JPH07318055A - Ceramic heat generator - Google Patents
Ceramic heat generatorInfo
- Publication number
- JPH07318055A JPH07318055A JP11841894A JP11841894A JPH07318055A JP H07318055 A JPH07318055 A JP H07318055A JP 11841894 A JP11841894 A JP 11841894A JP 11841894 A JP11841894 A JP 11841894A JP H07318055 A JPH07318055 A JP H07318055A
- Authority
- JP
- Japan
- Prior art keywords
- silicon nitride
- sintered body
- heating element
- nitride sintered
- grain boundary
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は各種加熱用ヒーター等に
好適な高温用のセラミック発熱体に関し、とりわけディ
ーゼルエンジンの始動時やアイドリング時に副燃焼室内
を急速に予熱する自己飽和型のグロープラグに用いられ
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 high temperature ceramic heating element suitable for various heating heaters, and more particularly to a self-saturation type glow plug which rapidly preheats a sub combustion chamber at the time of starting or idling a diesel engine. The present invention relates to a ceramic heating element used.
【０００２】[0002]
【従来の技術】従来よりディーゼルエンジンの始動促進
に用いられるグロープラグや各種点火用及び加熱用ヒー
ターとして、耐熱金属製のシース内に耐熱絶縁粉末とと
もにニッケル（Ｎｉ）−クロム（Ｃｒ）等を主体とする
高融点金属線から成る発熱抵抗体を埋設したシーズヒー
ターや、高電圧の火花放電を利用する各種点火装置が使
用されていた。2. Description of the Related Art Conventionally, nickel (Ni) -chromium (Cr) and the like are used in a sheath made of a heat-resistant metal together with a heat-resistant insulating powder as a glow plug and various ignition and heating heaters used to accelerate the starting of a diesel engine. A sheathed heater having a heating resistor made of a high melting point metal wire embedded therein and various ignition devices utilizing high-voltage spark discharge have been used.
【０００３】しかしながら、前記シーズヒーターは、耐
熱絶縁粉末を介して発熱抵抗体の熱を伝えるため、急速
昇温が困難であり、その上、耐摩耗性や耐久性に劣ると
いう問題があり、更に、前記火花放電を利用した各種点
火装置も、点火時に雑音等の電波障害を生じたり、確実
な点火と未着火の場合の安全性という点からの信頼性に
欠ける等の欠点があった。However, since the sheathed heater transfers the heat of the heat-generating resistor through the heat-resistant insulating powder, it is difficult to rapidly raise the temperature, and in addition, there is a problem that it is inferior in wear resistance and durability. The various ignition devices using the spark discharge also have drawbacks such as occurrence of radio interference such as noise at the time of ignition, and lack of reliability in terms of reliable ignition and safety in case of non-ignition.
【０００４】そこで、熱伝達効率が優れ、急速昇温が可
能で、電波障害が発生せず、しかも確実に点火して安全
性を確保し、耐摩耗性と耐久性に優れた信頼性の高い発
熱体として、セラミック焼結体中に高融点金属等の無機
導電材から成る発熱抵抗体を埋設したセラミック発熱体
が、内燃機関のグロープラグをはじめ、各種加熱用ヒー
ターとして広く利用されるようになってきた。Therefore, the heat transfer efficiency is excellent, the temperature can be rapidly raised, the radio wave interference does not occur, the ignition is surely performed to ensure the safety, and the wear resistance and durability are excellent and the reliability is high. As a heating element, a ceramic heating element in which a heating resistor made of an inorganic conductive material such as a high melting point metal is embedded in a ceramic sintered body is widely used as a heater for various heating such as a glow plug of an internal combustion engine. It's coming.
【０００５】前記セラミック発熱体の基体は、耐熱性や
耐熱衝撃性、耐酸化特性に優れるという点から窒化珪素
質焼結体が採用される場合が多いが、記窒化珪素質焼結
体と発熱抵抗体との熱膨張差により窒化珪素質焼結体自
体にクラックが発生し易い上、そのようなセラミック発
熱体を通電加熱により１０００℃以上に発熱させると前
記窒化珪素質焼結体の粒界相が一般にガラス質を形成し
ていることから、粒界相の軟化による焼結体の強度劣化
や、粒界相のイオン移動による組織劣化を引き起こし、
セラミック発熱体の基体にクラックが発生したり、基体
の窒化珪素質焼結体が酸化されて発熱抵抗体の抵抗値が
変化したりして、やがて発熱抵抗体自体が断線する等の
欠点があった。As the substrate of the ceramic heating element, a silicon nitride-based sintered body is often used because of its excellent heat resistance, thermal shock resistance and oxidation resistance. Cracks are likely to occur in the silicon nitride sintered body itself due to the difference in thermal expansion from the resistor, and when such a ceramic heating element is heated to 1000 ° C. or more by electric heating, the grain boundaries of the silicon nitride sintered body are increased. Since the phase generally forms a glassy material, it causes strength deterioration of the sintered body due to softening of the grain boundary phase and structure deterioration due to ion migration of the grain boundary phase,
There are drawbacks such as cracks occurring in the base of the ceramic heating element and changes in the resistance value of the heating resistor due to oxidation of the silicon nitride sintered body of the substrate, which eventually causes the heating resistor to break. It was
【０００６】そこで、前記欠点を解消するために、従来
から添加する焼結助剤の種類と添加量が種々検討されて
おり、それに伴い窒化珪素質焼結体の粒界相を結晶化す
ること等が提案されている（特開平１−３１３３６２号
公報参照）。Therefore, in order to solve the above-mentioned drawbacks, various kinds and amounts of sintering aids to be added have been studied conventionally, and along with that, crystallize the grain boundary phase of the silicon nitride sintered body. Have been proposed (see Japanese Patent Laid-Open No. 1-313362).
【０００７】[0007]
【発明が解決しようとする課題】しかしながら、前記窒
化珪素質焼結体と発熱抵抗体との熱膨張差を小さくする
ために、焼結助剤としてＭｏＳｉ2 を用いた場合、埋設
した発熱抵抗体を焼結一体化する際に、発熱抵抗体自身
が珪化され易く、珪化した発熱抵抗体部分が通電稼働中
に短期間にクラックを生じ、抵抗変化を起こして耐久性
に劣るという課題があった。However, when MoSi 2 is used as a sintering aid in order to reduce the difference in thermal expansion between the silicon nitride sintered body and the heating resistor, the embedded heating resistor is used. However, there was a problem that the heat-generating resistor itself was easily silicified during the sintering and integration, and the silicified heat-generating resistor part generated cracks in a short period during energization, causing resistance change and inferior durability. .
【０００８】また、昨今セラミック発熱体の使用環境は
更に過酷でかつ高酸化性雰囲気となりつつあり、粒界相
を結晶化した窒化珪素質焼結体を基体とするセラミック
発熱体を、内燃機関のグロープラグや各種点火用および
加熱用ヒーターとして１０００℃以上の高温用として用
いた場合、一般に点火時には１０００〜１３００℃とな
り、更には点火した火炎に曝されて１３５０℃を越える
ような状況となり、このような加熱冷却が反復されるこ
とにより、埋設した無機導電材から成る発熱抵抗体が経
時変化を起こし、短時間で１０％を越える抵抗変化を生
じ、やがて発熱抵抗体が断線してしまう恐れがある他、
窒化珪素質焼結体自体が酸化され易く、実用上、耐久性
に欠けるという課題があった。In recent years, the environment in which ceramic heating elements are used is becoming more severe and highly oxidative, and ceramic heating elements based on a silicon nitride sintered body in which a grain boundary phase is crystallized are used as internal combustion engine internal combustion engines. When used as a glow plug or a heater for ignition and heating at various temperatures of 1000 ° C. or higher, the temperature is generally 1000 to 1300 ° C. at the time of ignition and further exposed to an ignited flame to exceed 1350 ° C. By repeating such heating and cooling, the heating resistor made of the embedded inorganic conductive material may change over time, causing a resistance change of more than 10% in a short time, and eventually the heating resistor may be broken. In addition,
The silicon nitride sintered body itself is easily oxidized, and there is a problem in that it lacks durability in practical use.
【０００９】[0009]
【発明の目的】本発明は前記欠点に鑑みなされたもの
で、その目的は、焼結一体化時に発熱抵抗体が珪化され
難く、得られたセラミック発熱体は常温付近から１００
０℃付近の高温に瞬時に発熱させることを長時間にわた
り何度も繰り返したり、１０００℃以上の高温で長時間
の連続稼働をしても、発熱抵抗体の抵抗変化率が大きく
変化しないことは勿論、発熱抵抗体が断線したりセラミ
ック発熱体の基体にクラックが発生したり、窒化珪素質
焼結体自体が酸化したりせず、耐久性に優れたセラミッ
ク発熱体を提供することにある。SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned drawbacks, and it is an object of the present invention that the heating resistor is less likely to be silicified at the time of sintering and integration, and the ceramic heating element thus obtained has a temperature of 100 to 100 ° C.
The resistance change rate of the heating resistor does not change significantly even if instant heat generation at a high temperature near 0 ° C is repeated many times over a long period of time or even after continuous operation at a high temperature of 1000 ° C or more for a long time. Of course, it is an object of the present invention to provide a ceramic heating element having excellent durability without breaking the heating resistor, cracking the base of the ceramic heating element, or oxidizing the silicon nitride sintered body itself.
【００１０】[0010]
【課題を解決するための手段】本発明者等は、埋設する
発熱抵抗体の珪化を防止するためには、焼成過程でＳｉ
の生成を阻止すること、また、セラミック発熱体の抵抗
変化を抑制して高温耐久性を向上するためには、窒化珪
素質焼結体の粒界相をより融点の高い結晶相のみで構成
する事が肝要であるとの見地から種々検討した結果、前
記窒化珪素質焼結体の粒界相にＭｏ4.8 Ｓｉ3 Ｃ0.6 と
ＭｏＳｉ2 の結晶を共存させることにより、Ｓｉの生成
が阻止でき、また前記窒化珪素質焼結体の熱履歴前の粒
界に存在する結晶相に、ＲＥ2 Ｏ3 ・ＳｉＯ2 （以降、
ＲＥは周期律表第３ａ族元素をいう）で表されるモノシ
リケートが存在することにより、セラミック発熱体の抵
抗変化を抑制できることを見いだし、本発明に至った。In order to prevent silicidation of the embedded heating resistor, the inventors of the present invention have adopted Si during the firing process.
In order to prevent the formation of the above, and to suppress the resistance change of the ceramic heating element and improve the high temperature durability, the grain boundary phase of the silicon nitride sintered body is composed only of the crystal phase having a higher melting point. As a result of various studies from the viewpoint that it is essential, the coexistence of Mo 4.8 Si 3 C 0.6 and MoSi 2 crystals in the grain boundary phase of the silicon nitride sintered body can prevent Si generation, In addition, in the crystal phase existing in the grain boundary before the thermal history of the silicon nitride sintered body, RE 2 O 3 · SiO 2 (hereinafter,
It has been found that the presence of a monosilicate represented by Group 3a element of the periodic table (RE) can suppress the change in resistance of the ceramic heating element, and has reached the present invention.
【００１１】即ち、本発明のセラミック発熱体は、無機
導電材から成る発熱抵抗体を埋設した基体である窒化珪
素質焼結体の粒界相が、Ｍｏ4.8 Ｓｉ3 Ｃ0.6 とＭｏＳ
ｉ2の結晶を共存し、かつ前記窒化珪素質焼結体の熱履
歴前の粒界相が、該粒界相に存在するＲＥのシリケート
から成る結晶相の内、ＲＥ2 Ｏ3 ・ＳｉＯ2 で表される
モノシリケートを含有することを特徴とするものであ
る。That is, in the ceramic heating element of the present invention, the grain boundary phase of the silicon nitride sintered body, which is the substrate in which the heating resistor made of an inorganic conductive material is embedded, is Mo 4.8 Si 3 C 0.6 and MoS.
i 2 of coexisting crystal, and thermal history before the grain boundary phase of the silicon nitride sintered body, of the crystalline phase consisting of a silicate of RE present in particulate boundary phase, RE 2 O 3 · SiO 2 It is characterized by containing a monosilicate represented by.
【００１２】また、前記窒化珪素質焼結体中のＲＥ2 Ｏ
3 に対するＳｉＯ2 のモル比が０．８〜１．８の範囲、
あるいはＡｌ2 Ｏ3 が０．５〜１．０重量％の範囲で含
有していること、あるいはＲＥ2 Ｏ3 ・ＳｉＯ2 で表さ
れるモノシリケートのＲＥが、ＹｂまたはＹ、Ｈｏ、Ｅ
ｒ、Ｌｕのいずれかであることがより望ましいものであ
る。In addition, RE 2 O in the silicon nitride sintered body
The molar ratio of SiO 2 to 3 is in the range of 0.8 to 1.8,
Alternatively, Al 2 O 3 is contained in the range of 0.5 to 1.0% by weight, or the monosilicate RE represented by RE 2 O 3 .SiO 2 is Yb or Y, Ho, E.
More preferably, it is either r or Lu.
【００１３】[0013]
【作用】本発明のセラミック発熱体によれば、窒化珪素
質焼結体の粒界相がＭｏ4.8 Ｓｉ3 Ｃ0.6 とＭｏＳｉ2
の結晶を共存することにより、埋設した発熱抵抗体が珪
化されない状態で焼結が進み、それとともに窒化珪素質
焼結体と発熱抵抗体との熱膨張差が小さくなる。According to the ceramic heating element of the present invention, the grain boundary phases of the silicon nitride sintered body are Mo 4.8 Si 3 C 0.6 and MoSi 2
The coexistence of the crystals of (1) causes sintering to proceed in a state where the embedded heating resistor is not silicified, and at the same time, the difference in thermal expansion between the silicon nitride sintered body and the heating resistor is reduced.
【００１４】更に、窒化珪素質焼結体の熱履歴前の粒界
相が、ＲＥ2 Ｏ3 ・２ＳｉＯ2 で表されるダイシリケー
トより更に融点が高く、窒化珪素質焼結体との熱膨張差
が小さく、かつ耐熱性に優れたＲＥ2 Ｏ3 ・ＳｉＯ2 で
表されるモノシリケートを含有していることから、長時
間に及ぶ昇温、降温の繰り返しでも通電時のイオン移動
が起こり難く、その結果、抵抗変化を生じ難く、高温強
度と耐酸化特性等が維持され、急速昇温特性を損なうこ
となく好適な自己飽和温度特性が得られ、耐久性及び信
頼性が向上することになる。Further, the grain boundary phase of the silicon nitride sintered material before the thermal history has a higher melting point than that of the die silicate represented by RE 2 O 3 .2SiO 2 , and the thermal expansion with the silicon nitride sintered material. Since it contains a monosilicate represented by RE 2 O 3 · SiO 2 with a small difference and excellent heat resistance, it is difficult for ion migration during energization to occur even after repeated heating and cooling for a long time. As a result, resistance change is unlikely to occur, high-temperature strength, oxidation resistance, etc. are maintained, suitable self-saturation temperature characteristics are obtained without impairing rapid temperature rise characteristics, and durability and reliability are improved. .
【００１５】また、前記モノシリケートを含有する窒化
珪素質焼結体を高温の酸化性雰囲気に長期間暴露してい
ると、窒化珪素質焼結体表面を通して酸素が拡散され、
窒化珪素質焼結体が酸化されてシリカ（ＳｉＯ2 ）を生
成するようになり、該ＳｉＯ2 は、相平衡上、ＲＥ2 Ｏ
3 ・ＳｉＯ2 と平衡には存在できず、反応してＲＥ2Ｏ
3 ・２ＳｉＯ2 が生成されるようになる。When the silicon nitride sintered body containing the monosilicate is exposed to a high temperature oxidizing atmosphere for a long period of time, oxygen is diffused through the surface of the silicon nitride sintered body,
The silicon nitride sintered body is oxidized to form silica (SiO 2 ), and the SiO 2 has a phase equilibrium with RE 2 O.
3・ SiO 2 cannot exist in equilibrium and reacts with RE 2 O
3 · 2SiO 2 is to be produced.
【００１６】しかしながら、いったん窒化珪素質焼結体
表面近傍の粒界相に形成されたＲＥ2 Ｏ3 ・２ＳｉＯ2
は、ＳｉＯ2 とは高温まで安定であり、反応も拡散も起
こさず平衡に存在できることから、耐熱安定性は逆に増
加する。However, once RE 2 O 3 .2SiO 2 is formed in the grain boundary phase near the surface of the silicon nitride sintered material.
Is stable up to a high temperature with respect to SiO 2 and can exist in equilibrium without causing reaction or diffusion, so that heat resistance stability is increased.
【００１７】[0017]
【実施例】以下、本発明のセラミック発熱体を図面に基
づき詳述する。図１は本発明のセラミック発熱体の一実
施例の正面の要部を示す断面図であり、図２は本発明の
セラミック発熱体の側面の要部を示す断面図である。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The ceramic heating element of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a sectional view showing an essential part of a front surface of an embodiment of the ceramic heating element of the present invention, and FIG. 2 is a sectional view showing an essential part of a side surface of the ceramic heating element of the present invention.
【００１８】図１及び図２において、１は窒化珪素質焼
結体２中に、略平行な２層の無機導電材から成る略Ｕ字
状を成す層状の発熱抵抗体３と、発熱抵抗体３の各端部
に少なくとも一部を重ねて形成した層状の発熱抵抗体４
を介して接続した高融点金属の線材から成るリード線５
と、リード線５にそれぞれ接続した無機導電材から成る
複数個に分割した電極取り出し層６を埋設し、電極取り
出し層６の一部が窒化珪素質焼結体２の外周面に露出す
るとともに、その先端が略球面で、断面が円形を成した
セラミック発熱体である。In FIGS. 1 and 2, reference numeral 1 denotes a silicon nitride sintered body 2 having a substantially U-shaped layered heating resistor 3 made of two substantially parallel inorganic conductive materials, and a heating resistor. Layered heating resistor 4 formed by overlapping at least a part on each end of 3
Lead wire 5 made of a high melting point metal wire connected through
And a plurality of divided electrode lead-out layers 6 each made of an inorganic conductive material connected to the lead wire 5 are buried, and a part of the electrode lead-out layer 6 is exposed on the outer peripheral surface of the silicon nitride sintered body 2, and It is a ceramic heating element having a substantially spherical tip and a circular cross section.
【００１９】前記窒化珪素質焼結体２の組成は、ＲＥ2
Ｏ3 に対するＳｉＯ2 のモル比が、粒界相を高い融点に
保ち、かつ粒界相の耐酸化性に優れるという観点から
は、０．８〜１．８の範囲であることが望ましい。The composition of the silicon nitride sintered body 2 is RE 2
The molar ratio of SiO 2 to O 3 is preferably in the range of 0.8 to 1.8 from the viewpoint of keeping the grain boundary phase at a high melting point and excellent in the oxidation resistance of the grain boundary phase.
【００２０】また、前記窒化珪素質焼結体２の１４００
℃以上における高温での耐酸化性および粒界相のＭｏ
4.8 Ｓｉ3 Ｃ0.6 の耐酸化性を増強するという観点から
は、Ａｌ2 Ｏ3 の含有量が０．５〜１．０重量％の範囲
がより望ましい。Further, 1400 of the above-mentioned silicon nitride sintered body 2
Oxidation resistance at high temperature above ℃ and Mo of grain boundary phase
From the viewpoint of enhancing the oxidation resistance of 4.8 Si 3 C 0.6 , the content of Al 2 O 3 is more preferably in the range of 0.5 to 1.0% by weight.
【００２１】更に、前記窒化珪素質焼結体２の熱履歴前
の粒界相における結晶相として、後述するＸ線回折法に
より同定したピーク強度の比率が、ＲＥ2 Ｏ3 ・ＳｉＯ
2 で表されるモノシリケートに関しては２０％以上、と
りわけ２５％以上がより望ましいものである。Further, as the crystal phase in the grain boundary phase before the thermal history of the silicon nitride sintered body 2, the ratio of peak intensities identified by the X-ray diffraction method described later is RE 2 O 3 .SiO 2.
With respect to the monosilicate represented by 2 , 20% or more, particularly 25% or more is more desirable.
【００２２】また、ＲＥ2 Ｏ3 ・２ＳｉＯ2 で表される
ダイシリケートは、前記モノシリケートと共存していて
も良い。Further, the disilicate represented by RE 2 O 3 .2SiO 2 may coexist with the monosilicate.
【００２３】また、前記モノシリケートの生成には、原
料中の酸素量、とりわけ窒化珪素原料中の酸素量を極力
低減し、焼結助剤として添加するＲＥ2 Ｏ3 の量も１
０．５〜１５％程度に増加させ、焼成中に酸素量やＳｉ
Ｏ2 が増加しないようにＳｉ／ＳｉＯ2 雰囲気を調整す
ることが望ましい。Further, in the formation of the monosilicate, the amount of oxygen in the raw material, particularly the amount of oxygen in the silicon nitride raw material is reduced as much as possible, and the amount of RE 2 O 3 added as a sintering aid is also 1.
0.5 to 15% to increase the amount of oxygen and Si during firing.
It is desirable to adjust the Si / SiO 2 atmosphere so that O 2 does not increase.
【００２４】尚、前記ＳｉＯ2 とは、いわゆる焼結体中
に存在する過剰酸素であり、具体的には焼結体中の全酸
素量から焼結体中のＲＥが化学量論的に酸化物を形成し
た場合に元素に結合している酸素を除いた残りの酸素量
であり、そのほとんどは窒化珪素原料に含まれる酸素で
ある。The above-mentioned SiO 2 is so-called excess oxygen existing in a so-called sintered body, and specifically, RE in the sintered body is stoichiometrically oxidized from the total amount of oxygen in the sintered body. It is the amount of oxygen remaining excluding oxygen bound to the element when a substance is formed, and most of it is oxygen contained in the silicon nitride raw material.
【００２５】また、前記焼結助剤として添加するＲＥ2
Ｏ3 は、焼結過程で窒化珪素粒子との反応により液相と
なって焼結を促進するが、冷却後そのまま粒界相にガラ
ス相として残存すると耐酸化特性を劣化させてしまうた
め、所定の冷却過程あるいは熱処理により粒界に結晶相
として析出させることが必要である。RE 2 added as the sintering aid
O 3 becomes a liquid phase by a reaction with silicon nitride particles during the sintering process and promotes sintering, but if it remains as a glass phase in the grain boundary phase as it is after cooling, it deteriorates the oxidation resistance property. It is necessary to precipitate as a crystal phase at the grain boundary by the cooling process or heat treatment of.
【００２６】尚、本発明に用いられるＲＥとしては、イ
ットリウム（Ｙ）やランタノイド元素が挙げられるが、
耐酸化性の点からはイオン半径が小さいＹｂまたはＹ、
Ｈｏ、Ｅｒ、Ｌｕが、とりわけＹｂが最も好ましい。Examples of RE used in the present invention include yttrium (Y) and lanthanoid elements.
From the viewpoint of oxidation resistance, Yb or Y with a small ionic radius,
Ho, Er and Lu are most preferable, and Yb is most preferable.
【００２７】また、窒化珪素質焼結体中には不可避不純
物としてＡｌ、Ｃａ、Ｍｇ、Ｆｅ等が含まれることがあ
るが、これらの元素は酸化物として低融点物質を形成し
易く、高温特性を劣化させる傾向を示すことから、これ
らの成分は酸化物換算で０．５重量％以下に制御するこ
とが望ましい。Although the silicon nitride sintered material may contain Al, Ca, Mg, Fe and the like as unavoidable impurities, these elements easily form a low melting point substance as an oxide and have high temperature characteristics. It is desirable to control these components to 0.5 wt% or less in terms of oxides, since they tend to deteriorate.
【００２８】その他、窒化珪素質焼結体の特性、特に前
記粒界相の結晶化に悪影響を及ぼさない範囲で、Ｔｉ
Ｃ、ＴｉＮ、ＷＣ、ＷＯ3 、ＮｂＣ、ＴａＣ、ＭｏＳｉ
2 等の周期律表第４ａ、５ａ、６ａ族元素の炭化物、窒
化物、酸化物、炭窒化物、珪化物等も、窒化珪素質焼結
体と電極材料との熱膨張差を減少させて耐熱衝撃性を向
上させ、焼結助剤としても有効な点から添加することが
できる。In addition, in the range that does not adversely affect the characteristics of the silicon nitride sintered material, particularly the crystallization of the grain boundary phase, Ti
C, TiN, WC, WO 3 , NbC, TaC, MoSi
Carbides, nitrides, oxides, carbonitrides, silicides, etc. of Group 4a, 5a, 6a elements of the periodic table such as 2 also reduce the difference in thermal expansion between the silicon nitride sintered body and the electrode material. It can be added from the viewpoint of improving the thermal shock resistance and being effective as a sintering aid.
【００２９】また、無機導電材から成る発熱抵抗体３、
４あるいは電極取り出し層６の主成分は、タングステン
（Ｗ）、モリブデン（Ｍｏ）、レニウム（Ｒｅ）等の高
融点金属やその合金の他、例えばタングステンカーバイ
ド（ＷＣ）、窒化チタン（ＴｉＮ）や硼化ジルコニウム
（ＺｒＢ2 ）等の第４ａ族、第５ａ族、第６ａ族の炭化
物または窒化物等があり、とりわけ高温まで無機導電材
として窒化珪素質焼結体との熱膨張差が小さく、熱衝撃
抵抗性に優れ、安定した特性を有するタングステンカー
バイド（ＷＣ）が好ましい。Further, the heating resistor 3 made of an inorganic conductive material,
4 or the main component of the electrode take-out layer 6 is not only a refractory metal such as tungsten (W), molybdenum (Mo), rhenium (Re) or an alloy thereof, but also tungsten carbide (WC), titanium nitride (TiN) or boron. There are carbides or nitrides of Group 4a, Group 5a, and Group 6a such as zirconium nitride (ZrB 2 ) and the like, and the difference in thermal expansion between the silicon nitride sintered body as an inorganic conductive material is small up to a high temperature. Tungsten carbide (WC) having excellent impact resistance and stable properties is preferable.
【００３０】一方、リード線５には、導電性の点から高
融点金属であるタングステン（Ｗ）、モリブデン（Ｍ
ｏ）、レニウム（Ｒｅ）やその合金等が上げられるが、
とりわけ設計のし易さからはタングステン（Ｗ）が好適
である。On the other hand, the lead wire 5 has high conductivity metals such as tungsten (W) and molybdenum (M) from the viewpoint of conductivity.
o), rhenium (Re) and its alloys, etc.
Above all, tungsten (W) is preferable from the viewpoint of easy design.
【００３１】また、セラミック発熱体の先端を略球面と
し、その断面を円形と成したのは、先端部近傍に最高発
熱部を有し、外周に効果的に均一に発熱させるためであ
り、この形状に限定されるものではない。The reason why the ceramic heating element has a substantially spherical tip and a circular cross section is to have a maximum heat generating portion near the tip and to effectively and uniformly generate heat on the outer periphery. The shape is not limited.
【００３２】次に、本発明のセラミック発熱体を評価す
るにあたり、先ず、比表面積が７〜１５ｍ2 ／ｇ、含有
する不可避不純物としての酸素量が１．５重量％以下、
金属不純物が０．０５重量％以下の窒化珪素（Ｓｉ3 Ｎ
4 ）粉末に、焼結助剤として周期律表第３ａ族元素の酸
化物とアルミナ（Ａｌ2 Ｏ3 ）、珪化モリブデン（Ｍｏ
Ｓｉ2 ）を焼結体組成が表１及び表２となるように秤量
したものを添加混合して調製し、得られた造粒体を使用
し、プレス成形法等、周知の成形法により平板状の窒化
珪素を主成分とするセラミック成形体を作製する。但
し、表１及び表２に示す焼結体組成中の珪化モリブデン
量はＭｏ4.8 Ｓｉ3 Ｃ0.6 とＭｏＳｉ2 の合計量であ
る。Next, in evaluating the ceramic heating element of the present invention, first, the specific surface area is 7 to 15 m 2 / g, the oxygen content as an inevitable impurity is 1.5 wt% or less,
Silicon nitride (Si 3 N containing less than 0.05% by weight of metal impurities)
4 ) Add powder of oxide of Group 3a element of the periodic table, alumina (Al 2 O 3 ), molybdenum silicide (Mo) to the powder as a sintering aid.
Si 2 ) was prepared by adding and mixing those weighed so that the composition of the sintered body was as shown in Table 1 and Table 2, and using the obtained granulated body, a flat plate was formed by a well-known molding method such as press molding method. A ceramic molded body containing silicon nitride as a main component is produced. However, the amount of molybdenum silicide in the composition of the sintered body shown in Tables 1 and 2 is the total amount of Mo 4.8 Si 3 C 0.6 and MoSi 2 .
【００３３】次に、タングステンカーバイド（ＷＣ）の
微粉末８０重量％と窒化珪素（Ｓｉ3 Ｎ4 ）の微粉末２
０重量％の混合粉末に溶媒を加えて調製したペーストを
使用して、スクリーン印刷法等により略Ｕ字形状のパタ
ーンで、セラミック焼結体の先端より５ｍｍ以内に位置
するようにそれぞれ別のセラミック成形体の表面に、厚
さ約４０μm の発熱抵抗体３を形成する。Next, 80% by weight of fine powder of tungsten carbide (WC) and fine powder of silicon nitride (Si 3 N 4 ) 2
Using a paste prepared by adding a solvent to 0% by weight of mixed powder, a different U-shaped pattern is formed by a screen printing method or the like so that each ceramic is positioned within 5 mm from the tip of the ceramic sintered body. A heating resistor 3 having a thickness of about 40 μm is formed on the surface of the molded body.
【００３４】次に、８５重量％のタングステンカーバイ
ド（ＷＣ）と１５重量％の窒化珪素（Ｓｉ3 Ｎ4 ）の各
微粉末から成るペーストを使用して、前記発熱抵抗体３
の端部に一部重なるようにして厚さ約４０μm の発熱抵
抗体４を形成する。Next, the heating resistor 3 is formed by using a paste composed of fine powders of 85% by weight of tungsten carbide (WC) and 15% by weight of silicon nitride (Si 3 N 4 ).
A heating resistor 4 having a thickness of about 40 μm is formed so as to partially overlap with the end of the heating resistor 4.
【００３５】一方、電極取り出し層６も、発熱抵抗体４
と同一組成のペーストを使用して前記セラミック成形体
表面の他端に、前記同様にして幅０．７ｍｍ、厚さ７０
μmのパターンを４個、セラミック成形体の側面まで平
行に所定の配置でそれぞれ形成した。On the other hand, the electrode lead-out layer 6 also includes the heating resistor 4
0.7 mm in width and 70 mm in thickness in the same manner as described above on the other end of the surface of the ceramic molded body using a paste having the same composition as
Four μm patterns were formed in parallel to the side surface of the ceramic molded body in a predetermined arrangement.
【００３６】次に、発熱抵抗体３、４及び電極取り出し
層６をそれぞれ印刷形成したセラミック成形体の上に、
直径０．２５ｍｍのタングステン（Ｗ）線を発熱抵抗体
４と各電極取り出し層６にそれぞれ接続するように載置
して重ね、その上に発熱抵抗体と電極取り出し層を印刷
形成していないセラミック成形体を重ねた後、Ｓｉ／Ｓ
ｉＯ2 雰囲気を調整した炭素（Ｃ）を含む還元性の雰囲
気下、１７５０℃の温度で１時間、加圧焼成した。Next, the heating resistors 3 and 4 and the electrode lead-out layer 6 are respectively formed on the ceramic formed body by printing,
A tungsten (W) wire having a diameter of 0.25 mm is placed and stacked so as to be connected to the heating resistor 4 and each electrode lead-out layer 6, respectively, and the heating resistor and the electrode lead-out layer are not formed on the ceramic by printing. After stacking compacts, Si / S
It was pressure-fired at a temperature of 1750 ° C. for 1 hour in a reducing atmosphere containing carbon (C) with an adjusted iO 2 atmosphere.
【００３７】その後、窒素ガス中、１４００℃の温度で
２４時間、熱処理をして粒界相を結晶化した。Then, heat treatment was performed in nitrogen gas at a temperature of 1400 ° C. for 24 hours to crystallize the grain boundary phase.
【００３８】かくして得られた窒化珪素質焼結体２の周
囲を研磨し、先端を球面とするとともに断面円形に加工
し、埋設した各電極取り出し層６の端面を円柱側面に露
出させ、直径約３．５ｍｍのセラミック発熱体を作製し
た。The periphery of the thus obtained silicon nitride sintered body 2 is polished, the tip is made spherical and processed to have a circular cross section, and the end surface of each of the embedded electrode take-out layers 6 is exposed to the side surface of a cylinder, and the diameter is about A 3.5 mm ceramic heating element was prepared.
【００３９】先ず、前記セラミック発熱体の表面を１０
０μm 以上研磨除去した後、乳鉢で粗粉砕して前記無機
導電材を除去し、微粉砕した窒化珪素質焼結体の粉末を
燃焼式ガス分析装置により酸素量を測定した。First, the surface of the ceramic heating element
After polishing and removing it by 0 μm or more, the inorganic conductive material was removed by coarse pulverization in a mortar, and the finely pulverized powder of the silicon nitride sintered body was measured for oxygen content by a combustion gas analyzer.
【００４０】その後、測定した前記酸素量から焼結助剤
として添加した酸化物が含有する酸素量を算出して差し
引き、残った酸素量が全てＳｉＯ2 として含有されてい
るとしてＳｉＯ2 量を計算して求め、更にＲＥ2 Ｏ3 に
対するＳｉＯ2 のモル比を算出した。Thereafter, the amount of oxygen contained in the oxide added as a sintering aid is calculated from the measured amount of oxygen and subtracted, and the amount of SiO 2 is calculated assuming that the remaining amount of oxygen is contained as SiO 2 . Then, the molar ratio of SiO 2 to RE 2 O 3 was calculated.
【００４１】次に、前記セラミック発熱体を用いて、少
なくとも電極取り出し層の露出部にメタライズ法やメッ
キ法等によりニッケル（Ｎｉ）等の金属被膜を形成した
後、セラミック発熱体の側面に露出した一方の電極取り
出し層と接続するように筒状金具を外嵌めし、還元ガス
雰囲気中で銀ろうにて接合して負電極とし、他方の電極
取り出し層に、線材またはキャップ状の金具より成る電
極取り出し金具を前記同様に銀ろうにて接合して正電極
として接続し、正負の電極を導出した評価用のセラミッ
ク発熱体を作製した。Next, using the ceramic heating element, a metal coating such as nickel (Ni) is formed on at least the exposed portion of the electrode extraction layer by a metallizing method or a plating method, and then exposed on the side surface of the ceramic heating element. A tubular metal fitting was fitted to connect to one electrode extraction layer, and was joined with silver braze in a reducing gas atmosphere to form a negative electrode.An electrode composed of a wire rod or a cap-shaped metal fitting was attached to the other electrode extraction layer. Similar to the above, the take-out metal fittings were joined by silver brazing and connected as a positive electrode to produce a ceramic heating element for evaluation in which positive and negative electrodes were led out.
【００４２】次いで、前記評価用のセラミック発熱体を
使用し、該セラミック発熱体が１４００℃の温度で飽和
する１０〜３５Ｖの直流電圧を５分間通電した後、通電
を停止して１分間圧搾空気を吹きつけ強制冷却する工程
を１サイクルとする高負荷耐久試験を行い、２００００
サイクル実施し、両電極間の抵抗値を測定し、試験開始
前の両電極間の抵抗値に対する変化率が１０％以下のも
のを良、越えるものを不良として耐久性を評価するとと
もに、セラミック発熱体表面を肉眼で観察し、更に蛍光
浸透探傷法でクラックの有無を調査した。Then, using the ceramic heating element for evaluation, a direct current voltage of 10 to 35 V at which the ceramic heating element saturates at a temperature of 1400 ° C. is applied for 5 minutes, then the energization is stopped and compressed air is applied for 1 minute. A high load endurance test with one cycle consisting of blowing and forcibly cooling the
The resistance value between both electrodes is measured by carrying out a cycle, and the durability is evaluated as if the rate of change with respect to the resistance value between both electrodes before the test is 10% or less is good, and if it exceeds 100%, the durability is evaluated and the ceramic heat The surface of the body was observed with the naked eye, and the presence or absence of cracks was further investigated by the fluorescence penetration flaw detection method.
【００４３】尚、前記セラミック発熱体の基体をなす窒
化珪素質焼結体の粒界相の結晶相は、前記高負荷耐久試
験に用いたものと同一仕様の熱履歴前のセラミック発熱
体を用い、その外周を研磨除去した後、窒化珪素質焼結
体を微粉砕してＸ線回折を行い、２θが４１．８°のピ
ークからＭｏ4.8 Ｓｉ3 Ｃ0.6 （表３及び表４中、と
記す）を、また２θが４４．７°のピークからＭｏＳｉ
2 （表３及び表４中、と記す）を同定した。As the crystal phase of the grain boundary phase of the silicon nitride sintered material forming the base of the ceramic heating element, a ceramic heating element before the heat history having the same specifications as that used in the high load endurance test is used. After polishing and removing the outer periphery, the silicon nitride sintered body was finely pulverized and subjected to X-ray diffraction, and from the peak at 2θ of 41.8 °, Mo 4.8 Si 3 C 0.6 (in Table 3 and Table 4, From the peak where 2θ is 44.7 °.
2 (indicated in Tables 3 and 4) were identified.
【００４４】また、２θが３４．８°のα−Ｓｉ3 Ｎ4
と、２θが３３．６°のβ−Ｓｉ3Ｎ4 のピーク高さの
合計を基準とし、このピーク高さを１００として２θが
２８．７°である（−１２１）面のモノシリケート（表
３及び表４中、Ｍと記す）及び２θが２８．０°である
（２０１）面のダイシリケート（表３及び表４中、Ｄと
記す）のピーク高さを求め、α−Ｓｉ3 Ｎ4 とβ−Ｓｉ
3 Ｎ4 のピーク高さの合計に対する比率を算出して、窒
化珪素質焼結体の粒界相のそれぞれの結晶相を同定し
た。また、本発明に係る窒化珪素質焼結体の代表的なＸ
線回折記録図を図３〜図６に、本発明に係る窒化珪素質
焼結体の代表的な結晶構造を表す組織写真を図７に示
す。Also, α-Si 3 N 4 having a 2θ of 34.8 °
Based on the sum of the peak heights of β-Si 3 N 4 having 2θ of 33.6 °, and assuming that the peak height is 100, 2θ is 28.7 ° (−121) plane monosilicate (table) 3 and in Table 4), and the peak height of the (201) plane disilicate (denoted as D in Tables 3 and 4) having a 2θ of 28.0 °, α-Si 3 N 4 and β-Si
The ratio of the peak height of 3 N 4 to the total of the peak heights was calculated to identify each crystal phase of the grain boundary phase of the silicon nitride sintered body. Further, a typical X of the silicon nitride sintered body according to the present invention
3 to 6 are line diffraction recording diagrams, and FIG. 7 is a microstructure photograph showing a typical crystal structure of the silicon nitride sintered body according to the present invention.
【００４５】尚、本発明外の代表的なＸ線回折記録図と
結晶構造を表す組織写真を、図８及び図９に示す。Incidentally, a representative X-ray diffraction recording diagram outside the present invention and a structure photograph showing the crystal structure are shown in FIGS. 8 and 9.
【００４６】[0046]
【表１】 [Table 1]
【００４７】[0047]
【表２】 [Table 2]
【００４８】[0048]
【表３】 [Table 3]
【００４９】[0049]
【表４】 [Table 4]
【００５０】表１〜表４の結果からも明らかなように、
窒化珪素質焼結体の粒界相にＭｏ4.8 Ｓｉ3 Ｃ0.6 とＭ
ｏＳｉ2 の２結晶が共存していない試料番号３８、３
９、４０、あるいは窒化珪素質焼結体の粒界相にダイシ
リケートのみしか検出されない試料番号４５、５０、５
５、６０、６５は、いずれも高温負荷耐久試験で１０％
を越える抵抗変化を示し、また試料番号４５、５０、５
５、６０、６５ではクラックも発生している。As is clear from the results of Tables 1 to 4,
Mo 4.8 Si 3 C 0.6 and M were added to the grain boundary phase of the silicon nitride sintered body.
Sample Nos. 38 and 3 in which two crystals of oSi 2 do not coexist
9, 40, or sample numbers 45, 50, 5 in which only disilicate is detected in the grain boundary phase of the silicon nitride sintered body
5, 60, 65 are all 10% in high temperature load endurance test
Shows a change in resistance of over 50% and sample numbers 45, 50, 5
Cracks have also occurred in 5, 60, and 65.
【００５１】それに対して、本発明のセラミック発熱体
はいずれも１４００℃の２００００サイクルに及ぶ高温
負荷耐久試験に異常は認められない。On the contrary, none of the ceramic heating elements of the present invention was found in the high temperature load endurance test of 1400 ° C. for 20000 cycles.
【００５２】また、図７と図９の組織写真から明らかな
ように、本発明外の図９では粒界相にＭｏＳｉ2 ９の結
晶だけが存在するのに対して、本願発明の窒化珪素質焼
結体の粒界相の結晶構造を示す図７では、ＭｏＳｉ2 ８
の結晶中にＭｏ4.8 Ｓｉ3 Ｃ0.6 ７の結晶が共存してい
ることが分かる。Further, as is clear from the microstructure photographs of FIGS. 7 and 9, in FIG. 9 outside the present invention, only the crystal of MoSi 2 9 exists in the grain boundary phase, whereas the silicon nitride based material of the present invention is present. In FIG. 7, which shows the crystal structure of the grain boundary phase of the sintered body, MoSi 2 8
It can be seen that the crystal of Mo 4.8 Si 3 C 0.67 coexists in the crystal of No.
【００５３】尚、前記評価用のセラミック発熱体に最大
電圧１４．３Ｖを印加し、最高発熱部が８００℃に到達
する時間を測定したところ、本発明のセラミック発熱体
はいずれも２．１秒以内の急速昇温特性を有しているこ
とが確認できた。A maximum voltage of 14.3 V was applied to the ceramic heating element for evaluation, and the time required for the maximum heating portion to reach 800 ° C. was measured. All the ceramic heating elements of the present invention were 2.1 seconds. It was confirmed that it has a rapid temperature rising characteristic within the range.
【００５４】更に、本願発明のセラミック発熱体を極寒
から熱帯まで種々の温度環境下で使用可能とするため、
窒化珪素質焼結体の粒界相が酸化され易い６００℃と９
００℃の温度で１００時間放置試験を行ったが、本発明
のセラミック発熱体はいずれも異常は認められなかっ
た。Furthermore, since the ceramic heating element of the present invention can be used under various temperature environments from extremely cold to tropical,
The grain boundary phase of the silicon nitride sintered body is easily oxidized at 600 ° C and 9
After a standing test at a temperature of 00 ° C. for 100 hours, no abnormality was found in any of the ceramic heating elements of the present invention.
【００５５】[0055]
【発明の効果】叙上の如く、本発明のセラミック発熱体
は、窒化珪素質焼結体の粒界相がＭｏ4.8 Ｓｉ3 Ｃ0.6
とＭｏＳｉ2 の結晶を共存し、かつ窒化珪素質焼結体の
熱履歴前の粒界相がＲＥ2 Ｏ3 ・ＳｉＯ2 で表されるモ
ノシリケートを含有していることから、焼結一体化時に
発熱抵抗体が珪化され難く、その上、長時間に及ぶ昇
温、降温の繰り返しでも発熱抵抗体の抵抗変化率が大き
く変化せず、しかも発熱抵抗体が断線したりセラミック
発熱体の基体にクラックが発生したりすることがなく、
高温強度と耐酸化特性が維持され、急速昇温特性を損な
うことなく好適な自己飽和温度特性が得られ、どのよう
な環境下においても耐久性と信頼性に優れたセラミック
発熱体を得ることができる。As described above, in the ceramic heating element of the present invention, the grain boundary phase of the silicon nitride sintered material is Mo 4.8 Si 3 C 0.6.
And a crystal of MoSi 2 coexist, and the grain boundary phase before the thermal history of the silicon nitride sintered body contains the monosilicate represented by RE 2 O 3 · SiO 2 , so that it is sintered and integrated. At times, the heating resistor is less likely to be silicified, and the rate of change in resistance of the heating resistor does not change significantly even when the temperature is raised or lowered over a long period of time. There are no cracks,
High temperature strength and oxidation resistance are maintained, suitable self-saturation temperature characteristics are obtained without impairing rapid temperature rise characteristics, and a ceramic heating element with excellent durability and reliability in any environment can be obtained. it can.
【図１】本発明のセラミック発熱体の一実施例の正面の
要部を示す断面図である。FIG. 1 is a cross-sectional view showing a front main part of an embodiment of a ceramic heating element of the present invention.
【図２】本発明のセラミック発熱体の側面の要部を示す
断面図である。FIG. 2 is a sectional view showing a main part of a side surface of a ceramic heating element of the present invention.
【図３】本発明のセラミック発熱体の代表的な窒化珪素
質焼結体のＸ線回折記録図である。FIG. 3 is an X-ray diffraction recording diagram of a representative silicon nitride sintered body of the ceramic heating element of the present invention.
【図４】本発明のセラミック発熱体の他の代表的な窒化
珪素質焼結体のＸ線回折記録図である。FIG. 4 is an X-ray diffraction recording diagram of another typical silicon nitride-based sintered body of the ceramic heating element of the present invention.
【図５】本発明のセラミック発熱体の他の代表的な窒化
珪素質焼結体のＸ線回折記録図である。FIG. 5 is an X-ray diffraction recording diagram of another typical silicon nitride-based sintered body of the ceramic heating element of the present invention.
【図６】本発明のセラミック発熱体の他の代表的な窒化
珪素質焼結体のＸ線回折記録図である。FIG. 6 is an X-ray diffraction recording diagram of another typical silicon nitride-based sintered body of the ceramic heating element of the present invention.
【図７】本発明のセラミック発熱体の代表的な窒化珪素
質焼結体の粒界相の結晶構造を示す組織写真である。FIG. 7 is a microstructure photograph showing a crystal structure of a grain boundary phase of a representative silicon nitride sintered body of the ceramic heating element of the present invention.
【図８】本発明外のセラミック発熱体の窒化珪素質焼結
体のＸ線回折記録図である。FIG. 8 is an X-ray diffraction recording diagram of a silicon nitride-based sintered body of a ceramic heating element other than the present invention.
【図９】本発明外のセラミック発熱体の窒化珪素質焼結
体の粒界相の結晶構造を示す組織写真である。FIG. 9 is a microstructure photograph showing a crystal structure of a grain boundary phase of a silicon nitride-based sintered body of a ceramic heating element other than the present invention.
１ セラミック発熱体 ２ 窒化珪素質焼結体 ３、４ 発熱抵抗体 ５ リード線 ６ 電極取り出し層 ７ Ｍｏ4.8 Ｓｉ3 Ｃ0.6 ８ ＭｏＳｉ２ 1 Ceramic Heating Element 2 Silicon Nitride Sintered Body 3, 4 Heating Resistor 5 Lead Wire 6 Electrode Extraction Layer 7 Mo 4.8 Si 3 C 0.6 8 MoSi 2
Claims (4)
体を介して少なくとも２層の無機導電材から成る発熱抵
抗体層を埋設したセラミック発熱体において、前記窒化
珪素質焼結体の粒界相がＭｏ4.8 Ｓｉ3 Ｃ0.6 とＭｏＳ
ｉ2 の結晶を共存し、かつ前記窒化珪素質焼結体の熱履
歴前の粒界に存在するＲＥ（ＲＥは周期律表第３ａ族元
素）のシリケートから成る結晶相が、ＲＥ2 Ｏ3 ・Ｓｉ
Ｏ2 で表されるモノシリケートを含有することを特徴と
するセラミック発熱体。1. A ceramic heating element in which at least two heating resistor layers made of an inorganic conductive material are embedded in a silicon nitride sintered body with the silicon nitride sintered body interposed therebetween. The grain boundary phase of the aggregate is Mo 4.8 Si 3 C 0.6 and MoS
The crystal phase consisting of a silicate of RE (RE is an element of Group 3a of the periodic table) existing at the grain boundary before the thermal history of the silicon nitride sintered body coexisting with the crystal of i 2 is RE 2 O 3・ Si
A ceramic heating element containing a monosilicate represented by O 2 .
するＳｉＯ2 のモル比が０．８〜１．８であることを特
徴とする請求項１記載のセラミック発熱体。2. The ceramic heating element according to claim 1, wherein the molar ratio of SiO 2 to RE 2 O 3 in the silicon nitride sintered body is 0.8 to 1.8.
０．５〜１．０重量％含有していることを特徴とする請
求項１記載のセラミック発熱体。3. The ceramic heating element according to claim 1, wherein the silicon nitride sintered body contains Al 2 O 3 in an amount of 0.5 to 1.0% by weight.
シリケートのＲＥ（ＲＥは周期律表第３ａ族元素）がＹ
ｂまたはＹ、Ｈｏ、Ｅｒ、Ｌｕのいずれかであることを
特徴とする請求項１記載のセラミック発熱体。4. The monosilicate RE (RE is an element of Group 3a of the periodic table) represented by RE 2 O 3 .SiO 2 is Y
The ceramic heating element according to claim 1, wherein the heating element is b, or Y, Ho, Er, or Lu.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6118418A JP3004168B2 (en) | 1994-03-30 | 1994-05-31 | Ceramic heating element |
| US08/305,085 US5750958A (en) | 1993-09-20 | 1994-09-13 | Ceramic glow plug |
| DE4433505A DE4433505C2 (en) | 1993-09-20 | 1994-09-20 | ceramic glow |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6103194 | 1994-03-30 | ||
| JP6-61031 | 1994-03-30 | ||
| JP6118418A JP3004168B2 (en) | 1994-03-30 | 1994-05-31 | Ceramic heating element |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH07318055A true JPH07318055A (en) | 1995-12-08 |
| JP3004168B2 JP3004168B2 (en) | 2000-01-31 |
Family
ID=26402084
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP6118418A Expired - Fee Related JP3004168B2 (en) | 1993-09-20 | 1994-05-31 | Ceramic heating element |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3004168B2 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2005117492A1 (en) * | 2004-05-27 | 2005-12-08 | Kyocera Corporation | Ceramic heater, and glow plug using the same |
| WO2012133083A1 (en) * | 2011-03-30 | 2012-10-04 | 京セラ株式会社 | Heater |
| JP2019021501A (en) * | 2017-07-18 | 2019-02-07 | 日本特殊陶業株式会社 | Ceramic heater and glow plug |
-
1994
- 1994-05-31 JP JP6118418A patent/JP3004168B2/en not_active Expired - Fee Related
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2005117492A1 (en) * | 2004-05-27 | 2005-12-08 | Kyocera Corporation | Ceramic heater, and glow plug using the same |
| JPWO2005117492A1 (en) * | 2004-05-27 | 2008-04-03 | 京セラ株式会社 | Ceramic heater and glow plug using the same |
| US7935912B2 (en) | 2004-05-27 | 2011-05-03 | Kyocera Corporation | Ceramic heater, and glow plug using the same |
| WO2012133083A1 (en) * | 2011-03-30 | 2012-10-04 | 京セラ株式会社 | Heater |
| CN103460793A (en) * | 2011-03-30 | 2013-12-18 | 京瓷株式会社 | Heater |
| JPWO2012133083A1 (en) * | 2011-03-30 | 2014-07-28 | 京セラ株式会社 | heater |
| JP5665971B2 (en) * | 2011-03-30 | 2015-02-04 | 京セラ株式会社 | heater |
| US9681498B2 (en) | 2011-03-30 | 2017-06-13 | Kyocera Corporation | Heater with particle shield for noise |
| JP2019021501A (en) * | 2017-07-18 | 2019-02-07 | 日本特殊陶業株式会社 | Ceramic heater and glow plug |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3004168B2 (en) | 2000-01-31 |
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