Exhaust gas sensor including a composite tile sensing element and methods of making the same.

摘要

The mfr. of exhaust sensor substrates comprises co-depositing first and second compatible compsns.. The first compsn. comprises a dielectric material and the second comprises an electrolyte material. The compsns. are co-fired to form a substrate comprising and electrolyte portion, a dielectric portion and a transition portion comprising a variant gradient of dielectric and electrolyte material. Also claimed is a process for making the substrate. The process comprises delivering in a side-by-side relationship: (i) a dielectric powder and binder; and (ii) an electrolyte powder and binder to a compaction press and compressing the powders to form a tape. The tape is fired to form a substrate with a dielectric portion, an electrolyte portion and a transition portion as above. Also claimed is a process comprising delivering an electrolyte tape and a dielectric powder including a binder to a compaction press and compressing the powder and tape into a single-piece composite tape with a thickness of 0.003-0.05 inches. Further claimed is a process for mfg. a protective coating for an exhaust sensor. The process comprises co-depositing first and second compatible compsns. comprising alumina over an outer electrode formed on a substrate including a dielectric portion and an electrolyte portion. The first compsn. is deposited over the dielectric portion of the substrate and the second compsn. is deposited over the electrolyte portion of the substrate. The compsns. are fired to form a protective film and the film over the electrolyte portion of the substrate has a grater porosity than the porosity of the film over the dielectric portion of the substrate. The portion of the film with greater porosity allows exhaust to flow to the electrolyte portion of the substrate. The film over the dielectric portion of the substrate prevents damage to the remainder of the electrode.