JPH0854363A - Capacitance type carbon dioxide sensor - Google Patents
Capacitance type carbon dioxide sensorInfo
- Publication number
- JPH0854363A JPH0854363A JP19141094A JP19141094A JPH0854363A JP H0854363 A JPH0854363 A JP H0854363A JP 19141094 A JP19141094 A JP 19141094A JP 19141094 A JP19141094 A JP 19141094A JP H0854363 A JPH0854363 A JP H0854363A
- Authority
- JP
- Japan
- Prior art keywords
- detector
- carbon dioxide
- sensor
- capacitance type
- capacitance
- 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.)
- Pending
Links
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- Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)
Abstract
Description
【0001】[0001]
【産業上の利用分野】本発明は、CO2センサ、特に金
属酸化物のCO2雰囲気下での静電容量の変化特性を利
用した静電容量型炭酸ガスセンサに関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a CO 2 sensor, and more particularly to a capacitance type carbon dioxide gas sensor utilizing the change characteristic of the capacitance of a metal oxide in a CO 2 atmosphere.
【0002】[0002]
【従来の技術】近年、金属酸化物の静電容量の変化特性
を利用してCO2を検知する静電容量型炭酸ガスセンサ
が開発されている。2. Description of the Related Art In recent years, a capacitance type carbon dioxide gas sensor has been developed which detects CO 2 by utilizing the change characteristic of capacitance of metal oxide.
【0003】以下に従来の静電容量型炭酸ガスセンサに
ついて説明する。静電容量型炭酸ガスセンサとしては、
例えば、ペロブスカイト金属酸化物と非複合系金属酸化
物とを混合してCO2検知体を形成し、作動温度456
℃〜555℃においてCO2検知体中の非複合系金属酸
化物とCO2との可逆的な炭酸塩形成・分解反応によ
り、CO2検知体の静電容量を変化させ、この静電容量
の変化からCO2濃度を検知する静電容量型炭酸ガスセ
ンサが特開平4−24548号公報に開示されている。A conventional capacitance type carbon dioxide gas sensor will be described below. As a capacitance type carbon dioxide sensor,
For example, a perovskite metal oxide and a non-composite metal oxide are mixed to form a CO 2 detector, and the operating temperature is 456.
° C. The reversible carbonate formation and decomposition reaction of the non-composite metallic oxide and CO 2 in the CO 2 sensing member in at ~555 ° C., by changing the capacitance of the CO 2 sensing elements, the capacitance An electrostatic capacitance type carbon dioxide gas sensor for detecting the CO 2 concentration from the change is disclosed in JP-A-4-24548.
【0004】[0004]
【発明が解決しようとする課題】しかしながら上記従来
の構成では、静電容量型炭酸ガスセンサが、作動温度5
60℃未満での炭酸塩形成・分解反応の反応速度が遅い
ために、CO2濃度の変化に追従できず、この結果、C
O2濃度に対する感度にばらつきがあったり、CO2濃度
がゼロになっても静電容量がもとの値に回復しない等、
CO2濃度の繰り返し測定を行う上で再現性、安定性に
欠けるという問題点を有していた。However, in the above conventional configuration, the capacitance type carbon dioxide gas sensor has an operating temperature of 5
Since the reaction rate of the carbonate formation / decomposition reaction at a temperature lower than 60 ° C. is slow, it cannot follow the change in the CO 2 concentration. As a result, C
There are variations in sensitivity with respect to the O 2 concentration, and even if the CO 2 concentration becomes zero, the capacitance does not recover to the original value.
There was a problem that reproducibility and stability were lacking when repeatedly measuring the CO 2 concentration.
【0005】本発明は上記従来の問題点を解決するもの
で、作動温度を560℃以上の高温域にすることにより
炭酸塩形成・分解反応の反応速度を速めてCO2の濃度
変化を迅速に検知するとともに、繰り返し測定しても高
精度で安定した静電容量の変化が得られる信頼性に優れ
た静電容量型炭酸ガスセンサを提供することを目的とす
る。The present invention solves the above-mentioned problems of the prior art. By increasing the operating temperature to a high temperature range of 560 ° C. or higher, the reaction rate of the carbonate formation / decomposition reaction is accelerated and the change in CO 2 concentration is promptly changed. It is an object of the present invention to provide a highly reliable electrostatic capacitance type carbon dioxide gas sensor that can detect and repeatedly obtain a highly accurate and stable change in electrostatic capacitance even when repeatedly measured.
【0006】[0006]
【課題を解決するための手段】この目的を達成するため
に本発明の請求項1に記載の静電容量型炭酸ガスセンサ
は、ペロブスカイト酸化物とCuOとの混合物で形成さ
れたCO2検知体を有する静電容量型炭酸ガスセンサで
あって、前記CO2検知体の作動温度が560℃以上,
好ましくは600℃〜800℃である構成を有してい
る。請求項2に記載の静電容量型炭酸ガスセンサは、請
求項1において、前記ペロブスカイト酸化物がBaTi
O3を含有する構成を有している。In order to achieve this object, the electrostatic capacitance type carbon dioxide gas sensor according to claim 1 of the present invention comprises a CO 2 detector formed of a mixture of perovskite oxide and CuO. A capacitance type carbon dioxide gas sensor having, wherein the operating temperature of the CO 2 detector is 560 ° C. or higher,
It preferably has a constitution of 600 ° C to 800 ° C. According to a second aspect of the present invention, in the electrostatic capacitance type carbon dioxide gas sensor according to the first aspect, the perovskite oxide is BaTi.
It has a structure containing O 3 .
【0007】ここで、CO2検知体の作動温度として
は、560℃以上,好ましくは600℃〜800℃がC
O2の吸着量が最も多く炭酸塩形成・分解反応の反応速
度が速くCO2センサとして好適な温度範囲である。The operating temperature of the CO 2 detector is 560 ° C. or higher, preferably 600 ° C. to 800 ° C.
The adsorption amount of O 2 is the largest and the reaction rate of the carbonate formation / decomposition reaction is fast, which is a temperature range suitable for a CO 2 sensor.
【0008】[0008]
【作用】この構成によって、ペロブスカイト酸化物とC
uOの混合物のCO2検知体を560℃以上の高温域で
作動させることにより、炭酸塩形成・分解反応の反応速
度を速くして、センサ特性として十分良好な感度と応答
性、再現性を得ることができる。With this structure, perovskite oxide and C
By operating the CO 2 detector of the mixture of uO in the high temperature range of 560 ° C. or higher, the reaction rate of carbonate formation / decomposition reaction is accelerated, and sufficiently good sensitivity, responsiveness and reproducibility are obtained as sensor characteristics. be able to.
【0009】[0009]
【実施例】以下、本発明の一実施例における静電容量型
炭酸ガスセンサについて、図面を参照しながら説明す
る。図1(a)は本発明の一実施例における静電容量型
炭酸ガスセンサの平面図であり、図1(b)は本発明の
一実施例における静電容量型炭酸ガスセンサの側面図で
ある。1は本発明の一実施例における静電容量型CO 2
センサ、2はペロブスカイト型酸化物とCuOの混合物
からなる円盤形状の導電性のCO2検知体、3はCO2検
知体2の両面に積層形成された銀製の電極である。EXAMPLE An electrostatic capacitance type device according to an example of the present invention will be described below.
The carbon dioxide sensor will be explained with reference to the drawings.
It FIG. 1A shows a capacitance type according to an embodiment of the present invention.
FIG. 1B is a plan view of a carbon dioxide sensor, and FIG.
FIG. 1 is a side view of a capacitance type carbon dioxide gas sensor according to an embodiment.
is there. 1 is a capacitance type CO in one embodiment of the present invention 2
Sensor, 2 is a mixture of perovskite type oxide and CuO
Disk-shaped conductive CO2Detector body, 3 is CO2Inspection
It is a silver electrode laminated on both sides of the knowledge body 2.
【0010】以上のように構成された静電容量型CO2
センサ1について、以下その製造方法を説明する。The electrostatic capacitance type CO 2 configured as described above
The method of manufacturing the sensor 1 will be described below.
【0011】まず、CO2検知体2の原料としてBaC
O3(商品名:炭酸バリウム、和光純薬製)及びTiO2
(商品名:P25、日本アエロジル社製)を等モル組成
秤量し、混合らいかい機(商品名:石川式混合らいかい
機)を用いて混合粉砕する。次に、この混合物を120
0℃で12時間焼成してBaTiO3を得る。次に、こ
のBaTiO3とCuO(商品名:酸化銅、和光純薬
製)とを等モル組成秤量して同じく混合らいかい機を用
いて混合する。次に、この混合物を成型プレス機(油圧
式25トン)を用いて3ton/cm2の成型圧で直径1
2mm,厚さ0.5mmの円盤形状に成形し、これを700
℃で5時間焼成してCO2検知体2を得る。次に、この
CO2検知体2の両面に銀ペースト(商品名:SP−5
1、田中貴金属製)を塗布し、100℃で2時間乾燥さ
せて銀製の電極3を積層形成し、この電極3上に白金の
リード線(図示せず)を付加して静電容量型CO2セン
サ1を得た。First, as a raw material for the CO 2 detector 2, BaC is used.
O 3 (trade name: barium carbonate, Wako Pure Chemical Industries) and TiO 2
(Product name: P25, manufactured by Nippon Aerosil Co., Ltd.) is weighed in an equimolar composition, and mixed and pulverized using a mixing raisage machine (Product name: Ishikawa type mixing raisage machine). This mixture is then added to 120
BaTiO 3 is obtained by firing at 0 ° C. for 12 hours. Next, this BaTiO 3 and CuO (trade name: copper oxide, manufactured by Wako Pure Chemical Industries, Ltd.) are weighed in equimolar compositions and mixed using the same mixing / raising machine. Then, this mixture was molded with a molding press (hydraulic 25 tons) at a molding pressure of 3 ton / cm 2 to a diameter of 1
Molded into a disc shape with a thickness of 2 mm and a thickness of 0.5 mm
A CO 2 detector 2 is obtained by firing at 5 ° C. for 5 hours. Next, a silver paste (trade name: SP-5) is formed on both sides of the CO 2 detector 2.
1, made by Tanaka Kikinzoku Co., Ltd., and dried at 100 ° C. for 2 hours to form a laminated electrode 3 made of silver, and a platinum lead wire (not shown) is added on the electrode 3 to form a capacitance type CO 2 sensor 1 was obtained.
【0012】以上のようにして製造された本発明の一実
施例における静電容量型炭酸ガスセンサを用い、その感
度特性試験を行った。Using the capacitance type carbon dioxide sensor according to the embodiment of the present invention manufactured as described above, the sensitivity characteristic test was conducted.
【0013】(実験例)本発明の一実施例における静電
容量型CO2センサ1を用いてCO2に対する感度特性を
測定した。測定方法は、CO2を含有しない空気から2
%のCO2を含有する空気に切り換えた時の静電容量型
CO2センサ1の静電容量の変化、及びCO2を含有する
空気からCO2を含有しない空気に切り換えた時の静電
容量の変化をインピーダンスアナライザ(商品名:41
92A、YHP社製)を用いて周波数50KHzの条件
下で感度測定を行った。ここで、感度とは、CO2を含
有しない空気中の静電容量に対するCO2を含有する空
気中での静電容量の比(Cco2/Cair)とした。
まず、CO2を含有しない空気雰囲気での感度(検体
1)、次に、CO2を2%含有したCO2雰囲気に切り換
えて2分後の感度(検体2)、更に、再度CO2を含有
しない空気雰囲気に切り換えて2分後の感度(検体3)
を、作動温度350,450,550,560,70
0,800℃においてそれぞれ2回繰り返して測定し
た。その結果を(表1)に示す。Experimental Example Sensitivity characteristics to CO 2 were measured using the capacitance type CO 2 sensor 1 in one example of the present invention. The measurement method is 2 from air containing no CO 2.
% Change in capacitance of the capacitance type CO 2 sensor 1 when switching to air containing CO 2 and capacitance when switching from air containing CO 2 to air not containing CO 2. Change of impedance analyzer (Product name: 41
92A, manufactured by YHP), and the sensitivity was measured under the condition of a frequency of 50 KHz. Here, sensitivity and was the ratio of the capacitance in air containing CO 2 to the electric capacitance in the air not containing CO 2 (Cco 2 / Cair) .
First, the sensitivity of an air atmosphere containing no CO 2 (sample 1), then switch the CO 2 2% containing the CO 2 atmosphere after 2 minutes Sensitivity (subject 2), further containing again CO 2 Sensitivity 2 minutes after switching to the air atmosphere (Sample 3)
Operating temperature 350,450,550,560,70
The measurement was repeated twice at 0 and 800 ° C. The results are shown in (Table 1).
【0014】[0014]
【表1】 [Table 1]
【0015】この(表1)から明らかなように、550
℃以下の温度範囲においてはCO2を含有する空気から
CO2を含有しない空気に切り換えた後の静電容量の回
復が悪く繰り返し使用において問題があるものの、56
0℃以上の温度範囲での感度は検体1及び検体3は共に
1.0、検体2では2.1以上となり、再現性もよくセ
ンサ特性として十分良好な静電容量の変化及びその回復
が認められた。As is clear from this (Table 1), 550
In the temperature range of ℃ or less, although the recovery of the electrostatic capacity after switching from the air containing CO 2 to the air not containing CO 2 is poor and there is a problem in repeated use,
The sensitivities in the temperature range of 0 ° C or higher are 1.0 for both Sample 1 and Sample 3 and 2.1 or higher for Sample 2, and the reproducibility is good and the change in the capacitance and its recovery are sufficiently good as sensor characteristics. Was given.
【0016】また、この静電容量型CO2センサ1の熱
分析測定を行った。その結果を図2に示す。図2は実験
例における静電容量型炭酸ガスセンサの温度変化に対す
る重量変化の割合を示す図である。図2から明らかなよ
うに、空気雰囲気下においては温度上昇に伴い重量の減
少は約300℃から約600℃まで認められる。一方、
CO2雰囲気下において重量の減少はT1℃からはじまり
高温側へシフトしていることから、この重量減少はCO
2吸着量を表していると考えられる。従って、CO2セン
サとして用いるためにはCO2の吸着量の多い温度領域
を用いればよく、図2から560℃以上,好ましくは6
00℃〜800℃が好適であることが分かった。Further, thermal analysis measurement of this capacitance type CO 2 sensor 1 was performed. The result is shown in FIG. FIG. 2 is a diagram showing a ratio of weight change to temperature change of the capacitance type carbon dioxide sensor in the experimental example. As is clear from FIG. 2, in an air atmosphere, a decrease in weight is recognized from about 300 ° C. to about 600 ° C. as the temperature rises. on the other hand,
In the CO 2 atmosphere, the weight loss starts from T 1 ° C and shifts to the high temperature side.
2 It is considered to represent the amount of adsorption. Therefore, in order to use it as a CO 2 sensor, it is sufficient to use a temperature range in which the amount of CO 2 adsorbed is large, and it can be seen from FIG.
It has been found that a temperature of 00 ° C to 800 ° C is suitable.
【0017】以上のように本実施例によれば、ペロブス
カイト酸化物とCuOの混合物のCO2検知体を560
°C以上の高温域で作動させることにより、炭酸塩形成
・分解反応の反応速度を速くして、CO2の濃度変化を
迅速に検知するとともに、繰り返し測定しても高精度で
安定した静電容量の変化を得ることができる。As described above, according to this embodiment, the CO 2 detector of the mixture of the perovskite oxide and CuO is 560.
By operating in a high temperature range of ° C or higher, the reaction rate of carbonate formation / decomposition reaction is accelerated to detect CO 2 concentration change rapidly, and even if repeated measurement is performed, highly accurate and stable electrostatic A change in capacity can be obtained.
【0018】[0018]
【発明の効果】以上のように本発明は、ペロブスカイト
酸化物とCuOの混合物のCO2検知体を560°C以
上の高温域で作動させることにより、センサ特性として
十分良好な感度と応答性、再現性を得ることができる信
頼性に優れた静電容量型炭酸ガスセンサを実現できるも
のである。As described above, according to the present invention, the CO 2 detector of the mixture of perovskite oxide and CuO is operated in the high temperature range of 560 ° C. or higher, so that the sensor characteristics sufficiently good sensitivity and responsiveness, It is possible to realize a highly reliable electrostatic capacitance type carbon dioxide gas sensor capable of obtaining reproducibility.
【図1】(a)本発明の一実施例における静電容量型炭
酸ガスセンサの平面図 (b)本発明の一実施例における静電容量型炭酸ガスセ
ンサの側面図FIG. 1A is a plan view of an electrostatic capacity type carbon dioxide gas sensor according to an embodiment of the present invention. FIG. 1B is a side view of an electrostatic capacity type carbon dioxide gas sensor according to an embodiment of the present invention.
【図2】実験例における静電容量型炭酸ガスセンサの温
度変化に対する重量変化の割合を示す図FIG. 2 is a diagram showing a ratio of weight change with respect to temperature change of the capacitance-type carbon dioxide sensor in an experimental example.
1 静電容量型CO2センサ 2 CO2検知体 3 電極1 Capacitance type CO 2 sensor 2 CO 2 detector 3 electrode
Claims (2)
で形成されたCO2検知体を有する静電容量型炭酸ガス
センサであって、前記CO2検知体の作動温度が560
℃以上であることを特徴とする静電容量型炭酸ガスセン
サ。1. A capacitance type carbon dioxide gas sensor having a CO 2 detector formed of a mixture of perovskite oxide and CuO, wherein the operating temperature of the CO 2 detector is 560.
A capacitance-type carbon dioxide gas sensor characterized by having a temperature of ℃ or higher.
を含有することを特徴とする請求項1に記載の静電容量
型炭酸ガスセンサ。2. The perovskite oxide is BaTiO 3
The capacitance-type carbon dioxide gas sensor according to claim 1, which contains:
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP19141094A JPH0854363A (en) | 1994-08-15 | 1994-08-15 | Capacitance type carbon dioxide sensor |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP19141094A JPH0854363A (en) | 1994-08-15 | 1994-08-15 | Capacitance type carbon dioxide sensor |
Publications (1)
Publication Number | Publication Date |
---|---|
JPH0854363A true JPH0854363A (en) | 1996-02-27 |
Family
ID=16274149
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP19141094A Pending JPH0854363A (en) | 1994-08-15 | 1994-08-15 | Capacitance type carbon dioxide sensor |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH0854363A (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2009139362A (en) * | 2007-12-10 | 2009-06-25 | Korea Electronics Telecommun | Nano-crystalline composite-oxide thin film, environmental gas sensor equipped with it, and its manufacturing method |
-
1994
- 1994-08-15 JP JP19141094A patent/JPH0854363A/en active Pending
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2009139362A (en) * | 2007-12-10 | 2009-06-25 | Korea Electronics Telecommun | Nano-crystalline composite-oxide thin film, environmental gas sensor equipped with it, and its manufacturing method |
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