JPH0798692B2 - Ceramics complex - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a ceramic composite. More specifically, it relates to a ceramic composite for firing which is resistant to thermal shock and whose density can be changed by changing the raw material particle size and the amount of fiber added.

[Prior Art] Various crucibles and firing materials such as molded sheath materials used at high temperatures have been conventionally made of ceramics such as magnesia, alumina, cordierite, etc. In the field of ceramics firing materials for ceramics, it is often used under severe conditions such as exposure to extremely high temperatures, rapid temperature changes, and exposure to special atmospheres. In such cases, Conventional firing materials are not suitable because they are weak against thermal shock and often lose strength as a structure against a special atmospheric gas, and have many drawbacks. In particular, in recent years, due to the development and sophistication of electronic equipment, and in the situation where even higher purity is demanded, contamination does not occur more rigorously, and the properties of the firing material can be controlled even under severe conditions. High-quality materials that do not change are desired.

Further, crucibles and the like are required to be fired at high temperature and used at high temperatures, and the usage conditions are becoming more severe. Therefore, high-temperature stability is required, and a relatively inexpensive material that can withstand expansion and property changes associated with temperature changes is required.

Since the MgO sintered body is dense and has a high-temperature melting point, it is a monolithic and excellent firing material, and has been used as a firing sheath material and a crucible material. However, the MgO sintered body is very vulnerable to thermal shock, and cracks due to thermal shock during firing.
It was prone to cracking and could not be used under severe conditions.

[Problems to be Solved by the Invention] It is an object of the present invention to provide a composite ceramic body for various uses such as a setter material for firing, a sheath material for firing and a crucible which meet the above strict requirements. Another object of the present invention is to provide a composite ceramic body which is free from cracks at high temperatures and has excellent heat resistance, and a method for producing the same. A further object of the present invention is to provide a composite ceramic material that can be used in a crucible for producing an electronic material used for high temperature firing. It is another object of the present invention to provide a composite ceramic material capable of producing a high temperature resistant sagger material for firing, crucible and the like having improved strength, and a method for producing the same.

[Means for Solving Problems] In the present invention, 1 to 40 of zirconia fiber is added to MgO fine powder.
A ceramic composite for firing, which is characterized in that it is produced by mixing it in a weight percentage, adding an appropriate amount of a binder to obtain an appropriate viscosity mixture, molding it into an appropriate shape, and firing. Furthermore, 1 to 40 parts of zirconia fiber was added to MgO fine powder.
This is a method for producing a ceramic composite for firing which is characterized in that the mixture is mixed by weight%, the binder is added in an appropriate amount to obtain a mixture having an appropriate viscosity, the mixture is formed into an appropriate shape, and the mixture is fired.

The present invention uses a composite material of a sintered body of MgO fine powder, to which a tough zirconia fiber is added, as a firing material. For crucibles and firing sheaths that can prevent thermal shock cracking. That is, a suitable material of is obtained. Fine powder of MgO, zirconia fiber, and an appropriate binder are used as an appropriate amount, and they are mixed in an appropriate ratio to obtain a mixture having an appropriate viscosity, which is then subjected to slip casting or die press, extrusion molding, suction press molding, etc. Molded into a shape, and this molded body is approximately 1400 to 1800
It was baked at ℃.

The ceramic composite of the present invention has a raw material particle size of fine powder,
By changing the amount of zirconia fiber added, the properties such as the density of the manufactured ceramic composite can be changed. The smaller the raw material particle size, the higher the density of the manufactured ceramic composite.
On the other hand, the density decreases as the amount of zirconia fiber added increases.

In addition, the properties of the manufactured ceramic composite are changed by changing the aspect ratio of the zirconia fiber used. That is, by adding fibers having a large aspect ratio, the density of the produced ceramic composite can be reduced, and a ceramic body having a small heat capacity can be produced.

The ceramic composite of the present invention is of a zirconia fiber-added composite (hybrid) type,
Therefore, it could be used as a firing material such as a setter material and a sheath material that are resistant to thermal shock. Since the zirconia fiber acts to pull the matrix magnesia, the strain energy is absorbed, and it has the effect of softening the crack generation. That is, the strength is improved by the zirconia fiber, and a ceramic composite for firing having high high temperature strength is obtained.

The ceramic composite of the present invention can control or change the density of the manufactured ceramic composite to some extent by the addition amount of the added zirconia fiber, that is, produce a porous ceramic composite.

The ceramic composite obtained according to the present invention is a polymorph and can be formed into an arbitrary shape at the time of molding, so that a sintered body having an arbitrary shape can be easily obtained. It is possible to obtain a high-grade sintered body having an arbitrary shape.

According to the present invention, the ceramic composite of the present invention is preferably fired within a firing temperature range in which MgO of the matrix and zirconia fiber do not react. This is because the zirconia fiber is not thermally deteriorated during firing. In addition, since the magnesia of the matrix reacts with the zirconia fibers and melts each other, the mechanical strength of the zirconia fibers cannot be maintained or the zirconia fibers are thermally deteriorated.
It must be fired in a way that prevents it.

The fine powder of MgO, which is the raw material, is preferably as fine as possible so that the sinterability is improved. The fine powder raw material can be easily produced by a usual ceramic fine particle production technique, for example, a sol-gel method using a metal alkoxide as a starting raw material.

As the zirconia fiber that can be used, a commercially available zirconia fiber can be used. For example, Saffil zirconia fiber can be sufficiently used. Further, the usable aspect ratio range is preferably about 10 to 10000, and the aspect ratio can be selected according to the required properties of the firing material.

The range of the amount of zirconia fiber added is 1 to 40% by weight, and it is preferable to select it appropriately according to the desired properties. If it is 1% by weight or less, the thermal shock resistance and the composite strength are not significantly improved. Further, when 40 wt% or more of fiber is included, boring and cracking occur, which makes it difficult to handle. Therefore, the range of addition amount of zirconia fiber is 1 to 40 wt% with respect to MgO.

The ceramic composite obtained by the present invention is suitable for a firing setter material, a firing sheath, a melting crucible, a crucible for various glasses, a crucible for melting a general metal, a crucible for firing an electronic ceramic, or a refractory sheath. .

Next, the method for producing the ceramic composite of the present invention will be described, but the present invention is not limited to the following examples.

[Example] Example 1 A raw material of MgO fine powder and zirconia fiber were mixed well in a ratio of parts by weight shown in Table 1, an organic binder was added, and the mixture was kneaded and kneaded. About 1600
It was calcined at ℃ for about 3 hours.

The density of this sintered ceramics composite was measured. The results are shown in Table 1. Furthermore, further thermal shock tests show that the thermal shock resistance is higher and the high temperature strength is improved compared to the results of the MgO single component monolithic body.

In the above table, MgO and fiber show the ratio in parts by weight, and both were formed by press molding.

Example 2 Next, 100 parts by weight of fine powder magnesia and 20 parts by weight of zirconia fiber were mixed by changing the aspect ratio of the zirconia fiber, and the mixture was kneaded with a binder and molded in the same manner as in Example 1, and the temperature was about 3 at 1600 ° C. Burned for hours. When the density of the produced fired body was measured, the results were as shown in Table 2 below.

By changing the aspect ratio of the zirconia fiber as described above, the density of the manufactured ceramic composite can be changed and controlled.

Ceramic composites with higher densities can be made with smaller aspect ratios. That is, when the aspect ratio is small, it is easy to mix, and the structure can be made uniform without the formation of fiber lumps, and a fired body with a high density can be obtained.

On the contrary, by using zirconia fiber having a large aspect ratio, a ceramic composite having a low density can be manufactured, that is, a ceramic composite having a small heat capacity can be provided.

[Advantages of the Invention] The ceramic composite of the present invention has, due to the structure and manufacturing method described above, firstly, a setter material for firing which has excellent thermal shock resistance as compared with conventional firing materials. Saya materials and crucible materials were provided. Secondly, it was possible to provide ceramic composites whose heat capacity and density could be adjusted by changing the ratio of the raw materials and the aspect of the fiber. Thirdly, therefore, the raw materials By changing the fine powder particle size, fiber addition amount and fiber aspect of
The density and heat capacity of the manufactured ceramic composites can be reduced, the furnace can be made uniform in a short time, heat loss can be reduced, and
We were able to provide a ceramic composite material that can be used for firing setter bodies, firing sheath bodies, crucible materials, etc. that do not cause thermal non-uniformity in the fired products. Fourth, improved strength,
Technical effects such as the ability to manufacture chemically and thermally stable firing setter bodies, sheath bodies, and crucibles were obtained.

Claims (2)

[Claims] 1. A zirconia fiber is added to a fine powder of MgO.
A ceramic composite for firing characterized in that it is prepared by mixing up to 40% by weight, adding a proper amount of a binder to obtain a mixture having a proper viscosity, molding it into a proper shape, firing and manufacturing. 2. A zirconia fiber is added to a fine powder of MgO.
A method for producing a ceramic composite for firing, which comprises mixing up to 40% by weight, adding an appropriate amount of a binder to obtain an appropriate viscous mixture, shaping the mixture into an appropriate shape, and firing.