摘要:
A ceramic heater which can be produced easily, induces no increase of production cost and can restrict the resistance change of a heating body due to migration. According to the present invention, a gap is formed between a ceramic sintered body and a heating body. Thus, migration in which cations are seized within the gap is caused so as to impede the cations from entering into the heating body. This makes it difficult for the cations to migrate and the volume in which the heating body is expanded is secured by the gap 13.
摘要:
An oxygen concentration detector provides high durability by increasing the thermal stability of coating layers applied to an electrode face thereof. A catalyst layer is formed on an outer surface of an electrode at the analysis gas side of a partition wall made of an ion oxygen conductive ceramic for generating electromotive force according to the difference between the concentration of oxygen in the analysis gas and the concentration of oxygen in the reference gas. The catalyst layer is composed of heat resistant ceramic particles and a particulate metallic catalyst made of platinum, rhodium or the like, supported by the surface of the heat resistant ceramic particles. The catalyst layer is formed so that the catalyst is supported by the heat resistant support particles. The support particles are heat treated to grow to a particle size so that particle growth can be restrained when the support particles are exposed to the exhaust gas from an internal combustion engine. The outside of the electrode of the partition wall is covered with support particles having such heat treated large cohered catalyst particles, and good responsivity of the sensor is thereby maintained.
摘要:
A measuring electrode and a reference plate are formed on the front and rear surfaces, respectively, of the electrolytic plate. The vent plate is provided with a vent channel. The heater base comprises a heating element. The electrolytic plate is made of a green sheet of zirconium oxide consisting of 5 to 7 molar % Y.sub.2 O.sub.3 and 0 to 5 parts by weight of aluminum oxide. The average particle diameter of the zirconium oxide powder is less than 2.0 .mu.m. The green sheet of zirconium oxide has a thickness of 50 to 300 .mu.m. The heater base is made of a green sheet of aluminum oxide consisting of aluminum oxide powder having an average particle diameter of less than 1.0 .mu.m and 0 to 10 parts by weight of zirconium oxide or yttria-stabilized zirconium oxide. The green sheet of aluminum oxide is at least 4 times the thickness of the green sheet of zirconium oxide. To complete the oxygen sensor, these four components are sintered together at 1300.degree. to 1600.degree. C. to be integrated.
摘要:
An oxygen sensor having an oxygen-ion-conductive element made of a metal oxide with an outer electrode composed of three layers, one of which is the thinnest, second of which is the intermediate in thickness and the third of which is the thickest. This oxygen sensor maintains quick response characteristics over a long period of time.
摘要:
According to the present invention, an oxygen sensor element includes a solid electrolyte having a side surface at one side thereof, the side surface being contactable with a gas to be measured, a skeletal electrode provided on the side surface and having a plurality of pore portions, each of the pore portions passing through the skeletal electrode up to the solid electrolyte, and a reactive electrode made of a porous film and provided in each of the pore portions, a thickness of the porous film being smaller than that of said skeletal electrode. An area percentage (SH/SZ) which is a ratio of a total area (SH) of the reactive electrode to a total area (SZ) of the skeletal electrode and the reactive electrode is in a range from 10 to 50%, an average area (SA) of the pore portions is 100 .mu.m.sup.2 or less, a film thickness of the skeletal electrode is in a range from 1.5 to 4 .mu.m, and the film thickness of the reactive electrode is in a range from 0.6 to 1.5 .mu.m. The oxygen sensor element is superior in the heat resistance characteristics and the response characteristics.
摘要:
This invention aims at providing an oxygen concentration sensor having electrodes which are excellent in heat resistance and durability and maintain quick response. An electrode 26 on an exhaust side is formed on one of the side surfaces of a solid electrolyte 25, and an electrode 24 on an atmosphere side is formed on the other side surface. The electrode 26 on the exhaust side has a composite structure comprising a skeletal electrode 26a and a reaction electrode 26a. The skeletal electrode 26a has a film thickness of 5 to 20 .mu.m and a porosity of less than 10%, and is a heat-resistant thick film for primarily forming a skeletal region. In contrast, the reaction electrode 26b has a film thickness of 0.5 to 2 .mu.m and a porosity of 10 to 50%, and is a high response thin film for primarily forming a reaction region.
摘要:
A limiting current type oxygen analyzer designed for detecting oxygen concentration comprising a solid electrolyte element made from an oxygen ion conductive metal oxide and a pair of porous film electrodes provided on the inner and outer sides of said element respectively, at least one side electrodes being coated with a gas-diffusive resistive layer made from a porous insulating metal oxide, wherein the oxygen ions in the gas to which said element is exposed are caused to diffuse in the inside of said electrolyte element by applying a given voltage across said both electrodes and the limiting current corresponding to the concentration of said diffused oxygen ions is measured to determine the oxygen concentration in the gas to be analyzed, further characterized in that said gas-diffusive resistive layer is composed of a three-layer structure consisting of the first, second and third layers counted from the electrode side, said first layer having porosity of 11-15%, the second layer 6-8% and the third layer 15-20%.
摘要:
A device for sensing the oxygen concentration in an exhaust gas has a cup-like oxygen-ion permeable cylindrical member made of solid electrolyte consisting of oxygen-ion conducting metal oxide. The cylindrical member has an inner circumferential surface communicating with the atmosphere and an outer circumferential surface communicating with the exhaust gas for producing an electromotive force corresponding to a difference between the oxygen concentrations on the inner circumferential surface and on the outer circumferential surface and has a negative-resistance temperature characteristic. A pair of first electrodes serving as a lean sensor each comprise a thin film made of porous metal material and are provided on the inner circumferential surface and outer circumferential surface of the cylindrical member, respectively, in opposed relationship to each other. An oxygen-gas diffusion limiting layer covers the lean sensing electrode on the outer circumferential surface of the cylindrical member. A pair of second electrodes for sensing the oxygen concentration under high load drive mode and the temperature of the cylindrical member each comprises a thin film made of porous metal material and are provided, respectively, on those portions of the inner and outer circumferential surfaces of the cylindrical member which are different from the portions where the first electrodes are provided in opposed relationship to each other. A heater is disposed in the cylindrical member for heating the cylindrical member.
摘要:
An oxygen concentration sensor including a solid electrolyte member having two portions, one portion being exposed to a gas of interest and the other portion being exposed to the atmosphere, an inner cover formed with a first space communicating portion arranged to communicate with the other portion of the solid electrolyte member, and a water-proof cover enclosing the inner cover to define a ventilating passage between the inner cover and the water-proof cover and formed with a second space communicating portion maintaining the first space communicating portion of the inner cover in communication with the atmosphere through the ventilating passage. The second space communicating portion of the water-proof cover is axially spaced apart from the first space communicating portion of the inner cover by a predetermined distance. Also included is structure to prohibit the flow of water through said ventilating passage. The second space communicating portion is separated from this structure.
摘要:
A measuring electrode and a reference plate are formed on the front and rear surfaces, respectively, of the electrolytic plate. The vent plate is provided with a vent channel. The heater base comprises a heating element. The electrolytic plate is made of a green sheet of zirconium oxide consisting of 5 to 7 molar % Y.sub.2 O.sub.3 and 0 to 5 parts by weight of aluminum oxide. The average particle diameter of the zirconium oxide powder is less than 2.0 .mu.m. The green sheet of zirconium oxide has a thickness of 50 to 300 .mu.m. The heater base is made of a green sheet of aluminum oxide consisting of aluminum oxide powder having an average particle diameter of less than 1.0 .mu.m and 0 to 10 parts by weight of zirconium oxide or yttria-stabilized zirconium oxide. The green sheet of aluminum oxide is at least 4 times the thickness of the green sheet of zirconium oxide. To complete the oxygen sensor, these four components are sintered together at 1300.degree. to 1600.degree. C. to be integrated.