JP2835076B2 - Jig for ceramic firing and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a ceramic firing jig used for firing a ceramic molded product and a method for manufacturing the same, and particularly to a ceramic product having a flaw or the like. The present invention relates to a ceramic firing jig capable of producing high-quality sintered products at a high yield without causing color unevenness and having little seizure with a ceramic molded product, and a method for producing the same.

(Prior art) Ceramic products made of silicon nitride (Si ₃ N ₄ ) or alumina (Al ₂ O ₃ ) are formed by molding a powdery or slurry-like raw material into a predetermined shape by a molding press or the like. Thereafter, the molded article is obtained by firing. The baking process is usually performed in a hydrogen or nitrogen atmosphere to prevent oxidation or deterioration of the product.
It is performed by heating to ~ 1800 ° C high temperature.

Conventionally, when such a ceramic molded product is fired, a predetermined number of formed products are placed on the upper surface of a thick plate-shaped firing jig formed of the same ceramic material as the product material, and the firing jig is mounted. Are stacked in multiple stages and housed in a heating furnace for firing.

However, when firing is performed using a conventional ceramic firing jig, since the contact area between the ceramic molded product and the firing jig is large, both are welded at the contact portion,
After the firing is completed, the sintered body cannot be removed, and the atmosphere in the furnace does not sufficiently fall into the contact area, resulting in uneven density of the sintered body, uneven color, and loss of value as a product. Disadvantages, such as reduced soldering strength.

Further, in the case of the conventional thick firing jig, the number of jigs that can be accommodated in the firing furnace is small, so that there is a problem that the manufacturing efficiency of the ceramic product is reduced.

Among these problems, in order to eliminate fusion between the firing jig and the molded product, a firing jig in which the surface of the jig body is roughened by performing honing has been proposed.

By using the firing jig, the ceramic molded product and the jig are in point contact with each other due to the surface roughness, and it is possible to prevent seizure of both, thereby improving the production efficiency and yield of the ceramic product. be able to.

(Problems to be Solved by the Invention) However, the surface of the firing jig whose surface was roughened by honing was used as a honing material.
Fine abrasive grains such as Al ₂ O ₃ or SiC adhere and remain. These honing materials are difficult to remove even by ultrasonic cleaning.

The remaining honing material reacts with the ceramic molded product during firing, causing color unevenness and discoloration on the surface of the sintered body, thereby deteriorating the quality and yield of the ceramic product.

In addition, a needle-like sharp end is formed on the jig surface by the honing process, and the sharp end comes into contact with and damages the ceramic molded product, and similarly, the quality of the ceramic product and the yield are often reduced. In particular, the occurrence of color unevenness and flaws in a sintered part having a high decorative element is fatal, and some measures have been desired.

The present invention has been made in order to solve the above-mentioned problems, and there is no possibility that scratches or color unevenness is generated in a ceramic product, and a high quality product which is less likely to cause seizure with a ceramic molded product. It is an object of the present invention to provide a ceramic firing jig which can be manufactured at a high yield and a method for manufacturing the same.

[Configuration of the invention]

(Means for Solving the Problems) In order to achieve the above object, a ceramic firing jig according to the present invention forms an uneven portion on the surface of a jig main body made of a single element of M ₀ or W or an alloy thereof. The sharp peaks of the projections are formed in a curved shape, and the surface roughness of the jig body is set to 20 μm or more as a ten-point average roughness.

Further, the method for manufacturing a ceramic firing jig of the present invention,
M _0, W and the jig body is formed consisting of simple substance or its alloy material, after roughening treatment of the surface by colliding fine abrasive grains to the jig body surface, the sharp tip produced by the first roughening treatment It is characterized in that a non-sharpening smoothing process is performed.

Here, the smoothing treatment is preferably performed by an etching treatment method or a barrel polishing treatment method.

In addition, a single powder of M ₀ or W or an alloy powder thereof may be used as the roughening treatment abrasive grains.

(Function) According to the jig for slamic firing and the method for manufacturing the same according to the above configuration, since the jig body is formed of a single element of M ₀ , W or an alloy thereof, when heated to a high firing temperature, Is also less likely to be welded to the ceramic molded product.

In addition, since the sharp apex of the convex portion on the surface of the jig body is formed in a curved surface, there is no possibility of flawing the ceramic molded body.

Furthermore, since the surface roughness is set to 20 μm or more, the contact area between the ceramic molded product and the firing jig is small, seizure is prevented, and a space where the atmosphere in the furnace is sufficiently circulated between the two is secured. You. Therefore, non-uniformity of the density of the sintered body does not occur, color unevenness and discoloration can be prevented, and the yield and quality of the product can be significantly improved.

Further, it is possible to thin the jig body with a metal material of high strength such as M ₀ and W, it is possible to increase the number of jigs which can be accommodated in a firing furnace in a single firing operation, ceramic products Can greatly improve the production efficiency.

In the method of manufacturing a firing jig, the roughened jig body is further subjected to a smoothing process by an etching process or a barrel polishing process, so that the sharp tip generated by the roughening process is more effectively processed. It is possible to smooth. Therefore, the quality and yield of the product can be significantly improved without causing any scratches on the product.

In particular, the use of the etching method effectively dissolves and removes highly reactive abrasive grains such as Al ₂ O ₃ and SiC remaining on the jig surface due to roughening, resulting in discoloration and color during firing. The occurrence of unevenness can be effectively prevented.

Al ₂ O ₃ or S with high reactivity as roughening abrasive
By using a single powder of M ₀ or W or an alloy powder thereof without using iC or the like, discoloration and uneven color can be almost completely eliminated.

Example An example of the present invention will be described below. The ceramic firing jig according to the present embodiment is formed by forming an uneven portion on the surface of a jig main body made of a single substance of M ₀ or W or an alloy thereof, and forming a sharp apex of the convex portion into a curved surface. The surface roughness of the main body is set to 20 μm or more as a ten-point average roughness.

Since the jig body is formed of a single element of M ₀ or W or an alloy thereof having excellent high-temperature resistance, fusion of the jig body and the fired component during firing is prevented. In addition, since the sharp apex of the jig body surface is formed in a curved surface, the molded product is not scratched.

Further, the reason for setting the surface roughness to 20 μm or more is that if the surface roughness is less than 20 μm, the contact area between the fired component and the firing jig increases, and the effect of preventing fusion cannot be sufficiently exhibited. .

In order to manufacture a ceramic firing jig having such surface properties, the following manufacturing method is desirable.
That is, a jig body made of a single substance of M ₀ or W or an alloy material thereof is formed, and the surface of the jig body is roughened by colliding fine abrasive grains with the surface of the jig. This is a method of performing a smoothing process for making the portion non-sharp.

As this roughening treatment method, for example, Al ₂ O
Honing process, in which a honing material such as ₃ or SiC particles is sprayed onto the surface of the jig body together with high-pressure air, or a method in which the jig body is pressed with a press machine equipped with an upper die and a lower die with fine irregularities formed on the surface and so on.

On the other hand, as a smoothing treatment method, the jig body is immersed in an electrolytic solution or a corrosive acidic solution, and an etching method in which the sharp tip is corroded and dissolved, or the jig body and the abrasive are put in a rotating or vibrating barrel. There is a barrel polishing method in which a sharp tip is polished to form a curved surface.

In particular, according to the etching method, the honing materials such as Al ₂ O ₃ and SiC used in the roughening process are also effectively dissolved and removed, so that the occurrence of uneven color and discoloration during firing can be almost eliminated. .

In addition, Al ₂ O ₃
By using a single element powder of M ₀ or W or an alloy powder thereof having excellent high temperature resistance without using SiC or SiC, it is possible to almost completely suppress color unevenness and discoloration during firing.

Next, the effects and the like of the ceramic firing jig according to the present invention will be described based on more specific examples.

Examples 1-4, honing applied as roughening treatment M ₀ thick plate 3mm as Comparative Examples 1-2 Examples 1-4, the surface roughness (Rz) 28.2-102
It was adjusted to the range of μm. Honing is a grain size # 16
Using Al ₂ O ₃ particles as a honing material, the blast pressure was 6 to 8 kg / cm ² , the nozzle inner diameter was 4 mm, the spray distance was 10 cm, and the nozzle spray angle was 30 degrees.

Next, the roughened jig body is immersed in a nitric acid solution at room temperature (25 ° C.) for 5 minutes to perform etching, thereby dissolving the sharp peak formed on the surface and removing the attached honing material. Dissolve and remove to a final surface roughness of 21.5
A ceramic firing jig was obtained by adjusting the thickness to a range of about 90.0 μm.

Next, using the obtained ceramic firing jig,
A total of 1,000 or more Si ₃ N ₄ compacts with a thickness of 30 mm and a width of 30 mm and a thickness of 3 mm were fired, and the resulting sintered bodies were inspected.
The number of defects that caused color unevenness and discoloration were measured, and the results shown in Table 1 were obtained.

Here, the effect of removing the honing material by the etching process will be described based on the third embodiment. FIG. 1 shows a third embodiment.
4 is a graph showing the relationship between the etching time and the remaining amount of the honing material (Al ₂ O ₃ ) in Table 1 together with the change in surface roughness (Rz). The remaining amount of the honing material was measured by a fluorescent X-ray analyzer.

As is clear from FIG. 1, if the etching time is set to about 5 minutes, almost 100% of the Al ₂ O ₃ particles remaining as the honing material are removed. Therefore, there is no possibility of causing color unevenness or discoloration during firing. In addition, the surface roughness (Rz) is less reduced by the etching, and the function of preventing the fusion of the fired parts is not impaired.

On the other hand, as Comparative Examples 1 and 2, using a ceramic firing jig whose surface roughness (Rz) was adjusted to 10 μm by honing a jig body surface formed of an M ₀ plate and a Si ₃ N ₄ plate, respectively. Producing fired parts under the same conditions as in Examples 1 to 4,
Similarly, the number of defects was measured, and the results shown in Table 1 were obtained.

Here, a change in the surface roughness (Rz) of the jig body surface due to the etching process will be described with reference to FIGS. 2 (a) and 2 (b). 2 (a) and 2 (b) are graphs showing enlarged cross-sectional waveforms of the jig body surface before and after the etching process, respectively.

The sharp peaks a ₁ , a _2, ... Of the satin-like irregularities formed by the honing process as shown in FIG. 2 (a) are smoothed by etching, and the sharp portions as shown in FIG. 2 (b). As a result, a less uneven portion is formed. For this reason, there is little generation of flaws in the sintered body.

From the results shown in Table 1, when using a firing jig having a surface roughness of 20 μm or more by performing an etching treatment after roughening treatment as in Examples 1 to 4, fusion, flaws, uneven color, and discoloration are caused. It is clear that a high quality sintered body can be manufactured with a high yield with a small number of defects such as defects.

On the other hand, when using the firing jigs of Comparative Examples 1 and 2 in which the surface roughness (Rz) is less than 20 μm and the etching process is not performed, many defects occur, and the quality, yield, and manufacturing efficiency are all reduced. Turns out.

Examples 5-6, Comparative Examples 3-4 As Examples 5-6, a W plate having a thickness of 2 mm was subjected to a roughening treatment using Al ₂ O ₃ particles as a honing material, and the surface roughness (Rz) was 7
The surface roughness (Rz) was adjusted to 5.1 to 45.6 μm and immersed in a nitric acid solution for 5 minutes to obtain a surface roughness (Rz) of 65.3 to 4 μm.
A firing jig was formed at 2.3 μm. Using the obtained firing jig, the ceramic molded body was fired in the same manner as in Examples 1 to 4, and the number of generated defects was measured.

On the other hand, as Comparative Examples 3 and 4, a jig which was subjected to only roughening treatment and not subjected to etching treatment was adjusted in the same manner as in Examples 5 and 6, and subjected to a firing operation in the same manner, and the number of defects was measured. The result was obtained.

As is clear from the results shown in Table 1, even when the jig body was formed of a W plate, the sharpening apex was smoothed by etching and the honing material was removed by dissolving and removing the honing material. Tools give good results.

On the other hand, in the firing jigs of Comparative Examples 3 and 4 in which the etching treatment was not performed, although the fusion was small, the number of flaws was large and the yield of the product was lowered.

Example 7, after the roughening treatment was carried out surface roughness of SiC particles in the M ₀ thick plate 3mm Comparative Example 5 Example 7 as honing material was prepared jig body of 42.1Myuemu, barrels smoothing Polishing was performed to adjust the surface roughness to 38.1 μm. The barrel polishing treatment was performed by throwing three jig bodies into a barrel filled with 50 kg of alumina particles (MT-6) and applying rotational vibration for 10 minutes to polish the surface.

On the other hand, as Comparative Example 5, a jig body roughened in the same manner as in Example 7 was prepared.

A firing operation was performed using the firing jigs obtained in Example 7 and Comparative Example 5 under the same conditions as in Examples 1 to 4, and the number of defects in the obtained sintered body was measured. The results shown in the table were obtained.

The results shown in Table 1 demonstrate that the sharp apex of the jig main body surface is smoothed even by the barrel polishing treatment, so that a sintered body with less flaws can be obtained.

Each M ₀ plate surface of 3mm thick as Example 8-9 following Examples 8, 9 M ₀
Powder and W powder are roughened using a honing material.
The surface roughness was adjusted to 35.5 μm and 36.5 μm, and then immersed in a commercially available nitric acid solution for 5 minutes to perform a smoothing treatment, thereby preparing a firing jig having a surface roughness of 32.1 μm and 33.5 μm. Using the obtained firing jig, the ceramic molded body was fired under the same conditions as in Examples 1 to 4, and the number of defects of the obtained sintered body was measured to obtain the results shown in Table 1.

From the results in Table 1, M ₀ powder or W was used as the honing material.
In firing jigs that have been roughened using powder,
It can be seen that since the reaction of the honing material remaining in the roughening treatment does not occur at the time of firing, no unevenness or discoloration of the sintered body occurs and a sintered body having extremely excellent quality can be obtained.

In the above Examples 1 to 9, an example in which an etching method or a barrel polishing method is used as a smoothing method is shown, but glass beads having a particle size of about 80 # are applied at a pressure of 4 to 6 kg / cm.
^A similar effect could be obtained by blowing the jig body surface using about ² high-pressure air.

〔The invention's effect〕

As described above, according to the ceramic firing jig and the method for manufacturing the same according to the present invention, since the jig body is formed of a single element of M ₀ or W or an alloy thereof, the jig is heated to a high firing temperature. Also, there is little possibility that the ceramic molded product and the jig are welded.

Further, since the sharp apex of the convex portion on the surface of the jig body is formed in a curved shape, there is no possibility of scratching the ceramic molded body.

Furthermore, since the surface roughness is set to 20 μm or more, the contact area between the ceramic molded product and the firing jig is small, seizure is prevented, and a space where the atmosphere in the furnace is sufficiently circulated between the two is secured. You. Therefore, non-uniformity of the density of the sintered body does not occur, color unevenness and discoloration can be prevented, and the yield and quality of the product can be significantly improved.

Further, it is possible to thin the jig body with a metal material of high strength such as M ₀ and W, it is possible to increase the number of jigs which can be accommodated in a firing furnace in a single firing operation, ceramic products Can greatly improve the production efficiency.

In the method of manufacturing a firing jig, the roughened jig body is further subjected to a smoothing process by an etching process or a barrel polishing process, so that the sharp tip generated by the roughening process is more effectively processed. It is possible to smooth. Therefore, the quality and yield of the product can be significantly improved without causing any scratches on the product.

In particular, when the etching method is used, reactive abrasive grains, such as Al ₂ C ₃ and SiC, remaining on the jig surface due to the roughening treatment are effectively dissolved and removed, resulting in discoloration and color during firing. The occurrence of unevenness can be effectively prevented.

In addition, the highly reactive Al ₂ O
By using a single powder of M ₀ or W or an alloy powder thereof without using ₃ or SiC, discoloration and uneven color can be almost completely eliminated.

[Brief description of the drawings]

FIG. 1 is a graph showing the relationship between the etching time and the remaining amount of the honing material, and FIGS. 2 (a) and 2 (b) are sectional waveform diagrams of the jig body surface before and after the etching process, respectively. a ₁ , a ₂ …… a sharp peak.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tomoaki Ikura 8 Shinsugita-cho, Isogo-ku, Yokohama-shi, Kanagawa Prefecture Inside the Toshiba Yokohama Office (72) Inventor Noboru Kitamori 8 Shinsugita-cho, Isogo-ku, Yokohama-shi, Kanagawa Toshiba Corporation (56) References JP-A-52-58713 (JP, A) JP-A-63-176990 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) C04B 35/64

Claims (2)

(57) [Claims] An uneven part is formed on the surface of a jig body made of a single element of M ₀ or W or an alloy thereof, and the sharp apex of the convex part is formed in a curved surface so as to reduce the surface roughness of the jig body. A ceramic firing jig having a point average roughness set to 20 μm or more. 2. A jig body made of M ₀ or W alone or an alloy thereof is formed, and the surface of the jig body is roughened by colliding fine abrasive grains with the surface of the jig body. A method for manufacturing a ceramic firing jig, comprising performing a smoothing process for making a sharpened tip non-sharpened.