Ngk Spark Plug Company, Limited

Shinichi Nakagawa

Takio Kojima

Yoshihiro Nakano

Masahito Kida

Yuichi Koyama

There is provided a gas sensor, including a gas sensing film formed of an oxide semiconductor material and a gas-permeable protection layer formed of oxide particles and arranged on the gas sensing film. The oxide particles of the protection layer have an average particle size of 500 nm or smaller.

Gas sensor

There is provided an oxidizing gas sensor that includes an insulating substrate, a gas sensing layer laminated on the insulating substrate and substantially made of tin oxide so as to make resistance changes in response to concentration variations in oxidizing gas and a plurality of catalyst grains applied to a surface of the gas sensing layer and substantially made of gold, wherein 20% or more of the catalyst grains have an aspect ratio of 2.0 or greater when viewed at from the surface of the gas sensing layer.

Oxidizing gas sensor and production method thereof

The present invention provides a gas sensor having excellent humidity resistance even if used in a high temperature and high humidity atmosphere. According to the present invention, a gas sensor is comprised of: a silicon substrate; a metal-oxide semiconductor portion comprised mainly of SnOand formed on the substrate; and a catalytic portion comprised of Pd and dispersed on a surface of the metal-oxide semiconductor portion, wherein the metal-oxide semiconductor portion and the catalytic portion constitute a gas sensing portion. Furthermore, an insulating portion comprised mainly of SiOis formed dispersedly on a surface of the gas sensing portion. Further, the catalytic portion and the insulating portion are formed on the surface of the metal-oxide semiconductor portion so that the surface additive rate, which is expressed by Si/(Pd+Si) representing the ratio in the number of atoms of Si to Pd, of the gas sensing portion having the insulating portion may be 65% or more to 97% or less, and so that the surface additive rate, which is expressed by Si/(Sn+Si) representing the ratio in the number of atoms of Si to Sn, of the gas sensing portion may be 75% or more to 97% or less.

Growing community of inventors

Konan-ku, Japan

Shinichi Nakagawa