Abstract: An exhaust sensor comprises a sensing electrode and a reference electrode each in contact with an electrolyte. At least one of the sensing electrode and the reference electrode are formed by depositing an electrode precursor material on an electrolyte precursor material and sintering the combination at a sufficient temperature for a sufficient time to achieve densification of the electrolyte, wherein the electrode precursor material comprises an alkali salt. Electrode patterns having enhanced perimeter ratios are also disclosed. The resulting exhaust sensor is capable of providing a usable output at a reduced operating temperature.

Abstract: A sensor element includes a substrate (10) having a coating (31) on a portion of the substrate (10). The coating (31) is applied to the substrate (10) by dipping the portion of the substrate (10) into a slurry which includes a pulverized mineral and water, extracting the substrate (10) from the slurry in a direction along an axis, drying the coated substrate (10), and firing the coated substrate (10) so as to promote densification of the mineral and adhesion of the mineral to the substrate (10). The coating (31) after firing has a minimum thickness of about 100 microns at every location around the periphery of a cross section through the substrate (10) taken in a plane normal to the axis. A method for making a coated sensor element is also disclosed.

Abstract: A sensor element includes a substrate having a coating on a portion of the substrate. The coating is applied to the substrate by dipping the portion of the substrate into a slurry which includes a pulverized mineral and water, extracting the substrate from the slurry in a direction along an axis, drying the coated substrate, and firing the coated substrate so as to promote densification of the mineral and adhesion of the mineral to the substrate. The coating after firing has a minimum thickness of about 100 microns at every location around the periphery of a cross section through the substrate taken in a plane normal to the axis. A method for making a coated sensor element is also disclosed.

Abstract: A planar device includes a heating circuit that is disposed between ceramic layers in a planar device and co-fired with the ceramic. The heating circuit material and geometry are controlled so as to provide a targeted resistance characteristic as a function of temperature that allows interchangeability in an engine management system that was designed for a heater circuit based on a material system that cannot be co-fired with the planar device.

Abstract: A planar device includes a heating circuit that is disposed between ceramic layers and co-fired with the ceramic. The heating circuit comprises palladium, and the co-firing of the palladium and ceramic is performed in an oxidizing atmosphere. The formation of defects in the planar device that would otherwise be induced as a result of the palladium oxidizing during the co-firing process is prevented by control of the firing profile, by the geometry of the pattern of the heating circuit, and/or by modifying the palladium to reduce its tendency to oxidize.

Abstract: An exhaust sensor comprises a sensing electrode and a reference electrode each in contact with an electrolyte. At least one of the sensing electrode and the reference electrode are formed by depositing an electrode precursor material on an electrolyte precursor material and sintering the combination at a sufficient temperature for a sufficient time to achieve densification of the electrolyte, wherein the electrode precursor material comprises an alkali salt. Electrode patterns having enhanced perimeter ratios are also disclosed. The resulting exhaust sensor is capable of providing a usable output at a reduced operating temperature.

Abstract: In one embodiment, a protective coating for an electrode of a sensor is described, the protective coating comprising an annealed catalyst, said annealed catalyst comprising at least one metal that has been subjected to thermal energy that is at least equivalent to or greater than that received from calcining the at least one metal for 24 hours at a temperature of 930 degrees C in air. In another embodiment, the annealed catalyst will comprise at least one metal that has been subjected to thermal energy that is equal to or less than that received from calcining the at least one metal for 24 hours at 1030 degrees C in air. In one exemplary embodiment, the annealed catalyst will comprise at least one metal that has been subjected to thermal energy that is equal to that received from calcining the at least one metal for 24 hours at 980 degrees C in air.

Abstract: An exhaust sensor includes a first sheet of ceramic that is perforated with a vent orifice and, a second sheet of ceramic that is laminated to the first sheet. A palladium circuit trace is positioned between the first sheet and the second sheet of ceramic and a fugitive ink is printed on one of the sheets that is in communication with the vent orifice and the palladium. The fugitive ink volatilizes during a firing process and created a void space that is occupied by a palladium oxide that forms at temperatures around 625-900C.

Abstract: In one embodiment, a protective coating for an electrode of a sensor is described, the protective coating comprising an annealed catalyst, said annealed catalyst comprising at least one metal that has been subjected to thermal energy that is at least equivalent to or greater than that received from calcining the at least one metal for 24 hours at a temperature of 930 degrees C. in air. In another embodiment, the annealed catalyst will comprise at least one metal that has been subjected to thermal energy that is equal to or less than that received from calcining the at least one metal for 24 hours at 1030 degrees C. in air. In one exemplary embodiment, the annealed catalyst will comprise at least one metal that has been subjected to thermal energy that is equal to that received from calcining the at least one metal for 24 hours at 980 degrees C. in air.

Abstract: A conductive shield for routing mobile ions to contact pad in accordance with an exemplary embodiment is provided. The conductive shield includes a first conductive path electrically coupled to the contact pad. The conductive shield further includes a second conductive path electrically coupled to first and second locations on the first conductive path such that when a physical break occurs in the first conductive path between the first and second locations, mobile ions in the first conductive path are still routed to the contact pad through the second conductive path.

Abstract: In one embodiment, a method of making a sensor comprises: forming a slurry comprising a metal oxide, a binder, an acetate, and a reducing material, applying the slurry to at least a portion of a sensing element comprising two electrodes with an electrolyte disposed therebetween, and calcining the slurry to form a protective coating. In one embodiment, a gas sensor, comprises: a sensing element comprising a sensing electrode and a reference electrode having an electrolyte disposed therebetween, and a protective coating disposed over the sensing electrode, wherein the protective coating comprises aluminum oxide, an alpha alumina and about 2 wt % to about 15 wt % solid solution, based upon the total weight of the protective coating.

Abstract: In one embodiment, a method of making a sensor comprises: forming a slurry comprising a metal oxide, a binder, an acetate, and a reducing material, applying the slurry to at least a portion of a sensing element comprising two electrodes with an electrolyte disposed therebetween, and calcining the slurry to form a protective coating. In one embodiment, a gas sensor, comprises: a sensing element comprising a sensing electrode and a reference electrode having an electrolyte disposed therebetween, and a protective coating disposed over the sensing electrode, wherein the protective coating comprises aluminum oxide, an alpha alumina and about 2 wt % to about 15 wt % solid solution, based upon the total weight of the protective coating.

Abstract: A gas sensor comprises a first electrode and a second electrode; and an electrolyte disposed between the first electrode and the second electrode. The electrolyte is shaped into a cylinder having an axial open end portion, an axial middle portion, and an axial closed end portion. The axial closed end portion has a uniform wall thickness equal to or less than about 1.5 millimeters. A radial transition in an interior region of the electrolyte between the middle and the closed end portions forms a shoulder. Processes for sensing exhaust gas generally includes disposing the gas sensor in an exhaust stream, contacting the closed end portion of the sensor with exhaust gas, and creating an electromotive force. The sensor activates quickly due to the close proximity to a rod heater and the low thermal mass resulting from the small inner diameter and thin wall section of the closed end portion.

Abstract: A sensor and a method for making a sensor is disclosed. The method for making the sensor comprises: mixing a first metal oxide stabilized alumina with alpha alumina in a liquid to create a base slurry, mixing into said base slurry a second metal oxide stabilized alumina and a fugitive material to create a composition; applying said composition to at least a portion of a sensing element comprising two electrodes with an electrolyte disposed therebetween; and calcining said sensing element.

Abstract: A method for making a sensor is disclosed. The method comprises: disposing an electrolyte between a first side of sensing electrode and a first side of reference electrode, disposing a first side of a protective layer adjacent to said a second side of said sensing electrode, applying a mixture of a metal oxide, a fugitive material, and a solvent to a second side of the protective layer, and calcining the applied mixture to form said a protective coating on the second side of the protective layer.

Abstract: Disclosed herein are electrodes, sensors, and methods for making and using the same. In one embodiment, the sensor comprises: a co-fired sensing electrode comprising the reaction product of about 50 wt % to about 95 wt % noble metal, about 0.5 wt % to about 15.0 wt % yttria-stabilized zirconia, and about 1 wt % to about 6 wt % yttria, based upon a total combined weight of the noble metal, yttria-stabilized zirconia, and yttria, a reference electrode, and a co-fired electrolyte disposed between and in ionic communication with the co-fired sensing electrode and the reference electrode.

Abstract: An exhaust gas sensor element having an electrochemical cell, a protective material in fluid communication with the electrochemical cell, and a reactive inhibitive coating disposed over the protective material. The reactive inhibitive coating prevents the reaction of compounds with acids(e.g., phosphates) in the exhaust gas, which may form a dense glass layer on the outside of the gas sensor. The reactive inhibitive coating is either an alkaline earth oxide ethoxide, and/or carbonate that is deposited on the gas sensor to a thickness so as to preferably provide an excess of either the alkaline earth material.

Abstract: A sensor is disclosed that comprises an electrolyte disposed between and in intimate contact with a sensing electrode and a reference electrode. A protective coating is disposed on the protective layer adjacent to the sensing electrode. The protective coating comprises a mixture of a metal oxide, a zeolite, and an alumina. A method for making the sensor is also disclosed.

Abstract: A sensor comprising an electrochemical cell (sensing electrode, reference electrode, and electrolyte disposed therebetween) has a protective silica coating at least on a side of the sensing electrode opposite the electrolyte. This protective silica coating can be an aerogel which is optionally also disposed on a side of the reference electrode opposite the electrolyte.

Abstract: An exhaust gas sensor element having an electrochemical cell, a protective material in fluid communication with the electrochemical cell, and a reactive inhibitive coating disposed over the protective material. The reactive inhibitive coating prevents the reaction of compounds with acids(e.g., phosphates) in the exhaust gas, which may form a dense glass layer on the outside of the gas sensor. The reactive inhibitive coating is either an alkaline earth oxide ethoxide, and/or carbonate that is deposited on the gas sensor to a thickness so as to preferably provide an excess of either the alkaline earth material.