JPS6071543A - Process for preparing humidity sensitive compound sintered body - Google Patents

Abstract

PURPOSE:To prepare a humidity sensitive compound sintered body having superior characteristics by mixing glass powder comprising a specified compsn. of P2O5, BaO, ZnO, MoO3, Cr2O3, and TeO2 with fiber of potassium hexatitanate in a specified proportion, and molding the product and calcining. CONSTITUTION:90pts.wt. mixture consisting of 65-75wt% P2O5, 10-15wt% BaO, and 5-10wt% ZnO is mixed with qopts.wt. mixture of MoO3 (or Cr2O3) and TeO2, or with 8-10pts.wt. TeO2 alone, is melted in a heat resistant vessel at ca.1,050-1,100 deg.C for 15-20min to obtain a glass. The glass is crushed, pref. pulverized, and 100pts.wt. glass powder is mixed with 8-10pts.wt. potassium hexatitanate fiber, and the mixture is molded in a metal mold. Obtd. molded body is calcined at 400-500 deg.C depending on the change of the compsn. By this method, a humidity sensitive compound sintered body is easily and inexpensively obtd. Obtd. sintered body has superior reproducibility and can be utilized as a humidity sensing material usable in a wide temp. range including high temp. range.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is inspired by a method for producing MA wet association sintered bodies, and more specifically, detects the phenomenon of moisture adsorption on the surface of the sintered body by a change in air resistance, and '#Relating to a method for manufacturing a sensing material for a humidity sensor that measures the humidity of an surrounding air.

Conventionally, detection materials for humidity sensors include organic polymers,
Gold M# oxides, composite metal oxides, and ceramics are known, and many proposals have been made.

In recent years, as humidity-sensitive devices have become smaller and recording density has increased, there has been a demand for moisture-sensitive sensing materials that have improved performance and can be manufactured at low cost.

However, conventional moisture-sensitive sensing materials, with the exception of organic polymers, have shortcomings in measurement accuracy and reproducibility, and organic polymers are said to have limited humidity and durability problems. There is.

Therefore, the present invention was made in view of the current situation, and has excellent moisture sensitivity performance, can be manufactured at low cost,
The present invention also provides a moisture-sensitive sensing material with excellent measurement accuracy and reproducibility.

That is, the method for manufacturing a moisture-sensitive composite sintered body of the present invention includes i
A total of 90 of Prom 65-75, BaO 10-15, and ZnO 5-10 in t%, and Mo 03 or C
xoffiit% of a mixture of r20B and TeO2 or 8-10% by weight of TeO2 alone is mixed and melted, the resulting glass is crushed, and 100 parts by weight of this glass powder and 8-10 parts by weight of potassium hexatitanate fibers are mixed and melted. This method is characterized by mixing the parts, molding the mixture in a mold, and firing the molded body.

First, the sintered body in the present invention contains PzOs 6 in weight%.
The basic components are 5-75 BaO, 10-15 BaO, and 5-10 ZnO, totaling 90.

In addition, in the present invention, MoO3 and Te are added to the basic components.
A mixture of O2, 20g of Cr and 1og of a mixture of TeO2
t% or 8-10% by weight of TeO2 alone is mixed. If P2O11 is less than 65% by weight, vitrification will not occur.
Although it is possible, the dispersibility and adhesion of potassium hexatitanate fibers described later are poor, and if the amount exceeds 751%, the chemical stability of the glass will deteriorate.

The upper and lower limits for BaO and Zoo, respectively, are in ranges that provide chemical stability to the glass without impairing moisture sensitivity.

Preferably, hos 75, Ba010, Zn in weight%
The total number of O5 is 90.

MoO3, Cr20B and TeO2 are added to further reduce the electrical resistance value of the surface when sintered as described later.Mo01 or Cr1O1 and T
M
The mixing ratio of o01, Cr2O3 and TeO2 or the usage amount of Te02 can be selected as appropriate.

Preferably, in order to maximize the change in electrical resistance value with respect to the change in relative humidity of the sintered body, Mo0g! y 10T
erms 5, or Cr2017 + Teb023
, or Taxi 10 is selected.

Next, in the present invention, a total of 90ffit% of PH05+BaO+ZnO, MoO3+Tera, C!
Os + TeO2.

Alternatively, 10% by weight of Te01 alone is thoroughly mixed and melted.

Normally, 1
Glass is obtained by melting at 050-1100° C. for 15-20 minutes. The obtained glass is pulverized, preferably finely pulverized, and 100 parts by weight are mixed with 8 to 10 parts by weight of potassium hexatitanate fibers.
Mix with parts by weight. Potassium hexatitanate is 6T10a,
KxO or 6Ti sham.

It is expressed as K, 0, 1/2 Ba0, has hygroscopicity,
The fibers usually have a diameter of 0.2 to 0.5μ and a length of about 10μ, and are relatively inexpensive and commercially available.
It has a melting point of 0°C or higher.

Such potassium hexatitanate fibers are added in order to synergistically exhibit the respective advantages in the iν aggregation with the glass powder, thereby making it a moisture-sensitive sensing material that can be used at high temperatures. The amount added is 8 to 10 parts by weight per 100 parts by weight of the glass powder. The amount of potassium hexatitanate fiber added is less than 8 parts by weight, or 1
If the number is more than 0, the sintered body may be used at high temperatures at intervals, and the dispersibility and contact with the glass may deteriorate, which is not preferable. When a mixture of glass powder and potassium hexatitanate fibers is molded in a mold and the resulting molded body is fired,
A moisture-sensitive composite sintered body is obtained. The mold is selected according to the shape of the intended sintered body, and the firing temperature is 500 to 600°C depending on the composition change.

The moisture-sensitive composite sintered body obtained according to the present invention has a microstructure with appropriate gaps that is effective for adsorbing and desorbing moisture, has good reproducibility, and is made of potassium hexatitanate fibers. The use can enable use at high temperatures. Furthermore, since the electrical resistance changes gracefully in response to changes in relative humidity, it can be used as a moisture-sensitive sensing material over a wide humidity range.

Furthermore, the moisture-sensitive composite sintered body of the present invention can be easily produced using commercially available materials with simple operations, and does not require sophisticated crystal control like conventional moisture-sensitive ceramic sintered bodies. Therefore, since precise sintering technology is not required, the product has great stability and can be manufactured at low cost.

Therefore, the moisture-sensitive composite sintered body in the present invention can be used for industrial equipment,
It can be used as a detection material for a wide range of humidity sensors such as household appliances.

Hereinafter, the present invention will be explained based on examples.

Example' P2O5, Bad, ZnO, TeO1,' Mo
A certain amount of each of O3 and Cr20B was collected and the well-mixed mixture was prepared in an alumina crucible with 1050-11
Glass was obtained by melting at 00°C for 15-20 minutes. The obtained glass is finely pulverized, 10 parts by weight of potassium hexatitanate fibers are thoroughly mixed with 100 parts by weight of this glass powder, and the mixture is molded in a mold, and the obtained molded body is fired at 500 to 600°C. did. The surface of the obtained disk-shaped sintered body was thoroughly polished to obtain a sintered body with a diameter of 10 mm and a thickness of 2 mm.

Silver paste was applied to the surface of this sintered body at intervals of 0.5 am and baked at 100° C. to form parallel electrodes. This was placed in a constant temperature bath capable of converting to a constant humidity, and changes in electrical resistance with respect to changes in humidity were measured using an insulation resistance meter. The obtained glass composition is shown in Table 1, the composition of the sintered body is shown in Table 2, and its fM characteristics are shown in Table 3 and the figures.

(Margins below this page) Table 1 (Margins below this page) 1. Second. As is clear from Table 3 and the figures, the composite sintered body of the present invention has a relative humidity of 18% to 70%.
During the change in humidity, the electrical resistance of one line turns into ashes by a maximum of about 1000 times, so if this is detected by a detection device, it is possible to respond to a wide range of humidity changes.

[Brief explanation of the drawing]

The figure is a diagram showing a change in electrical resistance value with respect to a change in relative humidity of an example of a moisture-sensitive composite sintered body obtained by the present invention. Special pestle applicant: Director of the Agency of Industrial Science and Technology Kawa 1) Hirobe designated agent: Director of the Osaka Institute of Industrial Technology, Agency of Industrial Science and Technology Naito-Oo procedural amendment (spontaneous) March 10, 1980 1, Indication of the case 1988 Patent Application No. 178846 No. 2, Name of the invention, Method for manufacturing a moisture-sensitive composite sintered body 3, Relationship with the case of the person making the amendment Patent applicant address: 1-3-1 Kasumigaseki, Chiyoda-ku, Tokyo Name (
114) Director of the Agency of Industrial Science and Technology Hirobe Yoda 4, Designated Agent 6, Number of inventions increased by amendment 0 8, Contents of the amendment 1) Change "500 to 600 degrees Celsius" on page 5, line 19 of the specification to "400 to 600 degrees Celsius" 500℃”. 2) Add the following sentence to the next line of page 5, line 19 of the specification. "X-ray analysis during this firing process revealed the precipitation of TiP2O7 crystals." 3) The product was fired at a temperature of 1500 to 600°C as shown in page 7, line 6 of the specification. " was corrected to "Calcined at 400-500°C."

Claims (1)

[Claims] 11 with a total of 90 of Psis 65-75, BaO10-15 and znO5-10, and Mo os or Cr
20 g of TeO2 and 10 mt% of a mixture of TeO2 or 8 to 10 mt% of T@ot alone are mixed and melted, the resulting glass is crushed, and 100 parts by weight of this glass powder and potassium hexatitanate fibers are mixed and melted. 8 to 10 parts by weight are mixed, the mixture is molded in a mold, and the molded body is fired.