JPH09162014A - High temperature thermistor element - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To provide a high temperature thermistor element capable of low temperature firing and having stable high temperature load test characteristics. A _{3Y 2 O 3 (5-x} -y) Fe 2 O 3 xAl
Yttrium-iron garnet structure oxide 1 having a composition formula of ₂ O ₃ yCr ₂ O ₃ (0 ≦ x <1, 0 ≦ y <1)
With respect to 00 parts by weight, 0.1% of CaCO ₃ was added as an accessory component.
~ 1.00 parts by weight were added.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a high temperature thermistor element.

[0002]

2. Description of the Related Art Mn-N has been conventionally used as a thermistor material.
A thermistor element using an i-based or Mn-Ni-Co-based oxide is used as a temperature sensor or for temperature compensation.
The use temperature range of these thermistor elements is limited to 300 ° C. or less.

On the other hand, as a high temperature thermistor material used at around 1000 ° C., Zr-Y system, Mg-Al-Cr-Fe.
A high temperature thermistor element using a Co-Al-Cr-based oxide is used. These thermistor elements are used for automobile sensors.

[0004]

In such a conventional structure, in order to obtain a high temperature thermistor element, the firing temperature is as high as 1600 ° C. or higher, and it is difficult to fire in an ordinary electric furnace. There is a problem in that the resistance value change of the high temperature load test characteristics of the high temperature thermistor element is large.

The present invention solves such problems, and an object thereof is to easily provide a high temperature thermistor element which can be fired at a low temperature and has stable high temperature load test characteristics.

[0006]

In order to solve these problems, according to the present invention, as a result of studying various oxide materials, 3Y ₂ O ₃ (5-xy) Fe ₂ O _{3 was obtained.} xAl
₂ O ₃ yCr ₂ O ₃ (0 ≦ x <1, 0 ≦ y <1) is added to an oxide of yttrium-iron garnet structure represented by a composition formula, and CaCO ₃ is added as a sub-component in an amount of 0.1 to 1. It is intended to provide a high temperature thermistor capable of low temperature firing by adding 0 parts by weight and having stable high temperature load test characteristics.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The high temperature thermistor element according to claim 1 of the present invention focuses on the fact that a garnet-type ferrite material is fired at a relatively low temperature, and CaCO ₃ is added as an auxiliary component. As a result, the sintered body becomes dense and the high temperature load test characteristics become stable.

[0008]

An embodiment of the present invention will be described below.
Commercially available _{Y 2 O 3, Fe 2 O} 3, Al 2 O 3, Cr 2 O 3, CaC
O ₃ was blended so as to have the composition shown in (Table 1).

[0009]

[Table 1]

In the manufacturing process of the high temperature thermistor element, the composition blended in (Table 1) is wet mixed in a ball mill and the slurry is dried. After that, coarse pulverization, calcination at 1000 ° C., and wet pulverization again. The obtained slurry is dried and polyvinyl alcohol is added as a binder to form a molded body 12 having two holes 11 as shown in FIG.
Insert the Pt electrode 13 into the temperature of 1400 to 1450 ° C
Bake in air at. The thus obtained high temperature thermistor element was subjected to a high temperature load test of DC 2V at 1000 ° C. The rate of change in resistance value after the high temperature load test is shown in FIG. FIG.
Added subcomponent CaCO ₃ as shown in the present invention product (2
7 to 7), the resistance value change rate in the high temperature load test is small and stable. If the addition amount is less than 0.1 wt% (1), the stability in the high temperature load test is insufficient, and if it is more than 1.00 wt% (8), cracks occur in the element after firing, so it is excluded from the scope of the present invention. .

[0011]

As described above, the high temperature thermistor device of the present invention can be fired at a low temperature and exhibits excellent stability in a high temperature load test. Therefore, it is possible to provide a high temperature thermistor element that is easy to manufacture.

[Brief description of the drawings]

FIG. 1 is a diagram showing a resistance value change rate after a high temperature load test of a high temperature thermistor element according to an embodiment of the present invention.

FIG. 2 is a sectional view of a high temperature thermistor element according to an embodiment of the present invention.

FIG. 3 is a sectional view of a high temperature thermistor element according to an embodiment of the present invention.

[Explanation of symbols]

 11 hole 12 molded body 13 Pt electrode

Claims (1)

[Claims] 1. 3Y ₂ O ₃ (5-xy) Fe ₂ O ₃ xAl
₂ O ₃ yCr ₂ O ₃ (0 ≦ x <1) (0 ≦ y <1) is added to 100 parts by weight of the main component composed of the yttrium-iron garnet structure oxide represented by the composition formula. A high temperature thermistor element characterized by adding 0.1 to 1.00 parts by weight of CaCO ₃ as a component.