摘要:
The invention relates to composite systems having at least two layers which comprise different inorganic, ceramic phases and are produced by cosintering of different, finely divided inorganic materials arranged in layers. The composite systems are characterized in that at least two adjacent layers comprise a dense phase largely free of macropores. The layers are durably bonded to one another by sintering together of particles of the different materials at the phase boundary or boundaries. The composite systems and the processes for the production thereof are used, for example, in the manufacture of gas sensors.
摘要:
A polarographic sensor for determining concentration of certain components including oxygen or combustible fractions, such as hydrocarbons, hydrogen and carbon monoxide, in the exhaust gas of an internal combustion engine, includes a pump cell having an anode, a cathode, and an oxygen ion-conducting solid electrolyte provided between the anode and the cathode, wherein the cathode is provided with a diffusion barrier, wherein the anode is provided with a diffusion barrier, and wherein the concentration of the certain components is determined by measurement of a limiting current through the electrolyte and across one of the diffusion barriers to the corresponding anode or cathode.
摘要:
A resistance probe is proposed for detecting gas compositions, particularly in the exhaust gases of internal combustion engines. This resistance probe has the advantage over prior art resistance probes that, with a short response time, it is considerably more aging resistant. This is accomplished in that the resistance layer configured as a semiconductor layer is introduced or sintered into recesses or slits provided for this purpose in the prefabricated sensor carrier body and above it is applied a porous, electrically non-conductive engobe or a protective layer structure in the form of a grid or raster. These measures enable the measuring gas to gain access to the semiconductor layer, but the semiconductor layer is simultaneously protected against corrosive, erosive and/or cavitative attacks from the exhaust gas.
摘要:
A sintered layer system, includes an ion-conductive solid electrolyte layer which has a high oxygen ion conductivity and which is comprised of a solid electrolyte material comprising at least one oxide of tetravalent metals and at least one stabilizer oxide; and at least one functional layer which comprises a mixture of the solid electrolyte material and at least one further material, wherein the solid electrolyte material of the ion-conductive solid electrolyte layer and the solid electrolyte material of the at least one functional layer are comprised of nanocrystallites having a mean diameter of
摘要:
A sensor element for determining concentration of at least one constituent of a gas mixture operates on an electro-chemical measuring process and includes a gas measuring chamber; a pair of electrodes and an electrode chamber located between the pair of electrodes; and a diffusion conduit adjoining the electrode chamber and having a gas input which connects with the gas measuring chamber, having a gas output which connects with the electrode chamber, and having at least one cross-sectional area including a height, w, and a length, L, which height, w, has a preselected minimum value, and which length, L, has a value which is equal to or greater than the preselected minimum value of the height, w. The constituent of the gas mixture has a mean free path length through the sensor element, the gas measuring chamber has a cross-sectional area including a height and a length each of which are at least as large as the minimum height, w, of the diffusion conduit, and the height, w, of respective ones of the at least one cross-sectional area of the diffusion conduit is at least a multiple of the mean free path length of the constituent of the gas mixture to be measured. Advantageously, substantially only gaseous phase diffusion occurs when the predetermined minimum value of the height, w, is at least a multiple of a minimum value of the mean free path length for the gas constituent measured.
摘要:
A sensor for determining gas components and/or gas concentrations in gas mixtures, in particular in exhaust gases of internal combustion engines. The sensor has an oxygen pump cell and a measuring element having a sensitive region. Provided between the pump cell and the gas mixture is a diffusion path in which there are formed an oxygen gradient XO.sub.2 and a gradient X.sub.CO of the gas component to be determined, which extend respectively in opposite directions. The measuring element is positioned relative to the pump cell and the diffusion path in such a way that an excess of oxygen is present on the sensitive region of the measuring element.
摘要:
A sensor element for broad band sensors to determine the .lambda.-value of gas mixtures is suggested. This sensor element can be manufactured in ceramic-sheet and screen-printing technology and is provided in the diffusion gap (7) downstream from a pair of pump electrodes (8,8"), arranged on both sides of the diffusion gasp (7), with a Nernst electrode (9) which functions as an exhaust gas electrode. Due to this arrangement of the Nernst electrode (9), it is possible in a simple manner to effectively protect the pump cell formed by the interior pump electrodes (8,8') from overload and to prevent falsification of the sensor signal.
摘要:
A ceramic layer system including at least two layers having respective ion conductivities which are substantially different includes a substrate layer composed of a ceramic material and having substantially no ion conductivity; and at least one conducting layer positioned adjacent to the substrate layer, containing coated ceramic particles composed of ceramic particles composed of a ceramic material having no substantial ion conductivity which are coated with a material having a substantial ion conductivity so that each conducting layer of the at least one conducting layer has a continuous phase after sintering composed of the material which has a substantial ion conductivity and so that the at least one conducting layer has an ion conductivity effective to conduct ions. A method of producing a gas sensor for detecting small quantities of at least one gas in gas mixtures includes providing a substrate layer composed of ceramic particles composed of a material having substantially no ion conductivity; applying a layer composed of coated ceramic particles onto the substrate layer, the coated ceramic particles being composed of ceramic particles composed of a material that has no substantial ion conductivity coated with a material which has a substantial ion conductivity at the operating temperature of the gas sensor; applying at least one functional layer onto the layer composed of coated ceramic particles to provide a green body; preheating the green body to remove binding agents, plastifying agents, and any additional organic constituents; and sintering the green body after preheating by heating to a temperature effective to sinter the green body so that the layer comprised of coated ceramic particles has a continuous phase comprised of the material which has a substantial ion conductivity.
摘要:
An electrochemical measuring sensor having a solid electrolyte, a first electrode exposed to a gas to be measured and a second electrode exposed to a reference gas, with the electrodes preferably being arranged on opposite sides of the solid electrolyte. At least one of the electrodes (16, 20) is provided with a contouring (24) on its side (22) that is exposed to the gas to be measured or to the reference gas, with the contouring being a trench-shaped groove (26) embossed into the surface of the electrode such that the electrode is pressed into the adjacent solid electrolyte in the region of the groove. According to the method, the embossing is done while the electrode and the solid electrolyte are in the non-sintered state, and the sensor is subsequently sintered.
摘要:
The invention relates to a measuring sensor having pump reference for measuring the oxygen content of gas mixtures, particularly exhaust gases of internal combustion engines. The sensor includes a measuring cell (A) and a reference cell (B) each having a pair of electrodes, with one of each respective pairs of electrodes being common to the two cells, and having a fixed electrolyte. Reference cell (B) has defined therein an internal oxygen reference zone which is hermetically sealed from the gas mixture and which is connected to the atmosphere by way of a pressure-equalization line. The measuring cell (A) and the reference cell (B) can be heated by heating apparatus to a temperature at which the fixed electrolyte has an ionic conductivity which is sufficiently high. The heating apparatus and a porous insulation are advantageously disposed in the vicinity of the electrode of the reference cell which is not in common with the measuring cell and which is porous so that the porous insulation, together with the porous electrode, form the internal oxygen reference zone and, together with the porous electrode and its porous conductor track, form the pressure-equalization line.