Abstract: The invention relates to a method of producing a gas sensor element having a porous film formed by a thick-film technique on a ceramic substrate surface so as to cover selected portions of electrode films precedingly formed on the substrate surface. The electrode material is a noble metal such as platinum. Both the electrode films and the gas sensitive porous thick-film are formed by known methods. To improve the contact between the gas sensitive porous thick-film and the electrode films both mechanically and electrically and stabilize the internal resistance of the sensor element by depositing a noble metal such as platinum at the interface between the porous thick-film and each electrode film, the porous thick-film is impregnated with a solution of a noble metal compound such as chloroplatinic acid and thereafter maintained in a reducing gas atmosphere having a controlled humidity in the range from 5 to 90% (relative humidity) at a temperature in the range from 10.degree. C. to 135.degree. C.

Abstract: A gas sensing element, such as may be used to sense the presence of oxygen contained in the exhaust from a burner or internal combustion engine, whereby, by preventing the re-sintering of functional layers of the sensing element, a deterioration of the performance of the element under high-temperature operating conditions is prevented. The inventive sensing element includes a ceramic susbtrate, an electrode layer formed on the ceramic substrate, a first functional layer overlying the ceramic susbtrate and the electrode layer and which contains a transition metal oxide as a main component, and a second functional layer that cover the first functional layer and which contains 1 to 30 wt % of an anti-sintering agent and has a transition metal oxide as a main component.

Abstract: A gas sensor has a ceramic substrate carrying a pair of electrodes embedded therein, which substrate has an opening bored at a surface portion thereof so as to expose tip portions of the electrodes. A thick gas-sensitive film is provided at the opening in such a manner that a gap between the electrode tip portions is filled by the gas-sensitive film while the metallic material of the electrodes is caused to precipitate on the boundary between the electrodes and the gas-sensitive film, so that the performance characteristics of the sensor is stabilized and its durability is improved.

Abstract: A laminar gas-sensitive thick film consisting of ceramic semiconductor and metallic catalyzer is formed across a pair of electrodes carried by a ceramic substrate, and the nature of metallic catalyzer on an outer surface layer of the thick film is different from that of metallic catalyzer in that portion of the thick film which is in the proximity of the electrodes.

Abstract: An apparatus for evaluating an oxygen sensor includes a device for mixing a fuel and an oxygen-containing gas in an appropriate ratio to prepare a fuel mixture. A burner is connected to the mixing device for burning the fuel mixture to produce a gaseous combustion product. A tubular member extends from the burner for supplying the combustion product. A nozzle is connected to the tubular member for introducing a fuel and an oxygen-containing gas into the tubular member so that the combustion product is of a desired excess air ratio (air-fuel ratio) and a mounting device for the sensor to be evaluated is disposed on the tubular member, downstream of the nozzle.

Abstract: A roughened surface is formed on an insulating ceramics substrate having an electrode pattern by bonding or partially thrusting ceramics particles to or in the substrate, and a gas-sensitive metal oxide thick film is firmly bonded to the roughened surface.

Abstract: A roughened surface is formed on an insulating ceramics substrate having an electrode pattern by bonding or partially thrusting ceramics particles to or in the substrate, and a gas-sensitive metal oxide thick film is firmly bonded to the roughened surface.

Abstract: A gas sensor has a ceramic substrate carrying a first ceramic layer formed thereon and a second ceramic layer formed on the first layer, the two layers having successive setbacks from one edge of the substrate so as to form a staircase-like edge structure, and a gas-sensitive layer is formed on the staircase-like edge portion of said substrate, height of said gas-sensitive layer above the substrate being less than the thickness of the first ceramic layer.

Abstract: A gas sensor has an elongated planar ceramic substrate carrying a gas-sensitive layer at one end thereof, and a ceramic layer overlaid on the substrate with a setback from the gas-sensitive layer so as to form a staircase-like step on the substrate, the setback edge surface of the ceramic layer being non-linear in the width direction of the substrate but preferably perpendicular to the plane of substrate.

Abstract: A gas sensor has a 100-400 .mu.m thick gas-sensitive layer containing 5-30 mole % of a platinum group metal or an alloy thereof.

Abstract: A gas sensor has a heater circuit with a voltage-dividing element, and a voltage to energize the heater circuit is applied through a resistive lead wire element, while a sensor voltage to measure the resistance of a gas-sensitive element is branched from the heater circuit.

Abstract: A gas component detecting plug including a gas component-sensitive element, lead wires connected to the gas component-sensitive element, a tubular or board-like insulator which supports both the gas component-sensitive element and the lead wires, and an enclosure, the insulator being sealed to the enclosure so that the gas component-sensitive element is positioned on a leg portion side, characterized in that a spacer is disposed and retained in a gap formed between the insulator and the enclosure, in that a space on a head portion side formed by the insulator, enclosure, spacer and electrode wires is filled with glass and in that a rubbery elastic member having an insulating property is inserted in the head portion side. The gas component detecting plug is superior in water-proofness, gas-tightness, heat insulating property and productivity.

Abstract: A metal-ceramic bonded material is described wherein a metal member comprising a metal film and an oxide film as an upper layer is bonded to a ceramic member by a heat-resistant adhesive so that the surface of the oxide film of said metal member faces the surface of the ceramic member.

Abstract: Gold-plated electronic components are disclosed, as well as a process for producing the same, wherein an alloy of nickel and cobalt or an alloy containing these elements as essential ingredients is used as an undercoat for the gold-plated layer.

Abstract: A gas component detector having a gas component detecting element made of sintered metal oxide for indicating an electrical resistance according to the components of a gas to be detected. A pair of electrodes transmit the electrical resistance indicated by the gas component detecting element and a ceramic tube has through-holes into which said pair of electrodes are inserted. The ceramic tube has a cylindrical ceramic heater which is prepared by having a piece of wet ceramic sheet on which a print pattern is formed with metal paste for forming a heat generator wound on and bonded to the outer wall of the ceramic tube before sintering. The heater is then sintered to be integral with the ceramic tube.

Abstract: A gas sensing element having an oxide semiconductor element is provided with lead wires partially embedded therein. The lead wires are formed of a nickel core and a cover layer of at least 5.mu. in thickness and made of platinum or platinum alloy containing from 1 to 10 percent low catalytic metal.

Abstract: A strong and biocompatible sintered phosphate of calcium ceramics are obtained by sintering a powdery material substantially consisting of phosphate of calcium having a Ca/P ratio of 1.4-1.75, e.g. apatite group and/or tricalcium phosphate, and not exceeding 15% by weight of CaO-P.sub.2 O.sub.5 frit having a Ca/P ratio of 0.2-0.75. Y.sub.2 O.sub.3 incorporation therein improves the bending strength of the ceramics. Furthermore, a P.sub.2 O.sub.5 -metal oxide frit wherein metal oxide being one or more selected from BaO, CaO, MgO, ZnO, NaO and K.sub.2 O provides a more improved bending strength. The Y.sub.2 O.sub.3 incorporation herein still improves the strength of the sintered product.

Abstract: A gas detecting element including a semiconductor wafer formed of a transition-metal oxide with an electrode layer bonded to both sides of the wafer and a protective layer overlaid on the surface of the electrode layer. A metal lead wire is attached to each electrode layer by means of an electrically conductive adhesive wherein the region at which the metal lead wire is bonded to the electrode layer is reinforced by an insulating adhesive that covers the region. A process for producing such a gas detecting element is also disclosed.

Abstract: A laminar gas-sensitive thick film consisting of ceramic semiconductor and metallic catalyzer is formed across a pair of electrodes carried by a ceramic substrate, and the nature of metallic catalyzer on an outer surface layer of the thick film is different from that of metallic catalyzer in that portion of the thick film which is in the proximity of the electrodes.

Abstract: Gold-plated electronic components are disclosed, as well as a process for producing the same, wherein an alloy of nickel and cobalt or an alloy containing these elements as essential ingredients is used as an undercoat for the gold-plated layer.