Patent ID: 8795491
Filing Date: 2014-08-05
Classification: G01N

Abstract:
1. A method of processing a sensor element comprising the steps of: (a) preparing a gas atmosphere containing hydrocarbon, having an air-fuel ratio of .080 to 0.9999, and having NO as an oxidizing gas added thereto such that a NO concentration is 0.05 or more and less than 1.0% by volume ratio; and (b) subjecting said sensor element to a heat treatment in said gas atmosphere at a temperature of 500° C. or higher for 15 minutes or longer, wherein said sensor element includes an electrochemical pumping cell constituted of an oxygen-ion conductive solid electrolyte and an electrode having a NOx reducing ability, a NOx gas in a measurement gas is reduced or decomposed in said electrode, and a NOx concentration in said measurement gas is obtained based on a current which flows in said electrochemical pumping cell at a time of said reduction or decomposition.