JP2008046091A - Hydrogen gas sensor - Google Patents

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JP2008046091A
JP2008046091A JP2006224493A JP2006224493A JP2008046091A JP 2008046091 A JP2008046091 A JP 2008046091A JP 2006224493 A JP2006224493 A JP 2006224493A JP 2006224493 A JP2006224493 A JP 2006224493A JP 2008046091 A JP2008046091 A JP 2008046091A
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hydrogen gas
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Mari Yabuuchi
真理 藪内
Mariko Sugimura
真理子 杉村
Mitsuji Kira
満治 吉良
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FIS Inc
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydrogen gas sensor capable of reducing variations in detection sensitivity even if exposed to an acid or an oxidizing gas and accurately detecting concentration. <P>SOLUTION: A sensitive element 1 includes an oxide semiconductor which is sensitive to hydrogen to change its electric resistance value. At least either an acid or thiourea is added to the sensitive element 1. In this case, even if the sensitive element 1 is exposed to the acid or an oxidizing gas, it is possible to reduce variations in detection sensitivity. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

本発明は、酸化物半導体からなる感応素子の電気抵抗値の変化により水素ガスを検出する水素ガスセンサに関するものである。   The present invention relates to a hydrogen gas sensor that detects hydrogen gas by a change in electric resistance value of a sensitive element made of an oxide semiconductor.

近年、地球規模の環境問題の解決が要望されるなか、クリーンエネルギー技術の開発が活発となっており、このような技術として燃料電池が注目されている。燃料電池は水素と酸素との燃焼反応等を利用して起電力を発生させるものであり、エネルギー変換率が高く、クリーンで環境にやさしい発電装置として期待されている。またこのような燃料電池を電源として用いた燃料電池自動車の開発も活発に進められている。   In recent years, the development of clean energy technology has become active as a solution to environmental problems on a global scale is demanded, and fuel cells are attracting attention as such technology. A fuel cell generates an electromotive force by utilizing a combustion reaction between hydrogen and oxygen, and is expected as a clean and environmentally friendly power generation device having a high energy conversion rate. In addition, development of fuel cell vehicles using such a fuel cell as a power source is being actively promoted.

燃料電池は、一般的には燃料である天然ガス等から硫黄化合物を除去する脱硫器、脱硫された燃料を水素とＣＯ及びＣＯ2に変成する改質器、及びＣＯをＣＯ2に変化させる変成器から構成される改質装置を備えており、この改質装置によって、天然ガス等の燃料から水素ガスに富んだ燃料ガス（改質ガス）が生成される。そして燃料電池本体において、この燃料ガス中の水素ガスと空気中の酸素とを電気化学的に反応させて直流電力を得るものである。 A fuel cell generally includes a desulfurizer that removes sulfur compounds from natural gas, which is a fuel, a reformer that converts desulfurized fuel into hydrogen, CO, and CO 2, and a converter that converts CO into CO 2. A reformer constituted by a vessel is provided, and by this reformer, fuel gas rich in hydrogen gas (reformed gas) is generated from fuel such as natural gas. In the fuel cell main body, the hydrogen gas in the fuel gas and the oxygen in the air are reacted electrochemically to obtain DC power.

上記の燃料ガス中には数１０〜１００％という高濃度の水素ガスが含まれるが、この燃料ガスのガス漏れが起こると燃料電池が正常に動作しなくなり、また水素ガスは可燃性が高く、ガス漏れが起こると非常に危険である。このため、ガス漏れの有無を検知するための水素ガスセンサを設ける必要がある。   The above-mentioned fuel gas contains hydrogen gas with a high concentration of several tens to 100%, but if this fuel gas leaks, the fuel cell will not operate normally, and hydrogen gas is highly flammable, It is very dangerous if a gas leak occurs. For this reason, it is necessary to provide a hydrogen gas sensor for detecting the presence or absence of gas leakage.

ここで、燃料電池用の水素ガス濃度を検知するための水素ガスセンサとして、例えば特許文献１に開示されているものが提案されている。この水素ガスセンサは、酸素濃度検知セルと酸素ポンプセルとを固体電解質の両側に多孔質の電極を配置して構成し、この各セルの一方の電極を間隔をあけて対向させると共にこの各電極間の空間を外部から閉塞して空隙を形成し、空隙内側に配置されている各セルの電極を接地し、更にこの空隙と外部との間に水素ガスが通過可能なガス拡散制限部を設けて構成されたものである。   Here, as a hydrogen gas sensor for detecting the hydrogen gas concentration for a fuel cell, for example, one disclosed in Patent Document 1 has been proposed. In this hydrogen gas sensor, an oxygen concentration detection cell and an oxygen pump cell are configured by disposing porous electrodes on both sides of a solid electrolyte, and one electrode of each cell is opposed to each other with a gap therebetween. The space is closed from the outside to form a gap, the electrode of each cell arranged inside the gap is grounded, and a gas diffusion restriction part that allows hydrogen gas to pass between this gap and the outside is provided. It has been done.

このように構成される水素ガスセンサは、酸素ポンプセルの外面側の電極が燃料電池に供給される水素を含む燃料ガスの気流中に露出するように配される。ここで燃料ガスには水蒸気が添加されるものである。この状態で酸素ポンプセルの電極間に電圧を印加すると、外面側の電極において水が分解されると共に、酸素イオンが固体電解質中を通過して空隙内に導入される。一方、空隙内にはガス拡散制限部を介して水素も導入され、空隙内で酸素イオンと水素とが反応して水が生成される。また酸素濃度検知セルの電極間には一定の微少電流が通電され、電極間に空隙内の酸素濃度に応じた電圧が発生するようにしている。そして、酸素濃度検知セルに発生する電圧が一定となるように酸素ポンプセルの電極間に印加する電圧を制御し、このときの酸素ポンプセルの電極間に印加する電圧の値から水素濃度を導出するものである。   The hydrogen gas sensor configured as described above is arranged so that the electrode on the outer surface side of the oxygen pump cell is exposed in the flow of the fuel gas containing hydrogen supplied to the fuel cell. Here, water vapor is added to the fuel gas. When a voltage is applied between the electrodes of the oxygen pump cell in this state, water is decomposed at the outer electrode, and oxygen ions pass through the solid electrolyte and are introduced into the gap. On the other hand, hydrogen is also introduced into the gap through the gas diffusion limiting portion, and oxygen ions and hydrogen react in the gap to generate water. A certain minute current is passed between the electrodes of the oxygen concentration detection cell, and a voltage corresponding to the oxygen concentration in the gap is generated between the electrodes. Then, the voltage applied between the electrodes of the oxygen pump cell is controlled so that the voltage generated in the oxygen concentration detection cell is constant, and the hydrogen concentration is derived from the value of the voltage applied between the electrodes of the oxygen pump cell at this time It is.

また、特許文献２には、燃料電池用の水素ガス濃度を検知するための水素ガスセンサとして、ＳｎＯ2、ＺｎＯ等の酸化物半導体から構成される半導体センサを用いることが開示されている。
特開２０００−９６８５号公報 特開平６−１９６１８８号公報 Patent Document 2 discloses that a semiconductor sensor made of an oxide semiconductor such as SnO 2 or ZnO is used as a hydrogen gas sensor for detecting the hydrogen gas concentration for a fuel cell.
Japanese Unexamined Patent Publication No. 2000-9985 JP-A-6-196188

しかし、上記の特許文献１に開示されている水素ガスセンサは、装置構成が複雑であり、しかも複雑な制御機構が必要とされるものであって、小型化が困難であり、また製造工程が煩雑となって製造に手間がかかると共に、製造コストも嵩むものであった。   However, the hydrogen gas sensor disclosed in the above-mentioned Patent Document 1 has a complicated apparatus configuration and requires a complicated control mechanism, and is difficult to downsize, and the manufacturing process is complicated. As a result, it takes a lot of time to manufacture, and the manufacturing cost increases.

一方、特許文献２に記載のように水素ガスセンサを半導体センサにて構成すると簡便な構成で安価に製造することができるが、従来から知られているＳｎＯ2等を主成分とする感応素子１にて構成される金属酸化物水素ガスセンサは、酸性雨に曝されるなどして硫酸被毒を受けたり、排気ガス中の窒素酸化物（ＮＯｘ）や硫黄酸化物（ＳＯｘ）等の酸化性ガスによる被毒を受けると、検知感度が変動し、正確な濃度検知ができなくなってしまうという問題がある。 On the other hand, when the hydrogen gas sensor is configured by a semiconductor sensor as described in Patent Document 2, it can be manufactured at a low cost with a simple configuration. However, in the conventional sensitive element 1 mainly composed of SnO 2 or the like. The metal oxide hydrogen gas sensor configured as described above is subjected to sulfuric acid poisoning by exposure to acid rain or the like, or by an oxidizing gas such as nitrogen oxide (NOx) or sulfur oxide (SOx) in the exhaust gas. When poisoning is received, there is a problem that detection sensitivity fluctuates and accurate concentration detection cannot be performed.

本発明は上記の点に鑑みて為されたものであり、酸や酸化性ガスに曝されても検知感度の変動が抑制され、正確な濃度検知が可能な水素ガスセンサを提供することを目的とするものである。   The present invention has been made in view of the above points, and it is an object of the present invention to provide a hydrogen gas sensor capable of accurate concentration detection by suppressing fluctuations in detection sensitivity even when exposed to an acid or an oxidizing gas. To do.

本発明に係る水素ガスセンサは、水素に感応して電気抵抗値の変化を生じる酸化物半導体を含有する感応素子１を備え、前記感応素子１には、酸とチオ尿素の少なくとも一方が添加されていることを特徴とするものである。   The hydrogen gas sensor according to the present invention includes a sensitive element 1 containing an oxide semiconductor that generates a change in electrical resistance in response to hydrogen, and at least one of acid and thiourea is added to the sensitive element 1. It is characterized by being.

この場合、感応素子１が酸や酸化性ガスに曝されても、検知感度の変動が抑制される。特に感応素子１にチオ尿素を添加した場合には、感応素子１が酸や酸化性ガスに曝された場合の検知感度の変動が非常に小さく、しかも、特に水素ガスが高濃度の場合に高い検知感度を有する。   In this case, even if the sensitive element 1 is exposed to an acid or an oxidizing gas, fluctuations in detection sensitivity are suppressed. In particular, when thiourea is added to the sensitive element 1, the variation in detection sensitivity when the sensitive element 1 is exposed to an acid or an oxidizing gas is very small, and particularly high when the hydrogen gas has a high concentration. Has detection sensitivity.

このような水素ガスセンサでは、上記感応素子１にアルミナゾルが添加されていることが好ましい。この場合、水素ガス検知時に感応素子１の電気抵抗値が速やかに安定化し、高い応答性を有する。   In such a hydrogen gas sensor, it is preferable that alumina sol is added to the sensitive element 1. In this case, when the hydrogen gas is detected, the electric resistance value of the sensitive element 1 is quickly stabilized and has high responsiveness.

また、上記感応素子１が、チオ尿素が添加された後、酸が添加されているものであることも好ましい。この場合、感応素子１が酸や酸化性ガスに曝された場合の検知感度の変動が特に小さくなり、且つ感応素子１への通電初期に、検知出力が安定化するまでに要する期間が非常に短くなるものである。   Moreover, it is also preferable that the sensitive element 1 is one in which an acid is added after thiourea is added. In this case, the fluctuation of the detection sensitivity when the sensitive element 1 is exposed to an acid or an oxidizing gas becomes particularly small, and the period required for the detection output to stabilize at the initial stage of energization of the sensitive element 1 is very long. It will be shorter.

本発明によれば、酸や酸化性ガスに対する耐性の高い水素ガスセンサを得ることができ、特に自動車等の燃料電池における燃料ガスのガス漏れを検知するために、好適なものである。   ADVANTAGE OF THE INVENTION According to this invention, the hydrogen gas sensor with high tolerance with respect to an acid and oxidizing gas can be obtained, and it is suitable especially in order to detect the gas leak of the fuel gas in fuel cells, such as a motor vehicle.

以下、本発明の実施の形態を説明する。   Embodiments of the present invention will be described below.

まず、水素ガスセンサの感応素子１の構成について説明する。   First, the configuration of the sensitive element 1 of the hydrogen gas sensor will be described.

感応素子１は、水素ガスを吸着することにより電気抵抗値が変化する酸化物半導体を含む。酸化物半導体としては前記特性を有する適宜のものが用いられるが、例えば酸化スズ（ＳｎＯ2）を用いることができる。感応素子１中の酸化物半導体の含有量は５０〜１００重量％の範囲が好ましい。 The sensitive element 1 includes an oxide semiconductor whose electric resistance value changes by adsorbing hydrogen gas. As the oxide semiconductor, an appropriate one having the above characteristics can be used. For example, tin oxide (SnO 2 ) can be used. The content of the oxide semiconductor in the sensitive element 1 is preferably in the range of 50 to 100% by weight.

この感応素子１中には、骨材を含有させても良い。骨材は、感応素子１の電気抵抗値の調整や強度向上等の目的で、使用することができる。骨材としては、例えばアルミナ等をあげることができる。感応素子１中の骨材の含有量は適宜調整されるが、例えば感応素子１の全量に対して０〜５０重量％とすることができる。   This sensitive element 1 may contain an aggregate. The aggregate can be used for the purpose of adjusting the electric resistance value of the sensitive element 1 and improving the strength. Examples of the aggregate include alumina. Although the content of the aggregate in the sensitive element 1 is appropriately adjusted, for example, it can be 0 to 50% by weight with respect to the total amount of the sensitive element 1.

また、感応素子１は、白金（Ｐｔ）、パラジウム（Ｐｄ）のうち少なくとも一方を含有しても良い。この場合、水素ガスの検知時の検知感度の向上に寄与すると共に、感応素子１の電気抵抗値が速やかに安定し、水素ガスの検知時の応答性が向上する。感応素子１中の白金、パラジウムの含有量は特に制限されないが、感応素子１に白金を含有させる場合は、感応素子１中の酸化物半導体全量に対し、白金を０．３〜１．５重量％の範囲で含有させることができる。また、感応素子１にパラジウムを含有させる場合には、感応素子１中の酸化物半導体全量に対し、パラジウムを０．３〜１．５重量％の範囲で含有させることができる。   The sensitive element 1 may contain at least one of platinum (Pt) and palladium (Pd). In this case, it contributes to the improvement of the detection sensitivity at the time of detection of hydrogen gas, the electrical resistance value of the sensitive element 1 is quickly stabilized, and the responsiveness at the time of detection of hydrogen gas is improved. The content of platinum and palladium in the sensitive element 1 is not particularly limited, but when the sensitive element 1 contains platinum, 0.3 to 1.5 weight of platinum with respect to the total amount of the oxide semiconductor in the sensitive element 1. % Can be contained. Further, when palladium is contained in the sensitive element 1, palladium can be contained in the range of 0.3 to 1.5 wt% with respect to the total amount of the oxide semiconductor in the sensitive element 1.

また、この感応素子１にはアルミナゾルを添加することも好ましい。アルミナゾルの添加にあたっては、感応素子１の周囲にアルミナゾルを塗布含浸させた後、焼成することができる。このときアルミナゾルに起因する微細粒径のアルミナ（γ−アルミナ）が感応素子１の内部にほぼ均一に分散した状態で存在することとなる。この場合、感応素子１の強度を向上することができ、且つ、水素ガスセンサによる水素ガス検知時に感応素子１の電気抵抗値が速やかに安定し、水素ガス検知時の応答性が向上する。このアルミナゾルの添加量は特に制限されないが、好ましくは感応素子１の全量に対してアルミナゾル中の固形分が０．６〜１０重量％の範囲とする。   It is also preferable to add alumina sol to the sensitive element 1. In the addition of the alumina sol, the alumina sol can be applied and impregnated around the sensitive element 1 and then fired. At this time, alumina having a fine particle diameter (γ-alumina) due to the alumina sol is present in a state of being almost uniformly dispersed inside the sensitive element 1. In this case, the strength of the sensitive element 1 can be improved, and the electric resistance value of the sensitive element 1 is quickly stabilized when the hydrogen gas is detected by the hydrogen gas sensor, and the responsiveness when detecting the hydrogen gas is improved. The amount of the alumina sol added is not particularly limited, but the solid content in the alumina sol is preferably in the range of 0.6 to 10% by weight with respect to the total amount of the sensitive element 1.

また、この感応素子１には、酸とチオ尿素のうち、少なくとも一方を添加する。酸の添加にあたっては、感応素子１の周囲に酸の水溶液を塗布含浸させた後、焼成することができる。また、チオ尿素の添加にあたっては、感応素子１の周囲にチオ尿素を塗布含浸させた後、焼成することができる。酸を添加する場合には例えば硫酸を使用することができる。硫酸を使用する場合、感応素子１中の硫酸の添加量は適宜設定される。またチオ尿素を添加する場合、感応素子１中のチオ尿素の添加量は適宜設定されるが、感応素子の全量に対して０．０５〜０．５重量％の範囲で添加することが好ましい。このように感応素子１にチオ尿素を添加した場合には感応素子１の内部にはチオ尿素に起因する硫黄がほぼ均一に分散した状態で存在することとなり、また酸として硫酸を添加した場合も感応素子１の内部には硫酸に起因する硫黄がほぼ均一に分散した状態で存在することとなる。   Further, at least one of acid and thiourea is added to the sensitive element 1. In the addition of the acid, the sensitive element 1 can be fired after being coated and impregnated with an aqueous acid solution. In addition, when thiourea is added, it can be fired after thiourea is applied and impregnated around the sensitive element 1. In the case of adding an acid, for example, sulfuric acid can be used. When using sulfuric acid, the addition amount of sulfuric acid in the sensitive element 1 is appropriately set. Further, when thiourea is added, the amount of thiourea in the sensitive element 1 is appropriately set, but it is preferably added in the range of 0.05 to 0.5% by weight with respect to the total amount of the sensitive element. In this way, when thiourea is added to the sensitive element 1, sulfur resulting from thiourea exists in the sensitive element 1 in an almost uniformly dispersed state, and also when sulfuric acid is added as an acid. In the sensitive element 1, sulfur resulting from sulfuric acid is present in a substantially uniformly dispersed state.

このように感応素子１に酸又はチオ尿素を添加することにより、感応素子１が硫黄酸化物（ＳＯｘ）、窒素酸化物（ＮＯｘ）等の酸化性ガスに曝された場合、並びに、硫酸等の酸に曝された場合の、水素ガスの検知感度の変化を抑制することができる。   Thus, by adding an acid or thiourea to the sensitive element 1, the sensitive element 1 is exposed to an oxidizing gas such as sulfur oxide (SOx), nitrogen oxide (NOx), and sulfuric acid. A change in detection sensitivity of hydrogen gas when exposed to an acid can be suppressed.

特に、感応素子１にチオ尿素を添加した場合には、感応素子１が酸や酸化性ガスに曝された場合の、感応素子１の検知感度の安定性が非常に高く、特に一旦感応素子１が酸や酸化性ガスに曝された後は検知感度の変化が非常に小さくなる。このため、感応素子１を予め酸や酸化性ガスに曝しておけば、検知感度の安定性を非常に高くすることもできる。更にこの場合、水素ガスの濃度変化に対する感応素子１の電気抵抗値の変化の勾配が大きくなり、特に高濃度の水素ガスを検知する場合に、ガス濃度の検知を高精度で行うことができる。   In particular, when thiourea is added to the sensitive element 1, the stability of the detection sensitivity of the sensitive element 1 when the sensitive element 1 is exposed to an acid or an oxidizing gas is very high. After exposure to acid or oxidizing gas, the change in detection sensitivity becomes very small. For this reason, if the sensitive element 1 is previously exposed to an acid or an oxidizing gas, the stability of the detection sensitivity can be made extremely high. Further, in this case, the gradient of the change in the electric resistance value of the sensitive element 1 with respect to the change in the concentration of the hydrogen gas is increased, and the gas concentration can be detected with high accuracy, particularly when high concentration hydrogen gas is detected.

更に、感応素子１にチオ尿素を添加した後、更に硫酸等の酸を添加すると、感応素子１が酸や酸化性ガスに曝された場合の、感応素子１の検知感度の安定性が特に高くなり、感応素子１が酸や酸化性ガスに曝される前後においても感応素子１の検知感度の変化が非常に小さくなるものである。また、感応素子１にチオ尿素を添加した場合には、感応素子１に通電を開始した初期にはこの感応素子１の電気抵抗値が安定せず、検知出力の安定化に長期間を要するものであるが、感応素子１にチオ尿素を添加した後、更に硫酸等の酸を添加すれば、感応素子１に通電を開始した場合、感応素子１の電気抵抗値が速やかに安定し、非常に短時間で検知出力が安定化するものである。   Furthermore, when thiourea is added to the sensitive element 1 and then an acid such as sulfuric acid is further added, the stability of the detection sensitivity of the sensitive element 1 when the sensitive element 1 is exposed to an acid or an oxidizing gas is particularly high. Thus, the change in the detection sensitivity of the sensitive element 1 is very small before and after the sensitive element 1 is exposed to an acid or oxidizing gas. In addition, when thiourea is added to the sensitive element 1, the electrical resistance value of the sensitive element 1 is not stable at the beginning of energization of the sensitive element 1, and it takes a long time to stabilize the detection output. However, if thiourea is added to the sensing element 1 and then an acid such as sulfuric acid is further added, when the sensing element 1 is energized, the electrical resistance value of the sensing element 1 quickly stabilizes and is very high. The detection output is stabilized in a short time.

水素ガスセンサは、上記のような感応素子１を具備し、この感応素子１を検知対象のガスに曝露した際の電気抵抗値の変化を検出することができるものであれば、従来公知の適宜の構成を採用することができる。   As long as the hydrogen gas sensor includes the sensitive element 1 as described above and can detect a change in the electric resistance value when the sensitive element 1 is exposed to the gas to be detected, the hydrogen gas sensor may be a conventionally known appropriate element. A configuration can be employed.

この水素ガスセンサでは、白金（Ｐｔ）、白金合金（Ｐｔ合金）等から形成されるヒータ及び電極をセンサ基体とし、このセンサ基体を覆うように感応素子１を設けることが好ましい。   In this hydrogen gas sensor, it is preferable that a heater and an electrode formed of platinum (Pt), platinum alloy (Pt alloy), or the like are used as a sensor base, and the sensitive element 1 is provided so as to cover the sensor base.

上記電極は、感応素子１の電気抵抗値測定用に設けられる。感応素子１を測定対象のガスを含む雰囲気中に配置した状態で、この電極間の電気抵抗値を測定し、この電気抵抗値に基づいてガス濃度を検出することができる。   The electrode is provided for measuring the electric resistance value of the sensitive element 1. In a state where the sensitive element 1 is arranged in the atmosphere containing the gas to be measured, the electric resistance value between the electrodes can be measured, and the gas concentration can be detected based on the electric resistance value.

また、上記ヒータは、感応素子１を一定の温度に保つために設けられる。ここで、感応素子１には、組成に応じて水素ガスを検知するための好適な温度（素子温度）がある。また素子温度が変動すると水素ガス感度が変動して正確な濃度を検知することが困難になる。このため、水素ガスの検出時には、ヒータにて素子温度を好適温度に保つことで、水素ガス濃度を正確に検知する。   The heater is provided to keep the sensitive element 1 at a constant temperature. Here, the sensitive element 1 has a suitable temperature (element temperature) for detecting hydrogen gas according to the composition. Further, when the element temperature fluctuates, the hydrogen gas sensitivity fluctuates and it becomes difficult to detect an accurate concentration. For this reason, at the time of detection of hydrogen gas, the hydrogen gas concentration is accurately detected by maintaining the element temperature at a suitable temperature with a heater.

以下、水素ガスセンサの具体的構造を例示する。   Hereinafter, a specific structure of the hydrogen gas sensor will be exemplified.

図１，２に示す水素ガスセンサでは、コイル状のヒータ兼用電極２５及び芯線状の電極２０をセンサ基体とする。このヒータ兼用電極２５及び電極２０を覆うように略球状（球体状、楕円球体状等）に感応素子１が形成されている。図示の例ではヒータ兼用電極２５は、コイル部分が、ビーズ状の感応素子１中に埋設されている。また、電極２０はヒータ兼用電極２５のコイル部分の中心を貫通するように感応素子１中に埋設されている。このため、ヒータ兼用電極２５及び電極２０がまとまり良く配設され、感応素子１の小型化が容易である。   In the hydrogen gas sensor shown in FIGS. 1 and 2, the coil-shaped heater combined electrode 25 and the core wire-shaped electrode 20 are used as a sensor base. The sensitive element 1 is formed in a substantially spherical shape (spherical shape, elliptical spherical shape, etc.) so as to cover the heater combined electrode 25 and the electrode 20. In the example shown in the figure, the heater combined electrode 25 has a coil portion embedded in the bead-like sensitive element 1. The electrode 20 is embedded in the sensitive element 1 so as to penetrate the center of the coil portion of the heater electrode 25. For this reason, the heater combined electrode 25 and the electrode 20 are arranged well and the sensitive element 1 can be easily downsized.

前記ヒータ兼用電極２５は白金（Ｐｔ）、白金合金（Ｐｔ合金）等から形成される。このヒータ兼用電極２５は、白金（Ｐｔ）、白金合金（Ｐｔ合金）等からなるリード線２０1，２０3の間に設けられている。これにより、ヒータ兼用電極２５、リード線２０1，２０3が、一体に形成されている。また電極２０は、白金（Ｐｔ）、白金合金（Ｐｔ合金）等からなるリード線２０2で形成されている。 The heater combined electrode 25 is made of platinum (Pt), platinum alloy (Pt alloy) or the like. The heater combined electrode 25 is provided between lead wires 20 1 and 20 3 made of platinum (Pt), platinum alloy (Pt alloy) or the like. Thereby, the heater combined electrode 25 and the lead wires 20 1 and 20 3 are integrally formed. The electrodes 20 are platinum (Pt), it is formed in the lead wire 20 2 made of platinum alloy (Pt alloy) or the like.

そして、樹脂等から形成されるベース３０に３本の端子１０1，１０2，１０3を貫通させ、この各端子１０1，１０2，１０3にリード線２０1，２０2，２０3を接続している。これにより、ベース３０に対して、感応素子１が固定して支持される。このベース３０に有底筒状のセンサ筐体４０を被嵌する。感応素子１は、センサ筐体４０の内側に収容される。センサ筐体４０の天上面にはガス導入用の開口４１が設けられている。この開口４１には必要に応じてガス導入用のステンレス製等の金網４１が張設される。 Then, three terminals 10 1 , 10 2 , 10 3 are passed through a base 30 formed of resin or the like, and lead wires 20 1 , 20 2 , 20 3 are connected to the terminals 10 1 , 10 2 , 10 3 , respectively. Connected. Thereby, the sensitive element 1 is fixedly supported with respect to the base 30. The bottomed cylindrical sensor housing 40 is fitted on the base 30. The sensitive element 1 is housed inside the sensor housing 40. An opening 41 for introducing gas is provided on the top surface of the sensor housing 40. A wire mesh 41 made of stainless steel for gas introduction is stretched in the opening 41 as necessary.

図３，４に示す水素ガスセンサでは、アルミナ基板等の絶縁体基板６をセンサ基体（平板型基体）として用いている。   In the hydrogen gas sensor shown in FIGS. 3 and 4, an insulating substrate 6 such as an alumina substrate is used as a sensor substrate (flat plate substrate).

この絶縁体基板６の一面には金等からなる膜状の二つの電極４Ａ、４Ｂが形成されている。この絶縁体基板６の他面には、金等からなる膜状の四つの電極２Ａ，２Ｂ，４Ａ′，４Ｂ′が形成されている。この絶縁体基板６には、前記電極４Ａと電極４Ａ′とを接続するスルーホール、及び前記電極４Ｂ及び電極４Ｂ′とを接続するスルーホールが形成されている。また、この絶縁体基板６の他面側の各電極２Ａ，２Ｂ，４Ａ′，４Ｂ′にはリードワイヤ５を夫々接続している。また、絶縁体基板６の他面には、白金印刷膜等からなるヒータ２５′が形成されている。このヒータ２５′は、二つの電極２Ａ，２Ｂに接続されている。   On one surface of the insulating substrate 6, two film-like electrodes 4A and 4B made of gold or the like are formed. On the other surface of the insulator substrate 6, four film-like electrodes 2A, 2B, 4A ', 4B' made of gold or the like are formed. The insulator substrate 6 is formed with through-holes connecting the electrodes 4A and 4A 'and through-holes connecting the electrodes 4B and 4B'. Further, lead wires 5 are connected to the electrodes 2A, 2B, 4A ', 4B' on the other surface side of the insulating substrate 6, respectively. On the other surface of the insulator substrate 6, a heater 25 'made of a platinum printed film or the like is formed. The heater 25 'is connected to the two electrodes 2A and 2B.

感応素子１は、上記絶縁体基板６の一面に、二つの電極４Ａ、４Ｂの間に亘って膜状に設けられている。   The sensitive element 1 is provided on one surface of the insulator substrate 6 in a film shape between the two electrodes 4A and 4B.

そして、樹脂等から形成されるベース３０に４本の端子１０，１０，１０，１０を貫通させ、このベース３０に上記絶縁体基板６を搭載する。また、各端子１０，１０，１０，１０に、リードワイヤ５，５，５，５を、それぞれ接続する。このベース３０に有底筒状のセンサ筐体４０を被嵌する。感応素子１を備える絶縁体基板６は、センサ筐体４０の内側に収容される。センサ筐体４０の天上面にはガス導入用の開口４１が設けられている。この開口４１には必要に応じてガス導入用のステンレス製等の金網４１が張設される。   Then, the four terminals 10, 10, 10, 10 are passed through the base 30 formed of resin or the like, and the insulator substrate 6 is mounted on the base 30. Further, lead wires 5, 5, 5, and 5 are connected to the terminals 10, 10, 10, and 10, respectively. The bottomed cylindrical sensor housing 40 is fitted on the base 30. The insulator substrate 6 including the sensitive element 1 is accommodated inside the sensor housing 40. An opening 41 for introducing gas is provided on the top surface of the sensor housing 40. A wire mesh 41 made of stainless steel for gas introduction is stretched in the opening 41 as necessary.

これらの水素ガスセンサの構成は例示であり、その他適宜の構造の水素ガスセンサを形成することができる。   The configurations of these hydrogen gas sensors are merely examples, and hydrogen gas sensors having other appropriate structures can be formed.

以下に、感応素子１の製造方法を例示する。   Below, the manufacturing method of the sensitive element 1 is illustrated.

感応素子１に含まれる酸化物半導体がＳｎＯ2である場合、適宜の手法で調整したＳｎＯ2の粉末を用いることができる。例えば、まずＳｎＣｌ4の水溶液をＮＨ4で加水分解してスズ酸ゾルを得る。このスズ酸ゾルを風乾した後に、空気中で例えば５５０〜７００℃で０．５〜３時間焼成する。この焼成により得られたＳｎＯ2を粉砕して、ＳｎＯ2の粉末を得ることができる。 When the oxide semiconductor contained in the sensitive element 1 is SnO 2 , SnO 2 powder adjusted by an appropriate method can be used. For example, first, an aqueous solution of SnCl 4 is hydrolyzed with NH 4 to obtain a stannic acid sol. The stannic acid sol is air-dried and then baked in air at, for example, 550 to 700 ° C. for 0.5 to 3 hours. SnO 2 obtained by this firing can be pulverized to obtain SnO 2 powder.

また、感応素子１に骨材を含有させる場合、骨材として例えばアルミナ（α−アルミナ）の粉末を用いることができる。   When the sensitive element 1 contains an aggregate, for example, an alumina (α-alumina) powder can be used as the aggregate.

酸化物半導体の粉末に、必要に応じて所望の量の骨材の粉末を混合し、更にポリエチレングリコール、グリセリン等の有機溶剤を加えて、ペースト状の混合物を調製する。   A desired amount of aggregate powder is mixed with the oxide semiconductor powder as necessary, and an organic solvent such as polyethylene glycol or glycerin is further added to prepare a paste-like mixture.

ここで、感応素子１中にＰｄを含有させる場合には、適宜の手法で上記混合物中にＰｄを含有させる。例えば上記混合物を調製する前に、予め酸化物半導体（ＳｎＯ2）の粉末にＰｄを担持させる。この場合、例えばＰｄを王水に溶解させると共に蒸留水で希釈したＰｄ濃度０．３〜１．５％の溶液を、酸化物半導体の粉末に混合し、空気雰囲気下で例えば５００℃で１時間焼成する。これにより、Ｐｄが担持された酸化物半導体の粉末が得られる。 Here, when Pd is contained in the sensitive element 1, Pd is contained in the mixture by an appropriate method. For example, before preparing the above mixture, Pd is supported on an oxide semiconductor (SnO 2 ) powder in advance. In this case, for example, a solution having a Pd concentration of 0.3 to 1.5% dissolved in aqua regia and diluted with distilled water is mixed with the oxide semiconductor powder and, for example, at 500 ° C. for 1 hour in an air atmosphere. Bake. Thus, an oxide semiconductor powder carrying Pd is obtained.

また、感応素子１中にＰｔを含有させる場合には、適宜の手法で上記混合物中にＰｔ又はその化合物を含有させる。例えば上記混合物を調製する前に、予め酸化物半導体（ＳｎＯ2）の粉末にＰｔ又は塩化白金酸を担持させる。この場合、例えば塩化白金酸水溶液を、酸化物半導体の粉末に混合し、空気雰囲気下で例えば５００℃で１時間焼成する。これにより、塩化白金酸が担持された酸化物半導体の粉末が得られる。また、このような手法の代わりに、上記ペースト状の混合物中に塩化白金酸水溶液を混合しても良い。 When Pt is contained in the sensitive element 1, Pt or a compound thereof is contained in the mixture by an appropriate method. For example, before preparing the above mixture, Pt or chloroplatinic acid is supported on an oxide semiconductor (SnO 2 ) powder in advance. In this case, for example, an aqueous chloroplatinic acid solution is mixed with the oxide semiconductor powder and fired at 500 ° C. for 1 hour in an air atmosphere. Thereby, an oxide semiconductor powder carrying chloroplatinic acid is obtained. Moreover, you may mix a chloroplatinic acid aqueous solution in the said paste-form mixture instead of such a method.

このように調製された混合物をセンサ基体に塗布する。この混合物を、適宜の条件、例えば空気雰囲気下で５００〜７００℃で１〜６０分間焼成することにより焼結させる。   The mixture thus prepared is applied to the sensor substrate. The mixture is sintered by firing under appropriate conditions, for example, at 500 to 700 ° C. for 1 to 60 minutes in an air atmosphere.

この混合物の焼結体には、必要に応じてアルミナゾルを添加する。例えば焼結体の表面にアルミナゾルを塗布し、例えば空気中で６５０℃で３分間焼成する。   An alumina sol is added to the sintered body of this mixture as necessary. For example, an alumina sol is applied to the surface of the sintered body and, for example, baked in air at 650 ° C. for 3 minutes.

次に、この焼結体に酸又はチオ尿素の少なくとも一方を添加する。   Next, at least one of acid or thiourea is added to the sintered body.

酸を添加する場合には、例えば５〜３０％濃度の硫酸水溶液を、焼結体の表面に塗布し、例えば４５０℃で３分間焼成することができる。このとき、必要に応じて硫酸水溶液の塗布と焼成とを複数回（例えば３０回）繰り返して行うことができる。   In the case of adding an acid, for example, an aqueous sulfuric acid solution having a concentration of 5 to 30% can be applied to the surface of the sintered body and fired at 450 ° C. for 3 minutes, for example. At this time, the application and baking of the sulfuric acid aqueous solution can be repeated a plurality of times (for example, 30 times) as necessary.

また、チオ尿素を添加する場合には、例えばチオ尿素を水に溶解させた０．１〜１％の濃度の溶液を、焼結体の表面に塗布し、例えば４５０℃で３分間の条件で焼成することができる。   In addition, when adding thiourea, for example, a 0.1 to 1% concentration solution in which thiourea is dissolved in water is applied to the surface of the sintered body, for example, at 450 ° C. for 3 minutes. It can be fired.

また、チオ尿素と酸とを共に添加する場合には、上記手法によって、まず焼結体にチオ尿素を添加した後に、この焼結体に酸を少なくとも一回添加する。   When both thiourea and an acid are added, the thiourea is first added to the sintered body by the above method, and then the acid is added to the sintered body at least once.

以上のようにして感応素子１が形成される。   The sensitive element 1 is formed as described above.

以下、本発明を実施例により更に詳述する。   Hereinafter, the present invention will be described in more detail with reference to examples.

（実施例１）
図１，２に示す構成の水素ガスセンサを作製した。このとき、感応素子１は次のようにして作製した。 (Example 1)
A hydrogen gas sensor having the configuration shown in FIGS. At this time, the sensitive element 1 was produced as follows.

ＳｎＣｌ4の水溶液をＮＨ4で加水分解してスズ酸ゾルを得た。このスズ酸ゾルを風乾した後に、空気中で６００℃で１時間焼成した。この焼成により得られたＳｎＯ2を粉砕して、ＳｎＯ2の粉末を得た。 An aqueous solution of SnCl 4 was hydrolyzed with NH 4 to obtain a stannic acid sol. The stannic acid sol was air-dried and then calcined in air at 600 ° C. for 1 hour. SnO 2 obtained by this firing was pulverized to obtain SnO 2 powder.

このＳｎＯ2の粉末と、α−アルミナの粉末とを、前者対後者が１：１の重量比となるように混合し、更にグリセリンを加えて、ペースト状の混合物を調製した。 The SnO 2 powder and the α-alumina powder were mixed so that the former to the latter had a weight ratio of 1: 1, and glycerin was further added to prepare a paste-like mixture.

このペースト状の混合物をセンサ基体に塗布し、５３０℃で３分間焼成して、焼結体を形成した。   This pasty mixture was applied to the sensor substrate and baked at 530 ° C. for 3 minutes to form a sintered body.

この焼結体の表面にアルミナゾルを塗布し、６５０℃で３分間焼成した。   Alumina sol was applied to the surface of the sintered body and fired at 650 ° C. for 3 minutes.

次に、焼結体の表面にチオ尿素の０．９％水溶液を塗布し、４５０℃で３分間焼成して、感応素子１を形成した。この感応素子１は長径０．５ｍｍ、短径０．３ｍｍの楕円球状に形成した。このとき感応素子１全量に対して０．１重量％のチオ尿素が添加され、また、この感応素子１中のアルミナゾルの固形分の含有量は０．６重量％となるようにした。   Next, a 0.9% aqueous solution of thiourea was applied to the surface of the sintered body and fired at 450 ° C. for 3 minutes to form the sensitive element 1. The sensitive element 1 was formed in an elliptical shape having a major axis of 0.5 mm and a minor axis of 0.3 mm. At this time, 0.1% by weight of thiourea was added to the total amount of the sensitive element 1, and the solid content of alumina sol in the sensitive element 1 was 0.6% by weight.

（実施例２）
実施例１において、上記チオ尿素の添加処理に代えて、焼結体に５％硫酸溶液を塗布した後に４５０℃で３分間焼成する操作を３０回繰り返し行い、硫酸を添加した。それ以外は実施例１と同様にして水素ガスセンサを作製した。 (Example 2)
In Example 1, instead of the above thiourea addition treatment, an operation of applying a 5% sulfuric acid solution to the sintered body and then baking at 450 ° C. for 3 minutes was repeated 30 times, and sulfuric acid was added. Other than that was carried out similarly to Example 1, and produced the hydrogen gas sensor.

（実施例３）
実施例１において、上記チオ尿素の添加処理の後、焼結体に３０％硫酸溶液を塗布した後に４５０℃で３分間焼成する操作を１回行い、硫酸を添加した。それ以外は実施例１と同様にして水素ガスセンサを作製した。 (Example 3)
In Example 1, after the thiourea addition process, a 30% sulfuric acid solution was applied to the sintered body and then baked at 450 ° C. for 3 minutes, and sulfuric acid was added. Otherwise, a hydrogen gas sensor was produced in the same manner as in Example 1.

（比較例１）
実施例１において、チオ尿素の添加処理を行わなかった。それ以外は実施例１と同様にして水素ガスセンサを作製した。 (Comparative Example 1)
In Example 1, thiourea addition treatment was not performed. Other than that was carried out similarly to Example 1, and produced the hydrogen gas sensor.

（水素ガス検知感度評価試験）
実施例１〜３及び比較例１で得られた水素ガスセンサについて、感応素子１を４５０℃に加熱した状態で感応素子１を空気雰囲気中に曝露し、この状態で感応素子１の電気抵抗値（Ｒａｉｒ）を測定した。 (Hydrogen gas detection sensitivity evaluation test)
About the hydrogen gas sensors obtained in Examples 1 to 3 and Comparative Example 1, the sensitive element 1 was exposed to an air atmosphere in a state where the sensitive element 1 was heated to 450 ° C., and the electrical resistance value of the sensitive element 1 ( Rair) was measured.

次に、感応素子１を水素ガスを含む雰囲気中に曝露し、雰囲気中の水素ガスの濃度変化に対する感応素子１の電気抵抗値（Ｒ）の変化を調査した。   Next, the sensitive element 1 was exposed to an atmosphere containing hydrogen gas, and changes in the electrical resistance value (R) of the sensitive element 1 with respect to changes in the concentration of hydrogen gas in the atmosphere were investigated.

図５のグラフに、各実施例１〜３及び比較例１についての、Ｒａｉｒ及びＲ／Ｒａｉｒの測定結果を示す。グラフの左側の縦軸はＲａｉｒの値、右側の縦軸はＲ／Ｒａｉｒの値を示す。   The graph of FIG. 5 shows the measurement results of Rair and R / Rair for each of Examples 1 to 3 and Comparative Example 1. The vertical axis on the left side of the graph shows the value of Rair, and the vertical axis on the right side shows the value of R / Rair.

図５から明らかなように、各実施例及び比較例では、良好な水素ガス濃度依存性がみられた。このうち、特にチオ尿素添加を施した実施例１及び３では、水素ガス濃度の変化に対するＲ／Ｒａｉｒの変化が大きく、高濃度の水素ガス濃度を高い検知精度で検知することができた。   As is clear from FIG. 5, in each of the examples and comparative examples, good hydrogen gas concentration dependency was observed. Among these, especially in Examples 1 and 3 to which thiourea was added, the change in R / Rair with respect to the change in hydrogen gas concentration was large, and a high concentration hydrogen gas concentration could be detected with high detection accuracy.

また、図６のグラフに、実施例１〜３及び比較例１について、Ｒａｉｒの値、及び高濃度水素中でのＲの値を示す。   In addition, the graph of FIG. 6 shows the value of Rair and the value of R in high-concentration hydrogen for Examples 1 to 3 and Comparative Example 1.

図６によれば、チオ尿素添加を施した実施例１及び３の方が、比較例１や、チオ尿素添加を施さない実施例２よりも、水素濃度変化に対する感応素子１の電気抵抗値の変化量が大きかった。このためチオ尿素添加を施した実施例１及び３が、特に高濃度の水素の検知に適していることが確認できた。   According to FIG. 6, the electric resistance value of the sensitive element 1 with respect to the change in the hydrogen concentration is higher in Examples 1 and 3 to which thiourea is added than in Comparative Example 1 and Example 2 to which no thiourea is added. The amount of change was great. For this reason, it was confirmed that Examples 1 and 3 to which thiourea had been added were particularly suitable for detecting high concentrations of hydrogen.

（耐酸被毒性評価試験）
実施例１，２及び比較例１について、検知感度が経時的に安定した状態の感応素子１に、感応素子１に硫酸５％水溶液を１回塗布し、４５０℃で３分間焼成した。次いで、処理後の感応素子１を用い、上記の場合と同様にして水素ガスを含む雰囲気中に曝露し、素子温度４５０℃での、雰囲気中の水素ガスの濃度変化に対する感応素子１の電気抵抗値（Ｒ）の変化を調査した。 (Acid resistance test)
In Examples 1 and 2 and Comparative Example 1, a 5% sulfuric acid aqueous solution was applied once to the sensitive element 1 in which the detection sensitivity was stable over time, and baked at 450 ° C. for 3 minutes. Next, the processed sensitive element 1 is exposed to an atmosphere containing hydrogen gas in the same manner as described above, and the electrical resistance of the sensitive element 1 with respect to a change in the concentration of hydrogen gas in the atmosphere at an element temperature of 450 ° C. The change in value (R) was investigated.

図７は実施例１、図８は実施例２、図９は実施例３、図１０は比較例１についての、上記酸被毒処理前での測定結果、処理後１日目での測定結果、並びに処理後４日目、６日目或いは７日目での測定結果を、併せて示す。   FIG. 7 shows Example 1, FIG. 8 shows Example 2, FIG. 9 shows Example 3, and FIG. 10 shows Comparative Example 1 before and after the acid poisoning treatment. In addition, the measurement results on the 4th, 6th, or 7th day after the treatment are also shown.

この結果、比較例１では、被毒処理後にＲａｉｒの値が大きく変化し、また水素ガス中でのＲの値の変化も大きいものであった。また被毒処理後、時間が経過することによりＲａｉｒの値及びＲの値が更に変動した。   As a result, in Comparative Example 1, the value of Rair changed greatly after the poisoning treatment, and the change of the value of R in hydrogen gas was also large. Further, after the poisoning treatment, the value of Rair and the value of R further fluctuated with the passage of time.

これに対して、実施例１〜３では、被毒処理前後でのＲａｉｒ及びＲの値の変動が小さかった。特に実施例１では感応素子１を一旦酸で被毒させた後は、電気抵抗値Ｒは殆ど変化せず、更に実施例３では被毒処理前後でも電気抵抗値Ｒに殆ど変化はみられなかった。   On the other hand, in Examples 1-3, the fluctuation | variation of the value of Rair and R before and behind poisoning processing was small. In particular, in Example 1, after the sensitive element 1 was once poisoned with acid, the electric resistance value R hardly changed, and in Example 3, the electric resistance value R hardly changed even before and after the poisoning treatment. It was.

（応答性評価試験）
実施例１について、約３分ごとに感応素子１の周囲への水素ガスの注入と感応素子１の周囲からの水素を含むガスの排気とを交互に行うことにより、感応素子１の周囲の雰囲気を空気雰囲気と、水素ガスを５０００ｐｐｍ含む雰囲気とに、交互に置換した。この場合の、感応素子１の電気抵抗値Ｒの経時変化を調査した。 (Response evaluation test)
About Example 1, the atmosphere around the sensitive element 1 is alternately performed by injecting hydrogen gas around the sensitive element 1 and exhausting the gas containing hydrogen from the sensitive element 1 every about 3 minutes. Were alternately replaced with an air atmosphere and an atmosphere containing 5000 ppm of hydrogen gas. In this case, the change with time of the electric resistance value R of the sensitive element 1 was investigated.

また、アルミナゾルを添加しなかった以外は実施例１と同様に形成した感応素子１を用いて水素ガスセンサを作製し（以下、実施例４という）、実施例１と同様に感応素子１の電気抵抗値Ｒの経時変化を調査した。   Further, a hydrogen gas sensor was produced using the sensitive element 1 formed in the same manner as in Example 1 except that no alumina sol was added (hereinafter referred to as Example 4). The time course of the value R was investigated.

実施例１の結果を図１１に、実施例３の結果を図１２に示す。尚、図中に現れている水素ガス注入時に生じる電気抵抗値Ｒのがたつきは、水素ガスの注入を３回に分けて行ったために生じたものである。   The result of Example 1 is shown in FIG. 11, and the result of Example 3 is shown in FIG. Note that the rattling of the electric resistance value R that occurs during the hydrogen gas injection appearing in the figure is caused by the hydrogen gas injection divided into three times.

この結果、アルミナゾルを添加していない実施例４と較べて、アルミナゾルを添加した実施例１では、感応素子１の周囲の雰囲気を置換した場合に、感応素子１の電気抵抗値がより速やかに安定し、特に水素ガスを５０００ｐｐｍ含む雰囲気から空気雰囲気に戻る場合に高い応答性を有することが確認できた。   As a result, compared with Example 4 in which no alumina sol was added, in Example 1 in which the alumina sol was added, the electrical resistance value of the sensitive element 1 was more quickly stabilized when the atmosphere around the sensitive element 1 was replaced. In particular, when returning from an atmosphere containing 5000 ppm of hydrogen gas to an air atmosphere, it was confirmed that the responsiveness was high.

（初期安定化時間評価試験）
実施例１及び実施例３について、感応素子１を通電して４５０℃に加熱した状態で放置した場合の、空気雰囲気下での電気抵抗値Ｒａｉｒと水素ガス雰囲気下（濃度１０００ｐｐｍ）での電気抵抗値Ｒの測定結果の変化を調査した。 (Initial stabilization time evaluation test)
About Example 1 and Example 3, when the sensitive element 1 is energized and left in a state heated to 450 ° C., the electrical resistance value Rair in an air atmosphere and the electrical resistance in a hydrogen gas atmosphere (concentration 1000 ppm) The change of the measurement result of the value R was investigated.

実施例１についての結果を図１３に、実施例３についての結果を図１４に、それぞれ示す。   The results for Example 1 are shown in FIG. 13, and the results for Example 3 are shown in FIG.

図示の通り、実施例１では、空気中での電気抵抗値Ｒａｉｒと、水素ガス含有雰囲気中での電気抵抗値Ｒとは、通電開始後、経時的に徐々に上昇し、値が安定するまで長期間を要した。これに対して実施例３では、通電開始後、電気抵抗値Ｒａｉｒ，Ｒは速やかに安定した。   As illustrated, in Example 1, the electrical resistance value Rair in the air and the electrical resistance value R in the hydrogen gas-containing atmosphere gradually increase over time after the start of energization until the value stabilizes. It took a long time. On the other hand, in Example 3, the electric resistance values Rair, R were quickly stabilized after the start of energization.

また、実施例１について上記と同様の試験を行った後、５０日目で感応素子１に実施例３と同様に硫酸を添加し、続いて同様に試験を行った。この結果を図１５に示す。   Further, after performing the same test as described above for Example 1, sulfuric acid was added to the sensitive element 1 in the same manner as in Example 3 on the 50th day, and then the test was performed in the same manner. The result is shown in FIG.

図示の通り、通電開始後、電気抵抗値Ｒａｉｒ，Ｒは徐々に上昇していったが、硫酸を添加した後は電気抵抗値Ｒａｉｒ，Ｒが速やかに安定化した。   As shown in the figure, the electrical resistance values Rair, R gradually increased after the start of energization, but after the addition of sulfuric acid, the electrical resistance values Rair, R were quickly stabilized.

本発明の実施の形態の一例を示す、ガスセンサの要部概略構成図である。It is a principal part schematic block diagram of the gas sensor which shows an example of embodiment of this invention. 同上の一部破断した正面図である。It is a partially broken front view same as the above. 本発明の実施の形態の他例の要部を示し、（ａ）は一面側から視た斜視図、（ｂ）は他面側から視た斜視図である。The principal part of the other example of embodiment of this invention is shown, (a) is the perspective view seen from the one surface side, (b) is the perspective view seen from the other surface side. 同上の一部破断した斜視図である。It is a partially broken perspective view same as the above. 実施例１，２及び比較例１の水素ガスセンサに関し、水素ガス検知感度評価試験により得られた、Ｒ／Ｒａｉｒの値の水素ガス濃度依存性を示すグラフである。It is a graph which shows the hydrogen gas concentration dependence of the value of R / Rair obtained by the hydrogen gas detection sensitivity evaluation test regarding the hydrogen gas sensors of Examples 1 and 2 and Comparative Example 1. 実施例１，２及び比較例１の水素ガスセンサに関し、水素ガス検知感度評価試験により得られた、感応素子の電気抵抗値Ｒの値の、水素ガス濃度依存性を示すグラフである。It is a graph which shows the hydrogen gas concentration dependence of the value of the electrical resistance value R of the sensitive element obtained by the hydrogen gas detection sensitivity evaluation test regarding the hydrogen gas sensors of Examples 1 and 2 and Comparative Example 1. 実施例１の水素ガスセンサに関し、耐酸被毒性評価試験により得られた、感応素子の酸被毒後の電気抵抗値Ｒの値の、水素ガス濃度依存性を示すグラフである。It is a graph which shows the hydrogen gas density | concentration dependence of the value of the electrical resistance value R after the acid poisoning of the sensitive element obtained by the acid poisoning resistance evaluation test regarding the hydrogen gas sensor of Example 1. 実施例２の水素ガスセンサに関し、耐酸被毒性評価試験により得られた、感応素子の酸被毒後の電気抵抗値Ｒの値の、水素ガス濃度依存性を示すグラフである。It is a graph which shows the hydrogen gas concentration dependence of the value of the electrical resistance value R after the acid poisoning of the sensitive element obtained by the acid poisoning resistance evaluation test regarding the hydrogen gas sensor of Example 2. 実施例３の水素ガスセンサに関し、耐酸被毒性評価試験により得られた、感応素子の酸被毒後の電気抵抗値Ｒの値の、水素ガス濃度依存性を示すグラフである。It is a graph which shows the hydrogen gas density | concentration dependence of the value of the electrical resistance value R after the acid poisoning of the sensitive element obtained by the acid poisoning resistance evaluation test regarding the hydrogen gas sensor of Example 3. 比較例１の水素ガスセンサに関し、耐酸被毒性評価試験により得られた、感応素子の酸被毒後の電気抵抗値Ｒの値の、水素ガス濃度依存性を示すグラフである。It is a graph which shows the hydrogen gas density | concentration dependence of the value of the electrical resistance value R after the acid poisoning of the sensitive element obtained by the acid poisoning resistance evaluation test regarding the hydrogen gas sensor of Comparative Example 1. 実施例１の水素ガスセンサに関し、応答性評価試験により得られた、感応素子の周囲の雰囲気を空気雰囲気と水素ガスを含む雰囲気とに交互に置換した場合での、感応素子の電気抵抗値Ｒの経時変化を示すグラフである。Regarding the hydrogen gas sensor of Example 1, the electrical resistance value R of the sensitive element in the case where the atmosphere around the sensitive element obtained by the response evaluation test is alternately replaced with an air atmosphere and an atmosphere containing hydrogen gas. It is a graph which shows a time-dependent change. 実施例４の水素ガスセンサに関し、応答性評価試験により得られた、感応素子の周囲の雰囲気を空気雰囲気と水素ガスを含む雰囲気とに交互に置換した場合での、感応素子の電気抵抗値Ｒの経時変化を示すグラフである。Regarding the hydrogen gas sensor of Example 4, the electrical resistance value R of the sensitive element in the case where the atmosphere around the sensitive element obtained by the response evaluation test is alternately replaced with an air atmosphere and an atmosphere containing hydrogen gas. It is a graph which shows a time-dependent change. 実施例１の水素ガスセンサに関し、初期安定化時間評価試験により得られた、空気中での電気抵抗値Ｒａｉｒと、水素ガス含有雰囲気中での電気抵抗値Ｒとの経時変化を示すグラフである。It is a graph which shows the time-dependent change of the electrical resistance value Rair in the air obtained by the initial stabilization time evaluation test, and the electrical resistance value R in the hydrogen gas containing atmosphere regarding the hydrogen gas sensor of Example 1. 実施例３の水素ガスセンサに関し、初期安定化時間評価試験により得られた、空気中での電気抵抗値Ｒａｉｒと、水素ガス含有雰囲気中での電気抵抗値Ｒとの経時変化を示すグラフである。It is a graph which shows the time-dependent change of the electrical resistance value Rair in the air obtained by the initial stabilization time evaluation test, and the electrical resistance value R in the hydrogen gas containing atmosphere regarding the hydrogen gas sensor of Example 3. 実施例１の水素ガスセンサに関し、初期安定化時間評価試験を行った後、５０日目で感応素子に硫酸を添加し、続けて初期安定化時間評価試験を行ったことにより得られた、空気中での電気抵抗値Ｒａｉｒと、水素ガス含有雰囲気中での電気抵抗値Ｒとの経時変化を示すグラフである。Regarding the hydrogen gas sensor of Example 1, after performing an initial stabilization time evaluation test, sulfuric acid was added to the sensitive element on the 50th day, and then the initial stabilization time evaluation test was performed in the air. It is a graph which shows a time-dependent change of electrical resistance value Rair in and electrical resistance value R in hydrogen gas containing atmosphere.

符号の説明Explanation of symbols

１ 感応素子   1 Sensitive element

Claims (3)

水素に感応して電気抵抗値の変化を生じる酸化物半導体を含有する感応素子を備え、前記感応素子には、酸とチオ尿素の少なくとも一方が添加されていることを特徴とする水素ガスセンサ。   A hydrogen gas sensor comprising a sensitive element containing an oxide semiconductor that changes in electrical resistance in response to hydrogen, wherein at least one of acid and thiourea is added to the sensitive element. 上記感応素子にアルミナゾルが添加されていることを特徴とする請求項１に記載の水素ガスセンサ。   The hydrogen gas sensor according to claim 1, wherein alumina sol is added to the sensitive element. 上記感応素子が、チオ尿素が添加された後、酸が添加されているものであることを特徴とする請求項１又は２に記載の水素ガスセンサ。
3. The hydrogen gas sensor according to claim 1, wherein the sensitive element is one in which an acid is added after thiourea is added.
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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2017161379A (en) * 2016-03-10 2017-09-14 株式会社東芝 Hydrogen sensor system

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS61117443A (en) * 1984-11-14 1986-06-04 Mitsui Toatsu Chem Inc Detection of gaseous hydride
JPS62261948A (en) * 1986-05-08 1987-11-14 Figaro Eng Inc Production of self-exothermic type gas sensor
JPS62261947A (en) * 1986-05-08 1987-11-14 Figaro Eng Inc Production of self-exothermic type gas sensor
JPH06196188A (en) * 1992-12-24 1994-07-15 Hitachi Ltd Fuel cell hydrogen supply system
JPH09166567A (en) * 1995-12-18 1997-06-24 F I S Kk Semiconductor type gas sensor and manufacture thereof
JP2000074866A (en) * 1998-06-16 2000-03-14 Figaro Eng Inc Co sensor and manufacture thereof
JP2002071611A (en) * 2000-08-30 2002-03-12 Fis Kk Gaseous hydrogen sensor
JP2005164566A (en) * 2003-11-12 2005-06-23 Fuji Electric Fa Components & Systems Co Ltd Thin-film gas sensor
WO2006011202A1 (en) * 2004-07-28 2006-02-02 Fis Inc. Semiconductor gas sensor

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS61117443A (en) * 1984-11-14 1986-06-04 Mitsui Toatsu Chem Inc Detection of gaseous hydride
JPS62261948A (en) * 1986-05-08 1987-11-14 Figaro Eng Inc Production of self-exothermic type gas sensor
JPS62261947A (en) * 1986-05-08 1987-11-14 Figaro Eng Inc Production of self-exothermic type gas sensor
JPH06196188A (en) * 1992-12-24 1994-07-15 Hitachi Ltd Fuel cell hydrogen supply system
JPH09166567A (en) * 1995-12-18 1997-06-24 F I S Kk Semiconductor type gas sensor and manufacture thereof
JP2000074866A (en) * 1998-06-16 2000-03-14 Figaro Eng Inc Co sensor and manufacture thereof
JP2002071611A (en) * 2000-08-30 2002-03-12 Fis Kk Gaseous hydrogen sensor
JP2005164566A (en) * 2003-11-12 2005-06-23 Fuji Electric Fa Components & Systems Co Ltd Thin-film gas sensor
WO2006011202A1 (en) * 2004-07-28 2006-02-02 Fis Inc. Semiconductor gas sensor

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2017161379A (en) * 2016-03-10 2017-09-14 株式会社東芝 Hydrogen sensor system

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