Ngk Insulators, Inc.

Shiho Iwai

Yusuke Watanabe

Takayuki Sekiya

Takashi Suzuki

Shuichi Ozawa

Atsushi Watanabe

Mika Kai

Takeya Miyashita

Hirohito Kiyota

Satoko Moriyama

Kengo Terasawa

A sensor element includes: a base part containing an oxygen-ion conductive solid electrolyte as a constituent material; at least one internal space into which a measurement gas is introduced; and at least one pump cell including an internal electrode disposed to face the at least one internal space, an out-of-space pump electrode disposed at a location other than the at least one internal space, and a portion of the base part located between these electrodes, the internal electrode includes: an upper layer consisting of a noble metal, the solid electrolyte, and a pore; and a lower layer consisting of the noble metal and the solid electrolyte, and a volume ratio of the solid electrolyte in the lower layer is greater than a volume ratio of the solid electrolyte in the upper layer.

Sensor element of NOsensor and method for manufacturing sensor element of NOsensor

A sensor element includes: a base part containing an oxygen-ion conductive solid electrolyte as a constituent material; at least one internal space into which a measurement gas is introduced; and at least one pump cell including an internal electrode disposed to face the internal space, an out-of-space pump electrode disposed at a location other than the internal space, and a portion of the base part located between these electrodes, the internal electrode includes a noble metal, the solid electrolyte, and a pore, and, in the internal electrode, a degree of variation of a boundary of a first region formed of the base part or the solid electrolyte contiguous with the base part and a second region occupied by the noble metal and the pore in a thickness direction of the element is 0.5 μm or more and 6.5 μm or less.

Sensor element of NOx sensor

A sensor element includes a base part containing a solid electrolyte as a constituent material; at least one internal space into which a measurement gas is introduced; and at least one pump cell including an internal space electrode disposed to face the internal space, an out-of-space pump electrode disposed at a location other than the internal space, and a portion of the base part located between these electrodes, the internal space electrode includes a noble metal, the solid electrolyte, and a pore, and, in the internal space electrode, a ratio of a length of a boundary of a first region formed of the base part or the solid electrolyte contiguous with the base part and a second region occupied by the noble metal and the pore to a length of a boundary of the solid electrolyte and the internal space electrode is 1.1 or more.

Sensor element of gas sensor

In a sensor element for a limiting-current type gas sensor measuring concentration of NOx in a measurement gas, an inner pump electrode located to face a first internal space communicating with a gas inlet through which the measurement gas is introduced from an external space under predetermined diffusion resistance is made of a cermet of a Pt—Au alloy and zirconia, and the inner pump electrode is located, from among surfaces defining the first internal space, at least on a surface farthest from a heater part in a thickness direction of the element, and is not located on a surface closest to the heater part in the thickness direction.

Sensor element

A sensor element includes an element body including an oxygen-ion-conductive solid electrolyte layer, the element body having a longitudinal direction, a measurement electrode disposed in the element body, a reference electrode disposed in the element body so as to come into contact with a reference gas, and a heater configured to heat the solid electrolyte layer. A center of gravity of the reference electrode overlaps the measurement electrode as viewed in a thickness direction of the solid electrolyte layer. A length of each of the reference electrode and the measurement electrode in a front-rear direction is less than or equal to 1.1 mm, the front-rear direction being a direction along the longitudinal direction of the element body. An area of the reference electrode as viewed in the thickness direction is greater than or equal to 1.0 mm.

Sensor element and gas sensor

A gas sensor includes a sensor element, a detection device, a reference gas regulating device. The sensor element includes an element body having disposed therein a measurement-object gas flow section, a measurement-object-gas-side electrode disposed in or out of the element body, a reference electrode disposed within the element body, and a reference gas introducing section that allows a reference gas to be introduced thereinto and to flow therethrough to the reference electrode. The reference gas regulating device allows an oxygen pump-in current to flow between the reference electrode and the measurement-object-gas-side electrode to pump oxygen into around the reference electrode from around the measurement-object-gas-side electrode. A ratio R/Rof a reaction resistance Rof the reference electrode to a diffusion resistance Rof the reference gas introducing section is greater than or equal to 0.1 and less than or equal to 2.0.

Gas sensor and sensor element

In a sensor element for a limiting-current type gas sensor measuring concentration of NOx in a measurement gas, an inner pump electrode located to face a first internal space communicating, under predetermined diffusion resistance, with a gas inlet through which a measurement gas is introduced from an external space is made of a cermet of a Pt&#x2014;Au alloy and zirconia, and includes a first portion located on a surface farther from a heater part and a second portion located on a surface closer to the heater part from among surfaces opposing each other in the first internal space, an Au content with respect to the Pt&#x2014;Au alloy as a whole of the second portion is 0.3 wt % or more smaller than that of the first portion, and a total area of the first portion and the second portion is 10 mmto 25 mm.

A gas sensor includes a structural body made from an oxygen ion conductive solid electrolyte, a gas introduction passage which is formed in the structural body and into which a gas to be measured is introduced, a main adjustment chamber that communicates with the gas introduction passage, and a measurement chamber that communicates with the main adjustment chamber. A buffer space that communicates with the gas introduction passage, and at least two diffusion rate control members that communicate with the buffer space, are provided between the gas introduction passage and the main adjustment chamber. The respective widths Wband Wbof the diffusion rate control members are less than the respective widths Wa, Wc, and Wd of the gas introduction passage, the buffer space, and the main adjustment chamber.

Gas sensor

A sensor element includes a layered body that includes a measurement-object gas flowing portion which a measurement object gas is introduced and flowed in and a reference electrode that is formed inside of the layered body and a reference gas introducing layer made of a porous material that introduces a reference gas being used as a standard for detection of a specific gas concentration in the measurement-object gas and that flows the reference gas to the reference electrode, the reference gas introducing layer including an inlet portion serving as an inlet of the reference gas and one or more gas flowing spaces provided over a region from the inlet portion to the reference electrode in a direction in which the reference gas is flowed.

A sensor elementincludes an element main bodythat includes oxygen ion-conductive solid electrolyte layers (to), and a porous protective layerthat covers at least part of the element main body. The porous protective layerincludes a porous inner protective layerand a porous outer protective layerdisposed on the outer side of the inner protective layerand having a smaller average pore diameter than the inner protective layer

A manufacturing method for a sensor element includes a forming step. The forming step includes: a step (a) of forming an unfired electrode on one of plural green sheets; a step (b) of forming an unfired electrode lead and an unfired lead insulating layer on the same green sheet as in the step (a), the unfired electrode lead and to be connected to the unfired electrode, the unfired lead insulating layer surrounding at least part of the unfired electrode lead; and a step (c) of forming an unfired bonding layer so as to fill at least part of a region without the unfired lead insulating layer on the green sheet subjected to the step (b) and so as to overlap at least part of an edge portion of the unfired lead insulating layer.

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Nagoya, Japan

Shiho Iwai