JP2825987B2 - Refractory shelf with sandwich construction - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refractory shelf plate having a sandwich structure used for firing ceramic products which are required to have no warpage, such as large grindstones and ceramic plates for electronic parts.

[0002]

2. Description of the Related Art Conventionally, ceramics such as glass, sanitary ware, tableware, ceramics such as tiles, large grindstones, and electronic parts have been fired in a firing furnace by means of pillars installed on a base. There is a method in which an alumina or silicon carbide refractory shelf is horizontally placed on a shelf assembly assembled in the above, and an article to be fired is placed thereon and fired.

[0003]

However, since the alumina-based refractory sheet material has a low high-temperature strength, there is a problem that the operating temperature of a target firing furnace is limited. On the other hand, refractories made of SiC have high high-temperature strength and are hard to be warped, and are widely used as shelf boards. However, depending on the type of the fired product, a chemical reaction occurs with a product to be fired, thereby causing a product defect. There was a problem.

[0004] Since a refractory plate made of SiC is extremely hard, it is molded and fired, and then subjected to a finishing process for polishing the surface of a receiving surface on which a product to be fired is mounted, or to a slight amount due to repeated use. If the warpage occurs one by one, there are various problems such as a large number of man-hours required for correction processing for correcting the warp, and the cost of working tools is high.

[0005]

The present inventor has made various studies to solve the above-mentioned conventional problems, and as a result, has completed the present invention. That is, according to the present invention, both surfaces of the SiC refractory layer are formed into a refractory layer formed of at least one selected from alumina, mullite, magnesia, cordierite, zirconia and chamotte refractories. A refractory plate having a sandwich structure, wherein the refractory plate comprises a SiC refractory layer containing coarse SiC particles of 20 mesh or more in an amount of 5 to 70 wt%. You.

In the present invention, the SiC refractory layer contains 3 to 50% by weight of fine SiC particles having a size of 100 mesh or less, and coarse particles having a size of 20 mesh or more are used as particles constituting the coated refractory layer. It is more preferable to contain 3 to 50% by weight of fine particles of 70% by weight and 100 mesh or less.

[0007]

FIG. 1 is a perspective view showing an example of a refractory shelf according to the present invention. The shelf board of the present invention has at least one selected from alumina, mullite, magnesia, cordierite, zirconia, and chamotte refractories on both sides of a SiC refractory layer (hereinafter referred to as a SiC layer) 1. A sandwich structure covered with a refractory layer (hereinafter referred to as a refractory layer of alumina or the like) 2 to be formed.

In this refractory shelf, the SiC particles constituting the SiC layer 1 are made of coarse S
Contains 5 to 70% by weight of iC particles. Further, by containing 3 to 50% by weight of fine SiC particles of 100 mesh or less,
Solid SiC with fine SiC particles entering between coarse C particles
The layer 1 is formed. Further, when the coarse particles of SiC form the uneven surface 3 on the surface of the SiC layer and cover both surfaces of the SiC layer 1 with the refractory layer 2 made of alumina or the like, the alumina material or the like enters the uneven surface 3 and the SiC layer is formed. It is firmly bonded to the layer 1 to prevent delamination.

Furthermore, coarse particles of 20 mesh or more are used as particles constituting the refractory layer 2 such as alumina.
0 wt%, preferably 20 to 50 wt%. Furthermore, 100
3-50wt%, preferably 15% of fine particles below the mesh
By containing 50 wt%, fine particles of alumina or the like enter between coarse particles of alumina or the like to form a strong layer of alumina or the like, and coarse particles of alumina or the like form a layer of alumina or the like. When forming the uneven surface 4 on the surface and coating the SiC layer 1, it is more preferable because it is strongly bonded to the SiC layer 1 to prevent delamination.

[0010] As described above, the shelf board of the present invention has a hard SiC refractory layer 1 that is hardly warped during firing as a shape-retaining core material, and has a refractory material such as alumina on both surfaces thereof. Although there is a warp in the firing process as described above, the refractory layer 2 which is easily polished has a sandwich structure in which the refractory layers 2 are integrally laminated, so that drying, firing distortion is less than that of the two-layer one, and the molding is performed. The plate material of the intermediate SiC layer 1 serves as a core material to prevent the refractory layer 2 from warping in the subsequent sintering process as well as during repeated use, so that the refractory layer 2 is hardly warped as a whole. In addition, after forming and firing, the finishing work performed by polishing the front and back surfaces to be the receiving surface of the article to be fired and the correction work to correct the warpage caused by repeated use are the polishing work of forming both surface layers. Since it is only necessary to perform the process on the soft refractory layer 2 which is easy, these operations are extremely easy, and the working tools may be inexpensive using a SiC grindstone. There is no peeling, and the refractory layers 2 and 2 on both sides can be used as a receiving surface of the article to be fired only by reversing. In addition, since the repair work is easy, polishing the refractory layer 2 for a long time is easy. It can be used repeatedly with the same surface accuracy as a new product, and the production cost and running cost are reduced, so that there is an extremely economical advantage.

Further, by covering both surfaces of the SiC layer with a refractory layer of alumina or the like, a chemical reaction between the SiC layer and the fired product can be prevented, and the quality of the fired product can be improved. The thickness of the plate material of the SiC layer 1 and the refractory layer 2,
The ratio of the total thickness of the refractory layers 2 is preferably in the range of 1: 1 to 5: 1, and the thickness of each refractory layer 2 is preferably 3 mm or more.

[0012]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples, but it will be apparent that the present invention is not limited to these Examples.

(Examples 1 to 7, Comparative Examples 1 to 3) Length 200 m
Specimens coated with a mullite refractory layer having an SiC refractory layer having a particle size shown in Table 1 and having a size of mx 200 mm and a thickness of 15 mm were prepared. Such a specimen was prepared as follows.

That is, the mold is filled with a mullite clay corresponding to the lower refractory layer 2 that is easily polished, and the lower refractory layer 2 is formed by embossing. The kneaded clay corresponding to the plate material of the layer 1 is filled in a layered form by a required thickness, and the mold is pressed again. Then, the mullite kneaded clay corresponding to the upper refractory layer 2 which is easily polished is similarly filled, A green body having a sandwich structure was formed by press-integrating a green body forming a middle layer with the kneaded clay corresponding to the plate material 1 to form a green body having a sandwich structure.

The obtained specimen was heated to 1000 ° C. and rapidly cooled to room temperature 20 times. Table 1 shows the results. From the results in Table 1, no peeling was observed in the test specimens of the present invention (Examples 1 to 7), and it was found that the adhesion performance between the SiC layer and the mullite layer was high.

[0016]

[Table 1]

[0017]

As described above, according to the refractory shelf having the sandwich structure of the present invention, the hard SiC refractory whose middle is hardly warped at the time of sintering, and the front and back layers are easily polished. It is a sandwich structure composed of a soft refractory material, and the particle size of SiC particles forming the SiC refractory material or the particle size of the SiC particles and the refractory particles of alumina or the like are set in a predetermined range. In addition, the bonding between the SiC layer and the refractory layer made of alumina or the like is performed firmly, and a shelf board having high delamination resistance and high heat resistance can be manufactured.

Further, since the shelf board of the present invention has a sandwich structure as described above, warpage and distortion that occur during production are extremely small, and finishing and repairing of the front and back surfaces are extremely easy. Can also be used as a receiving surface of a product to be fired, can be repeatedly used for a long period of time, and has a simple structure, so that it can be provided at a low cost, and thus has a very large practical value.

Furthermore, since both surfaces of the SiC layer are protected by a refractory layer of alumina or the like, a chemical reaction with a product to be fired can be prevented, and no product defects occur.
The quality of the article to be fired can be improved.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an example of a shelf board of the present invention.

[Description of Signs] 1 SiC refractory layer 2 Refractory layer such as alumina 3 Uneven surface of SiC refractory layer 4 Uneven surface of refractory layer such as alumina

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-217190 (JP, A) JP-A-3-177357 (JP, A) JP-A-2-30675 (JP, A) JP-A 61-217 86588 (JP, A) JP-A-61-175477 (JP, A) JP-A-2-69381 (JP, A) JP-A-2-111662 (JP, A) Jpn. (58) Field surveyed (Int. Cl. ⁶ , DB name) F27D 3/00-3/18 C04B 35/64

Claims (4)

(57) [Claims] The present invention provides an SiC refractory layer having both surfaces made of alumina,
A refractory plate material having a sandwich structure coated with a refractory layer formed of at least one selected from mullite, magnesia, cordierite, zirconia, and chamotte refractories, comprising a SiC refractory layer. Contains 5 to 70% by weight of coarse SiC particles having a standard sieve of 20 mesh or more. 2. The refractory shelf board with a sandwich structure according to claim 1, wherein the particles constituting the coated refractory layer include coarse particles having a standard sieve of 20 mesh or more in an amount of 5 to 70 wt%. . 3. A fine SiC having a standard sieve of 100 mesh or less.
The refractory shelf with a sandwich structure according to claim 1, comprising 3 to 50 wt% of grains. 4. The particle size of the coated refractory layer is 10
The refractory shelf board with a sandwich structure according to claim 2, comprising 3 to 50 wt% of fine particles having a size of 0 mesh or less.