Temperature Sensor Element

Patent metadata

Field	Value
Publication number	US-2018335348-A1
Application number	US-201815979830-A
Country	US
Kind code	A1
Filing date	May 15, 2018
Priority date	May 16, 2017
Publication date	Nov 22, 2018
Grant date	—

Abstract

A resistance pattern that contains platinum as a main component is formed into a meander shape and on a main surface of a ceramic substrate. A protective film layer that covers the resistance pattern has a two-layer structure including a trap layer as an inner layer and an overcoat layer as an outer layer. The trap layer contains alumina as a main component and 2 to 30 vol % of platinum. The overcoat layer contains alumina as a main component. With such a configuration, even when reactivity of the platinum resistance pattern becomes higher under high temperature use, platinum contained in the trap layer reacts with oxygen or impurities etc. contained in the ceramic substrate. Thus, reaction of the platinum resistance pattern can be suppressed.

First claim

What is claimed is:

1 . A temperature sensor element comprising:
a ceramic substrate; a resistance pattern that contains platinum as a main component, and that is formed on a main surface of the ceramic substrate; and a protective film layer that covers the resistance pattern; wherein: the protective film layer includes: a trap layer that contains alumina as a main component, and that is formed on the main surface of the ceramic substrate so as to cover the resistance pattern; and an overcoat layer that contains alumina as a main component, and that is formed on the trap layer; and the trap layer contains 2 to 30 vol % of platinum.

2 . A temperature sensor element comprising:
a ceramic substrate; a surface smoothening layer that contains alumina as a main component, and that is formed on a main surface of the ceramic substrate; a resistance pattern that contains platinum as a main component, and that is formed on the surface smoothening layer; and a protective film layer that contains alumina as a main component, and that covers the resistance pattern; wherein: the protective film layer includes: a trap layer that is formed on the surface smoothening layer so as to cover the resistance pattern; and an overcoat layer that is formed on the trap layer; and both the surface smoothening layer and the trap layer contain 2 to 30 vol % of platinum.

3 . A temperature sensor element according to claim 1 , wherein:
the trap layer has a two-layer structure including a lower layer and an upper layer; the lower layer is smaller in content of platinum than the upper layer and contains 0 to 10 vol % of platinum; and the upper layer contains 2 to 30 vol % of platinum.

4 . A temperature sensor element according to claim 1 , wherein:
the ceramic substrate is an alumina substrate whose alumina purity is 96% or higher; and the trap layer is larger in content of platinum than the sum of impurities contained in the alumina substrate and impurities contained in the protective film layer except alumina and platinum.

5 . A temperature sensor element according to claim 2 , wherein:
the trap layer has a two-layer structure including a lower layer and an upper layer; the lower layer is smaller in content of platinum than the upper layer and contains 0 to 10 vol % of platinum; and the upper layer contains 2 to 30 vol % of platinum.

Assignees

• Koa Corp

Inventors

• Miura Katsuya
• Shimodaira Masahiro

Classifications

• G01K1/10 Primary

  for preventing chemical attack · CPC title

• G01K2205/04

  for measuring exhaust gas temperature · CPC title

• G01K7/183

  characterised by the use of the resistive element · CPC title

• G01N27/4077

  Means for protecting the electrolyte or the electrodes · CPC title

• G01N27/4075

  Composition or fabrication of the electrodes and coatings thereon, e.g. catalysts · CPC title