JP4023774B2 - Heat-resistant jig - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a heat-resistant jig used when performing sintering or heat treatment of metal or ceramics.
[0002]
[Prior art]
Conventionally, a rare earth-alumina composite, which is one of chemically stable rare earth-containing oxide sintered bodies, is used to suppress the reaction between the product and the sintering jig during sintering or heat treatment of metal or ceramics. It has been proposed to use an oxide sintered body (see JP-A-5-85821). However, these rare earth-containing oxide sintered bodies (rare earth-alumina composite oxide sintered bodies) have low mechanical strength, particularly low toughness, and have a problem of frequent cracking during use, and have not been put into practical use.
[0003]
In order to compensate for this drawback, it has been studied to coat Y ₂ O ₃ or the like by using a thinning technique such as thermal spraying. For example, as a tray for sintering cermet at 1300 to 1500 ° C., a tray characterized in that a base material made of graphite is coated with Y ₂ O ₃ containing 20% by weight or less of ZrO ₂ has been proposed. (See Special Table 2000-509102). However, although the tray described in the above publication has a high mechanical strength, yttrium oxide and graphite react at 1400 ° C. or higher to change to yttrium carbide, or the thermal expansion coefficients of the oxide layer and the substrate match. Otherwise, there is a problem of peeling.
[0004]
Therefore, by providing a metal layer of Mo, W, Nb, Zr, Ta, etc. in the middle between yttrium oxide and graphite, it has been proposed to suppress the reaction between yttrium oxide and graphite and alleviate the difference in thermal expansion coefficient. ing. However, providing an intermediate layer increases the number of processes and leads to an increase in cost, and the difference in thermal expansion coefficient between the intermediate layer and yttrium oxide remains, which is not a fundamental solution.
[0005]
[Problems to be solved by the invention]
The present invention was made to improve the above circumstances, and has a high mechanical strength, excellent heat resistance, corrosion resistance, and non-reactivity when sintering or heat-treating metal, ceramics, or cermets. An object is to provide an inexpensive jig.
[0006]
[Means for Solving the Problems]
As a result of intensive studies to achieve the above object, the present inventor has found that the part in contact with the product is a rare earth element-containing oxide sintered body, the remaining part is a separate material, two or more materials and It has been found that the heat-resistant jig having a superposed structure has mechanical strength when performing sintering or heat treatment of metal or ceramics or cermet, and provides excellent heat resistance, corrosion resistance, and non-reactivity, The present invention has been reached.
[0007]
Therefore, the present invention provides a rare earth element-containing oxide sintered body member having a thickness of 0.5 mm or more and 10 mm or less, carbon and Al ₂ O in a heat resistant jig used for sintering or heat treatment of metal, ceramics or cermet. ₃ , BN, SiO ₂ , ZrO ₂ , a member comprising one or more selected from the group consisting of mullite and cordierite, and the rare earth element-containing oxide sintered member is the metal or ceramic or Provided is a heat-resistant jig characterized by contacting with a cermet.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in more detail.
The heat-resistant jig of the present invention is a tool used when sintering or heat-treating a metal, ceramics or cermet to be a product, and is used for the purpose of holding or fixing the product. Examples include setters, sheaths, trays, mortars, crucibles and the like. In particular, it is effective when the product is sintered in a vacuum, an inert atmosphere or a reducing atmosphere, but it can also be used in the atmosphere or an oxidizing atmosphere. It is necessary to optimize by changing the rare earth-containing oxide sintered body and the base material depending on the product, the operating temperature, and the type of gas used.
[0009]
The rare earth-containing oxide sintered body used in the present invention is an oxide sintered body containing a rare earth element selected from rare earth elements having atomic numbers 39 and 57 to 71, for example, a rare earth oxide sintered body. . In the case of the rare earth oxide sintered body, the rare earth is preferably medium or heavy rare earth such as Y, Gd, Er, Tm, Ln from the viewpoint of corrosion resistance. In addition to the rare earth, a metal oxide selected from 3A group to 8 group may be mixed at a ratio of 50% by weight or less. More preferably, in addition to the oxide containing a rare earth element, an oxide of one or more metals selected from the group consisting of Al, Mn, Si, Zr, and V may be used. In the case of the above complex oxide, light / medium rare earths such as Y, La, Ce, Nd, and Sm are economically preferable.
[0010]
The heat-resistant jig of the present invention comprises a rare earth element-containing oxide sintered body, carbon, Al ₂ O ₃ , AlN ( reference example ) , BN, SiO ₂ , SiC ( reference example ) , Si ₃ N ₄ ( Reference Example ) has a structure in which ZrO ₂ , a member having a material selected from mullite and cordierite are stacked. As a result, the rare earth element-containing oxide sintered body exhibits corrosion resistance and non-reactivity with the product. Carbon, Al ₂ O ₃ , AlN ( reference example ) , BN, SiO ₂ , SiC ( reference example ) , Si ₃ N ₄ (reference example), a member having a material selected from ZrO ₂ is compensated mechanical strength, resistance to thermal shock resistance. Especially when products are sintered under vacuum, inert atmosphere or reducing atmosphere, non-oxide materials such as carbon, AlN ( reference example ) , BN, SiC ( reference example ) , Si ₃ N ₄ ( reference example ) are used. It is valid. When sintering products in air or in an oxidizing atmosphere, oxide-based materials such as Al ₂ O ₃ , SiO ₂ , ZrO ₂ are effective. When the operating temperature is low, AlN ( reference example ) , BN Non-oxide materials such as SiC ( reference example ) and Si ₃ N ₄ ( reference example ) can be used.
[0011]
The thickness of the rare earth element-containing oxide sintered body used in the present invention is preferably 0.5 mm or more and 10 mm or less, more preferably 1 mm or more and 5 mm or less. If the thickness is less than 0.5 mm, it is too thin, the strength is a problem, and it is difficult to produce. On the other hand, if it is thicker than 10 mm, the material is wasted economically.
[0012]
The relative density of the rare earth element-containing oxide sintered body member used in the present invention is preferably 50% or more. More preferably, it is 80% or more and 95% or less. Relative density is a percentage of the density of the sintered body with respect to the true density. The true density can be measured using a true density meter (ulti-pycnometer), and the density of the sintered body is determined using the Archimedes method. Can be measured. If the relative density is less than 50%, the mechanical strength is weak and the porosity is high, which may cause a problem in that adsorbed gas / moisture may be released when the product is processed under vacuum or inert atmosphere.
[0013]
It is preferable that the rare earth element-containing oxide sintered member is divided so that the surface area is 1000 cm ² or less. More preferably, 50 cm ² or more and 600 cm ² or less. The surface area is the total surface area of the sintered body and can be calculated by measuring the shape. The larger the shape of the rare earth element-containing oxide sintered body member, the lower the mechanical strength and thermal shock resistance. When the surface area exceeds 1,000 cm ² , cracks increase due to thermal shock, which is a problem in use.
[0014]
In order to make the product easily shrink when the product is sintered, the surface of the rare earth element-containing oxide sintered member is preferably uneven. Preferably, regular irregularities with a depth of 0.1 mm or more and 5 mm or less are desirable. The pitch width of the unevenness is determined by the shape of the product placed on top. For example, when the product is a rectangular parallelepiped, a length of about 1/3 or less of one side of the product is preferable. The pitch of the unevenness is preferably 1 mm or more. The convex shape is preferably a square. In addition, when the product is a cylinder, it is desirable to have irregularities so that the cylinder does not roll, and the convex shape is preferably a triangle.
[0015]
As a method for producing the rare earth-containing oxide sintered member, a general ceramic production method may be used. The rare earth-containing oxide is sintered at a temperature below the melting point, particularly at 800 to 1800 ° C. in the atmosphere, vacuum or inert atmosphere. In other words, particles are grown and attached to each other, grain growth is performed, density is increased, and production is performed.
In the case of a flat plate, molding by slip casting is preferable. In the case of slip casting, a molded article with irregularities is obtained by casting into a mold having irregularities. In the case of a cylindrical shape, molding by CIP (cold isostatic pressing) is preferable. CIP is preferably polished and cut after sintering. The formed body is sintered to obtain a rare earth-containing oxide sintered body member.
[0016]
FIG. 1 includes a rare earth-containing oxide sintered body member 2 and one or more selected from carbon, Al ₂ O ₃ , AlN, BN, SiO ₂ , SiC, Si ₃ N ₄ , ZrO ₂ , mullite, and cordierite. In the case of a flat plate shape such as a tray, the rare earth-containing oxide sintered body is formed by making the base material 1 concave and placing the rare earth-containing oxide sintered body 2 on the concave portion. This is preferable because it prevents slipping. The product 3 is placed on the rare earth-containing oxide sintered body 2 and sintered or heat-treated. In the shape of a cylinder or a rectangular parallelepiped such as a mortar or crucible, the rare earth-containing oxide sintered body member is desirably divided into a bottom plate, a side surface, and a lid. This is because stress is applied to the contact point between the bottom plate and the side surface, and it is easy to cause cracking, so that cracking can be prevented by dividing. FIG. 1 shows an example in which a sintered body 2 is divided into two parts 2a and 2b and two products 3a and 3b are placed thereon.
[0017]
FIG. 2 shows a corrugated plate (convex shape) formed on a member 4 including one or more selected from carbon, Al ₂ O ₃ , AlN, BN, SiO ₂ , SiC, Si ₃ N ₄ , ZrO ₂ , mullite, and cordierite. ) And a cylindrical product 6 and a rectangular parallelepiped product 7 are mounted thereon.
[0018]
When carbon is used, the density of carbon is preferably 1.5 g / cm ³ or more. The true density of carbon is 2.26 g / cm ³ . If the density of the substrate is less than 1.5 g / cm ³ , the density is small and strong against thermal shock, but the porosity is high and it is easy to adsorb moisture and carbon dioxide in the atmosphere. Carbon dioxide may be released. In a vacuum or reducing atmosphere at a high temperature of 1600 ° C. or higher, carbon may react with yttrium to partially become yttrium carbide, resulting in weak mechanical strength. When used in a vacuum or a reducing atmosphere at a high temperature of 1600 ° C. or higher, it is preferable to coat the high-melting point metal such as Mo or W on the intermediate layer by thermal spraying as an intermediate layer.
[0019]
Any metal, ceramic, or cermet may be used as long as it is obtained by sintering or heat treatment. Cermet is a composite material of metal and ceramics, and many are made by mixing, molding and sintering powders of both.
As a metal, it is effective as a jig for powder sintering of a reactive metal. Specifically, as a material to be placed on a sintered member, a Cr alloy, a Ni alloy, a titanium alloy, a rare earth-transition metal alloy In particular, Sb-Dy-Fe alloys used in the manufacture of Sm-Co alloys, Nd-Fe-B alloys, Sm-Fe-N alloys used in sintered magnets and sintered magnetostrictive materials, and sintered regenerative heat storage In manufacturing an Er—Ni alloy used as a material, a member such as a jig of the present invention is effective.
Further, as the ceramic or cermet, tungsten carbide-Co-Ni, silicon carbide, silicon nitride, titanium boride, aluminum oxide, rare earth oxide, lithium manganese composite oxide, rare earth composite oxide (rare earth-aluminum composite oxide, Rare earth-titanium composite oxide, rare earth-manganese composite oxide), and the like. In particular, in the production of translucent ceramics such as rare earth-aluminum composite oxide (YAG) and cemented carbide such as tungsten carbide, the treatment of the present invention. A member such as a tool is effective.
[0020]
In particular, when a light-transmitting ceramic such as YAG is sintered, it is processed at 1600 to 1800 ° C. in a vacuum, an inert atmosphere, or a weak reducing atmosphere. What is not is a rare earth oxide sintered body. When the rare earth oxide is heated to 1500 ° C. or higher with carbon, it may easily become a carbide. It is preferable to use a jig in which a rare earth oxide sintered body is combined on a material obtained by coating carbon with Mo, Ta, or W.
[0021]
【Example】
EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated concretely, this invention is not restrict | limited to the following Example.
Example 1
3 g of peptizer (RA-20A manufactured by Matsumoto Yushi Co., Ltd.) is dissolved in 200 g of pure water, and 500 g of yttrium oxide (RU-PB product manufactured by Shin-Etsu Chemical Co., Ltd.) is gradually added to form a slurry. This slurry is poured into a gypsum mold (a mold in which 2 mm irregularities are provided on the surface at a pitch of 3 mm) to form a molded body. The molded body is dried and then sintered in the atmosphere at 1500 ° C. for 2 hours. The resulting concavo-convex yttrium oxide sintered body is processed to 100 × 50 × 2 mm. The density of the sintered body was measured by the Archimedes method, and the relative density was calculated. The relative density to the true density was 55%. Carbon having a shape of 120 × 120 × 5 mm (ER-53 manufactured by Nippon Carbon Co., Ltd.) was processed into a concave shape of 100 × 100 × 3 mm as shown in FIG. Two 100 × 50 × 2 mm yttrium oxide sintered bodies were placed in the recesses to produce a sintering tray. A Ti sintered body was placed on the tray, heated at 300 ° C./hr in vacuum, sintered at 1500 ° C. for 2 hours, the heater was turned off, and the furnace was cooled. The appearance of the product and the member after repeating this three times was observed. No contamination from the tray was detected in the product, and there were no cracks. The contamination state was measured by EPMA analysis (electronic microanalyzer).
[0022]
Example 2
3 g of peptizer (RA-20A manufactured by Matsumoto Yushi Co., Ltd.) is dissolved in 200 g of pure water, and 500 g of lanthanum oxide-aluminum oxide composite oxide (LAM manufactured by Shin-Etsu Chemical Co., Ltd.) is gradually added to form a slurry. This slurry is poured into a gypsum mold similar to that in Example 1 to produce a molded body. The molded body is dried and then sintered in the atmosphere at 1500 ° C. for 2 hours. The resulting sintered body is processed to 100 × 50 × 2 mm. The density of the sintered body was measured by the Archimedes method, and the relative density was calculated. The relative density was 65%. Similarly to Example 1, 120 × 120 × 5 mm-shaped carbon (ER-53 manufactured by Nippon Carbon Co., Ltd.) was formed into a concave shape of 100 × 100 × 3 mm and processed. Two 100 × 50 × 2 mm yttrium oxide-aluminum oxide composite oxide sintered bodies were placed thereon to produce a sintering tray. The Tb—Dy—Fe alloy sintered body was placed on the tray, heated at 300 ° C./hour in vacuum, sintered at 1200 ° C. for 2 hours, the heater was turned off, and the furnace was cooled. The appearance of the product and the member after repeating this three times was observed. No contamination from the tray was detected in the product, and there were no cracks.
[0023]
Comparative Example 1
6 g of peptizer (RA-20A manufactured by Matsumoto Yushi Co., Ltd.) is dissolved in 400 g of pure water, and 1 kg of yttrium oxide (RU-PB product manufactured by Shin-Etsu Chemical Co., Ltd.) is gradually added to form a slurry. This slurry is poured into a gypsum mold (a mold without unevenness) to form a molded body. The molded body is dried and then sintered at 1800 ° C. for 2 hours in the air. The resulting sintered body is processed to 120 × 120 × 8 mm. The density of the sintered body was measured by the Archimedes method, and the relative density was calculated. The relative density was 99%. The resulting sintered body is used as a sintering tray. A tungsten carbide-Co sintered body was placed on the tray, heated at 300 ° C./hour in vacuum, sintered at 1500 ° C. for 2 hours, the heater was turned off, and the furnace was cooled. The appearance of the product and member was observed. No contamination from the tray was detected on the product, but it cracked a second time.
[0024]
Comparative Example 2
120 × 120 × 5 mm carbon (ER-53 manufactured by Nippon Carbon Co., Ltd.) is used as a sintering tray. A Ti sintered body was placed on the tray, heated in vacuum at 300 ° C./hour, sintered at 1500 ° C. for 2 hours, the heater was turned off, and the furnace was cooled. The appearance of the product and the member after repeating this three times was observed. There was no cracking of the sintering tray, but carbon was detected in the product.
[0025]
The members of Examples 1 and 2 were not changed before and after sintering, and there was no contamination from the members to the product. On the other hand, the member of Comparative Example 1 was cracked by the stress considered to be a thermal shock, although there was no contamination from the member to the product. Moreover, although the member of the comparative example 2 was not broken, there was contamination from the member to the product.
[0026]
【The invention's effect】
The member of the present invention has good non-reactivity with a product, is excellent in heat resistance, mechanical strength, and thermal shock, and is effectively used for sintering or heat-treating metal, ceramics or cermet.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a heat-resistant jig and a product of the present invention.
FIG. 2 is a cross-sectional view showing a heat-resistant jig and product of the present invention.
[Explanation of symbols]
1 A member comprising one or more selected from carbon, Al ₂ O ₃ , AlN, BN, SiO ₂ , SiC, Si ₃ N ₄ , ZrO ₂ , mullite, cordierite 2 Rare earth element-containing oxide sintered member 2a Rare earth element-containing oxide sintered body member 2b Rare earth element-containing oxide sintered body member 3 Product 3a Product 3b Product 4 Carbon, Al ₂ O ₃ , AlN, BN, SiO ₂ , SiC, Si ₃ N ₄ , ZrO ₂ , Member comprising at least one selected from mullite and cordierite 5 Rare earth element-containing oxide sintered member 6 Product 7 Product

Claims (5)

In a heat-resistant jig used for sintering or heat treatment of metal, ceramics or cermet, a rare earth element-containing oxide sintered body member having a thickness of 0.5 mm or more and 10 mm or less, carbon, Al ₂ O ₃ , BN and SiO ₂ And a member comprising one or more selected from the group consisting of ZrO ₂ , mullite and cordierite, and the rare earth element-containing oxide sintered body member is in contact with the metal, ceramics or cermet Features a heat-resistant jig. The heat-resistant jig according to claim 1, wherein the rare earth element-containing oxide sintered body member is placed on the carbon member containing carbon . The rare earth-containing oxide sintered body member, the heat resistance jig according to 請 Motomeko 1 or claim 2 that have a relative density of 50% or more. The heat-resistant jig according to any one of claims 1 to 3, wherein the rare earth element-containing oxide sintered body member is divided so as to have a surface area of 1,000 cm ² or less . The heat-resistant jig according to any one of claims 1 to 4, wherein the rare earth element-containing oxide sintered body member has irregularities having a pitch of 1 mm or more on the surface of the rare earth element-containing oxide sintered body.

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