Abstract: An active liquid applicator is provided which is designed to coat a surface of an electronic parts such as an oxygen sensor with an active liquid for forming an electrode. The liquid applicator includes a nozzle head and a nozzle tube. The nozzle tube has disposed therein a pearmable member which produces capillary attraction of an active liquid thereinto and feed it to the nozzle head, thereby enabling formation of a thin active film on the electronic part which has the thickness controllable with high accuracy.

Abstract: A second protective layer is a ceramic porous protective layer comprising coarse particles and fine particles structurally arranged in such a manner that interparticle cavities formed between the coarse particles are filled with the fine particles. At least either of the coarse particles and the fine particles contain at least one selected from the group consisting of &ggr;-Al2O3, &thgr;-Al2O3, &dgr;-Al2O3 and solid solution having the same crystal structure as those of &ggr;-Al2O3, &thgr;-Al2O3, &dgr;-Al2O3.

Abstract: A multilayered gas sensing element 2 is positioned in a cylindrical housing 10 via a cylindrical insulator 3. The multilayered gas sensing element 2 includes a narrow-width portion 21 and a wide-width portion 22. The wide-width portion 22 is in a fixed relationship with respect to the insulator 3. The narrow-width portion 21 is in a floating relationship with respect to the insulator 3. The narrow-width portion 21 has a gas sensing portion for detecting the concentration of a specific gas contained in a measuring objective gas.

Abstract: A measuring objective gas side electrode is provided on a surface of a solid electrolytic substrate. A reference electrode is provided on another surface of the solid electrolytic substrate. The measuring objective gas side electrode is exposed to a chamber. A gas introducing passage extends to connect the chamber to an external environment of the gas sensing element. A relationship S/Ld≦1.5 is established, where S represents a cross-sectional area of an inner open end of the gas introducing passage opening to the chamber, L represents a circumferential length of the inner open end, and d represents a thickness of the chamber in the vicinity of the inner open end of the gas introducing passage.

Abstract: A gas sensor element is provided which is used in a gas sensor such as an oxygen sensor. The gas sensor element includes a solid electrolyte body, a target gas electrode provided on a surface of the solid electrolyte body so as to be exposed to a gas to be measured, and a reference gas electrode provided on a surface of the solid electrolyte body so as to be exposed to a reference gas. Each of the target gas electrode and the reference gas electrode is made up of a plurality of crystal grains defined by grain boundaries. The total length of the grain boundaries in each of the target gas electrode and the reference gas electrode is 1000 &mgr;m or more in a surface area of 1000 &mgr;m2. This ensures a sufficient degree of diffusion of the gasses in the target and reference gas electrodes, thereby providing a rapid response rate to the gas sensor element.

Abstract: A gas sensor element which may be employed in measuring the concentration of gas such O2, NOx, or CO. The gas sensor element consists of an electrochemical cell made up of a solid electrolyte body formed by a partially stabilized zirconia and a pair of electrodes disposed on the solid electrolyte body. The electrochemical cell is subjected to an aging treatment in which the dc current is applied to the electrodes at a given voltage to enhance the activation of the electrochemical cell.

Abstract: A powder filler is stuffed in a filler space defined between a housing and a gas sensing element so as to airtightly seal a clearance between the housing and the gas sensing element. The powder filler contains grains whose diameter is in a range from 80 &mgr;m to 5,000 &mgr;m when measured before being stuffed into the filler space. A weight percentage of the grains having the diameter of 80 &mgr;m to 5,000 &mgr;m is equal to or larger than 80% with respect to an overall weight of the powder filler.

Abstract: A gas sensor element is provided which is used in a gas sensor such as an oxygen sensor. The gas sensor element includes a solid electrolyte body, a target gas electrode provided on a surface of the solid electrolyte body so as to be exposed to a gas to be measured, and a reference gas electrode provided on a surface of the solid electrolyte body so as to be exposed to a reference gas. Each of the target gas electrode and the reference gas electrode is made up of a plurality of crystal grains defined by grain boundaries. The total length of the grain boundaries in each of the target gas electrode and the reference gas electrode is 1000 &mgr;m or more in a surface area of 1000 &mgr;m2. This ensures a sufficient degree of diffusion of the gasses in the target and reference gas electrodes, thereby providing a rapid response rate to the gas sensor element.

Abstract: A gas sensing element has a solid electrolytic body, a reference gas side electrode provided on a surface of the solid electrolytic body so as to be exposed to a reference gas, and a measured gas side electrode provided on another surface of the solid electrolytic body so as to be exposed to a measured gas. A crystal face strength ratio of the measured gas side electrode according to X-ray diffraction is 0.7≦{I(200)/I(111)} or 0.6≦{I(220)/I(111)}.

Abstract: A gas sensing element has a solid electrolytic body, a reference gas side electrode provided on a surface of the solid electrolytic body so as to be exposed to a reference gas, and a measured gas side electrode provided on another surface of the solid electrolytic body so as to be exposed to a measured gas. A crystal face strength ratio of the measured gas side electrode according to X-ray diffraction is 0.7≦{I(200)/I(111)} or 0.6≦{I(220)/I(111)}.

Abstract: A sensor element has a solid electrolyte body holding a reference gas side electrode and a measurement gas side electrode on surfaces thereof. The measurement gas side electrode is covered with a porous protective layer including a component as a lead getter, which reacts with lead contained in measurement gas. Accordingly, lead is removed from measurement gas by the protective layer not to be attached to the measurement gas side electrode. As a result, the sensor element can be used in measurement gas containing lead, without deteriorating responsibility and output thereof.

Abstract: An oxygen sensor element is provided which may be used in an oxygen sensor designed to measure the concentration of oxygen contained in exhaust gasses of an automotive internal combustion engine. The gas sensor element includes a solid electrolyte body, a target gas electrode, a reference gas electrode, and a catalytic layer formed over the target gas electrode. The catalytic layer is made of heat resisting ceramic grains which hold thereon catalytic metal grains whose average grain size is 0.3 to 2.0 &mgr;m, a weight of catalytic metal grains per unit area of the catalytic layer, as defined by projecting the target gas electrode on a plane, is 10 to 200 &mgr;g/cm2. This facilitates the reaction of exhaust gasses such as H2, NOx, and HC with O2 over the target gas electrode, thus resulting in improved accuracy of a sensor output over a wide temperature range.

Abstract: A gas sensing element has a solid electrolytic body, a reference gas side electrode provided on a surface of the solid electrolytic body so as to be exposed to a reference gas, and a measured gas side electrode provided on another surface of the solid electrolytic body so as to be exposed to a measured gas. A crystal face strength ratio of the measured gas side electrode according to X-ray diffraction is 0.7≦{I(200)/I(111)} or 0.6≦{I(220)/I(111)}.

Abstract: A solid electrolytic body has an inside space serving as a reference gas chamber. A sensing electrode and a reference electrode are formed on the surface of the solid electrolytic body. A heater is disposed in the reference gas chamber. A contact portion comprises a region where the heater is brought into contact with the inner surface of the solid electrolytic body and an opposing region on the outer surface of the solid electrolytic body. The sensing electrode includes at least part of the contact portion. A gas receiving surface region, exposed to the measuring gas, extends from an element tip to a position spaced by a distance L away from the element tip. At least part of the contact portion is located in a region extending from the element tip to a position spaced by a distance 0.4L away from the element tip. The sensing electrode is entirely located in a region extending from the element tip to a position spaced by a distance 0.8L away from the element tip.

Abstract: An improved structure of an oxygen sensing element installed in an oxygen sensor designed to measure an oxygen content in gases is provided. The structure includes a cup-shaped solid electrolyte body, an inner electrode, and an outer electrode. The solid electrolyte body has a portion exposed to the gases which has a given length. The inner electrode is formed on an inner wall of the solid electrolyte body and exposed to air. The outer electrode is formed on an outer wall of the solid electrolyte body and exposed to the gases through a protective layer. The oxygen content in the gases is measured based on output signals from the inner and outer electrodes. The outer electrode occupies an area on the outer wall of the solid electrolyte body within a range of 80% of the given length of the gas-exposed portion of the solid electrolyte body and has a thickness ranging from 1.2 to 3.0 &mgr;m.

Abstract: A gas sensor element is provided which is used in a gas sensor such as an oxygen sensor. The gas sensor element includes a solid electrolyte body, a target gas electrode provided on a surface of the solid electrolyte body so as to be exposed to a gas to be measured, and a reference gas electrode provided on a surface of the solid electrolyte body so as to be exposed to a reference gas. Each of the target gas electrode and the reference gas electrode is made up of a plurality of crystal grains defined by grain boundaries. The total length of the grain boundaries in each of the target gas electrode and the reference gas electrode is 1000 &mgr;m or more in a surface area of 1000 &mgr;m2. This ensures a sufficient degree of diffusion of the gasses in the target and reference gas electrodes, thereby providing a rapid response rate to the gas sensor element.

Abstract: A second protective layer is a ceramic porous protective layer comprising coarse particles and fine particles structurally arranged in such a manner that interparticle cavities formed between the coarse particles are filled with the fine particles. At least either of the coarse particles and the fine particles contain at least one selected from the group consisting of &ggr;-Al2O3, &thgr;-Al2O3, &dgr;-Al2O3 and solid solution having the same crystal structure as those of &ggr;-Al2O3, &thgr;-Al2O3, &dgr;-Al2O3.

Abstract: A method for manufacturing an oxygen sensor unit of the type which includes at least a shaped body of a solid electrolyte, an inner electrode provided on an inside surface of the shaped body and exposed to a reference gas, an outer electrode provided on an outside surface of the shaped body and exposed to a gas to be measured, and a porous protective layer covering the outer electrode and a portion of the shaped body adjoining to said outer electrode wherein the solid electrolyte is made of a mixture of zirconia and a stabilizer therefor and is constituted of a sintered product of partially stabilized zirconia. The method is characterized in that the partially stabilized, sintered zirconia is obtained according to a high temperature sintering process which includes at least the step of sintering the mixture at a temperature of 1200° C.

Abstract: In a method for forming an inside electrode within a cup-type electrolyte member of an O.sub.2 sensor element, firstly, a nozzle having a paste discharge hole is prepared. The nozzle is inserted into an inside space of the electrolyte member. Then, the paste discharge hole of the nozzle is relatively rotated with respect to the electrolyte member along an inside surface of the electrolyte member while discharging paste therefrom onto the inside surface. Accordingly, the inside electrode formation portion is formed. After forming the inside electrode formation portion, the electrolyte member is baked. As a result, the inside electrode can be disposed on a required portion of the electrolyte member with a uniform thickness.

Abstract: An oxygen concentration detector element 2 includes a cup-shaped solid electrolyte 20 with an inside chamber 25 opened at one end and closed at the other end. An external electrode 21 is formed on an outer surface of solid electrolyte 20 by dipping solid electrolyte 20 in first chemical plating liquid 81, while an internal electrode 22 is formed on an inner surface of solid electrolyte 20 by introducing second chemical plating liquid 82 into inside chamber 25. First, in an injecting step, an injection needle 11 is inserted into inside chamber 25 and second chemical plating liquid 82 is introduced into inside chamber 25 via injection needle 11, and then injection needle 11 is pulled out of inside chamber 25. Next, in a plating step, internal electrode 22 is formed on the inner surface of inside chamber 25 using second chemical plating liquid 82. Then, in a discharging step, residual second chemical plating liquid 82 is discharged from inside chamber 25.