heating apparatus 30 can be provided.

Such a heat generating module is an example, and the number of the electrodes may be changed to two to simplify and modify the same.

Although the present invention has been described in detail with reference to specific embodiments thereof, it will be apparent to those skilled in the art that various changes and modifications can be made within the spirit and scope of the present invention.

On the other hand, the present application is based on Japanese Patent Application (2013-139001) filed on July 2, 2013, which is incorporated by reference in its entirety. Also, all references cited herein are incorporated by reference in their entirety.

1: Nonmetal electrode
2: Semiconductor porcelain composition
3: low resistance layer
4: Reaction phase
5: Al particles
6: Pore
11: PTC element
20: Heating module
20a, 20b, 20c: power supply electrode
21a, 21b, 21c:
30a, 30b: switch
30c: Power supply

Claims (14)

A non-metallic electrode is formed on the semiconductor ceramic composition by baking,
Wherein the semiconductor ceramic composition has a perovskite structure of BaTiO ₃ type oxide,
Wherein the non-metal based electrode contains at least B as a main component and at least one of Al and Ni as a metal component,
Wherein a low-resistance layer having a resistance lower than that of the parent semiconductor phase composition is formed on the nonmetal-based electrode side of the semiconductor ceramic composition. The method according to claim 1,
Wherein the low-resistance layer has a thickness of 0.1 占 퐉 or more. 3. The method according to claim 1 or 2,
Wherein the low resistance layer has a thickness of 0.4 mu m or more and an interface resistance of the device per unit area (1 cm &lt; 2 &gt;) is 5 or less. 4. The method according to any one of claims 1 to 3,
Wherein a device resistance of the device per unit area (1 cm 2) is 10 Ω or less. 5. The method according to any one of claims 1 to 4,
Wherein the surface resistance is 10 m? Cm or less. 6. The method according to any one of claims 1 to 5,
Wherein a reaction phase consisting essentially of Ba oxide is present on the side of the semiconductor ceramic composition of said nonmetal based electrode. 7. The method according to any one of claims 1 to 6,
Wherein the nonmetal based electrode has a composition including 100 mass% of the total of Al, Ni, and B and 3 mass% or more and 25 mass% or less of B. 8. The method of claim 7,
Wherein the nonmetal based electrode contains Si as a metal component and contains 100 mass% of the total of Al, Ni, B and Si, 3 mass% to 25 mass% of B, 0 mass% to more than 26 mass % Or less. 9. The method according to claim 7 or 8,
Wherein the non-metallic electrode comprises Al in an amount of 100 mass% or more, and Al in an amount of 50 mass% or more. 10. The method according to any one of claims 7 to 9,
Wherein the non-metal based electrode contains Ni in an amount of 5 mass% or more and 40 mass% or less, the total amount of Al, Ni, B, and Si being 100 mass%. 11. The method according to any one of claims 1 to 10,
Wherein the non-metal based electrode has Al particles having an average particle diameter of 1.2 占 퐉 or more and 10 占 퐉 or less dispersed therein. 12. The method according to any one of claims 1 to 11,
The semiconductor ceramic composition may further comprise:
The composition formula of which the rare earth element containing _{[(BiA) x (Ba 1} -y R y) 1-x] [Ti 1-z Mz] O 3 (A is at least one kinds of Na, Li, K, R is Y, at least X, y, and z are 0 <x? 0.25, 0? Y? 0.052, 0? Z? 0.01 (where y + z> 0) Of the PTC element. 13. The method according to any one of claims 1 to 12,
Wherein the non-metallic electrode is baked at a temperature of 720 DEG C or more and 850 DEG C or less in an atmospheric environment. A heat generating module comprising the PTC element according to any one of claims 1 to 13, wherein the semiconductor ceramic composition generates heat.

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