Adduci, Mastriani, Schaumberg & Schill
Electrochemical element
 A solid electrolyte is interposed between a first electrode layer located while in contact with the gas to be measured and a second electrode layer located while in contact with a reference gas. The first electrode layer is covered on its high-temperature portion with a first porous protecting layer and on its low-temperature portion with a second porous protecting layer which is lower in gas permeability than the first porous protecting layer. This electrochemical element can be produced without detriment to the porous protecting layers, e.g., causing them to peel off or crack. In addition, it can be used while any lowering of insulating resistance between the first electrode layer and the associated metal holder, thereby providing an accurate detection of the concentration of a specific gas in the gas to be measured. 
NGK Insulators, Ltd.
G
G01N
inventional
Toshihiko Nobuhide Hitoshi
Suzuki Kato Nishizawa