JPS6165151A - Gas detecting element - Google Patents
Gas detecting elementInfo
- Publication number
- JPS6165151A JPS6165151A JP18648684A JP18648684A JPS6165151A JP S6165151 A JPS6165151 A JP S6165151A JP 18648684 A JP18648684 A JP 18648684A JP 18648684 A JP18648684 A JP 18648684A JP S6165151 A JPS6165151 A JP S6165151A
- Authority
- JP
- Japan
- Prior art keywords
- alumina
- coated
- sensitivity
- alcohol
- gas
- 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
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
- G01N27/04—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance
- G01N27/12—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance of a solid body in dependence upon absorption of a fluid; of a solid body in dependence upon reaction with a fluid, for detecting components in the fluid
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- Physics & Mathematics (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Investigating Or Analyzing Materials By The Use Of Fluid Adsorption Or Reactions (AREA)
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
この発明は、燃焼排気ガスやガスもれ等を検知するため
のガス検知素子に関するものである。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a gas detection element for detecting combustion exhaust gas, gas leakage, and the like.
従来から種々のガス検知素子が提案されているが、一般
にアルコールなどの雑ガスに対する選択性がないため酒
かん等による雑ガスをガスもれと判断してしまう。しか
も、経時的に高感度化の傾向にあり、特に雑ガスに討て
る/liJ!時高感度化率カー大きいため家庭用ガスも
れ警報dの誤報の原因となって(・る。Although various gas detection elements have been proposed in the past, they generally do not have selectivity for miscellaneous gases such as alcohol, and therefore miscellaneous gases from alcohol cans are determined to be gas leaks. Moreover, the sensitivity tends to increase over time, making it especially effective against miscellaneous gases/liJ! Due to the high sensitivity rate, it causes false alarms for household gas leak alarms.
このような雑ガスの対策として、Mn2O3とアルミナ
の混合物、あるいはCo3 o、−α−A120.をフ
ィルタとしてガス検知素子の表面に塗布したものが提案
されているが、これらは高温高湿中通電、あるいは長期
通電においてアルコールに対して経時高感度化の傾向か
みられる。これはMn2O3’PCo304粉末がシン
クし易いことなどのため酸化触媒としての活性が徐々に
低下して、アルコールを酸化除去するフィルタ効果が低
下していく結果と考えられろ。As a countermeasure against such miscellaneous gases, a mixture of Mn2O3 and alumina, or Co3o, -α-A120. It has been proposed to coat the surface of the gas detection element as a filter, but these tend to become more sensitive to alcohol over time when energized in high temperature, high humidity, or long-term energization. This is thought to be due to the fact that the Mn2O3'PCo304 powder is easy to sink, so its activity as an oxidation catalyst gradually decreases, and the filter effect for oxidizing and removing alcohol decreases.
この発明は、上述したアルコールなどの雑ガスに対する
感度を抑え、かつ、その特性を高湿中・還元性雰囲気、
被毒性雰囲気などの苛酷条件下にお(・でも長期間安定
に維持するよ5にすることを目的とする。This invention suppresses the sensitivity to miscellaneous gases such as alcohol mentioned above, and improves its characteristics in high humidity and reducing atmospheres.
The purpose is to maintain stability for a long period of time even under harsh conditions such as toxic atmospheres.
この発明は、雑ガスの除去層として、銅フルSネート、
ニッケルフルミネートなど、フルξすと他の金属とのU
含酸化物を用いて、これケ金属酸化物十4体ガス検知素
子の外層に多孔質1層として被覆したものである。This invention uses copper full S as a removal layer for miscellaneous gases.
When full ξ such as nickel fulminate, U with other metals
The outer layer of the 14-metal oxide gas detection element is coated with the oxide as a single porous layer.
この発明の複合酸化物は、活性アルミナにCu。The composite oxide of this invention includes activated alumina and Cu.
Co、 Mn+ Ni+ Feなとの塩の希薄水溶液を
含浸して焼成したとき、アルミナとこれらの金属イオン
とが結合して、Cu人1□04などの耐熱性、耐久性の
ある複合酸化物が形成され易く、α−A I 20 B
とではこのような結合は起らないことを見出したことに
基づくものである。例えばCLIO,Co3O4゜N
i Oは黒色の酸化物であるが、活性アルミナと結合し
て形成された複合酸化切、例えばCuAl□04゜Co
Al2O41Ni Ah O,はスピネル型結晶構造を
とり、淡青色を呈する。When impregnated with a dilute aqueous solution of salts such as Co, Mn + Ni + Fe, and fired, alumina and these metal ions combine to form heat-resistant and durable composite oxides such as Cu 1□04. easy to form, α-A I 20 B
This is based on the finding that such a combination does not occur in the case of . For example, CLIO, Co3O4゜N
iO is a black oxide, but it is a composite oxide formed by combining with activated alumina, such as CuAl□04゜Co.
Al2O41NiAhO, has a spinel crystal structure and exhibits a pale blue color.
従来から、M n 203とアルミナと混合して素子に
被覆する試みがある。また、α−AI 203に硝酸コ
バルトの水溶液を含浸して焼成しCo304−α〜Al
ρ。Previous attempts have been made to mix M n 203 and alumina to coat devices. In addition, α-AI 203 was impregnated with an aqueous solution of cobalt nitrate and fired to form Co304-α~Al
ρ.
を得てこれを用いることも提案されているが、この場合
、α−A120sはアルミナの中でも最も化学的に安定
な構造でありCOと反応することはなく、コバルトとア
ルミニウムはそれぞれの単独の酸化物として混合状、西
にあるにすぎない。この場合は黒色のCo3O4として
の色を呈する。It has also been proposed to obtain and use α-A120s, but in this case, α-A120s has the most chemically stable structure among aluminas and does not react with CO, and cobalt and aluminum are As a matter of fact, it is mixed, and it is only in the west. In this case, it exhibits a black color as Co3O4.
また、Cu、 Goなどの含有量は、従来例ではアルミ
ナに対してこれら金属の酸化物として5〜5゜wt、%
の高濃度であるが、この発明では活性アルミナの表面に
吸着した金属イオンのみを用いるもので、従来例に換算
丁れば七の濃度は5%以下でも有効であり、従来の常識
をはずれた領域に注目したものである。In addition, in conventional examples, the content of Cu, Go, etc. is 5 to 5% by weight as oxides of these metals relative to alumina.
However, in this invention, only metal ions adsorbed on the surface of activated alumina are used, and in terms of conventional methods, the concentration of 7 is effective even at 5% or less, which is contrary to conventional wisdom. It focuses on the area.
アルミナとの複合酸化物であるフルミネートは、熱的に
非常に安定で、ガス検知素子の動作温度の範囲(150
〜500℃)では、銅やコバルトの単独の位化物のよう
な・シンクなどによる活性低下を起てことはない。また
、還元性雰囲気におかれても、単独酸化物に比べ桁違い
に還元されにくく安定である。しかも、適度の酸化活性
を■することが見出された。すなわち、
(1) アルコールなどの雑ガスに対する燃焼活性は
非常に大きく、メタンやブタンに対するそれは小さい。Fulminate, which is a composite oxide with alumina, is very thermally stable and can be used within the operating temperature range of gas sensing elements (150
~500°C), there is no reduction in activity due to sinks, etc., such as those caused by single positional compounds of copper or cobalt. Furthermore, even when placed in a reducing atmosphere, it is much more stable and less likely to be reduced than a single oxide. Moreover, it was found that it has moderate oxidation activity. That is, (1) The combustion activity for miscellaneous gases such as alcohol is very high, but the combustion activity for methane and butane is small.
金属酸化物半導体ガス倹兄素子の外層にこれら複合酸化
物を多孔質層として被覆することによって、雑ガスを燃
焼除去し、素子の雑ガス感度を抑制することができる。By coating the outer layer of the metal oxide semiconductor gas-sparing element with these composite oxides as a porous layer, the miscellaneous gases can be burned off and the sensitivity of the element to miscellaneous gases can be suppressed.
(it) フルミネートは熱的にも化学的にも非常に
安定であり、単独酸化物では得られない耐久性が得られ
た。丁なわち、単独酸化物では、高温高湿雰囲気では水
蒸気の介在によって酸化物粒子の活性低下が起り易く、
ま1こ、水素などの還元性雰囲気では酸化物が還元され
ることによって特性も変りシンクなども起き易いが、こ
れらの点に関しこの複合酸化物は単独酸化物に比べて桁
違いに安定である。(it) Fulminate was extremely stable both thermally and chemically, and provided durability that could not be obtained with single oxides. In other words, in the case of a single oxide, the activity of the oxide particles tends to decrease due to the presence of water vapor in a high-temperature, high-humidity atmosphere.
First, in a reducing atmosphere such as hydrogen, the properties change and sinks are likely to occur as the oxide is reduced, but in these respects, this composite oxide is an order of magnitude more stable than a single oxide. .
(i+il 活性アルミナの細孔内面に複合酸化物が
形成され酸化触媒としての活性を呈するため、有機シリ
コーンや802などの被毒性物質はこの細孔被毒性ガス
の共存する雰囲気におし・でも耐久性に丁ぐれている。(i+il) Because a composite oxide is formed on the inner surface of the pores of activated alumina and exhibits activity as an oxidation catalyst, toxic substances such as organic silicone and 802 are durable even when exposed to an atmosphere where the pore-toxic gas coexists. I'm very particular about my gender.
活性なガンマアルミナ(比表面積1o o m”/g)
を濃度0.1モル/l の硝酸銅水溶液中に投入し、−
昼夜放置して含浸吸着させたのち、余剰液をろ過し、乾
燥後900℃で2時間焼成する。この場合の鋼の含有率
はガンマアルミナの吸着能力にもよるが、酸化銅換算で
ガンマアルミナに対して5%以下であった。他の金属塩
の場合も同様にして作成される。Active gamma alumina (specific surface area 1 o m”/g)
into a copper nitrate aqueous solution with a concentration of 0.1 mol/l, -
After being allowed to stand day and night for impregnation and adsorption, the excess liquid is filtered, dried and then baked at 900°C for 2 hours. Although the content of steel in this case depends on the adsorption capacity of gamma alumina, it was 5% or less of gamma alumina in terms of copper oxide. Other metal salts are prepared in the same manner.
この粉末を少量のアルミナ系バインダと共に水ねりして
金属酸化物半導体ガス検知素子の外層に盪布し、700
°Cで1時間焼結した。このようにして製造されたガ′
ス検知素子全第1図圧示す。This powder was soaked in water with a small amount of alumina binder and spread on the outer layer of a metal oxide semiconductor gas sensing element.
Sintered at °C for 1 hour. The gas produced in this way
The first figure shows the total pressure of the sensing element.
第1図で、1はアルミナ基孜(3X1.5X0.4問)
であり、下面に白金膜ヒータ2を備え、その上をヒータ
保護膜3で覆っている。アルミナ基或1の上面には白金
膜電極4が設けられ、その上をSnO□焼結層5でおお
い、厚膜タイプの金属酸化物半導体ガス検知素子が構成
されている。そして、この金:% t’&化物半4体ガ
ス検知素子の外層に上述した手順によって形成した複合
酸化物である銅フルミネートの多孔質層6が設げられて
、この発明のガス検知素子が構成される。In Figure 1, 1 is Alumina Motoki (3X1.5X0.4 questions)
A platinum film heater 2 is provided on the lower surface, and a heater protective film 3 is placed on top of the platinum film heater 2 . A platinum film electrode 4 is provided on the upper surface of the alumina base 1, and is covered with a SnO□ sintered layer 5 to constitute a thick film type metal oxide semiconductor gas sensing element. Then, a porous layer 6 of copper fulminate, which is a composite oxide, formed by the above-mentioned procedure is provided on the outer layer of this gold:% t'& compound half-quadruple gas sensing element, and the gas sensing element of the present invention is obtained. configured.
第2図は熱線型半導体素子に適用した場合の実施例で、
Tはフィル状の白金ta兼上ヒータ5はS n Oを焼
結層で白金電極兼ヒータTのコイル部をおおうように形
成されている。この5n02!結眉5の外ノーに上述の
手順圧よってアルミネートの多孔質層6を塗布g8M乙
たものである。Figure 2 shows an example when applied to a hot wire type semiconductor device.
T is a fill-shaped platinum electrode/heater 5. The coil part of the platinum electrode/heater T is covered with a sintered layer of S.sub.nO. This 5n02! A porous layer 6 of aluminate was applied to the outside of the eyebrows 5 using the above-mentioned procedure and pressure.
なお、Cu、 Co+ Mn、 N+、 Feとアルミ
ナとの複合酸化物をつくる方法としては、共沈法、競争
吸着法など通常の触媒製造手段が適用できることはいう
までもない。Note that, as a method for producing a composite oxide of Cu, Co+Mn, N+, Fe and alumina, it goes without saying that ordinary catalyst production methods such as coprecipitation method and competitive adsorption method can be applied.
第3図は厚膜タイプのガス検知素子にこの発明による銅
フルミ不一トの被覆を実施した場合のガス検知素子のガ
ス感度の一度依存特性である。第4図の被覆しない従来
の素子にZける場合と比較するとエタノール感度が顕著
に抑制されていることがわかる。なお、この図の縦軸表
示はガス検知素子のガス感度な示すコンダクタンス変化
率で、Goは大気中での素子のコンタクタンス、Ggは
ガス中でのコンタクタンスである。FIG. 3 shows the once-dependent characteristic of the gas sensitivity of a thick film type gas sensing element in which the copper fluorite coating according to the present invention is applied. It can be seen that the ethanol sensitivity is significantly suppressed when compared with the conventional uncoated element shown in FIG. Note that the vertical axis in this figure represents the conductance change rate indicated by the gas sensitivity of the gas detection element, where Go is the contactance of the element in the atmosphere and Gg is the contactance in the gas.
第1表は高温高湿雰囲気におかれたときの素子の耐久性
を示すもので、H,0,1%共存、50℃。Table 1 shows the durability of the element when placed in a high-temperature, high-humidity atmosphere, with 0.1% H and 50°C.
95%の高湿中に30日間通を状聾で封入したのち通常
湿度にもどしてW綴器としての警報濃度を測定したもの
である。初期値と比較すると、M n203 *Cub
、 Co5t、の単独酸化物とアルミナの混合物を被覆
した例では、エタノール2水素に対して著しく鋭敏化し
ており誤報につながることが水硬される。この発明の各
独フルミネートでは耐久性良好である。第2表はSO2
0,5ppmの被毒性雰囲気中10日間封入テストの結
果である。同様にして各徨アルミネートにおいては初期
値と比較してあまり変化しておらず、耐毒性良好である
。After 30 days of hearing-impaired samples were sealed in 95% high humidity, the humidity was returned to normal, and the alarm concentration as a W binding device was measured. Compared to the initial value, M n203 *Cub
In an example in which a mixture of a single oxide of , Co5t, and alumina is coated, it becomes extremely sensitive to ethanol dihydrogen, leading to false alarms. The German fulminate of this invention has good durability. Table 2 shows SO2
These are the results of a 10-day encapsulation test in a 0.5 ppm toxic atmosphere. Similarly, each of the residual aluminates did not change much compared to the initial value, indicating good toxicity resistance.
この発明は以上説明したように、金属酸化物半導体ガス
検知素子の外層に、Cu r Co r Mn + N
+ rFeのアルミナとの複合酸化物のうちの少なく
とも−11からな乙多孔負層を被覆したので、アルコー
ルなどの雑ガスに対する感度を抑えることができ、しか
も、その特性を高温高湿の還元性雰囲気中、被毒性雰囲
気などの苛酷条件下においても、長期間安定に維持する
ことができる効果がある。As explained above, this invention includes Cu r Cor Mn + N in the outer layer of a metal oxide semiconductor gas sensing element.
Since it is coated with a porous negative layer made of at least -11 of the composite oxide of +rFe and alumina, it is possible to suppress the sensitivity to miscellaneous gases such as alcohol, and furthermore, its characteristics can be reduced to high temperature and high humidity. It has the effect of being able to be stably maintained for a long period of time even under harsh conditions such as in a toxic atmosphere.
第1図はこの発明の一夷2i!!i汐1]を示す厚膜型
のガス検知素子の断面図、第2図はこの発明の他の実施
−jを示す熱線型のガス暎知素子の断面図、餓3図はこ
の発明によるガス検知素子のガス濃度依存特性図、第4
図は従来のガス検知素子のガスa度1ム存特性図である
。
図中、1はアルミナ基板、2は白金膜ヒータ、3はヒー
タ保護膜、4は白金膜厄極、5はS n O!焼結層、
6は腹合酸化物の多孔式層、7はコイル状の白金+1極
兼ヒータである@
第2図Figure 1 shows the advantage of this invention: 2i! ! Figure 2 is a sectional view of a hot-wire type gas detection element showing another embodiment of the present invention, and Figure 3 is a cross-sectional view of a gas sensing element according to the present invention. Gas concentration dependence characteristic diagram of the sensing element, 4th
The figure is a diagram showing the gas a degree 1 temperature characteristic of a conventional gas detection element. In the figure, 1 is an alumina substrate, 2 is a platinum film heater, 3 is a heater protective film, 4 is a platinum film electrode, and 5 is S n O! sintered layer,
6 is a porous oxide layer, and 7 is a coiled platinum + single pole/heater.
Claims (1)
Mn、Ni、Feのアルミナとの複合酸化物のうちの少
なくとも一種からなる多孔質層を被覆したことを特徴と
するガス検知素子。The outer layer of the metal oxide semiconductor gas sensing element contains Cu, Co,
A gas sensing element coated with a porous layer made of at least one of composite oxides of Mn, Ni, and Fe with alumina.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP18648684A JPS6165151A (en) | 1984-09-07 | 1984-09-07 | Gas detecting element |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP18648684A JPS6165151A (en) | 1984-09-07 | 1984-09-07 | Gas detecting element |
Publications (2)
Publication Number | Publication Date |
---|---|
JPS6165151A true JPS6165151A (en) | 1986-04-03 |
JPH053897B2 JPH053897B2 (en) | 1993-01-18 |
Family
ID=16189326
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP18648684A Granted JPS6165151A (en) | 1984-09-07 | 1984-09-07 | Gas detecting element |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPS6165151A (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO1995016646A1 (en) * | 1993-12-18 | 1995-06-22 | Robert Bosch Gmbh | Method of producing one or more cavities in or under the coating of a substrate |
GB2503231A (en) * | 2012-06-19 | 2013-12-25 | Crowcon Detection Instr Ltd | Flameproof barrier for a gas detector |
EP2884273A1 (en) * | 2013-12-12 | 2015-06-17 | Delphi Technologies, Inc. | Thermal shock resistant coated exhaust sensor |
Citations (7)
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---|---|---|---|---|
JPS51130299A (en) * | 1975-05-07 | 1976-11-12 | Fuigaro Giken Kk | A gas detector which has selectirity of detectingas |
JPS51151193A (en) * | 1975-06-20 | 1976-12-25 | C-Hoo Beririumu Switch Kogyo Kk | Gas detector |
JPS5739341A (en) * | 1980-08-22 | 1982-03-04 | Toyota Motor Corp | Oxygen sensor |
JPS57200844A (en) * | 1981-06-04 | 1982-12-09 | Ngk Insulators Ltd | Oxygen concentration detector |
JPS5822947A (en) * | 1981-08-03 | 1983-02-10 | Yazaki Corp | Gas sensor using sno2 group |
JPS5892850A (en) * | 1982-11-12 | 1983-06-02 | Fuigaro Giken Kk | Detecting element of gas having selectivity of detecting gas |
JPS58191962A (en) * | 1982-05-07 | 1983-11-09 | Hitachi Ltd | Gas detector |
-
1984
- 1984-09-07 JP JP18648684A patent/JPS6165151A/en active Granted
Patent Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS51130299A (en) * | 1975-05-07 | 1976-11-12 | Fuigaro Giken Kk | A gas detector which has selectirity of detectingas |
JPS51151193A (en) * | 1975-06-20 | 1976-12-25 | C-Hoo Beririumu Switch Kogyo Kk | Gas detector |
JPS5739341A (en) * | 1980-08-22 | 1982-03-04 | Toyota Motor Corp | Oxygen sensor |
JPS57200844A (en) * | 1981-06-04 | 1982-12-09 | Ngk Insulators Ltd | Oxygen concentration detector |
JPS5822947A (en) * | 1981-08-03 | 1983-02-10 | Yazaki Corp | Gas sensor using sno2 group |
JPS58191962A (en) * | 1982-05-07 | 1983-11-09 | Hitachi Ltd | Gas detector |
JPS5892850A (en) * | 1982-11-12 | 1983-06-02 | Fuigaro Giken Kk | Detecting element of gas having selectivity of detecting gas |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO1995016646A1 (en) * | 1993-12-18 | 1995-06-22 | Robert Bosch Gmbh | Method of producing one or more cavities in or under the coating of a substrate |
GB2503231A (en) * | 2012-06-19 | 2013-12-25 | Crowcon Detection Instr Ltd | Flameproof barrier for a gas detector |
GB2503231B (en) * | 2012-06-19 | 2017-07-12 | Crowcon Detection Instr Ltd | Flameproof barrier |
EP2884273A1 (en) * | 2013-12-12 | 2015-06-17 | Delphi Technologies, Inc. | Thermal shock resistant coated exhaust sensor |
Also Published As
Publication number | Publication date |
---|---|
JPH053897B2 (en) | 1993-01-18 |
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