JP2012236379A - Method of producing sintered body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of producing a sintered body, by which the sintered body having a thickness can be produced without degrading its quality while using an existing hot pressing apparatus.SOLUTION: The method includes: an arranging step S1 of arranging a raw material powder 100 in the inside of a molding member 10 to cause the raw material powder 100 to be adjacent to first and second support members 30 and 50 through the molding member 10; a pressing step S2 of pressing the raw material powder 100 by using a pressing punch 20 to cause the raw material powder 100 to be adjacent to only the first support member 30 through the molding member 10 after the arranging step S1; a removing step S3 of removing the second support member 50 from the molding member 10 after the pressing step S2; and a pressing and sintering step S4 of heating the raw material powder 100 while pressing the raw material powder 100 by using the pressing punch 20, after the removing step S3.

Description

  The present invention relates to a method for manufacturing a sintered body, and more particularly to a method for manufacturing a thick-walled sintered body.

  Conventionally, a manufacturing method of a sintered body is known, in which a hot pressing apparatus having a cylindrical molded member having both ends opened is heated while applying pressure to a raw material powder that is a raw material of the sintered body ( For example, see Patent Document 1).

  In the manufacturing method of the sintered compact using a hot press apparatus, first, raw material powder is arrange | positioned inside a molded member. The raw material powder is heated by applying pressure to the raw material powder by a pair of pressing punches arranged at both ends of the molded member, thereby sintering the raw material powder. Thereby, a sintered compact is manufactured. At the time of manufacturing the sintered body, the outer periphery of the molded member is covered with a cylindrical support member so that the molded member is not deformed by the pressure generated by the pressing punch. The support member has rigidity capable of withstanding pressure, and supports the molded member. Thereby, it can suppress that a molding member swells outside by pressure.

JP 2001-48659 A

  When manufacturing a sintered body that is long in the opening direction of the molded member, that is, a thick sintered body (thick sintered body), the length in the opening direction of the molded member is limited. It was manufactured.

  First, raw material powder is arrange | positioned to a shaping | molding member. Next, pressure is applied to the raw material powder to compress the raw material powder. Thereby, since the bulk of the raw material powder is reduced, the raw material powder is further arranged by the reduced volume. Thereafter, the raw material powder is compressed by applying pressure to the already compressed raw material powder and the newly placed raw material powder. By repeating the arrangement and compression of the raw material powder, the thickness of the raw material powder can be secured. When the thickness of the raw material powder reached the desired thickness, a thick sintered body having a desired thickness was obtained by heating while applying pressure.

  However, since the raw material powder once pressured and the newly placed raw material powder have different density of the raw material powder, the pressurized raw material powder and the newly placed raw material It is difficult to be completely familiar with powder. For this reason, in a thick sintered body manufactured by repeating the placement and compression of the raw material powder, cracks perpendicular to the thickness direction occur near the boundary between the raw material powders with different numbers of compressions. It was easy. For this reason, when manufacturing a thick sintered compact using the existing hot press apparatus, there existed concern about the quality fall by a crack.

  Therefore, the present invention has been made in view of such a situation, and a sintered body capable of producing a thick sintered body while using an existing hot press apparatus without deteriorating quality. An object is to provide a manufacturing method.

  In order to solve the above-described problems, the present invention has the following features. A feature of the present invention is that a cylindrical molded member having an open end, a pair of pressing punches for pressing raw material powder as a raw material of a sintered body, and an outer periphery of the molded member are covered and the molded member is supported. Using a hot press device having a first support member and a second support member that is adjacent to the first support member and covers the outer periphery of the molding member and supports the molding member, the first support member and the first support member 2 Arrangement step of arranging the raw material powder inside the molding member such that the raw material powder is adjacent to the support member via the molding member, and after the arrangement step, the molding member via the molding member A pressing step of applying pressure to the raw material powder using the pressing punch so that the raw material powder is adjacent only to the first supporting member, and after the pressing step, the second support from the molding member Removing the member and removing the second support member. After the step of removing, and summarized in that and a pressure sintering step of heating while applying pressure to the raw material powder with the pressing punch.

  According to the feature of the present invention, since the raw material powder is arranged so that the raw material powder is adjacent to the first support member and the second support member via the molding member, more raw material powders are arranged than before. can do. For this reason, it is possible to produce a sintered body having a thickness greater than that of the conventional one. Even if more raw material powders are arranged than in the past, the second support member supports the molded member, so that the molded member is not deformed.

  Further, pressure is applied to the raw material powder so that the raw material powder is adjacent only to the first support member through the molding member. For this reason, even if a 2nd support member is removed and a raw material powder is pressurized before performing a pressure sintering process, a shaping | molding member does not deform | transform.

  In general, a hot press furnace for heating the sintered body has a size corresponding to the size of the molding member and the support member in order to efficiently heat the sintered body. That is, the inside of the hot press furnace has a structure in which no extra space is formed when the molding member and the support member are arranged. According to the feature of the present invention, since the second support member is removed before the pressure sintering step, it can be heated using an existing hot press furnace.

  Since the arrangement and compression of the raw material powder are not repeated, the sintered body is not cracked.

  As described above, a thick sintered body can be produced while using an existing hot press apparatus without degrading quality.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the sintered compact which can manufacture a sintered compact with thickness can be provided, using the existing hot press apparatus, without reducing quality.

FIG. 1 is a cross-sectional view of a hot press apparatus 1 according to this embodiment. FIG. 2 is a flowchart for explaining a method for manufacturing a sintered body according to the present embodiment. FIG. 3 is a cross-sectional view of the hot press apparatus 1 for explaining the method for manufacturing a sintered body according to the present embodiment. FIG. 4 is a diagram showing the results of an ultrasonic measurement test. FIG. 5 is a diagram displaying the points at which the density was measured. FIG. 6 is a diagram showing the results of the density measurement test.

  An example of a method for manufacturing a wafer holder according to the present invention will be described with reference to the drawings. Specifically, (1) a schematic configuration of the hot press apparatus 1, (2) a method for manufacturing a sintered body, (3) actions and effects, (4) comparative evaluation, and (5) other embodiments will be described.

  In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. It should be noted that the drawings are schematic and ratios of dimensions and the like are different from actual ones. Accordingly, specific dimensions and the like should be determined in consideration of the following description. Moreover, the part from which the relationship and ratio of a mutual dimension differ also in between drawings may be contained.

(1) Schematic Configuration of Hot Press Apparatus 1 A schematic configuration of the hot press apparatus 1 according to the present embodiment will be described with reference to FIG. FIG. 1 is a cross-sectional view of a hot press apparatus 1 according to this embodiment.

  As shown in FIG. 1, the hot press apparatus 1 includes a molding member 10, a press punch 20a, a press punch 20b, a press jig 22, a cylinder 24, a first support member 30, a cradle 40, a second support member 50, A spacer 60a and a spacer 60b are provided.

  The molding member 10 has a cylindrical shape, and an end portion is open. That is, the molding member 10 has an open end. In the present embodiment, the molding member 10 has a circular opening end. That is, the molding member 10 has a circular tube shape. The cylindrical shape extends in the longitudinal direction, has at least one end opened in the longitudinal direction, and is hollow inside. The cylindrical shape does not necessarily mean only a circular tube shape, but also includes a shape having a polygonal open end. The molding member 10 is formed of, for example, a flexible carbon sheet.

  In addition, let the direction which the edge part of a shaping | molding member opens be an opening direction. That is, the opening direction is a direction in which the central axis passing through the centers of both openings of the cylindrical molded member 10 extends, and is the thickness direction of the sintered body to be manufactured.

  The press punch 20a and the press punch 20b (hereinafter, appropriately abbreviated as the press punch 20) press the raw material powder 100 that is a raw material of the sintered body. The pressing punch 20 is located in the opening direction of the molding member 10. The pressing punch 20 has a size that can be inserted into the molding member 10 from the opening end of the molding member 10. In the present embodiment, the pressing punch 20a has a cylindrical shape. A pressing jig 22 and a cylinder 24 are arranged in the opening direction of the pressing punch 20a. The pressing punch 20b is disposed on the opposite side of the pressing punch 20a with the raw material powder 100 interposed therebetween. The pressing punch 20b is fixed.

  The pressing jig 22 is disposed between the pressing punch 20 a and the cylinder 24. The pressing jig 22 has a truncated cone shape. The upper surface (end portion with a large area) of the pressing jig 22 is in contact with the pressing punch 20 a, and the bottom surface (end portion with a large area) of the pressing jig 22 is in contact with the cylinder 24. By moving the cylinder 24 toward the pressing jig 22, pressure is applied to the raw material powder 100 via the pressing punch 20a.

  The first support member 30 covers the outer periphery of the molding member 10. Thereby, even if pressure is applied to the raw material powder 100, the first support member 30 supports the molding member 10, so that the molding member 10 is not deformed in the orthogonal direction orthogonal to the opening direction.

  The first support member 30 has a circular tube shape. The first support member 30 includes an inner sleeve 32, an outer sleeve 34, and a die 36. The inner sleeve 32 is in contact with the molding member 10 and covers the molding member 10. The inner sleeve 32 is a rigid body, and for example, a carbon material is used. The outer sleeve 34 contacts the inner sleeve 32 and covers the inner sleeve 32. The outer sleeve 34 is less rigid than the inner sleeve 32. The die 36 contacts the outer sleeve 34 and covers the outer sleeve 34.

  The opening direction end of the first support member 30 is fixed by the cradle 40. The cradle 40 is located at the opening direction ends of the molding member 10 and the first support member 30. The cradle 40 fixes the molding member 10 and the first support member 30 so that the position of each member does not shift in the orthogonal direction.

  The second support member 50 covers the outer periphery of the molding member 10. Similar to the first support member 30, the second support member 50 supports the molding member 10 so that the molding member 10 does not deform in the orthogonal direction. That is, the second support member has a rigidity capable of withstanding the pressure received from the molding member 10. The second support member 50 is adjacent to the first support member 30 in the opening direction.

  The second support member 50 has a circular tube shape whose inner diameter is larger than the outer diameter of the molding member 10. Thereby, the second support member 50 can be fitted to the molding member 10. The second support member 50 is removable from the molding member 10. Since the second support member 50 contacts the molding member 10, the outer diameter of the molding member 10 and the inner diameter of the second support member 50 are substantially equal.

  As a material of the second support member 50, for example, polyvinyl chloride (PVC) can be used. In the present embodiment, the end of the second support member 50 on the opening end side of the molding member 10 is at the same height as the opening end of the molding member 10.

  The spacer 60 a and the spacer 60 b (hereinafter, appropriately abbreviated as the spacer 60) are disposed between the press punch 20 and the raw material powder 100. The spacer 60 prevents the pressing punch 20 and the raw material powder 100 from coming into close contact with each other.

  The hot press apparatus 1 includes a hot press furnace for heating the raw material powder 100 (not shown). The hot press furnace is installed around the molding member 10 and the first support member 30.

(2) Method for Manufacturing Sintered Body A method for manufacturing a sintered body according to the present embodiment will be described with reference to FIGS. 1 to 3. FIG. 2 is a flowchart for explaining a method for manufacturing a sintered body according to the present embodiment. FIG. 3 is a cross-sectional view of the hot press apparatus 1 for explaining the method for manufacturing a sintered body according to the present embodiment.

  As shown in FIG. 2, the method for manufacturing a sintered body according to the present embodiment includes an arrangement step S1, a pressure step S2, a removal step S3, and a pressure sintering step S4.

(2.1) Arrangement process S1
The placement step S <b> 1 is a step of placing the raw material powder 100 inside the molded member 10.

  The raw material powder 100 is put into the molding member 10 from the opening end of the molding member 10 on the side where the pressing punch 20a is located. The raw material powder 100 is put into the first support member 30 and the second support member 50 through the molding member 10 until the raw material powder 100 is adjacent. Specifically, as shown in FIG. 1, the raw material powder 100 is disposed beyond the height of the first support member 30. That is, the raw material powder 100 is disposed beyond the surface S passing through the boundary between the first support member 30 and the second support member 50. The upper surface of the raw material powder 100 is adjacent to only the second support member 50 through the molding member 10.

  In addition, the raw material powder 100 is arrange | positioned after arrange | positioning the spacer 60b so that the raw material powder 100 may not contact | adhere to the press punch 20b. Further, after the raw material powder 100 is arranged so that the raw material powder 100 does not adhere to the pressing punch 20 a, the spacer 60 a is arranged on the upper surface of the raw material powder 100.

  The second support member 50 may be fitted to the molded member 10 before the raw material powder 100 is put, or may be fitted to the molded member 10 after the raw material powder 100 is put.

(2.2) Pressure process S2
The pressurizing step S <b> 2 is a step of applying pressure to the raw material powder 100 using the press punch 20. The pressurizing step S2 is performed after the arranging step S1.

  By moving the cylinder 24 toward the pressing jig 22, the pressing punch 20 is moved toward the raw material powder 100. The press punch 20 a applies pressure to the raw material powder 100 to compress the raw material powder 100. That is, the bulk of the raw material powder 100 is reduced by the pressure.

  Specifically, pressure is applied to the raw material powder 100 until the upper surface of the raw material powder 100 passes through the surface S and moves to the pressing punch 20b side. Thereby, the raw material powder 100 which was adjacent to the first support member 30 and the second support member 50 via the molding member 10 is adjacent only to the first support member 30 via the molding member 10 (see FIG. 3). ).

(2.3) Removal step S3
The removal step S <b> 3 is a step of removing the first support member 30 from the molding member 10. The removing step S3 is performed after the pressurizing step S2.

  The cylinder 24 is moved in a direction away from the raw material powder 100. Thereafter, the second support member 50 is removed from the molding member 10 (see FIG. 3).

(2.4) Pressure sintering step S4
In the pressure sintering step S <b> 4, the pressing powder 20 is used to heat the raw material powder 100 while applying pressure. The pressure sintering step S4 is performed after the removal step S3.

  The cylinder 24 is moved toward the pressing jig 22 to apply pressure to the raw material powder 100. A hot press furnace is installed around the molding member 10 and the first support member 30 to heat the raw material powder 100. The raw material powder 100 becomes a sintered body by heating the raw material powder 100 while applying pressure. The pressure during heating is preferably 200 kg or more per unit area.

  Through the above steps, a thick sintered body is manufactured.

(3) Effects According to the method for manufacturing a sintered body in the present embodiment, the molded member 10 is arranged such that the raw material powder 100 is adjacent to the first support member 30 and the second support member 50 via the molded member 10. Using the pressing punch 20 so that the raw material powder 100 is adjacent only to the first support member 30 via the molding member 10 after the placement step S1 of placing the raw material powder 100 inside The pressing step S2 for applying pressure to the raw material powder 100, the removing step S3 for removing the second support member 50 from the molding member 10 after the pressing step S2, and the pressing punch 20 after the removing step S3. A pressure sintering step S4 for heating the powder 100 while applying pressure thereto.

  In order to arrange the raw material powder 100 so that the raw material powder 100 is adjacent to the first support member 30 and the second support member 50 through the molding member 10, more raw material powders 100 are arranged than before. Can do. For this reason, it is possible to produce a sintered body having a thickness greater than that of the conventional one. Even if more raw material powders 100 are arranged than in the past, the second support member 50 supports the molding member 10, so that the molding member 10 is not deformed.

  Pressure is applied to the raw material powder 100 so that the raw material powder 100 is adjacent only to the first support member 30 through the molding member 10. For this reason, even if the 2nd support member 50 is removed and pressure is applied to the raw material powder 100 before performing pressure sintering process S4, the shaping | molding member 10 does not deform | transform.

  Usually, the hot press furnace for heating the sintered body has a size corresponding to the size of the molding member and the support member in order to efficiently heat the sintered body. That is, the inside of the hot press furnace has a structure in which no extra space is formed when the molding member and the support member are arranged. Even in an existing hot press furnace having such a structure, since the second support member 50 is removed before the pressure sintering step S4, it can be heated using the existing hot press furnace. It is.

  Since the arrangement and compression of the raw material powder 100 are not repeated, cracks perpendicular to the thickness direction of the sintered body do not occur.

  As described above, according to the present embodiment, it is possible to manufacture a thick sintered body while using the existing hot press apparatus 1 without reducing the quality.

(4) Comparative evaluation In order to confirm the effect of the present invention, the following evaluation was performed. In addition, this invention is not limited to a following example.

  Sintered silicon carbide sintered bodies according to Example 1, Example 2, and Comparative Examples 1 to 3 were manufactured using silicon carbide as a raw material powder.

  The sintered bodies according to Example 1 and Example 2 were manufactured through the same processes as those of the above-described embodiment. Since a circular tube-shaped member was used as the molded member, the manufactured sintered body has a cylindrical shape. The sintered body according to Example 1 has a diameter of 345 mm and a thickness of 110 mm. The sintered body according to Example 2 has a diameter of 380 mm and a thickness of 110 mm.

  The sintered bodies according to Comparative Example 1 to Comparative Example 3 produced sintered bodies having a thickness smaller than that of Example 1 and Example 2 using a conventionally known production method. That is, in the method for manufacturing a sintered body according to Comparative Example 1 to Comparative Example 3, the raw material powder was disposed so that the raw material powder was adjacent only to the first support member via the molded member. As in the example, since a circular tube-shaped member was used as the molding member, the manufactured sintered body has a columnar shape. The sintered bodies according to Comparative Examples 1 to 3 all have a diameter of 345 mm and a thickness of 110 mm.

(4.1) Evaluation of physical property values The physical property values of Example 1, Example 2, and Comparative Examples 1 to 3 were evaluated. The evaluated physical property values are density, silicon carbide purity, volume resistance, altitude, bending strength, elastic modulus, Poisson's ratio, and thermal expansion coefficient. The purity of silicon carbide was evaluated as being high (“◯”) when each element excluding Si and C was 0.3 ppm or less. The results are shown in Table 1.

  As shown in Table 1, all of the examples show physical property values equivalent to those of the comparative example. In any of the examples, the amount of impurities was below the reference value. That is, the purity was high. As a result, it was found that the quality of the sintered body according to the example did not deteriorate.

(4.2) Ultrasonic measurement test By the ultrasonic measurement test, the sintered bodies according to Example 1 and Example 2 were measured for damage such as cracks. Specifically, the sintered body according to the example was divided into an upper half and a lower half. The presence or absence of damage was measured by applying ultrasonic waves to each upper surface (A surface) and each lower surface (B surface) of the upper half and the lower half of the sintered body according to each example. The results are shown in FIG. FIG. 4 is a diagram showing the results of an ultrasonic measurement test.

  As shown in FIG. 4, no damage such as cracks was found in any of them. Thereby, it turned out that the quality of the sintered compact concerning an example has not fallen.

(4.3) Density measurement test The density of the sintered body according to Example 2 was measured in order to confirm whether the density was uneven. Specifically, a total of nine portions A0 to A8 shown in FIG. 5 are provided for the three portions of the uppermost surface portion, the inner surface portion 61 mm away from the uppermost surface, and the lowermost surface portion of the sintered body according to Example 2. Each density was measured. The diameter of the circle in which A1 to A4 is located is φ165mm, and the diameter of the circle in which A5 to A8 is located is φ330mm. The results are shown in FIG. Note that a point located on the solid line is a point on the x-axis, and a point located on the dotted line is a point on the y-axis (see FIG. 5).

  As shown in FIG. 6, the density at any point was within a certain range, and the density did not vary extremely. That is, the density of the sintered body of Example 2 is not extremely biased depending on the location. Therefore, it turned out that the sintered compact which concerns on an Example has fixed quality.

(5) Other Embodiments Although the contents of the present invention have been disclosed through the embodiments of the present invention, it should not be understood that the description and drawings constituting a part of this disclosure limit the present invention. The present invention includes various embodiments not described herein. Accordingly, the present invention includes various embodiments not described herein.

  Specifically, in the above-described embodiment, the first support member 30 and the second support member 50 are circular tube shapes, but are not limited thereto. The shapes of the first support member 30 and the second support member 50 can be appropriately changed according to the shape of the molding member 10. Any shape that can cover the outer periphery along the outer periphery of the molding member 10 may be used so that the molding member 10 is not deformed by the pressure of the raw material powder 100.

  In the present embodiment, the end of the second support member 50 on the opening end side of the molding member 10 is at the same height as the opening end of the molding member 10, but is not limited thereto. The height of the end portion of the second support member 50 may be higher or lower than the height of the end portion of the molding member 10. When the height of the end portion of the second support member 50 is lower than the height of the end portion of the molding member 10, the raw material powder 100 is not disposed beyond the height of the end portion of the second support member 50. To do.

  As described above, the present invention includes various embodiments not described herein. Therefore, the technical scope of the present invention is defined only by the invention specifying matters according to the scope of claims reasonable from the above description.

  DESCRIPTION OF SYMBOLS 1 ... Hot press apparatus, 10 ... Molding member, 20 (20a, 20b) ... Pressing punch, 22 ... Pressing jig, 24 ... Cylinder, 30 ... First support member, 32 ... Inner sleeve, 34 ... Outer sleeve, 36 ... Dies, 40 ... cradle, 50 ... second support member, 60 (60a, 60b) ... spacer, 100 ... raw material powder

Claims (1)

A cylindrical molded member having an open end, a pair of pressing punches that press raw material powder that is a raw material of the sintered body, a first support member that covers the outer periphery of the molded member and supports the molded member; Using a hot press device having a second support member adjacent to the first support member and covering the outer periphery of the molding member and supporting the molding member,
An arrangement step of arranging the raw material powder inside the molding member such that the raw material powder is adjacent to the first support member and the second support member via the molding member;
After the placing step, a pressing step of applying pressure to the raw material powder using the pressing punch so that the raw material powder is adjacent only to the first support member via the molding member;
After the pressing step, removing the second support member from the molded member;
After the process of removing the said 2nd supporting member, the pressure sintering process heated while applying a pressure to the said raw material powder using the said press punch, The manufacturing method of a sintered compact provided with.