JPS6096569A - Manufacture of ceramic 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 This invention relates to a method for manufacturing ceramic elements by extrusion molding of ceramics.

Structure of conventional example and its problems Conventionally, as shown in Figure 1, the method of manufacturing ceramic elements by extrusion molding involves mixing, dehydrating/drying, calcining, pulverizing, and drying raw materials, polyvinyl alcohol, and methyl cellulose. etc., and mixed with water and kneaded to make extrusion molding soil. Thereafter, the mixture was vacuum degassed and kneaded using a vacuum kneading machine, and a molded product having a predetermined cross-sectional shape was obtained using an extrusion molding machine. After drying and cutting, a fired product was obtained.

In the extrusion molding method, ceramic powder, which itself has no caking properties, and an organic binder solution to impart caking properties are uniformly mixed to form a viscous mass called clay. At this time, uniform mixing of the ceramic powder and the binder is required in order to give the clay plasticity of J181 degrees and sufficient mechanical strength after drying. Further, after sintering, the binder burns away, so the uneven distribution of the binder remains as pores, lowering the density of the sintered body and deteriorating its performance as a ceramic. For this reason, there are seven important points in the binder mixing process or extrusion molding.

The conventional binder mixing method involves dry mixing ceramic powder and organic binder powder, then gradually adding a solvent (water in the case of a water-soluble binder) to dissolve the binder while continuing to mix. Next, when the viscosity reached a high level, the kneader was used to vigorously knead with a device such as a clay kneader to disperse the binder.

Since the ceramic powder has a particle size of 1 to 3 .mu.m and the binder powder particle size has a maximum diameter of 1 kneading degree, uneven distribution of the binder powder particles could not be avoided even if considerable mechanical kneading was performed.

Reed, is there a way to mix the pre-melted binder and ceramic powder with another binder mixing horn?Since the binder melt has a high viscosity, is it likely to swell compared to dried ceramic powder? Bad, homogeneous clay or rtlK<
< , we have heard that it has a drawback of poor extrusion moldability.

In both of the above two methods, the ceramic raw material that has been wet-milled iron powder is dried thoroughly once, and the clay-like material is collected in a can. There is also a method of dissolving it. However, after mixing the binder, the viscosity always increases to 41°C, which requires time to collect and clean the equipment. In addition, in the case of mixed pulverization, water is used at 100% or more based on the raw F'l, but since the moisture content of the soil used for extrusion is around 10%, a dehydrator is used to increase the water content to 90% or more. Water and binder need to be washed away. Furthermore, unless the final moisture content is accurately controlled, the @hi of the binder cannot be controlled, which causes variations in the shrinkage rate and leads to dimensional variations in the sintered body.

Purpose of the Invention The present invention aims to solve the above-mentioned conventional drawbacks, and provides a method for manufacturing a ceramic element that is dense and highly dimensionally uniform by uniformly controlling the amount of binder. be.

Structure of the Invention In order to achieve this object, Mizumoto 11JI's method for manufacturing ceramic elements involves wet-pulverizing a warm water-soluble binder on ceramic powder, dehydrating it, and then heating and kneading it to dissolve the binder. , extrusion molding, drying, and firing.

With this configuration, the hot water-soluble binder added during pulverization is insoluble in cold water, so it
Thorough mixing with the ceramic powder takes place. Then, in the next dehydration operation, the binder is only mixed with the ceramic powder and not yet dissolved, so it will not be washed away with the water.

It is only when this is heated and kneaded in a device such as a kneader that the binder f begins to dissolve and a uniform clay is formed.

DESCRIPTION OF EMBODIMENTS The embodiments of Mizumotori J will now be described in detail. First, as a ceramic, lead zirconate titanate porcelain 4, IP)
(jllJ PZT porcelain material) was used. This addition was blended at a constant mixing ratio of 1j1° and mixed in a ball mill for 20 hours, dehydrated and dried, and then calcined at 900° C. for 2 hours. Next, it was wet-pulverized again in a ball mill for 17,110 minutes. At this time, the ratio of IJitFl to pure water is 1:1
It is. After that, completely saponified type (411
Water-soluble j'! Type f) polyvinyl alcohol (trade name, Cosenol NH-26, manufactured by Nippon Gosei Kagaku Kogyo Co., Ltd.) was added at a ratio of 4 Wt to the raw material. The particle size of this binder is 20
It was from all the songs of Mesosiyu Furui. Furthermore, after additional pulverization at 2 o'clock, pressure dehydration was performed using a tube press (trade name of a dehydrator manufactured by Ashizawa Tetsutama Co., Ltd.). The dehydration pressure at this time was 1ookg/d. Further, the water content of the dehydrated cake-like material was about 1 () wt%. This is 80 yen in kneaded
By continuing the addition iM kneading at ℃ for 30 minutes, a uniform top was obtained. Next, it was formed into a shape of 100 mφ using a vacuum clay kneading machine, and left for two days while preventing the clay from drying. This product was extruded using an extrusion molding machine in a mold of 3I+111φ, continuously dried in a drying oven, and then finely cut into 6.6 mm lengths. This was packed in an alumina pod and fired in a tunnel furnace at 1250°C for 1 hour. FIG. 2 shows the manufacturing process according to the present invention.

Next, a piezoelectric element (2.5 φ x 6
Table 1 shows a comparison of the characteristics of

In addition, Table 2 shows the results of 30.αη durability tests using this J(' as a piezoelectric spark plug element.
111'I in the table is the average value of 10 output voltages.

As shown in Table 2 below, the ceramic obtained by the Mizumoto IIJ method showed excellent performance in terms of sintered density, piezoelectric constant, and four-life characteristics as a ceramic, and the effects of the present invention are clearly recognized.

By using the above-described process, it is possible to obtain a rod mixed with binder without completely drying the ceramic raw material PI after cold crushing. , time and energy losses can be reduced.

Furthermore, once completely photo-dried, the finely pulverized ceramic particles form an agglomerate, which becomes strong secondary particles even during binder kneading and is not pulverized into primary particles, making it difficult to obtain a dense molded body. Therefore, the density of the sintered body will decrease, but this cannot occur because the sintered body according to the present invention is not completely dried.

In addition, the binder added during pulverization is not dissolved and is only mixed with the ceramic powder, so it will not be washed away (100% remains) during dehydration. Therefore, the ratio of the binder to the ceramic raw material is exactly 1. This has the advantage that the variation in the storage rate is small and the variation in final product dimensions is also small.

Furthermore, during heating and kneading, the binder is melted while cross-crossing operation is performed, but by lowering the temperature, the viscosity of the product decreases, and sufficient kneading becomes possible. A bar top is obtained. This makes it difficult to obtain good characteristics as described above.

Figure 1 shows the process of manufacturing a ceramic element by the conventional extrusion method, and Figure 2 shows the process of manufacturing the ceramic element by the extrusion method of the present invention. It is a figure showing a manufacturing process.

Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2

Claims (1)

[Claims] 1. A method for manufacturing a ceramic element, which comprises pulverizing a ceramic powder and a wet water-soluble binder, dehydrating the mixture, then heating and kneading the mixture to dissolve the binder, extrusion molding, drying, and firing.