JPS61113211A - Oxide semiconductor for thermistor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an oxide semiconductor for a thermistor having a negative temperature coefficient of resistance and which can be used as a temperature sensor in the range of 150°C to 500°C.

Conventional structure and problems The well-known Mn-Co-Ni-Cu oxide thermistor material has been mainly used as a general-purpose disk-type thermistor, but resistance value fluctuations occur under high-temperature use. Because of the large On the other hand, stabilized zirconia (Zr02-Y203r Z
r02-CaO, etc.), Mg-AI-Cr-Fe oxide spinel systems, etc. have been developed (Japanese Patent Publication No. 48-705
Publication No. 49-63995, Japanese Patent Publication No. 1987-63995
88756). However, these oxide materials also
The firing temperature must be a high temperature exceeding 1600℃,
It could not be fired using a normal electric furnace (maximum temperature of 1600°C).

Furthermore, even in the case of sintered bodies of these oxides, the resistance value changes significantly over time, and even those that are extremely stable have a resistance value of 10% (10%).
ooo hours), and there was a problem in stability over time.

In addition, the demand for thermistors with excellent stability at 200 to 500°C has increased in the sensor market, and thermistor materials that meet this demand (Mn-Ni-Al oxide system: JP-A-57-95608, NixMgshiZn7)M
n, 04 spinel system: JP-A-57-88701, (Ni,; Coy Fe, AI5Mnt) 04
Spinel-based materials (Japanese Patent Laid-Open No. 57-88702, etc.) have been proposed, but are still in the evaluation stage. The present inventor has also proposed a Mn--Ni Cr--Zr oxide system (Japanese Patent Application No. 1265/1983) in response to the above demand.

Purpose of the Invention The present invention has been made in view of the above problems, and its purpose is to provide an oxide semiconductor for a thermistor that exhibits an appropriate resistance value even at 300°C to 500°C and can be stably used. There is a particular thing.

Structure of the Invention In order to achieve the above objects, an oxide semiconductor for a thermistor according to the present invention is made of a sintered mixture of metal oxides, and the metal element thereof is manganese (Mn).

~98.5 at% nickel (Ni) 0.1~5.0 at%, chromium (Cr) o, a ~5.0 at%, yttrium (Y) 0.2~5.0 at%, and zirconium ( Zr) 0.5 to 28.0 atomic% of 5 types in total 1
It contains 00 atomic percent.

Furthermore, with respect to the above composition of 100 atomic %, silicon (
Si) may be contained in an amount of 2.0 atomic % or less (excluding 0 atomic %).

Description of examples Examples of the present invention will be described below.

Commercially available raw materials Mn CO3+ N i O+ Cr2o,
and Y2O, were blended so as to have a composition of K in atomic % as shown in the table below. To illustrate the thermistor manufacturing process, these blended compositions are wet mixed in a ball mill, and the slurry is dried and then
Calcined at 0°C, the calcined product was again wet-pulverized and mixed in a ball mill. After drying the obtained slurry, add and mix polyvinyl alcohol as a binder, take the required amount and add 30
01L A platinum electrode is provided, and the wafer provided with this electrode is cut into chips of desired dimensions.

This element is sealed in a glass tube in a neutral gas atmosphere such as argon gas or air, and hermetically isolated from the outside air. For the lead wire terminal, a slug lead such as Dumet wire or Kovar wire is used depending on the operating temperature. This glass-encapsulated thermistor was left in air at 500° C., and the change in resistance value after 100 hours was measured. Further, as initial characteristics, the specific resistance at 25° C. and the thermistor constant as a glass-encapsulated thermistor are also shown. Among these, the thermistor constant B was determined from the resistance values at two points measured at 800°C and 500°C. In addition, the element dimensions are 40011m x 400
The size was μm×800 μm. Table 1 (Mark 11 indicates a comparative sample) In the previous table, the comparative samples all had a resistance change rate over time of over 5% at 500°C, and lacked practical stability, so the present invention was excluded. was outside the range. On the other hand, the samples within the scope of the present invention all had resistance change rates over time of 5% or less at 500° C., indicating that the stability was improved.

The samples used this time were dry-molded and fired, but bead-type elements may also be used, and there are no restrictions on the element manufacturing method.

In the examples of the present invention, zirconia boulders were used for mixing raw materials and pulverizing and mixing calcined products.

As a result of elemental analysis of the sample (sintered body) of the above example, the amount of Zr mixed was 0.5 atomic % or less with respect to 100 atomic % of the thermistor constituent elements.

Further, when agate boulders were used, the amount of Si mixed was less than 1 atomic %. Among the samples shown in the table, all the samples containing Si were obtained using zirconia boulders.

Further, all Zr used in this example was obtained by reacting with Y, that is, itria partially stabilized zirconia. In principle, commercially available materials or samples obtained from manufacturers were used, but some were synthesized from oxalate and used.

Effects of the Invention As described above, the oxide semiconductor for thermistor according to the present invention is made of a sintered mixture of metal oxides, and its constituent metal elements include 60.0 to 985 at% of Mn, Ni
O, 1 to 5.0 at%, Cr O, 3 to 5.0 at%,
Y O, 2-5.0 at% and Zr0.5-28.0
It contains a total of 100 Kyoko% of 5 types of atomic%, so 8
It has excellent characteristics over time even in the range of 00°C to 500°C, making it most suitable for temperature measurements that require high reliability at medium and high temperatures. That is, it can be expected to contribute to fields of application such as temperature control in microwave ovens and oil burners. In addition to the above-mentioned constituent metal elements, when Si is contained in an amount of 2.0 atomic % or less (not including 0 atomic %), it exhibits a sintering promotion effect and obtains a dense ceramic. I can do it.

Claims (1)

[Scope of Claims] 1. Consisting of a sintered mixture of metal oxides, its constituent metal elements include 60.0 to 98.5 at. % of manganese, 0.1 to 5.0 at. % of nickel, and 0.0 to 5.0 at. % of chromium. 3-5.0 at%
, 0.2 to 5.0 atom % of yttrium, and 0.5 to 28.0 atom % of zirconium, in total 100 atom %. 2. Consisting of a sintered mixture of metal oxides, its constituent metal elements are 60.0 to 98.5 at.% of manganese, 0.1 to 5.0 at.% of nickel, and 0.3 to 5.0 at.% of chromium. %
, contains 5 types of yttrium 0.2 to 5.0 at % and zirconium 0.5 to 28.0 at %, totaling 100 at %, and silicon at an external ratio of 2.0 to the constituent metal elements.
An oxide semiconductor for a thermistor, characterized in that it contains atomic % or less (excluding 0 atomic %).