JPS5944801A - Moisture sensitive resistance element - 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] Organic polymers such as polyvinyl 1ide and polyethylene.

M lead oxide (ZnO), zinc titanate (Zn1Ti04
) and other metal oxides formed into a film are known.

Although organic polymer membranes have advantages such as being small, lightweight, and fast in response speed, they have the disadvantage that 1% stability becomes unstable at high temperature and high humidity.

It is said to be promising.

However, normally, metal oxides such as ZnO and Zn1Ti04 have a low resistivity, and the change in resistivity due to changes in humidity is small, and there is also hysteresis in the humidity-electrical resistance characteristics when the humidity increases and decreases.

difficult to use.

Therefore, the inventors conducted repeated research with the aim of overcoming these conventional drawbacks, and as a result, they came up with the present invention.

The P8 wet resistance element according to the present invention is obtained by firing an inexpensive metal oxide using conventional porcelain manufacturing techniques.

In other words, the present invention has moisture-sensing ability! ll! Consisting of a porous powder sintered body of x+ oxide and tricobalt tetroxide t
It is in the moisture-sensitive resistance element that is used as a % hoe.

The humidity-sensitive resistance element according to the present invention has a large change in resistivity due to changes in humidity over a wide humidity range from high humidity to low humidity, and the resistivity value is within a practical measurement range, so it is easy to use. Also.

When humidity rises and falls, specific resistance - relative humidity th
It has all excellent properties such as no hysteresis.

The present invention will be explained in more detail below.

The moisture-sensitive resistance element according to the present invention has a moisture-sensing ability.
It is a baked product from the Song Dynasty, which is a mixture of zinc oxide and trioxide (trioxide), and is porous with a porosity of 25 to 45%. The zinc oxide having the moisture-sensing ability is zinc oxide (ZnO
) or complex oxides of zinc and other metals, specifically titanate subs=+ (Znz TiO*
), zinc tetraate (Zn25n04), etc.

In general, the sub'fd oxide has a small change in resistivity with humidity, and also has a low F resistance to the change in resistivity, and the combined ratio of resistivity with respect to humidity changes is the molar ratio of (cobalt/zinc). When the humidity is in the range of 1 to 6, the humidity sensitive resistance element according to the present invention exhibits a change in specific resistance of about 100 to 1000 times relative to a change in relative humidity of 0 to 100%. Furthermore, the specific resistance of the 16 humidity resistance elements is within the range that can be measured with ordinary equipment, and exhibits excellent moisture sensitivity that is not easily affected by ambient temperature.

Furthermore, when the IN vs. humidity increases and decreases,
It also has the advantage of having no hysteresis in its resistivity-relative humidity characteristics.

The moisture-sensitive resistance element according to the present invention is produced by mixing so-called porcelain with a desired opening, pulverizing it into a powder having a particle size of 0.2 to 1/Z, and then preforming and calcining.

The conditions for the preliminary forming and calcining are as follows: When handling the resulting fired product, the powder is pressed strongly to the extent that it does not break.

For example, at relatively low temperatures of 700-800°C.

It is best to heat it for about 1 to 2 hours.

Next, the compact obtained by calcining is thoroughly crushed once again.
The above-mentioned two components are uniformly mixed into a powder, and the powder is further compacted at a knee pressure of 1 to 3 tons to form a compact again. At this time, in order to make it easier to compact and to make the molded body porous with excessive porosity through the first main firing, polyvinyl alcohol, etc., which would decompose and escape when heated, was removed. It may also be added as a binding agent.

Thereafter, the entire molded body is fired to obtain a moisture-sensitive resistance element according to the present invention. The nuclear version was fired (7).

It is preferable that the core 1g humidity resistance element has sufficient mechanical strength so as not to break even with normal handling, and has an appropriate level of porosity that does not lack responsiveness to humidity. , 14 physically at a temperature of 700-850°C.

It is best to heat for 1 to 2 hours. If the firing temperature is higher than the above range, the resulting humidity-sensitive resistance element will have low responsiveness to humidity. On the other hand, the firing temperature is within the above range! If the temperature is low, the mechanical strength of the resulting fired body is low, making it difficult to handle, and the length of the moisture-sensitive resistance element becomes short.

Note that the above-mentioned temporary forming and temporary firing process may be omitted.

The performance of the resulting moisture-sensitive resistance element remains almost unchanged.

It is also possible to obtain a mixed sintered body with other manufacturing methods of the moisture-sensitive resistance element according to the present invention.

and oxides of group ■ elements (MO2)i, (cobalt/
Zinc) molar ratio of 1 to 3. The mixture is mixed and pulverized to a molar ratio of (M/jlk lead) in the range of 0.5 to 5, and then molded and fired.

The thus obtained fired body contains ZnO and MO in the molded body.

Zn* is a composite oxide that is produced by firing in an atmospheric atmosphere.
The resultant MO4 becomes a moisture-sensitive resistance element according to the present invention.

However, depending on the component ratio, it may contain MO as an impurity. That is, this is the case where the molar ratio (M/zinc) is about 0.5 or more. The molar ratio is 0
．． 9MO for 5-5! teeth.

It hardly affects the moisture sensing ability of the 1θ humidity resistance element.

If the molar ratio exceeds 5, there is a disadvantage that the sensitivity to humidity, that is, the improvement in specific resistance to changes in humidity is reduced.

All embodiments according to the present invention will be explained below.

Example 1 Five types of mixtures with molar ratios of i, +, s, and 3 of t's compound id+ (Zno) and trioxide were prepared as output=m+Kyoto materials. After each mixture gold is ground well.

Pressure j ton/cJ Te diameter 10mm, thickness 1~2M
It was preformed into a disk shape of size M and calcined at a temperature of 800'C for 2 hours.

After that, grind all of these well with a mortar and pestle, and press 1 to
It was remolded into a disk shape with a diameter of 10 gg and a thickness of 1 MN using n/c-. Then the temperature was 800. The film was fired for 1.5 hours in an air atmosphere to obtain three types of moisture-sensitive resistance elements having different component compositions. The element has a porosity of about 60 mm.

Next, in order to investigate the humidity-sensitive characteristic sound of the above-mentioned humidity-sensitive resistance elements, ruthenium oxide (Rubs) was applied to the front and back surfaces of these elements.
Apply the paste to the entire surface and heat it in the air at a temperature of 800℃.
'O for 3 minutes to bake the electrode.

Furthermore, a part of the tW was baked with silver paste.

All lead wires were soldered to this, making it possible to measure moisture sensitivity.

To measure moisture sensitivity, place these elements in a humidity chamber.

Apply an alternating current with a frequency of 1KH2° and a voltage of 1 volt (effective value) between the electrodes through the lead wire (-), and find the relationship between resistivity and relative humidity of each element at an ambient temperature of 25°C for each row. Ta.

The results are shown in Figure 1. Curve lines 1.2 and 6 in the figure are the relationships for elements with (cobalt/zinc) molar ratios of 1.1.5 and 3, respectively.

From these results, the specific resistance of each element changes about 100 times when the relative humidity changes from 0 to 100%.

Moreover, the resistance value is within the range that can be measured with a normal resistance measuring device. In addition, the above relationship applies to humidification and dehumidification.
Does not exhibit hysteresis. Namely.

When the component ratio (cobalt/zinc) of the moisture-sensitive resistance element according to the present phosphorus invention is within the range of 1 to 3 as a 1 molar ratio,
The specific resistance of the humidity-sensitive resistance element changes about 100 times with respect to a change in relative humidity from 0 to 100%, and shows no hysteresis.

Next, in order to examine the influence of ambient temperature on the humidity sensitive resistor element having the above molar ratio of 1.5, the humidity sensitivity 'fc was measured with one ambient temperature changed. All measurement results are shown in curves 4 and 5 in FIG. Curve number 4 indicates a one round alloy. From these results, it can be seen that the relationship between the specific resistance of the humidity-sensitive resistive element and the humidity (phase A) is hardly affected by the ambient temperature.

Example 2 2110 and 00s O4f + (
Weigh and mix so that the molar ratio of cobalt/zinc) is 2,
It was ground into a mixture. Further, this was pre-molded and calcined in the same manner as in Example 1 to obtain a pre-fired body according to the present invention, and then the calcined body was ground again to obtain a mixed powder.

Next, add titanium oxide to the above powder? , (titanium/zinc) was mixed and ground so that the molar ratio was 4.1.5, 0.7, and 0.25, and 44 pieces with different titanium oxide contents were prepared.
A raw material powder of type m was prepared. The raw material powder obtained in this way was preformed, pulverized, and crushed in the same manner as above, and then compacted and molded into 9 ridges with a diameter of 10 mm and a thickness of 1 mm. A molded body was produced. The molding pressure in this case was 1 ton/Cn.

Thereafter, the molded body was completely fired under conditions of holding the molded body at a temperature of <850'C for 1.5 hours to obtain nine moisture-sensitive resistance elements according to the present invention.

In order to investigate the moisture-sensing ability of the moisture-sensitive resistance element according to the invention,
Electrodes were formed and lead wires were soldered in the same manner as in Example 1.

The measurement results are shown in Figure 2. The figure shows resistivity-relative humidity characteristics. Each curve in the figure shows the results for different component proportions of the TlO2 landscape. Curves 6, 7.8 and 9 in the figure each have a (titanium/zinc) molar ratio of 4.1.
．． 6111 constant results for cases of 5, 0.7 and 0.25. As is clear from this result, the relative humidity is 20~
It can be seen that when the resistance changes within a range of 100%, the specific resistance of the moisture-sensitive resistance element changes about 1000 times. Furthermore, there was no hysteresis in the above characteristics when the humidity increased and decreased.

Example 6 As raw materials, Znx T 1.04 and 00104
Weighed and mixed so that the molar ratio of (Kobal 1- / Ill! Obtained.

, f 亥 raw material powder is molded in the same manner as in Example 1, 'kt
All of the humidity-sensitive resistive elements according to the present invention were fabricated. Further, only +Z nx T i O4 was molded and fired in the same manner to fabricate a wet resistance element for comparison 1.

Thereafter, electrodes were formed and lead wires were attached to these humidity-sensitive resistive elements in the same manner as in Example 1, and each humidity-sensitive resistive element was connected to /i+i! Noh? I was joking.

Figure 6 shows the yllill determination results.

The figure shows all the resistivity vs. humidity characteristics.9 Each curve in the figure shows the results when the component ratios are different. Curves 10, 11, 12.15 and 14 in the figure each have a (cobalt/zinc) molar ratio of 0.05. 1, 1.5.
The measurement results for cases 5 and 30 are shown.

Further, 9-curved curves 15 and 15 degrees are the measurement results for the comparative humidity-sensitive resistance element. 15 is humidity"Nike (・hour, 1
5° is the result when the humidity decreases.

It is clear from these results that Zn2T1.0
The moisture-sensitive resistance element is a complete mixture of t and Comb4.

It can be seen that the specific resistance is lower than that of the sample without 00sJ added, and that the specific resistance change with respect to humidity changes is large. Furthermore, there was no hysteresis in the above characteristics when the humidity increased or decreased.

[Brief explanation of drawings]

1 to 6 are diagrams showing specific resistance-relative humidity characteristics measured for a humidity-sensitive resistance element according to an embodiment of the present invention. Applicant Toyota Central Research Institute Co., Ltd. Representative Patent Attorney Yasushi Akira Hashi Masaru Sugimoto Figure 1 0 20 40 60 δ0100 ≧1. Eyes Female Mi 1゛〕Supervisor a<”, N Figure 2 0 20 40 60 80 100th o
Versus Yo14ha [(5) 0 20 40 60 δ0 100th o's large star degree (o10n one bite)

Claims (4)

[Claims] (1) A moisture-sensitive resistance element comprising a porous powder sintered body of zinc oxide and tricobalt tetroxide, which have a high humidity ability. (2) Zinc oxide (ZnO) is a zinc oxide with moisture-sensing ability.
The moisture-sensitive resistance element according to claim 1, characterized in that: (3) The zinc oxide having moisture-sensing ability contains zinc. The moisture-sensitive resistance element according to claim 1, which is a composite oxide having a Nupinell structure. (4) The first aspect of the present invention is characterized in that the mixed composition of zinc oxide and tricobalt tetroxide having moisture-sensing ability is in a molar ratio of (cobalt/zinc) in the range of 1 to 3. Moisture-sensitive resistance element described in .