Denso Corporation

Nippon Soken, Inc.

Other

Horiba, Ltd.

Itsuhei Ogata

Kaoru Kuzuoka

Eturo Yasuda

Masanori Yamada

Daisuke Makino

Atsuhiro Sumiya

Atsushi Kurano

Takumi Kataoka

Tsukasa Satake

Juichiro Ukon

Hirofumi Suzuki

Muneo Yorinaga

Hiroshi Araki

Yasuhiro Oya

Chiaki Ogawa

Yasuki Aoi

Mitsuhiro Konno

A temperature sensor includes a metal tube having an opening tip portion, a temperature sensing element for measuring a temperature, a pair of lead wires contacting with a surface of the temperature sensing element, an insulating support material for insulating the pair of lead wires from the metal tube, and a coating material for covering the temperature sensing element, lead tip portions of the pair of lead wires, and a tip surface of the insulating support material at the opening tip portion of the metal tube. The coating material has a property of not allowing measurement target gas to pass through and contains oxide and at least one of platinum, platinum alloy, and platinum-containing oxide that are dispersed in the oxide.

Temperature sensor

An alumina sintered body comprises alumina crystals as a main phase and a grain boundary phase made up of crystalline YSiOand amorphous SiOat grain boundaries of the alumina crystals wherein when the alumina sintered body is taken as 100 wt %, the high melting phase is present in the range of from 0.1 wt % to 15 wt %. There is also provided a method for preparing the alumina sintered body, which method comprising a first mixing step Pof mixing, at least, a yttria powder having an average particle size of 60 to 100 nm and a silica powder having a given average particle size to provide a mixed slurry and a second mixing step of further mixing an alumina powder having an average particle size of 0.5 to 1.0 &#x3bc;m in the mixed slurry.

Alumina sintered body and method for manufacturing same, and spark plug comprising the alumina sintered body as an insulator

The thermistor portion of a thermistor device consists of a mixed sintered body of aY(CrMn)O.bAlOmade of the perovskite-type compound Y(CrMn)Oand AlO, or a mixed sintered body of aY(CrMn)O.b(AlO+YO) made of Y(CrMn)O, AlOand YO. The mole fractions a and b have the relationships 0.05&#x2266;a&#x3c;1.0, 0&#x3c;b&#x2266;0.95 and a+b=1. This is required to obtain a thermistor device that has stable characteristics and exhibits a small change in its resistance value, even in a heat history from room temperature to 1000&#xb0; C. or the like, and also has a resistance value of 50&#x3a9; to 100 k&#x3a9; in the temperature range from room temperature to 1000&#xb0; C. The precursor compounds triethoxy yttrium, diethoxy manganese and tris (2,4-pentadiono) chromium are mixed in a mixed solvent of ethanol and isopropyl alcohol, and refluxing is performed to obtain a composite metal alkoxide solution. Then the metal salt precipitating agent of deionized water is added, the mixture is stirred and mixed and refluxing is performed to obtain a gelatinous precipitate of metallic salts containing Y, Mn and Cr. This precipitate is separated by filtration, dried and calcined to obtain powdered raw material with a composition of 38Y(CrMn)O.62YO, the same as that of a thermistor device. Thereafter, this powdered raw material is molded and sintered to obtain the thermistor device as a sintered body. Thereby, the dispersion of the resistance value of the thermistor can be reduced. An anti-reducing coating made of an anti-reducing material such as YO, AlO, YAlO, 3AlO.SiO, YSiOor the like is formed on the surface of a thermistor portion consisting of a mixed sintered body of Y(CrMn)O.YO(or Y(CrMn)O.AlO) or the like to form a thermistor device with a pair of lead wires attached. Thereby, the thermistor device exhibits resistance value stability even when subjected to a reducing atmosphere.

Thermistor device, thermistor device manufacturing method and temperature sensor

A highly accurate reduction resistant thermistor exhibiting stable resistance characteristics even under conditions where the inside of a metal case of a temperature sensor becomes a reducing atmosphere, wherein when producing the thermistor comprised of a mixed sintered body (M1 M2)O.AO, the mean particle size of the thermistor material containing the metal oxide, obtained by heat treating, mixing, and pulverizing the starting materials, is made smaller than 1.0 &#x3bc;m and the sintered particle size of the mixed sintered body, obtained by shaping and firing this thermistor material, is made 3 &#x3bc;m to 20 &#x3bc;m so as to reduce the grain boundaries where migration of oxygen occurs, suppress migration of oxygen, and improve the reduction resistance.

Reduction resistant thermistor, method of production thereof, and temperature sensor

Thermistor elements composed mainly of a metal oxide sintered body are prepared by mixing a metal oxide precursor in a liquid phase to prepare a solution or slurry of the precursor. The precursor solution or slurry is sprayed to form droplet particles which are heat treated to form a thermistor raw material powder which powder is then molded and sintered into a shape to provide a metal oxide sintered body.

Method of producing thermistor element and production apparatus for production apparatus for producing raw materials for thermistor element

The thermistor element of the present invention is composed of a mixed sintered body aM M O bY O of a composition M M O (wherein M is Y, and M is at least one element selected from the elements such as Cr, Mn, Ti, etc.) as a perovskite compound and Y O , wherein molar fractions a and b satisfy the relations 0.05&lE;a<1.0, 0<b&lE;0.95 and a&plus;b&equals;1. Another wide-range type thermistor element of the present invention is composed of a perovskite compound M (M M )O , wherein M is at least one element selected from the elements of the groups II and IIIA excluding La in the Periodic Table, and each of M and M is at least one element selected from the elements of the groups IIB, IIIB, IVA, VA, VIA, VIIA and VIII. a and b satisfy the relations a&plus;b&equals;1 and 0<b<0.1, where a is a molar fraction of M and b is a molar fraction of M in M (M M )O .

Wide-range type thermistor element and method of producing the same

This invention provides a reducing-atmosphere-resistant thermistor element, the resistance of which does not greatly change even when the element is exposed to a reducing atmosphere, and which has high accuracy and exhibits excellent resistance value stability. The thermistor element has a construction in which an oxygen occlusion-release composition, having oxygen occlusion-release characteristics, such as CeO is dispersed in a composition containing a mixed sintered body (M1 M2)O .AO as a principal component. The oxygen occlusion-release composition emits absorbed oxygen in a reducing atmosphere and suppresses migration of oxygen from the composition constituting the element. Therefore, the resistance value does not greatly change even when the element is exposed to a reducing atmosphere, and the element can accurately detect the temperature for a long time. The present invention can thus provide a temperature sensor having high reliability.

Reducing-atmosphere-resistant thermistor element, production method thereof and temperature sensor

The thermistor portion of a thermistor device consists of a mixed sintered body of aY(Cr,Mn,)O,.bAl,O,made of the perovskite-type compound Y(Cr,Mn,)O,and Al,O,, or a mixed sintered body of aY(Cr,Mn,)O,.b(Al,O,&plus;Y,O,) made of Y(Cr,Mn,)O,, Al,O,and Y,O,. The mole fractions a and b have the relationships 0.05&lE;a>1.0, 0<b&lE;0.95 and a&plus;b&equals;1. This is required to obtain a thermistor device that has stable characteristics and exhibits a small change in its resistance value, even in a heat history from room temperature to 1000&deg; C. or the like, and also has a resistance value of 50&OHgr; to 100 k&OHgr; in the temperature range from room temperature to 1000&deg; C.

Thermistor device thermistor device manufacturing method and temperature sensor

The thermistor element of the present invention is composed of a mixed sintered body aM,M,O,.bY,O,of a composition M,M,O,(wherein M,is Y, and M,is at least one element selected from the elements such as Cr, Mn, Ti, etc.) as a perovskite compound and Y,O,, wherein molar fractions a and b satisfy the relations 0.05&lE;a<1.0, 0<b&lE;0.95 and a&plus;b&equals;1. Another wide-range type thermistor element of the present invention is composed of a perovskite compound M,(M,M,)O,, wherein M,is at least one element selected from the elements of the groups II and IIIA excluding La in the Periodic Table, and each of M,and M,is at least one element selected from the elements of the groups IIB, IIIB, IVA, VA, VIA, VIIA and VIII. a and b satisfy the relations a&plus;b&equals;1 and 0<b<0.1, where a is a molar fraction of M,and b is a molar fraction of M,in M,(M,M,)O,.

A solid object carrying a catalyzer thereon is placed in a closed reaction chamber into which test gases are supplied and is heated up to a temperature of 1000.degree. C. Adsorbates are formed on the surface of the solid object under the test gas flow in the closed reaction chamber. Infrared radiations radiated from the adsorbates are emitted through an infrared-transmissive window hermetically formed on a wall of the closed reaction chamber, and are analyzed by an infrared radiation spectrometer and observed by a microscope. The infrared-transmissive window is cooled down by a cooling device attached thereto so that the temperature of the window does not exceed a certain level, e.g., 200.degree. C. Thus, the adsorbates formed on the solid object can be detected and analyzed under conditions where the test gas is actually flowing and the temperature of the solid object is elevated up to a high level. Since the infrared-transmissive window is cooled down and prevented from being broken by heat, the detection and analysis of the adsorbates are performed safely.

Apparatus for detecting and analyzing adsorbates

An infrared spectrometer disperses a radiation ray from a catalyst which has been exposed to a gas for evaluation to adsorb adsorbates thereon, and outputs spectral data in accordance with a wavenumber of the radiation ray to a computer storing reference data. The computer normalizes the spectral data and the reference data, and then, it calculates a product of the normalized spectral data and the reference data. Thereafter, a function of the product is differentiated with respect to the wavenumber to obtain a differential function. Accordingly, a specified wavenumber for which the differential function is zero is determined, so that the common peak of the spectral data and the reference data at the specified wavenumber is accurately determined.

Growing community of inventors

Nishio, Japan

Itsuhei Ogata