Denso Corporation

Makoto Noguchi

Satoshi Suzuki

Mitsuhiro Yoshida

Kiyomi Kobayashi

Kei Sugiura

Tomofumi Fujii

Kazuki Yagi

A laminated gas sensor element is provided by laminating a plurality of ceramic layers. The gas sensor element includes: a solid electrolyte body having oxygen ion conductivity; a measurement electrode provided on a first principal surface of the solid electrolyte body; a reference electrode provided on a second principal surface of the solid electrolyte body; a chamber facing the measurement electrode and into which a measured gas is introduced; and a heater heating the solid electrolyte body. The chamber comprises at least one projecting corner portion, the at least one projecting corner portion projecting, on a cross section perpendicular to a longitudinal direction of the gas sensor element, in a width direction perpendicular to both of the longitudinal direction and a laminating direction. A tip of the projecting corner portion is disposed on a side closer to the heater than a center of the chamber in the laminating direction is.

Gas sensor element

A limiting current-type gas sensor element including a plurality of stacked ceramic layers and configured to output a limiting current value which depends on a concentration of a specific gas in a gas to be measured when a certain voltage is applied. The gas sensor element includes a solid electrolyte member having oxygen ion conductivity; a heater that heats the solid electrolyte member; a measurement electrode and a reference electrode provided on the solid electrolyte member; a chamber facing the measurement electrode and into which the gas to be measured is introduced; a gas inlet located to a tip side of the chamber in a longitudinal direction; and a diffusion resistance part provided in the gas inlet. A heating center of the heater is located further to the tip side than an electrode center of the measurement electrode is.

The invention relates to a solid electrolyte comprised of partially stabilized zirconia, and a gas sensor including the solid electrolyte. The partially stabilized zirconia includes crystal particles, the crystal particles include at least stabilizer low-concentration phase particles, and the partially stabilized zirconia further includes voids. Among the stabilizer low-concentration phase particles, the presence rate of the stabilizer low-concentration phase particles where each distance from a void is 5 μm or less is 65 volume percent or more. The stabilizer low-concentration phase particles include specific stabilizer low-concentration phase particles each having a distance of 5 μm or less from an adjacent void in the voids, a presence rate of the specific stabilizer low-concentration phase particles having 65 volume percent or more.

Solid electrolyte for gas sensor and gas sensor

A solid electrolyte includes partially stabilized zirconia in which a stabilizer forms a solid solution in zirconia. The partially stabilized zirconia includes, as crystal particles that configure the partially stabilized zirconia, stabilizer low-concentration phase particles of which concentration of the stabilizer at a particle center is less than 4.7 mol % and stabilizer high-concentration phase particles of which the concentration of the stabilizer at the particle center is equal to or greater than 4.7 mol %. The partially stabilized zirconia includes an adjacent particle portion in which two or more particles of the stabilizer low-concentration phase particles of which an average particle size is greater than 0.1 &#x3bc;m are adjacent. An abundance ratio of the stabilizer high-concentration phase particles on a cross-section of the solid electrolyte is equal to or greater than 70% in terms of area ratio relative to all crystal particles.

Solid electrolyte, manufacturing method thereof, and gas sensor

The invention relates to a solid electrolyte including partially stabilized zirconia, a producing method thereof, and a gas sensor including a solid electrolyte. The partially stabilized zirconia includes crystal particles, the crystal particles include mixed phase particles each having a high-concentration phase and a low-concentration phase, the high-concentration phase being defined such that a concentration of the stabilizer is 4.7 mol % or more, the low-concentration phase being defined as a concentration of the stabilizer is less than 4.7 mol %.

Solid electrolyte, producing method thereof, and gas sensor

A solid electrolyte includes partially stabilized zirconia in which a stabilizer forms a solid solution in zirconia. The partially stabilized zirconia includes at least monoclinic phase particles and cubic phase particles as crystal particles that configure the partially stabilized zirconia, and an abundance ratio of the monoclinic phase particle is 5 to 25% by volume. The partially stabilized zirconia includes stabilizer low-concentration phase particles of which concentration of the stabilizer at a particle center is equal to or less than 1 mol %, as the crystal particles. The stabilizer low-concentration phase particles have a particle-size distribution of number frequency thereof having a peak at which an average particle size is 0.6 to 1.0 &#x3bc;m, and a particle size at 10% of a cumulative number is 0.5 &#x3bc;m or greater, and of the overall low-concentration phase particles, 50% by volume or greater belong to the peak.

An electrode for a sensor elementthat detects a specific substance in a gas to be measured, wherein the electrode is embedded in an insulating substrate having a detection face to which the specific substance adheres, the electrode being embedded in such a manner that a part of the electrode is exposed at the detection face, the electrode comprises an alloy of Pt and at least one metal selected from the group consisting of Rh, Ru, Ir, Os, and Pd, and granular voids dispersed among the alloy, and the content of the metal in the alloy is 40 mass % or less, and the number of the granular voids per unit volume of the electrode for a sensor element is 3/100 &#x3bc;mto 50/100 &#x3bc;m.

Sensor element

A gas sensor has a gas sensor element which has a solid electrolyte body, a reference electrode and a measuring electrode. The solid electrolyte body contains partially stabilized zirconia as a main component in which zirconia is stabilized by stabilizer agent. Particle boundary parts are formed between crystal particles made of the partially stabilized zirconia. The particle boundary parts are made of a metal element such as yttria derived from the stabilizer agent, an alumina component and a silica component. A total content of the alumina component and the silica component in the particle boundary parts in the solid electrolyte body is within a range of 0.01 mass % to 1 mass % in terms of oxide in the solid electrolyte body. A ratio of the alumina component to the silica component in the particle boundary partsis within a range of 0.2 to 2.0 in terms of oxide.

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Kariya, Japan

Makoto Noguchi