Patent ID: 7484402
Filing Date: 2009-02-03
Classification: G01N

Abstract:
1. A gas sensor comprising: a gas sensing element detecting the concentration of a particular gas contained in measurement gas; a housing holding said gas sensing element; a seat surface formed on an inner surface of said housing receiving a contacting surface formed on an outside surface of said gas sensing element; a metal sealing member interposed between said seat surface of said housing and said a contacting surface of said gas sensing element to hermetically define an air chamber in which a base end side of said gas sensing element is disposed and a measurement gas chamber in which a top end side of said gas sensing element is disposed; and said metal sealing of an oxidized layer which is comprised a chrome oxide layer and a ferric oxide layer and has a thickness of at least 5 μm, after said metal sealing member is exposed to environmental conditions as follows: a cycle of changing temperature from 300° C. or less to 600° C. or more repeated 1000 times and more, and total hours at 600° C. or more is fifty hours or more.