JPS6022453B2 - Pyroelectric porcelain material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an excellent pyroelectric ceramic material having stable characteristics such as a large pyroelectric coefficient and a small specific electric yield rate.

As a method of measuring the surface temperature of an object near room temperature or the skin temperature of a human body without directly touching it, the intensity of infrared rays emitted from the object to be detected according to its temperature is detected using an electric infrared detection element. The method is widely used.

This tortoise-shaped detection element absorbs infrared rays emitted from the object to be detected, and uses changes in spontaneous polarization caused by temperature changes in the pyroelectric material as a signal. Temperature can be detected easily and accurately.

In addition, the infrared intensity corresponding to temperatures around room temperature has a wavelength of 1
It has a maximum value near 0 microns, and a method is usually used in which the maximum value is detected by an element. The dew-resistant material used in such dew-type infrared detection elements is characterized by changes in spontaneous polarization with respect to temperature changes, that is, the durability coefficient (hysteresis s/dT).
) is larger, and the dielectric constant (Es) is 4.0, the better the material, and it is industrially desirable that it be manufactured easily and inexpensively. Conventionally, such pyroelectric materials include glycine sulfate and lithium niobate (LINO).
03), single crystal materials such as lithium tantalate (LITa03), and magnetic materials such as lead titanate (PbTi03) and lead zirconate titanate (PrTi03) are known.

However, glycine sulfate crystals are water-soluble and brittle, and are difficult to process, making it difficult to produce pyroelectric materials.
Furthermore, the temperature at which Atsuki properties disappear, that is, the Curi temperature is 5? Since the temperature is ○ and extremely low, the temperature range in which it can be used is greatly limited. In addition, although lithium niobate crystal has good processability, it has a small haze coefficient (s/dT) and is expensive, making it undesirable for practical use, while lithium tantalate has good processability and a comparative exposure performance index. Although it is a preferable material because of its high cost, it is industrially disadvantageous because it is expensive. Furthermore, although lead titanate has a large rudder s/dT and a relatively low dielectric constant, it is difficult to bond, and the lead component evaporates during firing, resulting in a magnetic material with a uniform composition and stable pyroelectric properties. Lead zirconate titanate has a drawback of being difficult to obtain, and although lead zirconate titanate has good workability and a large dPs/dT, it has a drawback of a large Es. The present inventors have developed a lead zirconate titanate-based pyroelectric material that improves its drawback Es and has excellent pyroelectric performance, particularly for lead zirconate titanate materials that have good processability and excellent fertilization s/dT. As a result of repeated research to develop porcelain materials, we discovered a highly desirable pyroelectric material.

That is, in the present invention, the formula is represented by (PQNb207}X . 1
The main component is a lead zirconate titanate compound having a composition in the range of 0 to 0.40, and further contains manganese dioxide or chromium oxide, or both, in a range of 0.1 to 1.
．． The object of the present invention is to provide a pyroelectric magnetic material characterized in that the content is in the range of 5% by weight.

In the lead zirconate titanate compound represented by the above formula used in the material of the present invention, x is within the range of 0.005 to 0.06, and y is within the range of 0.10 to 0.40. If the combination is outside this range, the pyroelectric coefficient (rudder s/dT) becomes small or the relative yield ratio (Es) becomes large, which is undesirable because the characteristics as a pyroelectric material deteriorate.

The desirable ranges for each are 0.01 to 0.04 for x and y
is 0.15 to 0.3. Furthermore, Mn02 and Cr203 which are used in the acid combination in the material of the present invention are 0.0.
It is important that the content is 1 to 1.5% by weight. If it deviates from this range, d
Either or both of Ps/dT and Es would be highly undesirable and the object of the present invention would not be achieved. The zirconate titanate compound represented by the above formula can be easily prepared, for example, as follows.

Chemically high purity P. NbQ, Zr02 and Ti02
, determine the desired value of x and y in the above formula within their respective ranges, weigh out each metal oxide powder so that the x and y in the above formula are at the desired value, and then add Mh02 powder or Cr203 powder or both to the above value. 0 for the total amount of each metal oxide powder.
1 to 1.5% by weight is weighed out, mixed with the above-mentioned all metal oxides, and then sufficiently pulverized, preferably using a grinding mixer such as a ball mill, to form a homogeneous mixture as much as possible. For example, pre-firing is performed at a temperature of 800 oo for 2 hours. Next, this calcined product is again pulverized and mixed using a pulverizer such as a ball mill, and a commonly known organic binder such as polyvinyl alcohol is added and kneaded, and after being pressure-molded into a desired molded product, it is further pulverized at a higher temperature. For example 1200q0
Alternatively, the main firing is performed at a higher temperature, for example, for about 2 hours. The magnetic material fired in this way is composed mainly of a compound having predetermined x and y values represented by the above formula, and the molded material is heated at a temperature of, for example, 50 to 150°C by contacting electrodes on both sides of the molded material. A magnetic material with excellent pyroelectric properties is provided by applying a DC high voltage of Fox V/Fence in oil to polarize it.

The durable magnetic material of the present invention, which is easily prepared in this way, is extremely dense, has both a large s/dT and a small Es, is easy to manufacture and process, is inexpensive, and is stable and detectable. It has a wide temperature range and is extremely desirable as an Atsuru-type detection element both industrially and practically.

Hereinafter, the present invention will be explained in more detail with reference to Examples.

Examples 1-9 Powdered Pbo, Nb205, ZrQ and Ti02,
In the above formula, x and y are each weighed in proportions to form a compound having a predetermined value, and each of these metal oxides is thoroughly pulverized by putting it in a ball mill together with Nn02 powder corresponding to 0.5% by weight of the total weight. Mixed.

This finely powdered mixture was calcined at a temperature of 800° C. for about 2 hours, then sufficiently ground and mixed in a ball mill, and an organic binder was added thereto and kneaded.

The obtained hybrid product was crushed about 2 mm in diameter under ground pressure.
It was pressure-molded into a disk with a thickness of 1, and heated at 1200 qo for 2 hours to form the final product. Next, electrodes were brought into contact with both sides of the fired disc, immersed in oil at a temperature of about 10,000 °C, and both electrodes were
A durable porcelain material was prepared by applying a DC voltage and polarizing it.

In this way, x is a constant value of 0.03 and y is 0.10.
, 0.15, 0.20, 0.30 or 0.40 and y is 0.15 ÷ constant value and x is 0.005, 0
．． A disc-shaped pyroelectric magnetic material containing M2 (0.5 weight) of various compounds of 02, 0.04, or 0.06 was prepared, and Tanimura's pyroelectric coefficient (Hs/dT ) and specific electrical constant were measured.

Table 1 shows the x and y values of the compounds in each of these materials and the measurement results of each thermal properties.

Table 1 Examples 10 to 18 In the same manner as in the previous example, disk shapes were prepared from compositions in which x was 0.03 and y was 0.15, and the amount of Mn02 or Cr203 added or the combined amount of both components was varied. We created a pyroelectric porcelain material and investigated its thermal properties.

Table 2 shows the types of additive components, their amounts (% by weight) relative to the total weight of the metal oxides constituting the compound composition, and the measurement results of their properties. 2. Comparison of the pyroelectric properties and industrial evaluation of conventional pyroelectric materials with the porcelain material of the present invention, which is dense, stable, and inexpensive, and has excellent workability such as binding properties and pyroelectric properties as described above. This is shown in Table 3 for this reason.

From the above Table 3, it can be seen that the porcelain material of the present invention has superior practicality compared to conventional materials.

Claims (1)

[Claims] 1 Formula {1/2(Pb_2Nb_2O_7}_x·{Pb(
Zr_1_-_yTiy)O_3}_1_-_x, where x is 0.005 to 0.06 and y is 0
．． The main component is a lead zirconate titanate compound having a composition within the range of 10 to 0.40, and further contains manganese dioxide or chromium oxide in the range of 0.1 to 1.5% by weight of the compound. A pyroelectric porcelain material characterized by: