JP4164574B2 - Hydrogen sensor, hydrogen detection method and detection apparatus using optical reflectivity change - Google Patents
Hydrogen sensor, hydrogen detection method and detection apparatus using optical reflectivity change Download PDFInfo
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- 239000001257 hydrogen Substances 0.000 title claims description 99
- 229910052739 hydrogen Inorganic materials 0.000 title claims description 99
- 150000002431 hydrogen Chemical class 0.000 title claims description 63
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 title claims description 37
- 238000001514 detection method Methods 0.000 title claims description 19
- 238000001579 optical reflectometry Methods 0.000 title claims description 5
- 239000010409 thin film Substances 0.000 claims description 62
- 239000011777 magnesium Substances 0.000 claims description 40
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 claims description 37
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims description 37
- KDLHZDBZIXYQEI-UHFFFAOYSA-N Palladium Chemical compound [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 claims description 34
- 229910052749 magnesium Inorganic materials 0.000 claims description 29
- 239000000463 material Substances 0.000 claims description 25
- 229910052759 nickel Inorganic materials 0.000 claims description 17
- 229910052763 palladium Inorganic materials 0.000 claims description 17
- 238000000034 method Methods 0.000 claims description 16
- 230000003287 optical effect Effects 0.000 claims description 16
- 239000003054 catalyst Substances 0.000 claims description 15
- 229910000990 Ni alloy Inorganic materials 0.000 claims description 14
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 claims description 10
- 238000005984 hydrogenation reaction Methods 0.000 claims description 9
- ATTFYOXEMHAYAX-UHFFFAOYSA-N magnesium nickel Chemical compound [Mg].[Ni] ATTFYOXEMHAYAX-UHFFFAOYSA-N 0.000 claims description 7
- 238000012544 monitoring process Methods 0.000 claims description 6
- 239000004065 semiconductor Substances 0.000 claims description 6
- 229910052697 platinum Inorganic materials 0.000 claims description 5
- 238000001755 magnetron sputter deposition Methods 0.000 claims description 4
- 239000000203 mixture Substances 0.000 claims description 4
- 230000000704 physical effect Effects 0.000 claims description 2
- 239000010410 layer Substances 0.000 description 17
- 239000010408 film Substances 0.000 description 13
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 10
- 229910000861 Mg alloy Inorganic materials 0.000 description 8
- 238000004544 sputter deposition Methods 0.000 description 8
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 7
- 229910052710 silicon Inorganic materials 0.000 description 7
- 239000010703 silicon Substances 0.000 description 7
- 239000000758 substrate Substances 0.000 description 7
- 229910052786 argon Inorganic materials 0.000 description 5
- 238000006356 dehydrogenation reaction Methods 0.000 description 5
- 238000005516 engineering process Methods 0.000 description 5
- 238000002310 reflectometry Methods 0.000 description 5
- 238000002834 transmittance Methods 0.000 description 5
- 238000005229 chemical vapour deposition Methods 0.000 description 4
- 238000010438 heat treatment Methods 0.000 description 4
- 229910052751 metal Inorganic materials 0.000 description 4
- 239000002184 metal Substances 0.000 description 4
- 238000007740 vapor deposition Methods 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 2
- 238000000151 deposition Methods 0.000 description 2
- 230000008021 deposition Effects 0.000 description 2
- 238000004880 explosion Methods 0.000 description 2
- 239000000446 fuel Substances 0.000 description 2
- -1 fuel cell vehicles Chemical class 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- 239000002932 luster Substances 0.000 description 2
- 238000007747 plating Methods 0.000 description 2
- 229910052761 rare earth metal Inorganic materials 0.000 description 2
- 150000002910 rare earth metals Chemical class 0.000 description 2
- 230000035945 sensitivity Effects 0.000 description 2
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005566 electron beam evaporation Methods 0.000 description 1
- 238000010894 electron beam technology Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 239000005357 flat glass Substances 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 229910052746 lanthanum Inorganic materials 0.000 description 1
- FZLIPJUXYLNCLC-UHFFFAOYSA-N lanthanum atom Chemical compound [La] FZLIPJUXYLNCLC-UHFFFAOYSA-N 0.000 description 1
- HZZOEADXZLYIHG-UHFFFAOYSA-N magnesiomagnesium Chemical compound [Mg][Mg] HZZOEADXZLYIHG-UHFFFAOYSA-N 0.000 description 1
- 150000002680 magnesium Chemical class 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 229920003023 plastic Polymers 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 238000010248 power generation Methods 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 229910052709 silver Inorganic materials 0.000 description 1
- 239000004332 silver Substances 0.000 description 1
- 239000007779 soft material Substances 0.000 description 1
- XOLBLPGZBRYERU-UHFFFAOYSA-N tin dioxide Chemical compound O=[Sn]=O XOLBLPGZBRYERU-UHFFFAOYSA-N 0.000 description 1
- 229910001887 tin oxide Inorganic materials 0.000 description 1
- 238000007738 vacuum evaporation Methods 0.000 description 1
- 125000000391 vinyl group Chemical group [H]C([*])=C([H])[H] 0.000 description 1
- 229920002554 vinyl polymer Polymers 0.000 description 1
- 229910052727 yttrium Inorganic materials 0.000 description 1
- VWQVUPCCIRVNHF-UHFFFAOYSA-N yttrium atom Chemical compound [Y] VWQVUPCCIRVNHF-UHFFFAOYSA-N 0.000 description 1
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- Investigating Or Analyzing Non-Biological Materials By The Use Of Chemical Means (AREA)
- Investigating Or Analysing Materials By The Use Of Chemical Reactions (AREA)
Description
本発明は、表面の反射率変化を見ることで雰囲気中の水素濃度に関する情報を得る水素センサに関するものであり、更に詳しくは、本発明は、水素雰囲気に反応して水素化が起こり、その表面の光学反射率が変化する薄膜材料を用いた水素センサ、水素検出方法及び検出装置に関するものである。近年、燃料電池車を初めとして水素を用いた技術は大きく発展してきているが、一方、水素は、爆発の危険性のある材料として取り扱いに注意を要することから、水素センサの需要は今後大きく伸びることが予想される。本発明は、燃料電池車や小型発電システム等の水素エネルギーを利用した次世代の実用化技術に欠くことのできない水素センサの技術分野において、室温で作動し、しかも、非常に早い応答速度を持つ新しい水素センサ材料等を提供するものとして有用である。 The present invention relates to a hydrogen sensor that obtains information on the hydrogen concentration in the atmosphere by observing the change in reflectivity of the surface. The present invention relates to a hydrogen sensor, a hydrogen detection method, and a detection apparatus using a thin film material whose optical reflectance changes. In recent years, technologies using hydrogen, including fuel cell vehicles, have been greatly developed. On the other hand, hydrogen needs to be handled as a material with a risk of explosion, so the demand for hydrogen sensors will greatly increase in the future. It is expected that. The present invention operates at room temperature and has a very fast response speed in the technical field of hydrogen sensors indispensable for next-generation practical technology using hydrogen energy such as fuel cell vehicles and small power generation systems. This is useful for providing new hydrogen sensor materials and the like.
近年、環境や資源問題に関する関心の高まりから、水素エネルギーは、大きな注目を集めている。水素を扱う技術は、今後ますます発達すると思われるが、水素は、酸素がある雰囲気中で爆発の危険性を持つために、その取り扱いには非常に注意が必要である。空気中の水素濃度の検出には水素センサが用いられるが、今後、水素センサの需要は、飛躍的に増大することが予想される。 In recent years, hydrogen energy has attracted a great deal of attention due to growing interest in environmental and resource issues. The technology for handling hydrogen is expected to develop more and more in the future. However, since hydrogen has a risk of explosion in an atmosphere where oxygen is present, the handling thereof requires great care. Although a hydrogen sensor is used for detecting the hydrogen concentration in the air, the demand for the hydrogen sensor is expected to increase dramatically in the future.
水素の検出には水素センサが用いられるが、現在、水素センサとしては、酸化スズを用いた半導体センサが広く用いられている。このセンサは、感度及び信頼性が高く、優れた特質を備えているが、動作温度が４００℃程度であり、加熱を要することと、価格が高いという欠点がある。そのため、より価格が安く、また、加熱なしで常温で作動する水素センサが求められている。 A hydrogen sensor is used to detect hydrogen. Currently, a semiconductor sensor using tin oxide is widely used as the hydrogen sensor. This sensor has high sensitivity and reliability and has excellent characteristics, but has the disadvantages that the operating temperature is about 400 ° C., heating is required, and the price is high. Therefore, there is a need for a hydrogen sensor that is cheaper and that operates at room temperature without heating.
１９９６年に、オランダのグループにより、イットリウムやランタンなどの希土類の金属薄膜が、水素にさらすことにより鏡の状態から透明な状態に変化することが発見され、彼らにより調光ミラー（Ｓｗｉｔｃｈａｂｌｅ Ｍｉｒｒｏｒ）と命名された（非特許文献１）。これらの希土類金属薄膜は、水素ガスにより透過率や電気抵抗が変化することから水素センサとしての応用も検討されている。 In 1996, a Dutch group discovered that rare-earth metal thin films such as yttrium and lanthanum changed from a mirror state to a transparent state by exposure to hydrogen, which led to a dimming mirror (Switchable Mirror). (Non-Patent Document 1). These rare earth metal thin films have been studied for application as hydrogen sensors because their transmittance and electrical resistance are changed by hydrogen gas.
その後、２００１年に、アメリカのグループにより、マグネシウム・ニッケル合金のＭｇ2 Ｎｉが新たな調光ミラー材料として発見された（非特許文献２）。本発明者も、窓ガラスへの応用を目指した、マグネシウム・ニッケル合金薄膜の研究を行い、マグネシウム・ニッケル薄膜及びマグネシウム薄膜が調光ガラスとして優れた特性を持っていることを見出し、また、この研究の過程で、これらの材料が、常温で動作する優れた水素センサにもなることを見出し、特許申請を行った。 Thereafter, in 2001, a magnesium / nickel alloy Mg 2 Ni was discovered as a new light control mirror material by an American group (Non-patent Document 2). The present inventor also conducted research on magnesium / nickel alloy thin films aimed at application to window glass, and found that magnesium / nickel thin films and magnesium thin films have excellent characteristics as light control glass. In the process of research, we found that these materials could be excellent hydrogen sensors that operate at room temperature, and filed patent applications.
これまでは、マグネシウム・ニッケル合金薄膜もしくはマグネシウム薄膜を水素センサとして用いる場合、薄膜の電気抵抗の変化もしくは光学透過率の変化により水素の検知を行っていた。特に水素センサを水素のもれ検知用として利用する場合には、応答速度ができるだけ速いことが望まれるが、上記の検知方法では、水素検知に３０秒から１分程度の時間を要していた。また、マグネシウム薄膜を用いた場合は、常温では、水素化しても脱水素化が起こらず、元の状態に復帰しないという欠点があった。
このような状況の中で、本発明者は、上記従来技術に鑑みて、上記諸問題を解決することが可能な新しい水素センサを開発することを目標として鋭意研究を積み重ねた結果、薄膜の水素化を表面の光学反射率の変化をモニターすることで検知する手法を用いることにより、水素に対する応答速度が数秒程度と大幅に向上し、また、マグネシウム薄膜を用いた場合でも、脱水素化が起こって元の状態に復帰させることができることを見出し、本発明を完成するに至った。
本発明は、上記手法を用いることにより、常温で動作し、しかも、非常に早い応答速度を持つ新しいタイプの水素センサを提供することを目的とするものである。
また、本発明は、上記水素センサを用いた水素濃度検出方法及びその検出装置を提供することを目的とするものである。
Under such circumstances, the present inventor has conducted intensive research aimed at developing a new hydrogen sensor capable of solving the above-mentioned problems in view of the above-described conventional technology. By using a method that detects the change by monitoring the change in the optical reflectivity of the surface, the response speed to hydrogen is significantly improved to a few seconds, and dehydrogenation occurs even when a magnesium thin film is used. As a result, it was found that the original state can be restored, and the present invention has been completed.
An object of the present invention is to provide a new type of hydrogen sensor that operates at room temperature and has a very fast response speed by using the above-described method.
Another object of the present invention is to provide a hydrogen concentration detection method and a detection apparatus using the hydrogen sensor.
上記課題を解決するための本発明は、以下の技術的手段から構成される。
（１）水素を含んだ雰囲気に触れることで水素化して物性が変化する薄膜材料を用い、該薄膜表面の光学反射率の変化をモニターすることにより水素の検知を行う水素センサであって、
１）上記薄膜材料が、マグネシウム・ニッケル合金薄膜である、
２）上記薄膜材料の上にパラジウムもしくは白金の触媒層が形成されている、
３）触媒層の厚さが１ｎｍ−１００ｎｍである、
４）室温で水素と反応して触媒層に接した界面付近の部分のマグネシウム・ニッケル薄膜の水素化によって表面の光学反射率が変化する、
５）反射率変化は数秒で飽和する速い応答速度を有する、
６）マグネシウム・ニッケル合金薄膜の組成がＭｇＮｉｘ（０≦ｘ＜０．６）である、
ことを特徴とする水素センサ。
（２）上記薄膜及び触媒層が、マグネトロンスパッタにより成膜された材料である、前記（１）記載の水素センサ。
（３）前記（１）から（２）のいずれかに記載の水素センサを使用して、水素濃度を検出する方法であって、薄膜表面を光源で照らして該薄膜表面の反射光の強度を光検出器を用いてモニターすることを特徴とする水素濃度検出方法。
（４）光源として、半導体レーザ又は発光ダイオードを用いる、前記（３）記載の検出方法。
（５）前記（１）記載の水素センサを用いて水素濃度を検出するための検出装置であって、当該水素センサと光源と薄膜表面を光源で照らしたときの該薄膜表面の反射光の強度を検出する光検出器を組み合わせたことを特徴とする検出装置。
The present invention for solving the above-described problems comprises the following technical means.
(1) A hydrogen sensor that detects hydrogen by using a thin film material that changes its physical properties by being hydrogenated by touching an atmosphere containing hydrogen, and monitoring a change in optical reflectance of the surface of the thin film ,
1) the thin film material is a magnesium-nickel alloy thin film,
2) A palladium or platinum catalyst layer is formed on the thin film material.
3) The thickness of the catalyst layer is 1 nm-100 nm,
4) The optical reflectivity of the surface changes due to hydrogenation of the magnesium / nickel thin film near the interface that reacts with hydrogen at room temperature and contacts the catalyst layer .
5) The reflectance change has a fast response speed that saturates in a few seconds,
6) The composition of the magnesium-nickel alloy thin film is MgNix (0 ≦ x <0.6).
A hydrogen sensor characterized by that.
( 2 ) The hydrogen sensor according to (1), wherein the thin film and the catalyst layer are materials formed by magnetron sputtering.
( 3 ) A method for detecting hydrogen concentration using the hydrogen sensor according to any one of (1) to ( 2 ) above, wherein the intensity of reflected light on the surface of the thin film is determined by illuminating the surface of the thin film with a light source. A method for detecting a hydrogen concentration, wherein monitoring is performed using a photodetector.
( 4 ) The detection method according to ( 3 ), wherein a semiconductor laser or a light emitting diode is used as the light source.
( 5 ) A detection apparatus for detecting a hydrogen concentration using the hydrogen sensor according to (1), wherein the intensity of reflected light on the thin film surface when the hydrogen sensor, the light source, and the thin film surface are illuminated with the light source. A detection device comprising a combination of photodetectors for detecting light.
次に、本発明について更に詳細に説明する。
本発明は、マグネシウム・ニッケル薄膜からなる水素センサに係るものである。これらの薄膜は、スパッタリング法、真空蒸着法、電子ビーム蒸着法、化学気相蒸着法（ＣＶＤ）、めっき法等により作製することができる。しかし、これらの方法に制限されない。本発明では、上記マグネシウム・ニッケル合金薄膜の表面に触媒層が形成される。上記触媒層として、好適には、パラジウムもしくは白金が用いられる。しかし、これらに限定されるものではなく、これらと同効のものであれば同様に使用することができる。この触媒層は、好適には、上記マグネシウム・ニッケル薄膜の表面に１ｎｍ−１００ｎｍのパラジウムもしくは白金をコートして形成される。しかし、触媒層の形成方法及びその形態は特に制限されない。
Next, the present invention will be described in more detail.
The present invention according to the magnesium-nickel thin film or Ranaru hydrogen sensor. These thin films can be produced by sputtering, vacuum evaporation, electron beam evaporation, chemical vapor deposition (CVD), plating, or the like. However, it is not limited to these methods. In the present invention, the catalyst layer is formed on the surface of the magnesium-nickel alloy thin film. As the catalyst layer, palladium or platinum is preferably used. However, it is not limited to these, and can be used similarly if they have the same effect. This catalyst layer is preferably formed by coating the surface of the magnesium / nickel thin film with 1 nm to 100 nm of palladium or platinum. However, the formation method and form of the catalyst layer are not particularly limited.
上記触媒層は、スパッタリング法、真空蒸着法、電子ビーム蒸着法、化学気相蒸着法（ＣＶＤ）、めっき法等により作製することができる。しかし、これらの方法に制限されない。このように、これらのマグネシウム・マグネシウム薄膜及び触媒層の成膜は、好適には、例えば、上記マグネトロンスパッタ装置等を利用して行われる。上記水素センサ材料を任意の基板上に形成することにより、水素センサが得られる。基板としては、材料を選ばず、例えば、金属、ガラス、プラスティックのような堅いものから、ビニールシート、ラップのような柔らかい物まで、様々な種類のものの上に成膜することが可能である。 The catalyst layer can be produced by sputtering, vacuum vapor deposition, electron beam vapor deposition, chemical vapor deposition (CVD), plating, or the like. However, it is not limited to these methods. Deposition of such, these magnesium-magnesium thin film and the catalyst layer is preferably, for example, be performed using the magnetron sputtering apparatus or the like. A hydrogen sensor is obtained by forming the hydrogen sensor material on an arbitrary substrate. The substrate can be formed on various types of materials, for example, from a hard material such as metal, glass and plastic to a soft material such as a vinyl sheet and wrap.
このようにして作製したマグネシウム・ニッケル合金薄膜を用いて水素の検知を行う方法としては、電気抵抗の変化を見る方法や、光学透過率の変化を見る方法などがあるが、本発明では、表面の光学反射率の変化をみることによって検知を行う。本発明では、好適には、例えば、図１に示したように、光源と光検出器を組み合わせた検出装置を用い、薄膜表面を光源で照らして反射光の強度を光検出器を用いてモニターする。実施例で示すように、薄膜表面が水素を含んだ雰囲気に接すると、その光学反射率が大きく変化する。その変化をみることで、水素濃度に関する情報を得ることができる。 As a method of performing this way the detection of hydrogen using a magnesium-nickel alloy thin films produced, a method to see the change in electrical resistance, there is a method to see the changes in optical transmittance, in the present invention Detection is performed by looking at the change in the optical reflectance of the surface. In the present invention, preferably, for example, as shown in FIG. 1, a detection device in which a light source and a photodetector are combined is used, and the surface of the thin film is illuminated with a light source, and the intensity of reflected light is monitored using the photodetector. To do. As shown in the examples, when the surface of the thin film is in contact with an atmosphere containing hydrogen, the optical reflectance changes greatly. By seeing the change, information on the hydrogen concentration can be obtained.
光源としては、半導体レーザや、発光ダイオードが好適である。また、光検出器としては、シリコンフォトダイオードやＣＤＳ光検出器などが好適である。特に、価格的に安価な発光ダイオードとシリコンフォトダイオードを用いると、安価な水素センサーを実現することができる。 As the light source, a semiconductor laser or a light emitting diode is suitable. As the photodetector, a silicon photodiode, a CDS photodetector, or the like is suitable. In particular, when an inexpensive light emitting diode and silicon photodiode are used, an inexpensive hydrogen sensor can be realized.
本発明の水素センサーでは、水素を含んだ雰囲気に接した場合の反射率変化は早く、数秒程度で飽和することから、非常に応答速度の速い水素センサとなる。また、測定できる水素濃度の範囲は、マグネシウム・ニッケル層もしくはマグネシウム層の厚さのコントロールにより調節することができる。 In the hydrogen sensor of the present invention, the reflectance change is rapid when it comes into contact with an atmosphere containing hydrogen, and it saturates in about several seconds. Therefore, the hydrogen sensor has a very fast response speed. The range of hydrogen concentration that can be measured can be adjusted by controlling the thickness of the magnesium / nickel layer or the magnesium layer.
このように、本発明は、マグネシウム・ニッケル合金薄膜材料を用いた水素センサと、これを用いた水素検知方法に係るものである。本発明で材料として使用するマグネシウムとニッケルは、資源量が多く、価格も安い。また、触媒層に使用するパラジウムや白金は、価格は高いが、蒸着する厚さが１０ｎｍ程度と非常に薄いため、ごくわずかの量の使用で作製することができる。従って、本発明による水素センサは、非常に低価格で作製できる可能性を持っている。 Thus, the present invention relates to a hydrogen sensor using a magnesium / nickel alloy thin film material and a hydrogen detection method using the same. Magnesium and nickel used as materials in the present invention have a large amount of resources and are inexpensive. Palladium and platinum used for the catalyst layer are expensive, but the deposited thickness is as thin as about 10 nm, so that they can be produced with a very small amount. Therefore, the hydrogen sensor according to the present invention has a possibility of being manufactured at a very low cost.
今後、エネルギー資源として、水素は、ますます広く用いられるようになり、水素センサの需要も急速に高まることが予想されるが、本発明で示したような、常温で作動し、安価で、しかも、非常に応答の早い水素センサの開発の意義は大きい。 In the future, hydrogen will be used more and more widely as an energy resource, and the demand for hydrogen sensors is expected to increase rapidly. However, as shown in the present invention, it operates at room temperature, is inexpensive, The significance of developing a hydrogen sensor that is very responsive is significant.
本発明により、（１）本発明の水素センサ材料は、常温で動作し、加熱を必要としない、（２）本発明の水素センサ材料は、価格的に安いマグネシウム・ニッケルとごく微量のパラジウム等を用いるため、安価に製造できる、（３）本発明の水素センサ材料は、応答速度が非常に速い、（４）水素に対する応答速度が数秒程度である、（５）水素化後、脱水素化が起こって元の状態に復帰させることができる、という効果が奏される。 According to the present invention, (1) the hydrogen sensor material of the present invention operates at room temperature and does not require heating, and (2) the hydrogen sensor material of the present invention is inexpensive, such as magnesium / nickel and a very small amount of palladium. (3) The hydrogen sensor material of the present invention has a very fast response speed. (4) The response speed to hydrogen is about several seconds. (5) Dehydrogenation after hydrogenation. Can be restored to the original state.
次に、本発明を実施例に基づいて具休的に説明するが、本発明は、以下の実施例によって何ら限定されるものではない。 Next, the present invention will be described casually based on examples, but the present invention is not limited to the following examples.
本実施例では、水素センサとしてマグネシウム・ニッケル合金薄膜を用いた場合の例を示す。マグネシウム・ニッケル合金薄膜の成膜は、図２に示したような３連のマグネトロンスパッタ装置を用いて行った。３つのスパッタ銃に、ターゲットとして、それぞれ、金属マグネシウム、金属ニッケル、それに金属パラジウムをセットした。基板としては、厚さ０．５ｍｍのシリコン基板を用い、これを洗浄後、スパッタ装置の中にセットして真空排気を行った。成膜にあたっては、まず、マグネシウムとニッケルを同時スパッタしてマグネシウム・ニッケル合金薄膜を作製した。スパッタ中のアルゴンガス圧は、０．８Ｐａであり、直流スパッタ法によりマグネシウムに３０Ｗ、ニッケルには３０Ｗのパワーを加えてスパッタを行った。膜厚は、マグネシウム・ニッケル薄膜が約２５０ｎｍ、パラジウム薄膜が約１０ｎｍである。また、組成を分析すると、Ｍｇ2 Ｎｉに近い組成になっていた。蒸着後、真空中で６Ｗのパワーでパラジウムを蒸着してからスパッタ装置から取り出した。 In this embodiment, an example in which a magnesium / nickel alloy thin film is used as a hydrogen sensor is shown. The magnesium / nickel alloy thin film was formed using a triple magnetron sputtering apparatus as shown in FIG. Metal magnesium, metal nickel, and metal palladium were set as targets on the three sputter guns, respectively. As a substrate, a silicon substrate having a thickness of 0.5 mm was used. After cleaning, this was set in a sputtering apparatus and evacuated. In forming the film, first, magnesium and nickel were simultaneously sputtered to produce a magnesium / nickel alloy thin film. The argon gas pressure during sputtering was 0.8 Pa, and sputtering was performed by applying a power of 30 W to magnesium and 30 W to nickel by direct current sputtering. The film thickness is about 250 nm for the magnesium / nickel thin film and about 10 nm for the palladium thin film. When the composition was analyzed, the composition was close to Mg 2 Ni. After vapor deposition, palladium was vapor-deposited in vacuum with a power of 6 W and then taken out from the sputtering apparatus.
この試料に、波長６７０ｎｍの半導体レーザを照射し、反射したレーザー光の強度をシリコンフォトダイオードを用いて測定した。図３に、この試料表面に、アルゴンで希釈した濃度４％の水素をふきつけた場合の反射率の変化を示す。反射率は、シリコン基板上に蒸着した銀の反射率を１００％とした場合の相対的な反射率である。蒸着直後の膜は金属光沢を持っているが、水素にふれると濃い茶色に着色して反射率が下がる。この変化は早く、約６秒ほどで飽和する。水素をふきつけるのをやめると、また反射率が上がるが、この変化も早く、約６秒程度でもとの反射率に戻る。また、飽和状態における反射率は水素の濃度に依存していることから、これを見ることで水素濃度を検知できることがわかる。 This sample was irradiated with a semiconductor laser having a wavelength of 670 nm, and the intensity of the reflected laser light was measured using a silicon photodiode. FIG. 3 shows the change in reflectivity when 4% concentration of hydrogen diluted with argon is wiped onto the sample surface. The reflectance is a relative reflectance when the reflectance of silver deposited on the silicon substrate is 100%. The film immediately after deposition has a metallic luster, but when exposed to hydrogen, it is colored dark brown and the reflectivity decreases. This change is fast and saturates in about 6 seconds. When you stop squirting hydrogen, the reflectivity increases again, but this change is also fast, returning to the original reflectivity even in about 6 seconds. Further, since the reflectance in the saturated state depends on the hydrogen concentration, it can be seen that the hydrogen concentration can be detected by looking at this.
薄膜の水素化は、膜表面から基板側に向かって徐々に進行するため、抵抗率の変化や、光学透過率の変化をみる方法では、その変化はゆるやかで、飽和するまでに１分程度かかってしまう。これに対して、光学反射率の変化をみる方法では、マグネシウム・ニッケル合金薄膜とパラジウム薄膜との界面における光学定数の違いによって光学反射が決まるため、パラジウム薄膜層に接した部分のマグネシウム・ニッケル薄膜の水素化によって反射率が変化する。このように、界面付近だけの水素化によって変化が起こるため、反射率変化が非常に早く起こると考えられる。 Since the hydrogenation of the thin film gradually proceeds from the film surface toward the substrate side, the change in resistivity and optical transmittance change is slow and takes about 1 minute to saturate. End up. On the other hand, in the method of looking at the change in optical reflectivity, the optical reflection is determined by the difference in the optical constants at the interface between the magnesium / nickel alloy thin film and the palladium thin film, so the magnesium / nickel thin film in contact with the palladium thin film layer. The reflectance changes due to hydrogenation. As described above, since the change is caused by hydrogenation only in the vicinity of the interface, the reflectance change is considered to occur very quickly.
参考例
本参考例では、マグネシウム薄膜を用いた場合の例を示す。マグネシウム薄膜の成膜も実施例１の場合と同じものを用いた。まず、シリコン基板上にマグネシウム膜を蒸着し、次に、真空中でパラジウム膜を蒸着した。成膜条件は、ニッケルを飛ばさないことを除いて実施例１と同じである。マグネシウム層の厚さは約２５０ｎｍ、パラジウム層の厚さは約１０ｎｍである。得られた膜について、実施例１の場合と同じく、波長６７０ｎｍの半導体レーザを照射し、反射したレーザー光の強度をシリコンフォトダイオードを用いて測定した。図４に、アルゴンで希釈した４％水素を吹き付けた場合の反射率変化を示す。
Reference Example This reference example shows an example in which a magnesium thin film is used. The same magnesium thin film as in Example 1 was used. First, a magnesium film was deposited on a silicon substrate, and then a palladium film was deposited in vacuum. The film forming conditions are the same as those in Example 1 except that nickel is not blown. The thickness of the magnesium layer is about 250 nm, and the thickness of the palladium layer is about 10 nm. As in the case of Example 1, the obtained film was irradiated with a semiconductor laser having a wavelength of 670 nm, and the intensity of the reflected laser light was measured using a silicon photodiode. FIG. 4 shows the change in reflectance when 4% hydrogen diluted with argon is sprayed.
水素を含んだ雰囲気に接すると、マグネシウム・ニッケル薄膜の場合と同様、水素化が起こり、金属光沢を持っていた表面が濃い茶色に着色し、反射率が下がる。マグネシウム薄膜の場合も、この水素化による変化は早く、数秒で飽和する。水素雰囲気にさらすのをやめると、徐々に反射率が上がり、２０分程度でもとの反射率に復帰する。光学透過率をモニターする方法では、マグネシウム薄膜及びパラジウム層の厚さを５０ｎｍ以下にしなければならないが、その場合、水素化した膜はもとに戻らなかった。それに対して、光学反射率を見る方法では、膜厚を厚くすることができ、水素化したマグネシウムが脱水素化して元に戻るようになった。危険を知らせる水素のリーク検知器としては、水素化に対する応答速度はできるだけ速いことが求められるが、脱水素化に対しては、それほど早い応答速度は求められない。脱水素化の速度は、マグネシウム・ニッケル薄膜の場合と比べて遅いが、マグネシウム膜は、マグネシウム・ニッケル膜に比べて作製が容易であり、コスト的にも下げられる可能性を持っている。 When exposed to an atmosphere containing hydrogen, hydrogenation occurs, as in the case of magnesium / nickel thin films, and the surface having a metallic luster is colored dark brown and the reflectance is lowered. Also in the case of a magnesium thin film, this change due to hydrogenation is quick and saturates in a few seconds. When the exposure to a hydrogen atmosphere is stopped, the reflectance gradually increases and returns to the original reflectance even in about 20 minutes. In the method of monitoring the optical transmittance, the thickness of the magnesium thin film and the palladium layer must be 50 nm or less. In that case, the hydrogenated film did not return to its original state. On the other hand, in the method of observing the optical reflectance, the film thickness can be increased, and the hydrogenated magnesium is dehydrogenated and returned to its original state. A hydrogen leak detector that informs danger is required to have a response speed as fast as possible for hydrogenation, but not so fast for dehydrogenation. The dehydrogenation speed is slower than that of the magnesium / nickel thin film, but the magnesium film is easier to produce than the magnesium / nickel film and has the potential to reduce the cost.
以上詳述したように、本発明は、常温で動作し、応答速度の早い水素センサ材料と、これを用いた水素の検知方法に係るものであり、本発明の水素センサ材料は、常温で動作し、加熱を必要としない。本発明の水素センサ材料は、価格的に安いマグネシウム・ニッケルとごく微量のパラジウム等を用いるため、安価に製造できる。本発明の水素センサ材料は、応答速度が非常に速い。本発明は、次世代の水素エネルギーの実用化技術に欠くことのできない新しい高感度水素センサを提供するものとして有用である。 As described above in detail, the present invention relates to a hydrogen sensor material that operates at room temperature and has a fast response speed, and a method for detecting hydrogen using the same, and the hydrogen sensor material of the present invention operates at room temperature. And does not require heating. The hydrogen sensor material of the present invention can be manufactured at low cost because it uses inexpensive magnesium / nickel and a very small amount of palladium. The hydrogen sensor material of the present invention has a very fast response speed. INDUSTRIAL APPLICABILITY The present invention is useful for providing a new high sensitivity hydrogen sensor that is indispensable for next-generation hydrogen energy practical application technology.
Claims (5)
（１）上記薄膜材料が、マグネシウム・ニッケル合金薄膜である、
（２）上記薄膜材料の上にパラジウムもしくは白金の触媒層が形成されている、
（３）触媒層の厚さが１ｎｍ−１００ｎｍである、
（４）室温で水素と反応して触媒層に接した界面付近の部分のマグネシウム・ニッケル薄膜の水素化によって表面の光学反射率が変化する、
（５）反射率変化は数秒で飽和する速い応答速度を有する、
（６）マグネシウム・ニッケル合金薄膜の組成がＭｇＮｉｘ（０≦ｘ＜０．６）である、
ことを特徴とする水素センサ。 A hydrogen sensor that detects hydrogen by using a thin film material that changes its physical properties by being hydrogenated by touching an atmosphere containing hydrogen, and monitoring changes in the optical reflectivity of the thin film surface ,
(1) the thin film material is a magnesium-nickel alloy thin film,
(2) A palladium or platinum catalyst layer is formed on the thin film material.
(3) The thickness of the catalyst layer is 1 nm-100 nm,
(4) The optical reflectance of the surface changes due to hydrogenation of the magnesium / nickel thin film near the interface that reacts with hydrogen at room temperature and contacts the catalyst layer .
(5) The reflectance change has a fast response speed that saturates in a few seconds,
(6) The composition of the magnesium-nickel alloy thin film is MgNix (0 ≦ x <0.6).
A hydrogen sensor characterized by that.
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| JP4158862B2 (en) | 2005-10-17 | 2008-10-01 | 株式会社アツミテック | Hydrogen gas visualization device |
| JP4644869B2 (en) * | 2005-10-26 | 2011-03-09 | 独立行政法人 日本原子力研究開発機構 | OPTICAL HYDROGEN GAS DETECTING ELEMENT AND ITS MANUFACTURING METHOD, AND OPTICAL HYDROGEN GAS DETECTING DEVICE AND METHOD USING THE ELEMENT |
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| JP2007248424A (en) | 2006-03-20 | 2007-09-27 | Atsumi Tec:Kk | Hydrogen sensor |
| DE102006054165B3 (en) | 2006-11-16 | 2008-04-17 | Tyco Electronics Raychem Gmbh | Optical sensor i.e. hydrogen sensor, arrangement for detecting hydrogen in gaseous measuring medium, has transducer designed such that physical characteristic is changed in response to presence and/or concentration of analyte |
| JP4840773B2 (en) * | 2006-11-22 | 2011-12-21 | 株式会社アツミテック | Hydrogen sensor and hydrogen gas detector |
| JP4900954B2 (en) * | 2007-05-31 | 2012-03-21 | 独立行政法人産業技術総合研究所 | Hydrogen sensor using magnesium-niobium alloy thin film |
| JP2008298649A (en) * | 2007-05-31 | 2008-12-11 | National Institute Of Advanced Industrial & Technology | Hydrogen sensor using magnesium-titanium alloy thin film |
| JP5164435B2 (en) | 2007-06-04 | 2013-03-21 | 株式会社アツミテック | Hydrogen sensor |
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| WO2024064017A1 (en) * | 2022-09-19 | 2024-03-28 | Indrio Technologies, Inc. | Multipass hydrogenated palladium optical cavities for detection of hydrogen |
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