JP2002362985A - Member coated with ceramic and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a member coated with a ceramic which is obtained by coating a silicon carbide ceramic base body with the ceramic, has excellent heat resistance and oxidation resistance, and can be used as a firing tool without causing exfoliation and warpages of the coating film. SOLUTION: The member coated with the ceramic is obtained by coating a granulated material of zircon onto the surface of the silicon carbide ceramic base body and further coating zircon onto the coated granulated material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a ceramic coated member having excellent heat resistance and durability, and a method for producing the same. In particular, a jig for firing various parts, particularly a ceramic coating member suitable for a shelf board or the like for supporting the parts to be heat-treated in a heat treatment step of firing electronic parts or the like in an electric furnace and manufacturing the same. For how to.

[0002]

2. Description of the Related Art Conventionally, silicon carbide, silicon nitride, and the like are known as high-temperature heat-resistant structural materials used under severe conditions at high temperatures. However, although silicon carbide or silicon nitride is a high temperature heat-resistant material, a part of the material surface is oxidized into silicon dioxide by high-temperature oxidation or the like, and its heat resistance, thermal shock resistance, corrosion resistance, and the like are deteriorated. For this reason, for example, as disclosed in Japanese Patent Application Laid-Open No. 62-72582, a method has been proposed in which the surface is coated with zirconia as an oxide ceramic by plasma spraying for the purpose of improving the durability and oxidation resistance of the silicon nitride substrate. ing. Also, JP-A-8-73
No. 288 discloses that a ceramic substrate of silicon nitride or silicon carbide is coated with silicon nitride or silicon carbide by CVD (chemical vapor deposition), a zirconia paste or an alumina paste is applied thereto, and heat treatment is performed at a high temperature. A method for forming an object coating is disclosed.

However, when the surface of a silicon carbide substrate is coated with a ceramic by such a method as plasma spraying or CVD, peeling between the substrate and the coating film due to a difference in the coefficient of thermal expansion between the substrate and the oxide ceramic causes a problem. Residual local thermal strain or the like causes peeling or cracking from the ceramic substrate with long-term use, making it unsuitable as a firing jig, particularly a firing shelf for electronic components and the like.

[0004]

As described above, silicon carbide is a high-temperature-resistant ceramic material. However, silicon dioxide produced by high-temperature oxidation or the like causes volume expansion, resulting in a decrease in durability. There is a problem that it becomes glassy and contaminates the substrate surface, and it is important to stably solve these problems over a long period of time.

[0005]

SUMMARY OF THE INVENTION According to the present invention, a surface of a silicon carbide ceramic substrate is coated with granulated zircon,
A ceramic coating member further comprising a zircon coating thereon.

Another object of the present invention is that the ceramic coated member can be used repeatedly in a heat treatment step.

Further, the present invention is a method for producing a ceramic coating member, comprising coating a surface of a silicon carbide-based ceramic substrate with a granulated zircon, and further coating zircon thereon.

The present invention provides a method for producing a ceramic coated member, comprising coating a surface of a silicon carbide ceramic substrate with a zircon dispersion, heating and drying, further coating a zircon-containing slurry, and heating and drying. Is the way.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1, a ceramic coating member according to the present invention comprises a ceramic substrate 1, a zircon granulated coating layer 2, and a zircon coated layer 3 thereon. .

The silicon carbide-based ceramic as the ceramic substrate used in the present invention has a basic composition of Si
C means ceramic. However, other ceramics, for example, carbides such as WC, S
nitrides such as i ₃ N ₄ , MgO, Al ₂ O ₃ , Y ₂ O ₃
And the like, or may be a composite oxide composition of these. In particular, in the case of a shelf plate for firing or heat treatment, that is, a support member or the like for an object to be heat-treated, a large amount of these other ceramics may be contained. Examples of the silicon carbide-based ceramic substrate include a reaction sintered body, a normal pressure sintered body, a pressure sintered body, a hot press sintered body, and a hot isostatic pressing (HIP) method.
atic Press) A sintered body, a recrystallized body, or the like is used. The shape may be a plate, a rod, a board, a sphere, a ring, a trapezoid, or any other shape. For use as a jig for heat treatment, a jig having a thickness of 3 to 20 mm is preferable.

The silicon carbide ceramic substrate is coated with granulated zircon. The zircon, originally refers to silicate minerals zirconium narrowly, for example _SiO 2 34% before and _after, with tetragonal structure of ZrO 2 64-65% before and after the composition, the melting point of the neat refers to 2550 ° C., etc. However, in the present invention, it refers to zirconium silicate widely represented by the chemical formula of ZrSiO. The preferred zircon in the present invention is zirconium silicate, which is also registered as a chemical substance (1) -550, and is also called zircon flour or zircon powder. Etc. are commercially available. The theoretical composition of zircon is 34% of SiO _{2 and} 64% of ZrO ₂ , but these contain a small amount of Al ₂ O ₃ , Fe ₂ O ₃ , T
Although iO _{2 and the} like are included, they can be used without any problem. The average particle size of the zircon particles is preferably from 0.01 mm to 0.5 mm from the viewpoint of the formation of granules and the preparation of a zircon slurry.

The silicon carbide ceramic substrate is coated with granulated zircon. When the zircon has a particle size in the above range, the granulated zircon spontaneously aggregates into a granulated product. The surface of the porous ceramic substrate may be coated with a dispersion of zircon, preferably by spray coating or the like. In particular, it is preferable that a small amount of water be added to the zircon and, if necessary, silica (silicon dioxide) and colloidal silica be blended to spray-coat a porous granulated material having a diameter of about 0.3 to 3 mm. After coating, it is preferable to dry at about 200 ° C. or higher to increase the adhesion between the silicon carbide substrate and zircon. The coating of zircon granules is 0.01-0.2 m
m is preferable.

Then, after drying by heating, a slurry containing zircon is further applied. Preferably, a slurry composed of zircon, silicon dioxide and a binder is applied.
A preferred slurry composition is 90 to 9% by weight zircon.
6%, 4 to 10% of silicon dioxide, and 0.01 to 0.05% of a binder such as methylcellulose. Colloidal silica may be further added to this. The coating thickness is 0.0
It is preferably about 5 to 0.5 mm.

The coating process is repeated until a desired thickness is obtained.
Radiant heating at 300 ° C. Then 1000 to 1500
A heat treatment at a temperature of ° C. provides a ceramic coating member having excellent oxidation resistance and durability. The total thickness of the coating layer is preferably 0.1 to 1 mm, particularly 0.2 to 0.5 mm
It is preferred that

[0015] The ceramic coating member of the present invention comprises:
Unlike the conventional method of plasma spraying or CVD coating of zirconia, etc., the layer coated with zircon granules is further coated with zircon to form a strong and extremely stable coating layer on the silicon carbide substrate. It can be used as various jigs used for heat treatment at a high temperature. It has excellent heat resistance, thermal shock resistance and corrosion resistance, so that it can be repeatedly used at high temperatures for a long period of time, and the zircon coating layer is an extremely stable oxide layer. Does not migrate. Therefore, in particular,
It is suitable as a support member such as a shelf for an object to be processed when baking, firing, and heat-treating an electronic component or the like in an electric furnace.

[0016]

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

Example 1 After silicon carbide powder having an average particle size of 2 × 10 ⁻⁶ m was uniaxially pressed at a pressure of 9.8 × 10 ⁵ Pa, the formed body was subjected to 1650 in an inert atmosphere. It was recrystallized at a temperature of 1 hour to obtain a silicon carbide substrate.

Next, 95% (weight%, the same applies hereinafter) of zircon flour, silicon dioxide 3
%, Water 1%, and colloidal silica 1%, were spray-coated, and then dried at 200 ° C. to form a zircon granule layer having a thickness of about 0.1 mm.
Then, 100% of a composition consisting of 93% zircon flour, 6% silicon dioxide and 0.02% methyl cellulose,
A slurry containing 60% of colloidal silica has a thickness of 0.1 mm.
It was applied until it became 2 mm. Thereafter, the resultant was subjected to electric heat radiation drying at 250 ° C. to obtain a ceramic coated member.

After holding the ceramic coated member in an atmosphere at a furnace temperature of 1200 ° C. for one hour, it is taken out of the furnace, left at room temperature for 30 minutes, and again in an atmosphere at a furnace temperature of 1200 ° C. for one hour. The holding operation was repeated for 24 hours.

As a result of observing the surface condition of the ceramic coated member, no peeling of the zircon coating layer was found.

Comparative Example 1 In Example 1, no coating treatment was performed on the silicon carbide substrate. The result of the durability test performed in the same manner as in Example 1 showed that oxidation was caused on the surface of the ceramic substrate and glassy silicon dioxide was precipitated.

Comparative Example 2 The same procedure as in Example 1 was repeated except that the zircon coating was replaced with an alumina coating. As a result of the durability test performed in the same manner as in Example 1, peeling occurred in the alumina coating layer on the surface of the ceramic substrate.

[0023]

The ceramic coated member of the present invention uses zircon, which has a coefficient of thermal expansion similar to that of silicon carbide. Also, when forming the coated member, the surface of the substrate is coated with the zircon granules once, and then coated with zircon. Because the slurry is coated, the adhesion between the silicon carbide substrate and the coating layer,
It provides a ceramic coating member that has a large adhesive force, can prevent peeling of the coating during firing, warpage and diffusion of impurities from the substrate, and has excellent heat resistance, thermal shock resistance, and corrosion resistance. It is useful as a tool, especially as a shelf for firing and heat treatment.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of a ceramic coating member of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ceramic base 2 Coating layer 3 Coating layer

Claims (4)

[Claims] 1. A ceramic coating member comprising: a surface of a silicon carbide-based ceramic substrate coated with granulated zircon, and further coated with zircon. 2. The ceramic coated member according to claim 1, which can be used repeatedly in the heat treatment step. 3. A method for producing a ceramic coated member, comprising: coating a surface of a silicon carbide ceramic substrate with a zircon granule; and coating zircon thereon. 4. A method for producing a ceramic coating member, comprising coating a surface of a silicon carbide ceramic substrate with a zircon dispersion, heating and drying, coating a zircon-containing slurry, and heating and drying.