JPH08213155A - Manufacture of sic heater - Google Patents

Abstract

PURPOSE: To provide a safe and reliable SiC heater that can stand a long time of service by integrating a heat generating section formed out of a plurality of SiC sheets, with a non-heat generating section formed out of an odd number of alternately stacked SiC and NbB2 sheets. CONSTITUTION: An assistant and a binder are added to SiC powder, thereby forming an SiC sheet 1. On the other hand, a sheet 2 is formed, mainly composed of the boride, silicide, carbide or the like of metal such as Zr, W and Nb. Then, the odd number of the sheet 1, or five sheets 1, for example, are stacked to form a heat generating section. On the other hand, the sheet 1 and the sheet 2 such as an NbB2 sheet are alternately stacked on top of each other to form a non-heat generating section. The stacked body so made is molded under pressure and cut into a U-shaped form. This compact is sintered in N2 at a temperature approximately between 1,900 and 1,950 deg.C, thereby preparing a heater body element. Furthermore, a lead wire 5 is brazed to both ends of the element via a joint section 6, thereby providing an SiC heater body 7.

Description

【発明の詳細な説明】Detailed Description of the Invention

【０００１】[0001]

【産業上の利用分野】本発明は、ガスバーナの点火器等
各種燃焼機器の点火用及び加熱に用いるセラミック発熱
体に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ceramic heating element used for ignition and heating of various combustion equipment such as an igniter of a gas burner.

【０００２】[0002]

【従来の技術】従来、ガスバーナの点火用としては高電
圧の火花放電を利用する点火装置が用いられている。し
かしながら、この火花放電を利用した点火装置は点火時
に雑音等の電波障害を生じたり、点火に際しても信頼性
に欠け、未着火の場合には安全性にも大きな問題があっ
た。そこでこうした問題を解決するために電波障害がな
く、短時間の急速昇温が可能な点火器が要望されてい
た。2. Description of the Related Art Conventionally, an ignition device utilizing high-voltage spark discharge has been used for ignition of a gas burner. However, the ignition device using this spark discharge causes radio wave interference such as noise at the time of ignition, lacks reliability at the time of ignition, and has a serious problem in safety in case of no ignition. Therefore, in order to solve such a problem, there has been a demand for an igniter that has no electric wave interference and is capable of rapid temperature rise in a short time.

【０００３】[0003]

【発明が解決しようとする課題】こうした問題点を解決
するために、電波障害のない点火器で短時間の急速昇温
が可能なセラミック発熱体が提案されている。一方、セ
ラミック発熱体の中でもＳｉＣ発熱体はすぐれた耐熱性
と適当な抵抗値をもち、工業炉用加熱源として幅広く用
いられているが、上記の用途の点火器としても各種提案
されている。しかし、点火器はその使用上から寸法的に
小さいことが必要であるが、他方ＳｉＣは熱伝導率が高
く、小型にした場合、非発熱部と金属リード線との接合
部の信頼性に問題があった。例えば特公昭５７−９２０
３号で提案された小型ヒータは、実質的にＳｉＣからな
り発熱部と非発熱部とを形状的に断面積を変えてある。
この方法によれば、発熱部に対し、非発熱部はある程度
温度を下げられるが、ガス燃焼炉の点火用等、燃焼ガス
に長時間暴露されるような用途では接合部の信頼性が急
激に低くなり、問題であった。また他方、特開昭６０−
２５８８８９号でセラミックスシートを積層したＳｉＣ
発熱体が提案されているが、この方法によれば、非発熱
部は発熱部と同材質のＳｉＣのため、非発熱部の温度は
ほとんど下がらず、やはりガス燃焼炉の点火用等、燃焼
ガスに長時間暴露されるような用途では接合部の信頼性
が急激に低くなり、問題であった。In order to solve these problems, there has been proposed a ceramic heating element capable of rapidly raising the temperature in a short time with an igniter having no radio interference. On the other hand, among the ceramic heating elements, the SiC heating element has excellent heat resistance and an appropriate resistance value, and is widely used as a heating source for industrial furnaces, but various types of igniters have been proposed. However, the igniter needs to be small in size for its use, while SiC has a high thermal conductivity, and when it is made small, the reliability of the joint between the non-heat generating portion and the metal lead wire is a problem. was there. For example, Japanese Patent Publication No. 57-920
The small heater proposed in No. 3 is substantially made of SiC, and the heat generating portion and the non-heat generating portion have different cross-sectional areas.
According to this method, the temperature of the non-heat-generating part can be lowered to some extent with respect to the heat-generating part, but the reliability of the joint is drastically increased in applications such as ignition of a gas combustion furnace that is exposed to combustion gas for a long time. It became low and was a problem. On the other hand, JP-A-60-
SiC laminated ceramic sheets with No. 258889
Although a heating element has been proposed, according to this method, since the non-heating portion is made of SiC of the same material as that of the heating portion, the temperature of the non-heating portion hardly decreases, and the combustion gas is used for ignition of the gas combustion furnace. This is a problem in applications where the joint is exposed to light for a long time, resulting in a sudden decrease in reliability.

【０００４】[0004]

【課題を解決するための手段】本発明はこうした問題点
に鑑み、なされたもので、緻密なＳｉＣ発熱体の非発熱
部に関し、非発熱部の抵抗を大幅に低くおさえたＳｉＣ
発熱体の製造方法を提供するものである。すなわち、発
熱部と非発熱部とが一体成形されてなるＳｉＣ発熱体の
製造方法において、発熱部が実質的にＳｉＣシートの複
数層で構成され、非発熱部がＳｉＣシートのＺｒ，Ｗ，
Ｎｂよりなる群から選ばれた金属のホウ化物またはけい
化物または炭化物のシートを交互に奇数枚積層させて焼
結し、一体化することを特徴とする。SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and relates to a non-heat generating portion of a dense SiC heat generating element, in which the resistance of the non-heat generating portion is significantly reduced.
A method for manufacturing a heating element is provided. That is, in the method of manufacturing an SiC heating element in which the heating portion and the non-heating portion are integrally molded, the heating portion is substantially composed of a plurality of layers of the SiC sheet, and the non-heating portion includes Zr, W, and
It is characterized in that an odd number of sheets of a boride, silicide or carbide of a metal selected from the group consisting of Nb are alternately laminated and sintered to be integrated.

【０００５】[0005]

【作用】本発明はＳｉＣのグリーンシートと、より低抵
抗のセラミックシートを積層して発熱部と非発熱部とを
形成し、一体化してＳｉＣ発熱体を製造する方法であ
る。ここで、非発熱部をＳｉＣシートとＺｒ，Ｗ，Ｎｂ
よりなる群から選ばれた金属のホウ化物またはけい化物
または炭化物のシートを奇数枚積層としたのは、これら
の化合物はいずれも高融点化合物をつくり、しかもＳｉ
Ｃシートと熱膨張率がほぼ等しく焼結するのに適当であ
るからである。熱膨張率が大きく異なると焼結時に割れ
やキレツが生じるし、偶数枚の積層では非発熱部の抵抗
がそれほど小さくならないし、しかも反りを生じやすい
からである。The present invention is a method for producing a SiC heating element by stacking a green sheet of SiC and a ceramic sheet of lower resistance to form a heat generating portion and a non-heat generating portion. Here, the non-heat generating portion is made of SiC sheet and Zr, W, Nb.
An odd number of sheets of metal borides, silicides or carbides selected from the group consisting of these compounds are laminated because all of these compounds form a high melting point compound.
This is because it is suitable for sintering, which has almost the same coefficient of thermal expansion as the C sheet. This is because if the coefficient of thermal expansion is greatly different, cracks and crevices will occur during sintering, and the resistance of the non-heat generating portion will not be so small in the case of stacking even-numbered sheets, and moreover, warpage is likely to occur.

【０００６】[0006]

【実施例】本発明を実施例により詳細に説明する。EXAMPLES The present invention will be described in detail with reference to Examples.

【０００７】[0007]

【実施例１】ＳｉＣ粉末に対して助剤Ｂ，Ｃを添加して
発熱部原料にバインダーとしてポリビニルブチラール系
を用いてシートを作成し、また非発熱部としてホウ化ニ
オブ（ＮｂＢ_２）を主体としたシートを作成した。これ
らを図１に示すように発熱部にはＳｉＣシート５枚、非
発熱部にはＳｉＣシート２枚とホウ化ニオブシートを３
枚を積層して加圧した。さらにコの字型に切断して成形
体を得た。この成形体を窒素中１９００〜１９５０℃で
焼結し、発熱体素子とした。次に、発熱体素子の両端に
金属リード線をロウ付け接合し、ＳｉＣ発熱体とした。
ＳｉＣ発熱体の形状を図１に示した。このＳｉＣ発熱体
は割れや反り等なく、製作できた。このＳｉＣ発熱体を
１３００℃に通電発熱して接合部の温度を測定した。そ
の結果を図４−に示した。Example 1 Auxiliaries B and C were added to SiC powder to form a sheet by using polyvinyl butyral as a binder for a heat generating material, and niobium boride (NbB ₂ ) was mainly used as a non-heat generating material. Was created. As shown in FIG. 1, these are 5 SiC sheets in the heat generating portion, 2 SiC sheets and 3 niobium boride sheets in the non-heat generating portion.
The sheets were stacked and pressed. Further, it was cut into a U-shape to obtain a molded body. This molded body was sintered in nitrogen at 1900 to 1950 ° C. to obtain a heating element. Next, metal lead wires were brazed and joined to both ends of the heating element to obtain a SiC heating element.
The shape of the SiC heating element is shown in FIG. This SiC heating element could be manufactured without cracking or warping. This SiC heating element was heated at 1300 ° C. to generate heat, and the temperature of the joint was measured. The result is shown in FIG.

【０００８】[0008]

【実施例２】上記実施例１の発熱部シートと非発熱部シ
ートとして、ホウ化ジルコニウム（ＺｒＢ_２）シートを
準備した。これらを実施例１と同様の方法でＳｉＣ発熱
体を製作した。このＳｉＣ発熱体は割れや反り等なく、
製作できた。このＳｉＣ発熱体を１３００℃に通電発熱
して接合部の温度を測定した。その結果を図４−に示
した。Example 2 Zirconium boride (ZrB ₂ ) sheets were prepared as the heat generating sheet and the non-heat generating sheet of Example 1 above. A SiC heating element was manufactured from these by the same method as in Example 1. This SiC heating element has no cracks or warpage,
I was able to make it. This SiC heating element was heated at 1300 ° C. to generate heat, and the temperature of the joint was measured. The result is shown in FIG.

【０００９】[0009]

【実施例３】上記実施例１の発熱部シートと非発熱部シ
ートとして、炭化タングステン（ＷＣ）シートを準備し
た。これらを実施例１と同様の方法でＳｉＣ発熱体を製
作した。このＳｉＣ発熱体は割れや反り等なく、製作で
きた。このＳｉＣ発熱体を１３００℃に通電発熱して接
合部の温度を測定した。その結果を図４−に示した。Example 3 A tungsten carbide (WC) sheet was prepared as the heat generating part sheet and the non-heat generating part sheet of the above-mentioned Example 1. A SiC heating element was manufactured from these by the same method as in Example 1. This SiC heating element could be manufactured without cracking or warping. This SiC heating element was heated at 1300 ° C. to generate heat, and the temperature of the joint was measured. The result is shown in FIG.

【００１０】[0010]

【実施例４】上記実施例１の発熱部シートと、非発熱部
シートとして二けい化タングステン（ＷＳｉ_２）シート
を準備した。これらを実施例１と同様の方法でＳｉＣ発
熱体を製作した。このＳｉＣ発熱体は割れや反り等な
く、製作できた。このＳｉＣ発熱体を１３００℃に通電
発熱して接合部の温度を測定した。その結果を図４−
に示す。Example 4 The heat generating part sheet of the above example 1 and a tungsten disilicide (WSi ₂ ) sheet were prepared as non-heat generating part sheets. A SiC heating element was manufactured from these by the same method as in Example 1. This SiC heating element could be manufactured without cracking or warping. This SiC heating element was heated at 1300 ° C. to generate heat, and the temperature of the joint was measured. The result is shown in Figure 4-
Shown in

【００１１】[0011]

【比較例１】発熱部及び非発熱部ともにＳｉＣ粉末に対
して助剤Ｂ，Ｃを添加して、Ｗ５０×Ｌ５０×ｔ５のＳ
ｉＣ焼結体を得た。それを切断加工して非発熱部の断面
積が発熱部の断面積より大きくなるようにした。発熱体
形状を図２に示した。金属リード線は実施例１と同様に
ロウ付けした。このＳｉＣ発熱体を１３００℃に通電発
熱して接合部の温度を測定した。その結果を図４−に
示した。この時接合部の温度は短時間で５００℃以上に
なり、接合部が劣化し通電しなくなってしまった。[Comparative Example 1] Additives B and C were added to the SiC powder for both the heat generating portion and the non-heat generating portion, and S of W50 × L50 × t5 was added.
An iC sintered body was obtained. It was cut and processed so that the cross-sectional area of the non-heat generating portion was larger than that of the heat generating portion. The shape of the heating element is shown in FIG. The metal lead wire was brazed in the same manner as in Example 1. This SiC heating element was heated at 1300 ° C. to generate heat, and the temperature of the joint was measured. The result is shown in FIG. At this time, the temperature of the joint portion became 500 ° C. or higher in a short time, and the joint portion was deteriorated and no current was supplied.

【００１２】[0012]

【比較例２】ＳｉＣ粉末に対して助剤Ｂ，Ｃを添加して
ＳｉＣシートとＡｌＮ主体の絶縁性シートを作成して、
これら３枚を積層して加圧した。さらにコの字型に切断
して成形体を得た。この成形体を窒素中１９００〜１９
５０℃焼結し、発熱体素子とした。次に、発熱体素子の
両端に金属リード線をロウ付け接合し、ＳｉＣ発熱体と
した。ＳｉＣ発熱体の形状を図３に示した。このＳｉＣ
発熱体は割れや反り等なく、製作できた。このＳｉＣ発
熱体を１３００℃に通電発熱して接合部の温度を測定し
た。その結果を図４−に示した。この時接合部の温度
は短時間で５００℃以上になり、接合部が劣化し通電し
なくなってしまった。以上から比較例におけるセラミッ
ク発熱体が非発熱部の温度上昇により断線したりして長
時間の使用に耐えなかったのに対し、本発明のセラミッ
ク発熱体は非発熱部の温度上昇も少なく、長時間安定し
て使用できることがわかった。[Comparative Example 2] Auxiliaries B and C were added to SiC powder to prepare an SiC sheet and an AlN-based insulating sheet.
These three sheets were laminated and pressed. Further, it was cut into a U-shape to obtain a molded body. This molded body was placed in nitrogen at 1900 to 19
It was sintered at 50 ° C. to obtain a heating element. Next, metal lead wires were brazed and joined to both ends of the heating element to obtain a SiC heating element. The shape of the SiC heating element is shown in FIG. This SiC
The heating element could be manufactured without cracking or warping. This SiC heating element was heated at 1300 ° C. to generate heat, and the temperature of the joint was measured. The result is shown in FIG. At this time, the temperature of the joint portion became 500 ° C. or higher in a short time, and the joint portion was deteriorated and no current was supplied. From the above, the ceramic heating element in the comparative example could not withstand long-time use due to disconnection due to the temperature rise of the non-heating part, whereas the ceramic heating element of the present invention showed a small temperature rise of the non-heating part and It turns out that it can be used stably for a long time.

【００１３】[0013]

【発明の効果】本発明のセラミック発熱体はガス点火用
として従来にない安全で確実な点火器として使用でき
る。この点火器を使用すれば、長時間の使用に耐え、メ
ンテナンスを含めた大幅なコスト低減が可能となる。INDUSTRIAL APPLICABILITY The ceramic heating element of the present invention can be used as a safe and reliable igniter which has never been used for gas ignition. If this igniter is used, it can be used for a long time and the cost including maintenance can be significantly reduced.

【図面の簡単な説明】[Brief description of drawings]

【図１】本発明のＳｉＣ発熱体を示す図。FIG. 1 is a diagram showing a SiC heating element of the present invention.

【図２】従来のＳｉＣ発熱体を示す図。FIG. 2 is a diagram showing a conventional SiC heating element.

【図３】従来のＳｉＣ発熱体の他の実施例を示す図。FIG. 3 is a diagram showing another example of a conventional SiC heating element.

【図４】接合部の温度変化を示すグラフ。FIG. 4 is a graph showing a change in temperature of a bonded portion.

【符号の説明】[Explanation of symbols]

１．ＳｉＣシート ２．非発熱部シート ３．ＳｉＣ発熱体素子 ４．絶縁性シート ５．金属リード線 ６．接合部 ７．ＳｉＣ発熱体 1. SiC sheet 2. Non-heating part sheet 3. SiC heating element 4. Insulating sheet 5. Metal lead wire 6. Joint 7. SiC heating element

Claims (1)

【特許請求の範囲】[Claims] 【請求項１】 発熱部と非発熱部とが一体成形されて
なるＳｉＣ発熱体の製造方法において、発熱部が実質的
にＳｉＣシートの複数層で構成され、非発熱部がＳｉＣ
シートとＺｒ，Ｗ，Ｎｂよりなる群から選ばれた金属の
ホウ化物またはけい化物または炭化物のシートを交互に
奇数枚積層させて焼結し一体化することを特徴とするＳ
ｉＣ発熱体の製造方法。1. A method of manufacturing an SiC heating element, wherein a heating portion and a non-heating portion are integrally molded, wherein the heating portion is substantially composed of a plurality of layers of a SiC sheet, and the non-heating portion is SiC.
The sheet is characterized in that an odd number of sheets of boride, silicide or carbide of a metal selected from the group consisting of Zr, W and Nb are alternately laminated and sintered to be integrated.
iC heating element manufacturing method.