JPH07106055A - Quick temperature raising heating element and manufacture thereof - Google Patents

Abstract

PURPOSE:To provide a quick temperature raising heating element which is easily manufactured at low cost and has high durability and high performance. CONSTITUTION:A quick temperature raising heating element has an electrically insulating ceramic sinter layer 1, first and second high resistance conductive ceramic sinter layers 2a, 2b, and a high resistance conductive ceramic connecting part 2c which is unitedly formed with the ceramic sinter layers 2a, 2b, and also has a heating part 2 which forms a current path extending to other side through the connecting part 2c, and first and second lead layers 3, 4 formed with a low resistance conductive material on the same surface as the ceramic sinter layers 2a, 2b, or on at least part of the surface of the ceramic sinter layers 2a, 2b. The total thickness of the element is specified to 100-2000mum, the width to 200-500mum, and the length to 15-70mum.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rapid heating element.

[0002]

2. Description of the Related Art As a rapid heating element, for example, those disclosed in Japanese Patent Publication Nos. 1-28467 and 4-61832 are known.

The rapid temperature rising heating element disclosed in Japanese Examined Patent Publication No. 1-28467 is a glow plug for an automobile diesel engine. For example, a known sintering aid for silicon carbide (SiC) (for example, B ₄ C, Al ₂ O ₃ etc. added raw material powder is filled in a hot press mold, and a linear body having a linear heating portion made of a refractory metal mainly composed of tungsten, molybdenum, etc. at a predetermined position on the hot press mold. Is placed, the raw material powder is further filled therein, the linear body is embedded therein, and then pressure-fired by a hot pressing method at about 2000 ° C. to produce the exposed linear body. It is used by applying a voltage between both ends of the to generate heat.

On the other hand, the rapid heating element disclosed in Japanese Examined Patent Publication No. 4-61832 discloses a nitride selected from the group consisting of silicon nitride, aluminum nitride, boron nitride and a mixture thereof in an amount of 30 to 70% by volume. It is composed entirely of 10 to 45% by volume of silicon carbide and 5 to 50% by volume of molybdenum disilicide, and has a density of at least 85 of the theoretical density.
%, And an electric resistor having a heat generating zone and a non-heat generating end portion having different compositions, and specifically, a material having high resistance and a material having low resistance after firing are formed into two layers. Then, hot-press firing is performed, and the fired body is cut into a U-shape in a direction perpendicular to the layer direction by machining, and a voltage is applied between two free ends of the U-shape to connect them. Used to generate heat in the section.

[0005]

[Patent Document 1] Japanese Patent Publication No. 1-284
The rapid heating element disclosed in Japanese Patent Publication No. 67 is formed by hot pressing so that a linear body to be a heating element is embedded in a molded body made of ceramic raw material powder. However, since the heating elements must be manufactured almost completely individually, the manufacturing is inefficient, time-consuming, and expensive. Further, since the heater is embedded, the thermal efficiency is inferior to the structure in which the heater is exposed on the surface.

The rapid heating element disclosed in Japanese Patent Publication No. 4-61832 is manufactured by cutting a two-layered conductive sintered body having different resistance values into a predetermined shape, that is, a U shape by machining. However, since a high hardness material such as a sintered body of a ceramic material is processed, there is a problem that the processing cost is high and the manufacturing efficiency is low.

As a ceramic heater similar to the above, the one disclosed in Japanese Patent Application Laid-Open No. 61-104581 is known. Even in this ceramic heater,
When forming the U-shaped heater, it is necessary to manufacture each of the heaters one by one, and there is a problem that manufacturing is inefficient and expensive.

Further, the conventional ceramic heater has 10
If it is used as a rapid heating element with a heating rate of about a second or less, cracks easily occur due to thermal shock, and resistance deterioration occurs after long-term use, resulting in insufficient durability.

Therefore, an object of the present invention is to provide a rapid heating element which can be manufactured efficiently and inexpensively while maintaining the characteristics as a heating element and which has high durability. is there.

[0010]

The above objects are achieved by the present invention described in (1) to (17) below. (1) Electrically insulating ceramic sintered body layer, and first and second high resistance layers formed of a highly resistive conductive ceramic material on at least a part of both surfaces of the electrically insulating ceramic sintered body layer A conductive ceramic sintered body layer, a connecting portion integrally formed of the high resistance conductive ceramic material with the first and second high resistance conductive ceramic sintered body layers, and the first and second high resistance ceramic layers. The heat generating portion having a current path extending from one of the resistive conductive ceramic sintered body layers to the other portion through the connecting portion and the other, and the same surface as the first and second high resistive conductive ceramic sintered body layers, or At least a part of the surfaces of the first and second high resistance conductive ceramic sintered body layers are formed of a low resistance conductive material, and are electrically connected to the first and second high resistance conductive ceramic sintered body layers, respectively. First connected And a beauty second lead portion layer, the total thickness of the element is 100 to 2000, the width 200-50
A rapid heating element which has a length of 00 μm and a length of 15 to 70 mm. (2) The rapid heating element according to (1), wherein the connecting portion of the heat generating portion is formed of the same material as the material of the first and second high resistance conductive ceramics sintered body layers. (3) The rapid heating element according to (1) or (2), wherein the first and second lead layer are conductive ceramic sintered body layers made of a low resistance conductive ceramic material. (4) The electrically insulating ceramic sintered body layer and the first and second high resistance conductive ceramic sintered body layers each have a thickness of 1 to 1000 μm, and the entire heating portion has a thickness of 100 to 2
The rapid heating element according to any one of (1) to (4) above, which is set within a range of 000 μm. (5) The electrically insulating ceramic sintered body layer, the heat generating portion, the first and second lead portion layers are both an insulating first component which is the same metal oxide, and a silicide of the same metal, and / or
Alternatively, the above-mentioned (1) to (1), which is formed of a ceramic containing a conductive second component which is a carbide as a main component by changing the composition ratio.
The rapid heating element according to any one of (4). (6) An electrically insulating ceramic sintered body layer, a heating portion connected to the electrically insulating ceramic sintered body layer, and first and second lead portion layers for applying a voltage to the heating portion. The electrically insulating ceramic sintered body layer, the heat generating portion, the first and second lead portion layers are both an insulating first component that is the same metal oxide, and a silicide of the same metal, and / or
Alternatively, a rapid heating element which is made of a ceramic containing a conductive second component, which is a carbide, as a main component by changing the composition ratio. (7) In the electrically insulating ceramic sintered body layer, the heat generating portion, and the first and second lead portion layers, the composition ratio of the first component and the second component is 10: 0 by volume, respectively.
8: 2, 7.5: 2.5 to 5.5: 4.5 and 5: 5
The rapid heating element of (5) or (6), wherein the heating element is ˜0: 10. (8) The metal oxide is at least one of aluminum oxide, zirconium oxide, chromium oxide, titanium oxide, tantalum oxide, silicon oxide, magnesium aluminum oxide and silicon aluminum oxide, and the metal silicide is molybdenum or tungsten. And the silicide of chromium, and the metal carbide is at least one of carbides of silicon and titanium. (9) The above (5), wherein the second component is molybdenum silicide.
A rapid heating element according to any one of (8) to (8). (10) 10 wt% or less of an oxide of a rare earth metal containing an alkaline earth metal and Y is contained in at least one of the electrically insulating ceramic sintered body, the heat generating portion, and the first and second lead portion layers. The rapid heating element according to any one of (5) to (9) above. (11) The rapid heating element according to any one of (1) to (10), wherein the outer surface is covered with a heat-resistant and oxidation-resistant protective film that is chemically and thermally stable. (12) The rapid heating element according to (11), wherein the protective film is made of at least one of silica, alumina and chromia. (13) The above-mentioned (6) to (1), wherein at least one of the electrically insulating ceramic sintered body layer, the heat generating portion, and the first and second lead portion layers contains 2 wt% or less of silicon carbide.
2) Rapid heating element. (14) The rapid temperature rise according to any one of (1) to (13) above, in which the connecting portion is formed of three or more layers, and the resistance value of the middle portion is set to be larger than the resistance values of the upper and lower layers. Heating element. (15) The intermediate portion has substantially the same thickness as the electrically insulating ceramic sintered body layer or a thickness difference of ± 20% or less, and the electrically insulating ceramic sintered body layer. The rapid heating element according to (13) above, which is formed as an intermediate layer connected to the tip of the. (16) The resistance value of the first and second lead part layers is set to 1/10 or less of the resistance value of the heat generating part.
Thru | or the rapid temperature rising heat generating element in any one of said (14). (17) In the method for manufacturing the rapid heating element according to any one of (1) to (16), the electrically insulating ceramic sintered body layer, the heating portion, and the first and second lead portion layers are formed. A method for producing a rapid heating element, which is characterized in that the element is obtained by forming and stacking layers in a state before sintering and firing the layers.

[0011]

The rapid heating element of the present invention can be manufactured by laminating a ceramic green sheet on the main part or the whole, cutting it into strips, and then firing it. Up to the steps, it is possible to fabricate a plurality of elements integrally and simultaneously, efficiently, and in the subsequent steps as well, it is sufficient to simply cut the raw material before firing into strips and fire, so It can be manufactured at low cost.

Further, the rapid heating element of Japanese Patent Publication No. 4-61832 has a U-shape and has a notch space therein, which is weak in strength. It is necessary to set the thickness of the two vertical portions to be large to some extent, so that the overall size becomes large. Also, the durability is low. However, in the rapid heating element of the present invention, the electrically insulating ceramic sintered body layer is used, and the heating portion and the lead portion are integrated with this layer. The heat generating portion is integrated with the end surface and side surface of the tip portion of the electrically insulating ceramic.
And the whole structure is usually an integral plate. For these reasons, the strength is strong and downsizing is possible. With this miniaturization, there is a great advantage that the energy required for temperature rise is small, it is resistant to thermal shock, and has high durability against repeated rapid temperature rise.

Further, the electrically insulating ceramics sintered body layer, the heat generating portion and the lead portion are composed of an oxide and a silicide and / or a carbide as main components, which are the same as the constituent components of each layer. If the composition ratio is changed, cracking and resistance deterioration will not occur even if the temperature is rapidly raised for a long time, and high durability can be obtained. Further, when a nitride is used, it cannot be put into practical use because it shows NTC characteristics unless it is sintered in nitrogen, but if a nitride is not used as described above,
There is no restriction on the sintering conditions, excellent PTC characteristics can be stably obtained, and excellent temperature rising characteristics can be obtained.

JP-A-1-202470 discloses a heater in which a lead portion is bonded to a sintered body integrally formed on the upper and lower ends and one end portion of an electric insulating layer. However, since the lead layer is not integrally formed in this device, the entire element becomes a heating element and the temperature rises. Therefore, it is necessary to withstand the high temperature at the connecting portion of the lead portion. However, it is extremely difficult to maintain the adhesive strength of the connecting portion of the lead portion even at the time of high temperature heat generation, and it is not practical. It is conceivable to use a spring or the like to make contact with mechanical pressure, but there are few materials that can withstand high temperatures, and even if there are any, long-term use cannot be expected. It is conceivable to harden the joint with cement or the like, but in any case, an increase in the temperature of the joint is unavoidable.

[0015]

Specific Structure The specific structure of the present invention will be described in detail below.

1, 2 and 3 show three preferred examples of the rapid heating element of the present invention.

The rapid heating element of the present invention preferably has a rectangular plate shape as a whole, for example, and is provided with an electrically insulating ceramic sintered body layer 1, a heating portion 2, and first and second lead portions. ing. The overall shape of the element is usually preferably plate-like as described above, but may be cylindrical or the like. The heat generating portion 2 is made of a conductive ceramic material having a relatively high resistance on a whole surface (see FIG. 1) or a portion (see FIG. 2) of the front surface and the back surface of the electrically insulating ceramic sintered body layer 1 or a plane surface. From the first and second high resistance conductive ceramics sintered body layers 2a and 2b and the first and second high resistance conductive ceramics sintered body layers 2a and 2b formed in a curved plate shape to the other, A part of the peripheral edge of the electrically insulating ceramic sintered body layer, so as to form a current path extending along the tip portion in the case shown,
The conductive ceramic material has a relatively high resistance, and includes first and second high resistance conductive ceramic sintered body layers 2a and 2b and a connecting portion 2c integrally formed.

The first and second lead portion layers 3 and 4
Are the first and second high resistance conductive ceramic sintered body layers 2a, 2 as shown in FIGS. 1 and 3, respectively.
FIG. 2 shows that a step is provided at the rear end portion of b and is formed on the thin portion on the rear end side of the first and second high resistance conductive ceramic sintered body layers 2a and 2b. like,
On the electrically insulating ceramic sintered body layer 1, the first and second layers are formed.
The high resistance conductive ceramics sintered body layers 2a and 2b are connected so as to form a continuous surface.

In the above-mentioned structure, as is clear from the figures, the rapid heating element of the present invention is preferably formed in a rectangular plate shape as a whole, and the tip of the end portion in the longitudinal direction is formed. The heat generating portion 2 is formed on the.

The first and second lead portion layers 3 and 4
The external connection electrode layers 5 and 6 made of metal are formed on the top. The external connection electrode layers 5 and 6 may be located at any positions on the first and second lead part layers 3 and 4, but are not limited to the ends where the heating part 2 of the rapid heating element is formed. Is preferably provided at the end on the opposite side or in the vicinity thereof to prevent high temperature.

When the size of the connecting portion 2c of the heat generating portion 2 becomes large, only the first and second high resistance conductive ceramic sintered body layers 2a and 2b generate heat due to the size of the area. However, in this case, as shown in FIG. 3, a sandwich structure in which a high-resistance high-resistance layer 2d is sandwiched between the central portions may be provided so that the connecting portion 2c sufficiently generates heat.

Although not shown, it is desirable that the outer surface of the rapid heating element of the present invention is covered with a chemically and thermally stable heat-resistant and oxidation-resistant protective film.

In the rapid heating element of the present invention, the heating time from room temperature to 1000 to 1500 ° C. is set within 10 seconds, preferably 1 to 5 seconds. In the rapid heating element of the present invention, the element resistance varies depending on the power used and the voltage range used, but is generally 0.5 to 20.
It is set in the range of kΩ. And the resistance value of the heat generating part is
The resistance value of the first and second lead portion layers is set to be 10 times or more, particularly about 20 to 1000 times. As a result, it is possible to prevent the temperature of the terminal electrode portion from becoming too high. The resistance value increases about four times due to the PTC characteristic when the element heats up and the temperature rises from room temperature to 1000 ° C. Therefore, the resistance value at room temperature is about a quarter of the target value. May be set to lower.

The rapid heating element of the present invention has a thickness in the range of 100 to 2000 μm and a width in the range of 200 to 500.
It is desirable to set 0 μm, preferably 800 to 3000 μm, and its length to 15 to 70 mm, preferably 25 to 50 mm.

If the thickness is less than the above range, the mechanical strength is weak, and if it exceeds the above range, the heat capacity becomes too large and the rate of temperature rise becomes slower, and the thermal shock resistance lowers, and cracks are generated during rapid temperature rise. Cause of. If the width is less than the above range, the mechanical strength is weak and handling becomes difficult.
The heat generation capacity becomes smaller. Further, when the oxidation of the conductor progresses after a long period of use, the ratio of the oxide layer is likely to increase, and the influence of the oxidation becomes stronger. On the other hand, when it exceeds the above range, the heat capacity becomes too large and the temperature rising rate becomes slow. Moreover, even if the heat dissipation area becomes large, the temperature rise becomes slow. In addition, the thermal shock resistance is lowered, and it becomes a cause of cracking at the time of rapid temperature rise.

If the length of the element is less than the above range, it becomes difficult to install the terminal electrode sufficiently away from the heat generating portion, and the temperature of the terminal electrode portion becomes high.
On the other hand, when the length exceeds the above range, it becomes vulnerable to mechanical shock and the like, and it becomes difficult to handle.

The electrically insulating ceramic sintered body layer 1 and the first and second high resistance conductive ceramic sintered body layers 2
It is desirable that the thicknesses a and 2b are both set in the range of 1 to 1000 μm, preferably 10 to 500 μm. 1
If it is less than μm, it has no mechanical strength, and a through hole or the like is likely to occur, which easily causes an electrical short circuit.
On the other hand, when it exceeds 1000 μm, the heat capacity becomes large,
At the same time that the temperature rising rate becomes slower, the element is more likely to be destroyed by the thermal shock caused by the sudden temperature rise.

The total thickness of the heat generating portion is 100 to 200.
It is desirable to set in the range of 0 μm, preferably 500 to 1000 μm. If it is less than 100 μm, it has no mechanical strength and cannot be used. In addition, if it is used for a long time, it reacts with the oxide layer generated in the conductor, and the insulation deterioration easily occurs. On the other hand, when it exceeds 2000 μm, the heat capacity becomes too large, the temperature rise takes time, and the thermal shock resistance also decreases. Furthermore, in terms of heat generation characteristics,
It is desirable that the connecting portion 2c of the heat generating portion be present at 200 to 2000 μm on the tip side of the electrically insulating ceramic sintered body layer. The first and second high-resistance conductive ceramics sintered body layers 2a, 2b are formed on the electrically insulating ceramics sintered body layer 1 at a minimum of 100 μm, particularly at a minimum of 500 μm, and at a maximum of the maximum electrically insulating ceramics sintered body layer 1. It is desirable to exist in length. With such a length, the soaking area of the heat generating portion is expanded, the occurrence of cracks due to repeated temperature rise is reduced, and the thermal shock resistance and durability are improved.

Further, in order to make the rapid temperature rise better, it is preferable that the volume of the heat generating portion is 1 to 60%, preferably 5 to 40% of the whole element.

The thickness of the first and second lead portion layers 3 and 4 is about 1 to 1000 μm.

The electrically insulating ceramic sintered body layer comprises an insulating first component which is a metal oxide, a metal silicide and //
Alternatively, it is formed of a ceramic mainly containing a conductive second component which is a metal carbide. In this case, only the insulating first component may be used, but it is preferable to further contain the conductive second component. This improves durability.

As the metal oxide, aluminum oxide,
Zirconium oxide, chromium oxide, titanium oxide, tantalum oxide, silicon oxide, magnesium aluminum oxide, silicon aluminum oxide (for example, mullite 3Al ₂ O ₃ ·.
At least one powder of 2SiO ₂ and sillimanite Al ₂ O ₃ .SiO ₂ ) is used.

Further, as the metal silicide, at least one kind of powder of silicide of molybdenum, tungsten and chromium is used. As the metal carbide, at least one kind of powder of silicon and titanium carbide is used. Of the above, it is most preferable to use a silicide, especially molybdenum silicide, as the second component.

The composition ratio of the insulating first component and the conductive second component in the electrically insulating ceramic sintered body layer 1 is 10: 0 to 8: 2 by volume ratio, preferably 10: 0 to 9. 3: 0.
It is desirable to set it to 7, especially 9.8: 0.2 to 9.3: 0.7. When the conductive second component exceeds 20% by volume, the insulation due to the insulating first component breaks down and it becomes easier to have conductivity.

As in the case of the electrically insulating ceramic sintered body layer 1, the heat generating portion 2 is mainly composed of an insulating first component which is a metal oxide and a conductive second component which is a metal silicide and / or a metal carbide. It is made of ceramic. As the metal oxide, metal silicide and metal carbide, the same ones as described above can be used.

The composition ratio of the insulative first component and the electrically conductive second component in the heat generating part is particularly influenced by the particle size distribution, but the average particle size is about 2 μm, and the volume ratio is 7.5: 2.5. ~
It is desirable to set it to 5.5: 4.5, preferably 7: 3 to 7.6: 2.4. 25% by volume of the conductive second component
If it is less than 4.5%, the resistance becomes too high, and if it exceeds 4.5% by volume, the resistance becomes too low and the calorific value extremely decreases.

When the heat generating portion 2 has a structure as shown in FIG. 3, the high resistance layer 2d has a higher proportion of the insulating first component than the other portions and has a high resistance. I shall. This ratio is mainly for the first and second
It is determined by the resistance values of the first and second high resistance conductive ceramic sintered body layers 2a, 2b and the connecting portion 2c calculated based on the sizes of the high resistance conductive ceramic sintered body layers 2a, 2b and the connecting portion 2c. It

The first and second lead portion layers 3 and 4 are also the same as the electrically insulating ceramic sintered body layer 1 and the heat generating portion 2, and the insulating first component which is a metal oxide, and the metal silicide and / or It is formed of a ceramic mainly containing a conductive second component which is a metal carbide. At this time, the conductive second
Although only the component may be used, it is preferable to add the insulating second component in terms of durability and the like. As the metal oxide, metal silicide and metal carbide, the same ones as described above can be used.

The composition ratio of the insulating first component and the conductive second component in the first and second lead layers is 5: 5 by volume.
It is desirable to set it to ˜0: 10, preferably 5: 5 to 1: 9. When the content of the conductive second component is less than 50% by volume, heat generation in the lead layer becomes too large.

The first and second lead portion layers may be layers formed by baking a metal or an alloy, thermal spraying, plating, sputtering, etc., instead of the ceramic layers in some cases. Examples of metals that can be used include platinum,
As palladium and alloys, stainless steel, nickel-chromium-aluminum, cobalt, yttrium-based alloys Ni-Cr-Al-Y, Co-Cr-Al-Y, Ni-
Co-Cr-Al-Y and Ni-Cr are mentioned.

The terminal electrodes are formed of palladium, silver, nickel, aluminum, solder or the like. Palladium, silver, and nickel are formed by baking, and aluminum is formed by thermal spraying.

The protective film is made of at least one of silica, alumina, titania, chromia, tin oxide and the like. And its thickness is 0.1
˜100 μm, especially about 1-100 μm. The protective film may be formed by an oxidation treatment method, or may be formed by a method of dipping in a solution of the above metal, a sol-gel method, a coating method, or the like.

The electrically insulating ceramic sintered body layer, the heat generating portion, and the first and second lead portion layers are preferably composed mainly of the same insulating first component and the same conductive second component. It is desirable that the ceramic sintered bodies differ only in their composition ratio. In particular, the degree of bonding between the layers becomes strong and the durability is improved.

In this case, each layer may contain 2 wt% or less of silicon carbide. Further, as a sintering aid, an oxide of an alkaline earth metal, a rare earth metal containing Y, or a compound which becomes an oxide by firing, such as a carbonate, an oxalate, or a hydroxide, is added, and Ca, Ba, Mg etc., Y, L
One or more oxides such as a, Ce, Sm, Dy and Nd may be contained in an amount of 10 wt% or less, particularly 0.1 to 10 wt%. The addition of the sintering aid improves the surface smoothness. The insulating first component and the conductive second component are each 1 to
The grain size is about 50 μm and about 1 to 50 μm.

Next, a method for manufacturing the rapid heating element of the present invention will be described.

In this manufacture, first, raw materials for the electrically insulating ceramic sintered body layer, the heat generating portion and the first and second lead portion layers are prepared.

In this preparation, the powder of the insulating first component and the powder of the conductive second component were used for the above-mentioned electrically insulating ceramic sintered body layer, the heat generating portion and the first and second lead portion layers. , The above composition ratios are measured, and a binder and a solvent are added to them.

Powder of the above-mentioned insulating first component and conductive second
The average particle diameter of the component powder is preferably about 0.1 to 3 μm and about 0.5 to 8 μm, respectively. An acrylic binder can be used as the binder. Further, toluene can be used as the solvent.

The prepared materials are mixed into a slurry by, for example, a ball mill. The mixing time is, for example, 3 to 2
It may be about 4 hours. Using the slurry, three types of green sheets for the electrically insulating ceramic sintered body layer, the heat generating portion, and the first and second lead portion layers are produced by a normal doctor blade method or extrusion method.
The thickness of each green sheet is a value calculated and determined in advance so that the thickness after firing falls within the above range.

After that, the respective green sheets are laminated so that the cross section thereof becomes, for example, one of FIG. 1, FIG. 2 and FIG. This lamination is performed by thermocompression bonding under the conditions of a pressure of 50 to 2000 kg / cm ² and a temperature of 50 to 150 ° C.

The lamination can be carried out by repeating the screen printing method using various mixed and formed slurries without producing each sheet.

Thereafter, each element is cut into strips by a cutter. In this case, at most, four sides of the rectangle may be cut.

After the cutting, binder removal processing and firing are performed. The binder removal processing is desirably performed under the following conditions, for example.

Rate of temperature rise: 6 to 300 ° C./hour, especially 30
-120 ° C / hour Holding temperature: 250-380 ° C /, especially 300-350 ° C Holding time: 1-24 hours, especially 5-20 hours Atmosphere: Air, nitrogen gas, argon gas, nitrogen gas-
water vapor

The firing is preferably performed under the following conditions, for example.

Temperature rising rate: 300 to 2000 ° C./hour, particularly 500 to 1000 ° C./hour Holding temperature: 1400 to 1700 ° C. /, especially 1500 to 1
650 ° C. Holding time: 0.5 to 3 hours, especially 1 to 2 hours Cooling rate: 300 to 2000 ° C./hour, especially 500 to 1
000 ° C / hour

The firing atmosphere may be vacuum, argon gas, helium gas, hydrogen gas or the like. It is desirable not to use a nitrogen atmosphere. This is because if the heat generating portion or the like is nitrided, it will have a negative temperature characteristic.
The binder removal treatment and firing may be performed independently or continuously.

The surface of the sintered body obtained as described above is coated with the protective layer. This coating is performed by immersing it in a dispersion liquid in which the coating material is dispersed, or in a metal alkoxide or an alkoxide solution in which the coating material is dispersed, or when the coating material is silica, the silicon resin is applied to the surface of the sintered body. It can also be carried out by applying it to and baking it.

Finally, a terminal electrode is formed by baking silver or the like at predetermined positions on the surfaces of the first and second lead portion layers,
The manufacture of the rapid heating element of the present invention is completed. Further, the lead wire may be electrically connected and fixed with a socket.

The rapid heating element of the present invention manufactured as described above is used for a gas igniter or the like, and its driving voltage is
For example, it is set to about 12V to 400V of the car battery.

[0061]

EXAMPLES The present invention will be described in more detail below by showing specific examples of the present invention.

<Embodiment 1> Al ₂ O ₃ and MoSi are commonly used as the main components of the ceramics of the electrically insulating ceramic sintered body layer, the heating portion and the first and second lead portion layers.
₂ was used and compounded as follows. Al ₂ O ₃ MoSi ₂ Electrically insulating ceramic sintered body layer 95% by volume 5% by volume Heat generating part 70% by volume 30% by volume First and second lead layer 20% by volume 80% by volume Powder average particle size 0.4 μm 2μm binder methacrylic binder solvent toluene

The above was mixed in a ball mill for 24 hours to prepare slurries, and these were used to prepare a sheet by the doctor blade method. Further, a metal mold was formed so as to have the layer structure (not including the terminal electrodes) of FIG. 60 ° C. and 80 ° C. so that the entire thickness of the device becomes the thickness shown in Table 1 after firing.
Pressure molding was performed under the condition of 0 kg / cm ² .

Next, the molded body was cut into various dimensions shown in Table 1 (the dimensions show those after firing) so as to obtain the structure shown in FIG.

The cut molded body was heated in a nitrogen gas atmosphere at a temperature rising rate of 1 ° C./minute to 350 ° C.
It was held for a period of time, then heated to 900 ° C. at a temperature rising rate of 5 ° C./min, held at this temperature for 2 hours, cooled at 5 ° C./min, and subjected to binder removal treatment. The binder-removed molded body was heated to 1650 ° C. at a heating rate of 5 ° C./minute in vacuum, held at this temperature for 1 hour, and then heated to 300 ° C.
Firing was performed by cooling at a rate of / minute. However, 800
The autoclave was cooled below ℃.

Further, silicone is applied to the entire element,
Heat treatment in air at 1300 ° C for 1 hour to a thickness of about 1 μm
A silica protective film was formed. After that, the protective film of the terminal electrode portion was ground by sandblasting, and a silver electrode was baked on this portion, and sample Nos. 2 to 9 (Examples: Sample Nos. 2 and 3, Comparative Example: Sample) of the rapid heating element were heated. No.4
~ 9). In sample No. 1 of the example, each layer structure of the electrically insulating ceramic sintered body layer, the heat generating portion, and the first and second lead portion layers was produced by the screen printing method using each slurry described above. The resistance ratios of the heat generating part and the lead part layer of the above sample were all 50: 1.

With respect to the above samples, the rate of cracking when the temperature was raised from room temperature to 1100 ° C. when 20 V was applied, current was applied for 10 seconds, and 1 minute interval cutback was applied 10,000 times (10
(In 0 pieces) and the rate of change in resistance when held at 1500 ° C. for 50 hours were measured. The results are shown in Table 1.

[0068]

[Table 1]

As can be seen from Table 1, in samples Nos. 1 to 3 of the examples of the present invention, the temperature rising time up to 1100 ° C. was within 10 seconds, and no crack was generated.
Moreover, the resistance change rate was within 5%. On the other hand, the sample of the comparative example could not satisfy at least one of the conditions of temperature rising time of 10 or less, crack occurrence rate of 0, and resistance change rate of 5% or less. Sample No.
The heat generating part volumes of 1 to 3 were 10 to 20% of the whole.

<Embodiment 2> Next, the element shape is changed to a thickness of 800.
μm, width 1800 μm, length 35 mm, Al ₂ O ₃
And Sample Nos. 10 to 13 in the same manner as in Example 1 except that the composition ratio of MoSi ₂ and MoSi ₂ was changed as shown in Table 2.
Was produced.

For these samples, the temperature rising time and the resistance change rate were measured in the same manner as above. The results are shown in Table 2.

[0072]

[Table 2]

As is clear from this table, the samples of the examples of the present invention satisfied all the above conditions, but the samples of the comparative examples did not satisfy at least one of the conditions.

<Embodiment 3> First, which is the main component of ceramics
Sample Nos. 20 to 27 were produced in the same manner as Sample No. 10 of Example 2 except that the components and the second component were changed and combined as shown in Table 3. Also for these samples, the temperature rising time and the resistance change rate were measured in the same manner as above. The results are shown in Table 3.

[0075]

[Table 3]

As can be seen from these samples, even if the first and second components, which are the main components of the ceramic of each layer, are variously changed, the same effect as the combination of Al ₂ O ₃ and MoSi ₂ can be obtained.

For comparison, sample Nos. 28 and 29 were prepared in the same manner as the other samples except that silica and mullite were used as the first component, and a characteristic test was carried out. , Or did not fever.

Finally, as a protective layer, an alumina layer or a chromia layer having a thickness of 1 μm was provided for each of the above samples, and a characteristic test was conducted. As a result, an effect substantially equivalent to the characteristic of the above example was obtained.

[0079]

As described above, according to the rapid heating element of the present invention, it can be manufactured easily and inexpensively.
Moreover, it is possible to obtain a rapid heating element with excellent characteristics and excellent durability.

[Brief description of drawings]

FIG. 1 is a perspective view showing an example of the shape of a rapid heating element of the present invention.

FIG. 2 is a perspective view showing another example of the shape of the rapid heating element of the present invention.

FIG. 3 is a perspective view showing still another example of the shape of the rapid heating element of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Electrically insulating ceramics sintered body layer 2 Heating parts 2a, 2b 1st and 2nd high resistance conductive ceramics sintered body layer 2c Connection part 3, 4 1st and 2nd lead part layers 5, 6 Terminal electrode

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Etsuo Mitsuhashi 1-13-1, Nihonbashi, Chuo-ku, Tokyo TDC Corporation (72) Masatada Yodogawa 1-13-1 Nihonbashi, Chuo-ku, Tokyo TDC Co., Ltd. (72) Inventor Ryoichi Kondo 1-13-1 Nihonbashi, Chuo-ku, Tokyo TDC Inc.

Claims (17)

[Claims] 1. An electrically insulating ceramic sintered body layer, and first and second layers formed of a high resistance conductive ceramic material on at least a part of each of both surfaces of the electrically insulating ceramic sintered body layer. A high resistance conductive ceramic sintered body layer; a connecting portion integrally formed with the first and second high resistance conductive ceramic sintered body layers from a high resistance conductive ceramic material; 2 A heating portion having a current path extending from one of the high resistance conductive ceramics sintered body layers to the other through the connecting portion and the other, and on the same plane as the first and second high resistance conductive ceramics sintered body layers Alternatively, at least a part of the surface of the first and second high resistance conductive ceramics sintered body layers is formed of a low resistance conductive material, and the first and second high resistance conductive ceramics sintered body layers are respectively formed. Electrically connected to The first and second and a lead portion layer, the total thickness of the element is 100 to 2000, the width 200 was
A rapid heating element having a temperature of 5000 μm and a length of 15 to 70 mm. 2. The rapid heating element according to claim 1, wherein the connecting portion of the heat generating portion is formed of the same material as the material of the first and second high resistance conductive ceramics sintered body layers. 3. The rapid heating element according to claim 1, wherein the first and second lead portion layers are conductive ceramic sintered body layers formed of a low resistance conductive ceramic material. 4. The thickness of both the electrically insulating ceramic sintered body layer and the first and second high resistance conductive ceramic sintered body layers is 1 to 1000 μm, and the total thickness of the heat generating portion is 1.
It is set within the range of 00 to 2000 μm.
4. A rapid temperature rising heating element according to any one of 1 to 4. 5. The electrically insulating ceramic sintered body layer,
The heat generating part and the first and second lead part layers have a composition ratio of an insulating first component which is the same metal oxide and a conductive second component which is a silicide and / or carbide of the same metal. The rapid heating element according to any one of claims 1 to 4, which is made of ceramic as a main component instead. 6. An electrically insulating ceramic sintered body layer, and a heat generating portion connected to the electrically insulating ceramic sintered body layer,
A first and a second lead portion layer for applying a voltage to the heat generating portion are provided, and the electrically insulating ceramic sintered body layer, the heat generating portion, and the first and second lead portion layers are the same. A rapid heating element which is made of a ceramic containing an insulating first component, which is a metal oxide, and a conductive second component, which is a silicide and / or a carbide of the same metal, with different composition ratios. . 7. The electrically insulating ceramic sintered body layer,
In the heat generating portion and the first and second lead portion layers, the composition ratio of the first component and the second component is 1 by volume, respectively.
The rapid heating element according to claim 5, wherein the heating elements are 0: 0 to 8: 2, 7.5: 2.5 to 5.5: 4.5, and 5: 5 to 0:10. 8. The metal oxide is aluminum oxide,
At least one of zirconium oxide, chromium oxide, titanium oxide, tantalum oxide, silicon oxide, magnesium aluminum oxide and aluminum silicon oxide, wherein the metal silicide is at least one of molybdenum, tungsten and a silicide of chromium, The rapid heating element according to claim 5, wherein the metal carbide is at least one of silicon carbide and titanium carbide. 9. The rapid heating element according to claim 5, wherein the second component is molybdenum silicide. 10. The oxide of a rare earth metal containing alkaline earth metal and Y is contained in an amount of 10 wt% in at least one of the electrically insulating ceramic sintered body, the heat generating portion and the first and second lead portion layers. The rapid heating element according to any one of claims 5 to 9, which is contained below. 11. The rapid heating element according to claim 1, wherein the outer surface is covered with a chemically and thermally stable heat-resistant and oxidation-resistant protective film. 12. The rapid heating element according to claim 11, wherein the protective film is made of at least one of silica, alumina and chromia. 13. The electrically insulating ceramic sintered body layer, the heat generating portion, and / or at least one of the first and second lead portion layers contain silicon carbide in an amount of 2 wt% or less. Rapid heating element. 14. The connecting portion is formed of three or more layers,
14. The rapid heating element according to claim 1, wherein the resistance value of the intermediate portion is set to be higher than the resistance values of the upper and lower layers. 15. The intermediate portion has substantially the same thickness as the electrically insulating ceramic sintered body layer or a difference in thickness of ±.
14. The rapid heating element according to claim 13, which has a thickness within 20% and is formed as an intermediate layer connected to the tip of the electrically insulating ceramic sintered body layer. 16. The rapid heating element according to claim 1, wherein the resistance values of the first and second lead portion layers are set to 1/10 or less of the resistance value of the heating portion. . 17. The method for manufacturing the rapid heating element according to claim 1, wherein the electrically insulating ceramic sintered body layer, the heating portion, and the first and second lead portion layers are burned. A method for manufacturing a rapid heating element, which is characterized in that the element is obtained by forming and stacking layers in a state before binding and firing the layers.