KR102061269B1 - Mold system for hot pressed ceramic with cavity - Google Patents

Abstract

The present invention relates to a mold device and a hollow structure ceramic plate produced using the same and, more specifically, to a mold device for hot pressurized sintering to produce a hollow structure ceramic plate, which prevents the breakage caused by thermal expansion among a ceramic plate, a core, a sleeve and a housing generated during the production of the hollow structure ceramic plate by optimizing a material selection and a shape of the graphite constituting the mold device to produce a hollow structure and to a hollow structure ceramic plate produced using the same.

Description

Mold apparatus for hot press sintering for manufacturing hollow structure ceramic plate and hollow structure ceramic plate manufactured using the same {MOLD SYSTEM FOR HOT PRESSED CERAMIC WITH CAVITY}

The present invention relates to a mold apparatus and a hollow structure ceramic plate manufactured using the same, and more particularly, to a ceramic plate, a core, which is generated when the hollow structure ceramic plate is manufactured by optimizing the material selection and shape of the graphite constituting the mold apparatus. The present invention relates to a mold apparatus for hot press sintering for the production of a hollow structural ceramic plate to prevent breakage due to a thermal expansion difference between a sleeve and a housing, and to produce a hollow structural shape, and a hollow structural ceramic plate manufactured using the same.

With the rapid development of science and technology, modern technology and industry strive to contain more precise and more functions. To meet this, there is a need for materials and tools of higher physical, thermal and chemical properties, thereby increasing the demand for non-oxide ceramics.

Such non-oxide-based ceramics have strong covalent bonds in terms of material properties, and are known to have a considerable difficulty in sintering because of the large energy of grain boundaries and a low diffusion rate of grain boundaries.

Accordingly, high temperature and a special sintering technique are required to obtain dense non-oxide ceramics, and methods for sintering the same include non-pressure sintering, reaction bonded sintering, and hot press sintering. -Pressed Sintering).

These sintering methods have advantages and disadvantages, but the hot press sintering method is a method of applying pressure together with the temperature required for the sintering of non-oxide-based ceramics. It is emerging as the best way to achieve densification close to density.

Ceramic plates manufactured by hot pressure sintering are mostly manufactured in square and circular flat plate shapes. The hot pressure sintering method is a method of directly applying pressure to a ceramic plate at a high temperature, and may be damaged due to residual stress generated during sintering or cooling, and difference in thermal expansion between the ceramic plate and the mold. Due to the imbalance of the transmission, the generation of defects according to the shape, it is difficult to manufacture in the form of a hollow structure such as a donut or ring.

If such a shape is required, it must be manufactured by further processing. In particular, in order to manufacture a ceramic plate manufactured by hot pressure sintering in a hollow structure, a perforation should be performed in the center of the ceramic. Due to the high mechanical properties, workability is degraded, which is very likely to cause breakage.

In addition, even though processing is possible, high special processing costs are incurred due to the high mechanical properties of hot-pressing sintered ceramics, which also generates constraints on the thickness of the ceramics. This leads to an increase in the cost of ceramics and a decrease in production efficiency.

For these inefficient reasons, the utilization of the hollow structure shape of the ceramics manufactured by hot pressure sintering is limited in some cases.

However, as the industrial development increases the demand of ceramics manufactured by hot pressure sintering with a hollow structure, the shape of the ceramic itself needs to take a hollow structure.

The present invention is to meet the above requirements, by optimizing the material selection and shape of the graphite constituting the mold device to prevent damage caused by thermal expansion between the ceramic plate, core, sleeve and housing generated during the manufacture of the hollow structure ceramic plate It is an object of the present invention to provide a mold apparatus for hot press sintering for the production of a hollow structure ceramic plate to prevent the hollow structure shape to be produced, and a hollow structure ceramic plate manufactured using the same.

Features of the present invention for achieving the above object,

A mold apparatus for hot press sintering for manufacturing a hollow ceramic plate manufactured by hot press sintering using a powdery ceramic raw material, comprising: a support plate made of graphite; The outer surface is made of graphite in the same shape as that of the hole and is installed in the center of the base plate to form a hollow (cavity) selected from triangular, square, polygonal and circular in the ceramic plate to have a hollow structure. A core; It is installed on the upper surface of the support plate, spaced apart from the core to form a space to control the size of the ceramic plate, the ceramic plate is produced in any one form selected from triangular, square, polygonal, round, made of graphite A sleeve; A housing installed outside the sleeve on an upper surface of the support plate to fix the sleeve, the housing being made of graphite; A lower punch made of graphite in the same shape as the space part and positioned below the space part; An upper punch made of graphite in the same shape as the space part and positioned above the space part; And pressing the upper punch in a vertical downward direction to pressurize the ceramic raw material filled in the molding space between the lower punch and the upper punch, and to include a pressing plate made of graphite.

Here, the support plate, core, sleeve, housing, lower punch, upper punch and pressure plate are each made of graphite having a purity of 99% or more and having the same or different thermal expansion coefficients.

Here, the support plate has a seating groove is formed in the center of the upper surface, the core is formed with a stepped on the bottom surface to be inserted into the seating groove.

Here, the core and the sleeve are integrally formed or divided into two or more portions in the vertical direction.

In this case, the sleeve is formed by dispersing the pressure when the pressure is applied to the ceramic raw material to lower the lateral pressure, the upper end is narrower on the outer side and the upper end on the outermost side so that the ceramic plate is easily separated The first inclined surface is formed to be wider and narrower toward the lower end, and the housing has a second inclined surface formed on the inner surface to be interviewed with the first inclined surface.

Here, the mold apparatus for hot pressure sintering for manufacturing the hollow structure ceramic plate may have a plate shape in the same shape as the space portion on the bottom surface of the upper punch and the upper surface of the lower punch to provide the same pressure to the ceramic raw material. And a horizontal holding plate formed of graphite and made of graphite.

Here, the leveling plate is made of graphite having a purity of 99% or more and having a coefficient of thermal expansion equal to or different from that of the support plate, core, sleeve, housing, lower punch, upper punch, and pressure plate.

Another feature of the invention,

A hollow structure ceramic plate is manufactured by using a mold apparatus for hot press sintering for the production of the hollow structure ceramic plate.

According to the mold apparatus for hot-pressing sintering for the production of the hollow structure ceramic plate of the present invention configured as described above and the hollow structure ceramic plate manufactured using the same, the cavity using the core can be adjusted in various shapes and sizes. In addition, the pressure between the ceramic plate and the mold, which may be caused by the difference in the coefficient of thermal expansion of the ceramic plate and the mold apparatus during heating or cooling, may be alleviated to prevent damage to the ceramic and the mold.

In addition, according to the present invention, since the hollow structure ceramic plate is directly manufactured by hot pressure sintering, no additional processing is required, thereby lowering the manufacturing cost and shortening the manufacturing time.

1 is a perspective view showing the configuration of a mold apparatus for hot pressing sintering for the manufacture of a hollow structure ceramic plate according to an embodiment of the present invention.
2 is an exploded perspective view of FIG. 1.
3 is a side cross-sectional view of FIG. 1.
Figure 4 is a perspective view showing the configuration of a hollow structure ceramic plate manufactured using a mold apparatus for hot pressure sintering for the production of a hollow structure ceramic plate according to an embodiment of the present invention.

Hereinafter, with reference to the accompanying drawings, the configuration of a mold apparatus for hot pressure sintering for the production of a hollow structure ceramic plate according to an embodiment of the present invention will be described in detail.

In the following description of the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted. Terms to be described later are terms defined in consideration of functions in the present invention, and may be changed according to intentions or customs of users or operators. Therefore, the definition should be made based on the contents throughout the specification.

1 is a perspective view showing the configuration of a mold apparatus for hot pressing sintering for the manufacture of a hollow structure ceramic plate according to an embodiment of the present invention, Figure 2 is an exploded perspective view of Figure 1, Figure 3 is a side cross-sectional view of Figure 1 to be.

1 to 3, the mold apparatus 1 for hot-pressing sintering for the manufacture of a hollow structure ceramic plate according to an embodiment of the present invention includes a support plate 10, a core 20, and a sleeve 30. ), A housing 40, a lower punch 50, an upper punch 60, a pressing plate 70, and a horizontal holding plate 80.

In an embodiment of the present invention, a mold apparatus for manufacturing a ceramic plate in which a circular hole is formed in a central portion in the form of a disk, and the shape of each component may be changed according to the shape of the hole and the outer shape of the ceramic plate.

First, the support plate 10 is the core 20, sleeve 30 and the housing 40 is installed on the upper surface, the seating groove 11 is formed so that the core 20 is coupled to the right position in the upper center, the purity It is preferable that it is made of graphite of 99% or more and a coefficient of thermal expansion between 4.2 and 4.6.

At this time, the purity of the graphite used in the production of the support plate 10 is used more than 99%, if the purity is less than 99% due to the diffusion of impurities during the sintering process, defects such as contamination may occur in the ceramic plate is dense ceramic Hard to get a plate

In addition, when the coefficient of thermal expansion of the graphite used to fabricate the support plate 10 is less than 4.2, the core 20 or the support plate 10 may be damaged due to the tolerance of the stepped portion 21 and the seating groove 11 of the core 20 during cooling. If it exceeds 4.6, it may lead to breakage of the ceramic plate and the core 20 due to rapid shrinkage.

In addition, the core 20 forms a cavity of any one selected from triangular, square, polygonal, and circular in the ceramic plate to have a hollow structure, so that the outer surface has the same shape as the hole, 99% or more, and the coefficient of thermal expansion Is made of graphite between 4.8 ~ 6.6 is installed in the center of the upper surface of the base plate (10).

In addition, the core 20 is formed with a stepped jaw 21 of the same shape as the seating groove 11 on the bottom surface to be inserted into the seating groove 11, can be manufactured in one piece or multi-divided into two or more equal parts, of the ceramic plate Some shapes change in size depending on the shape.

At this time, the purity of the graphite used to fabricate the core 20 is used more than 99%, when the purity is less than 99% it is difficult to obtain a dense ceramic plate due to the generation of defects such as contamination in the ceramic in the hot pressurized sintering process.

In addition, when the thermal expansion coefficient of the graphite used to fabricate the core 20 is less than 4.8, the ceramic plate and the core 20 may be damaged by the compression pressure between the ceramic plate and the core 20 in the hot pressing process, and the thermal expansion coefficient is 6.6. If exceeded, the ceramic raw material C may leak due to a tolerance between the core 20 and other components.

Subsequently, the sleeve 30 is installed on the upper surface of the support plate 10, while accommodating the core 20 therein to form a space S spaced apart from the core to fill the ceramic raw material, thereby adjusting the size of the ceramic plate, The ceramic plate is manufactured in one of triangular, square, polygonal, and round shapes, and is made of graphite having a purity of 99% or more and a thermal expansion coefficient of 2.5 to 3.8.

In addition, the sleeve 30 is lowered to the side pressure imposed by dispersing the pressure when the pressure is applied to the ceramic raw material (C), the upper surface is narrower on the outer side and the outermost form or the outermost side so that the ceramic plate is easily separated A first inclined surface 31 having a wide upper end and narrowing toward a lower end is provided. At this time, the first inclined surface 31 is preferably to have a 6 ~ 10 ° inclination, when the angle is less than 6 ° working efficiency is insignificant when separated from the housing 40, if it exceeds 10 ° in the hot pressure sintering process It may be detached from the housing 40, the thickness of the housing 40 is relatively thin due to the high inclination angle, it is difficult to withstand the pressure generated during hot pressure sintering.

In addition, the sleeve 30 may be manufactured in two or more equal parts, and the shape of the size is changed depending on the shape of the ceramic plate.

And, the purity of the graphite used to manufacture the sleeve 30 is used more than 99%, when the purity is less than 99% it is difficult to obtain a dense ceramic plate due to the generation of defects such as contamination in the ceramic in the hot press sintering process.

On the other hand, when the thermal expansion coefficient of the graphite used to fabricate the sleeve 30 is less than 2.5, the ceramic raw material (C) may leak due to the tolerance between the sleeve 30 and other components in the hot pressure sintering process, and the thermal expansion coefficient is 3.8. When exceeding, the ceramic plate and the sleeve 30 may be damaged by the compression pressure between the ceramic plate and the sleeve 30 in the cooling process.

Subsequently, the housing 40 accommodates the core 20 and the sleeve 30 therein, and is installed outside the sleeve 30 on the upper surface of the support plate 10 to fix the sleeve 30, and has a purity of 99% or more, It is produced from graphite having a coefficient of thermal expansion of 4.2 to 5.6.

At this time, the housing 40 has a second inclined surface 41 is formed on the inner surface at the same angle as the first inclined surface 31 to be in contact with the first inclined surface 31 of the sleeve (30).

And, the purity of the graphite used to manufacture the housing 40 is used more than 99%, when the purity is less than 99% it is difficult to obtain a dense ceramic plate due to the generation of defects such as contamination in the ceramic in the hot press sintering process.

On the other hand, when the thermal expansion coefficient of the graphite used to manufacture the housing 40 is less than 4.2, due to the lateral pressure generated by the thermal expansion difference between the sleeve 30 and the housing 40 during hot pressure sintering, the ceramic plate or the housing 40 If it exceeds 4.7, it may lead to breakage of the ceramic plate, the sleeve 30 and the core 20 due to rapid shrinkage.

The lower punch 50 is made of graphite in the same shape as that of the space S, and is located below the space S, that is, on the upper surface of the support plate 10.

At this time, the purity of the graphite used to manufacture the lower punch 50 is made of graphite having a purity of 99% or more and a coefficient of thermal expansion of 4.2 to 4.6. If the purity is less than 99%, defects such as contamination of the ceramic in the hot pressurizing and sintering process It is difficult to obtain a dense ceramic plate due to the generation of, and when the coefficient of thermal expansion is less than 4.2, the coupling portion with the core 20 during cooling may damage the core 20 or the support plate 10 due to the tolerance, and the coefficient of thermal expansion exceeds 4.6 Rapid shrinkage may lead to breakage of the ceramic plate, sleeve 30 and core 20.

In addition, the upper punch 60 is made of graphite in the same shape as the space portion (S) is located above the space portion (S), it is preferably formed longer than the lower punch 50 to transmit the compressive force.

At this time, the purity of the graphite used to manufacture the upper punch 60 is made of graphite having a thermal expansion coefficient of more than 99%, the coefficient of thermal expansion of 4.2 ~ 4.6, if the purity is less than 99% defects such as contamination of the ceramic in the hot pressing sintering process It is difficult to obtain a dense ceramic plate due to the generation of, and when the coefficient of thermal expansion is less than 4.2, the coupling portion with the core 20 during cooling may damage the core 20 or the pressure plate 70 due to the tolerance, and the coefficient of thermal expansion exceeds 4.6 Rapid shrinkage may lead to breakage of the ceramic plate, sleeve 30 and core 20.

In addition, the pressure plate 70 presses the upper punch 60 in the vertical downward direction to pressurize the ceramic raw material C filled in the molding space between the lower punch 50 and the upper punch 60, and is made of graphite.

At this time, the purity of the graphite used in the production of the pressure plate 70 is made of graphite having a thermal expansion coefficient of more than 99%, 4.2 ~ 4.6, if the purity is less than 99% of the defects such as contamination of the ceramic in the hot pressing sintering process If it is difficult to obtain a dense ceramic plate due to the occurrence, and the coefficient of thermal expansion is less than 4.2, the upper punch 60 or the core 20 may be damaged due to the tolerance of the joint with the upper punch 60 during cooling, and the coefficient of thermal expansion may exceed 4.6. In this case, rapid shrinkage may lead to breakage of the ceramic plate, the sleeve 30 and the core 20.

Finally, the leveling plate 80 is located on the bottom of the upper punch 60 and the top of the lower punch 50, i.e., on the top and bottom of the ceramic raw material, to provide the same pressure horizontally to the ceramic raw material C. The same shape as the plate is made of graphite in the form of a plate.

At this time, the purity of the graphite used to manufacture the horizontal retaining plate 80 is made of graphite having a purity of 99% or more and a coefficient of thermal expansion of 4.2 to 4.6. If it is difficult to obtain a dense ceramic plate due to the generation of elements, and if the coefficient of thermal expansion is less than 4.2, the coupling portion with the core 20 during cooling may damage the core 20 or the horizontal retaining plate 80 due to the tolerance, and the coefficient of thermal expansion is 4.6. If exceeded, rapid shrinkage may lead to breakage of the ceramic plate, the sleeve 30 and the core 20.

In addition, the hollow structure ceramic plate 100 manufactured by the mold apparatus 1 for hot press sintering for the manufacture of the hollow structure ceramic plate according to the embodiment of the present invention has a circular shape in a central portion as shown in FIG. 4. The hole 110 is formed, and the edge is also formed in a disc shape, that is, a ring type.

Figure 4 is a perspective view showing the configuration of a hollow structure ceramic plate manufactured using a mold apparatus for hot pressure sintering for the production of a hollow structure ceramic plate according to an embodiment of the present invention.

On the other hand, the ceramic plate 100 can be produced in any one form selected from triangular, square, polygonal, circular, and the hole 110 in the center can also be produced in any one form selected from triangular, square, polygonal, circular. It is also possible to form a plurality of holes using a plurality of cores.

Hereinafter, a mold apparatus for hot pressure sintering for manufacturing a hollow structure ceramic plate according to the present invention will be described in detail through Examples and Comparative Examples. However, the present invention is not limited to the following examples.

The hollow structure ceramic plate was manufactured using the mold apparatus for hot pressure sintering for manufacture of the hollow structure ceramic plate which concerns on this invention of Table 1.

Specifically, the hollow structured ceramic specimens were manufactured in a circular ring type with an outer diameter of 300 mm and an inner diameter of 200 mm. Both the examples and the comparative examples have the same shape and size, but show the coefficient of thermal expansion of graphite. The application was made differently, as described above, and as the ceramic raw material used for hot press sintering, 13H of Saint Gobain was used in the same manner.

The prepared ceramic raw material was charged into a mold apparatus to prepare a hollow ceramic specimen by hot pressure sintering.

Table 2 shows the results of the ceramic specimens prepared under the conditions described in Table 1.

As a result, when the same thermal expansion coefficient of graphite is formed as shown in Table 2 and FIG. 5, the ceramic specimen itself is broken and cannot be manufactured. When the thermal expansion coefficient is changed as in the present invention, a ring-shaped ceramic specimen can be manufactured. .

As those skilled in the art would realize, the described embodiments may be modified in various ways, all without departing from the spirit or scope of the present invention. It is to be understood, however, that the invention is not limited to the specific forms referred to in the description, but rather includes all modifications, equivalents, and substitutes within the spirit and scope of the invention as defined by the appended claims. Should be.

10: base plate 20: core
30 sleeve 40 housing
50: lower punch 60: upper punch
70: pressure plate 80: leveling plate
100: ceramic plate 110: hole

Claims (8)

In the mold apparatus for hot pressure sintering for manufacturing a hollow ceramic plate manufactured by hot pressure sintering method using a ceramic raw material in powder form,
A support plate made of graphite having a purity of 99% or more and a coefficient of thermal expansion of 4.2 to 4.6;
The outer surface is the same shape as the hole to have a hollow structure by forming a cavity (cavity) of any one selected from triangular, square, polygonal, and circular in the ceramic plate with a purity of 99% or more and a coefficient of thermal expansion of 4.8 to 6.6 A core made of graphite therebetween and installed in a central portion of the upper surface of the support plate;
It is installed on the upper surface of the support plate, spaced apart from the core to form a space to control the size of the ceramic plate, and to produce the ceramic plate in any one form selected from triangular, square, polygonal, round, purity more than 99% A sleeve made of graphite having a coefficient of thermal expansion of 2.5 to 3.8;
A housing installed outside the sleeve on an upper surface of the support plate to fix the sleeve, the housing being made of graphite having a purity of 99% or more and a coefficient of thermal expansion of 4.2 to 5.6;
A lower punch made of graphite having a purity of 99% or more and a coefficient of thermal expansion of 4.2 to 4.6 in the same shape as that of the space part, and positioned below the space part;
An upper punch made of graphite having a purity of 99% or more and a coefficient of thermal expansion of 4.2 to 4.6 in the same shape as that of the space part, and positioned above the space part;
Pressing the upper punch in a vertical downward direction to pressurize the ceramic raw material filled in the molding space between the lower punch and the upper punch, and a pressure plate made of graphite having a purity of 99% or more and a coefficient of thermal expansion of 4.2 to 4.6; And
The lower surface of the upper punch and the upper surface of the lower punch are formed in the form of a plate in the same shape as the space part so as to provide the same pressure to the ceramic raw material, and are made of graphite having a purity of 99% or more and a coefficient of thermal expansion of 4.2 to 4.6. Mold apparatus for hot pressure sintering for the manufacture of a hollow structure ceramic plate, characterized in that it comprises a horizontal holding plate. delete The method of claim 1,
The support plate,
A seating groove is formed in the center of the upper surface,
The core is,
Hot pressing sintering mold apparatus for the manufacture of the hollow structure ceramic plate, characterized in that the step is formed on the bottom surface to be inserted into the seating groove. The method of claim 1,
The core and the sleeve,
Hot pressing sintering mold apparatus for the manufacture of a hollow structure ceramic plate, characterized in that divided into two or more in the vertical direction. The method of claim 1,
The sleeve,
When the pressure is applied to the ceramic raw material, the pressure is dispersed to lower the lateral pressure, and the upper end is narrower on the outer side and wider toward the lower side so that the ceramic plate is easily separated, or the upper end is wider on the outermost side and narrower toward the lower end. A first slope of form is provided,
The housing,
2. A mold apparatus for hot press sintering for the manufacture of a hollow structure ceramic plate, characterized in that the second inclined surface is formed on the inner surface so as to be interviewed with the first inclined surface. delete delete The hollow structure ceramic plate manufactured using the mold apparatus for hot pressure sintering for manufacture of the hollow structure ceramic plate of Claim 1.

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