JP5856743B2 - Method for producing metal-ceramic composite material - Google Patents

Description

The present invention is a metal - ceramic composite material, in particular ceramic filler having a low metal - relates to a method for producing ceramic composite materials.

  Metal-ceramic composite materials such as SiC / Si composite materials can control the coefficient of thermal expansion, Young's modulus, etc. by changing the ratio of metal and ceramics, and can be used in precision machines such as semiconductor manufacturing equipment and liquid crystal manufacturing equipment. Widely used.

  In general, when the occupancy ratio of ceramics in a metal-ceramic composite material (hereinafter referred to as ceramic filling ratio) is 50% by volume or more, a metal is pressed or non-applied to a porous body made of ceramic powder. Manufacture with pressure. On the other hand, when the ceramic filling rate is less than 50% by volume, it is produced by dispersing ceramic particles in molten metal.

  A SiC / Si composite material is generally formed by pressing a mixture of SiC powder, an organic binder, and, if necessary, carbon powder to form a molded body, and the binder is subjected to binder removal and sintering processes. To obtain a porous sintered body and impregnate the porous sintered body with metal Si (see, for example, Patent Documents 1 and 2).

  If the amount of carbon source added such as an organic binder or carbon powder is increased, the amount of carbon remaining after the binder removal treatment is increased, and this carbon and metal Si react to produce SiC, so SiC. It is considered that the occupation ratio of SiC in the / Si composite material (hereinafter referred to as SiC filling ratio) increases.

Japanese Patent Publication No. 36-8728 JP 2001-151579 A

  However, a method for producing a metal-based composite material having a low SiC filling rate, more generally, a ceramic-filling rate of a metal-ceramic composite material and having a homogeneous structure has not been established. In order to make the SiC filling rate less than 50% by volume, SiC may be added to the molten metal. However, since SiC particles settle with time, a difference occurs in the SiC filling rate above and below the material. Thereby, the deformation due to the difference in thermal expansion is likely to occur.

  Even if the amount of addition of the organic binder is reduced to the lower limit at which the molded body can be retained to suppress the reaction reaction amount of SiC, the SiC filling rate of the SiC / Si composite material cannot be made less than 50% by volume. Further, when the porosity of the porous sintered body made of SiC is increased, the porous sintered body itself cannot be obtained due to weakening.

The present invention has been made in view of these problems, the ceramic filling rate is low besides homogeneous metal - and to provide a method for producing ceramic composite materials.

Metal of the present invention - a ceramic manufacturing method of a composite material, Si C or in the Ranaru ceramic powder and an organic binder, S i or Ranaru metal mean particle size ratio is not more 1/2 to 2 for said ceramic powder A molded body obtained by molding a mixture to which powder is added is fired to obtain a porous sintered body having a porosity of 40 to 50%, and the porous sintered body is impregnated with the same metal as the metal powder, A manufacturing method for manufacturing a metal-ceramic composite material having a ceramic filling rate of 20 to 50% by volume , wherein the addition amount of the organic binder is generated when the ceramic powder and the metal powder are tapped into a mold. It is characterized by being 20 to 30% by volume of the void volume .

  According to the method for producing a metal-ceramic composite material of the present invention, by adding metal powder to the molding material in addition to the ceramic powder and the organic binder in advance, the initial filling rate of the ceramic in the molded body is lowered. Along with this, the porous sintered body obtained by sintering the molded body has a low ceramic filling rate and is excellent in strength without increasing pores. And by impregnating this porous sintered body with a metal, it is possible to obtain a metal-ceramic composite material having a low ceramic filling ratio and being homogeneous. In addition, the carbon component of the organic binder remaining after firing reacts with the metal to be permeated thereafter to become a carbide.

Is adjusted ceramic packing ratio in accordance with the amount of metal powder, by increasing the addition amount of the metal powder, it is possible to the ceramic filling factor and 20 to 50 vol%.

  When the particle size difference is large, fine particles enter the gaps between the coarse particles, and the filling rate of the mixed powder in the mold increases. If the particle size is about the same, the filling rate of the mixed powder does not increase, and the occupation ratio of SiC decreases by the amount of Si added. Therefore, in the method for producing a metal-ceramic composite material of the present invention, it is preferable that an average particle diameter ratio of the metal powder to the ceramic powder is 1/2 or more and 2 or less.

  In addition, when an organic binder in an amount exceeding 100 volume% of the void volume generated when the ceramic powder is tapped into the mold, the porosity of the porous sintered body is lowered, and the organic binder is thermally cured. The passage of condensation polymerization water generated by the condensation polymerization reaction is reduced. Therefore, the condensation polymerization water in the molded body suddenly undergoes volume expansion during the binder removal treatment, and there is a risk that cracks will occur.

  Therefore, in the method for producing a metal-ceramic composite material of the present invention, the amount of the organic binder added is 100% by volume or less of the volume of voids generated when the ceramic powder and the metal powder are tapped into a mold. It is preferable. In addition, the minimum of the addition amount of an organic binder is 10 volume% or more from the shape-retaining limit of a molded object, More preferably, it is 20-30 volume% or more.

The graph showing the relationship between the addition amount of metal Si powder, and the SiC filling rate of a SiC / Si composite material.

The metal-ceramic composite material manufactured by the metal-ceramic composite material manufacturing method of the present invention is obtained by impregnating a porous sintered body made of ceramic and matrix metal with metal, and the ceramic is SiC (silicon carbide ) . The matrix metal and the metal are the same type and Si (silicon), and the ceramic filling rate is 20 to 50% by volume.

Metal of the present invention - ceramic composite material is in the SiC or Ranaru ceramic powder and an organic binder by sintering a compact molded mixture was added S i or Ranaru metal powder to obtain a porous sintered body, The porous sintered body can be produced by the method for producing a metal-ceramic composite material of the present invention in which the same kind of metal as the metal powder is impregnated.

Hereinafter , a case where the SiC / Si composite material is manufactured according to the embodiment of the method for manufacturing a metal-ceramic composite material of the present invention will be described as an example. The SiC / Si composite material is a metal-ceramic composite material in which the matrix metal is Si and the reinforcing material is SiC.

  This SiC / Si composite material manufacturing method includes a molding step, a binder removal step, a sintering step, and an impregnation step in addition to a mixing step in which an organic binder is added to and mixed with SiC powder and metallic Si powder. In addition, a SiC / Si composite material having a SiC filling rate as low as 50% by volume or less can be manufactured. In addition, a shaping | molding process, a binder removal process, a sintering process, and an impregnation process are not limited to the method demonstrated below, Arbitrary known methods can be used.

  First, in a mixing process, an organic binder is added and mixed with SiC powder and metal Si powder which are raw material powder, and a shaping | molding raw material is produced. The mixing method may be either wet or dry, and for example, a mixer such as a ball mill or a vibration mill can be used. A small amount of additives such as a sintering aid may be added.

  The SiC powder preferably has a high purity, and the purity is preferably 96% or more, more preferably 98% or more.

The metal Si powder preferably has a high purity, and the purity is preferably 96% or more, more preferably 98% or more. The addition amount of the metal Si powder may be appropriately adjusted according to the SiC filling rate of the SiC / Si composite material, but is preferably 30 to 130 parts by weight with respect to 100 parts by weight of the SiC powder. Then, the average particle size ratio of the metal Si powder to the SiC powder is 1/2 to 2.

The organic binder is particularly preferably a phenol resin, but resins such as polyvinyl alcohol (PVA), methyl cellulose (MC), isoban, and polyethyleneimine are also preferable. The organic binder can be added in an amount of 20 to 30% by volume of the void volume generated when the ceramic powder and the metal powder are tap-filled into the mold from the lower limit value capable of retaining the molded body .

  The forming raw material obtained in the mixing step is press-molded into an appropriate shape in the forming step. The method is not particularly limited, and known molding methods such as uniaxial press molding, cold isostatic pressing (CIP), and pressure casting can be used. The molding pressure is preferably 2.0 to 5.0 MPa.

  In the binder removal step, the added organic binder is completely carbonized in the molded body obtained in the molding step. The binder removal treatment is preferably performed in a vacuum atmosphere at, for example, a temperature range of 250 to 1000 ° C. at a temperature increase rate of 30 ° C./hr or less. However, the temperature range and the temperature increase rate may be appropriately determined in consideration of production efficiency and the like. A trace amount of carbon component generated by carbonization remains in the molded body.

  In addition, it is preferable that the addition amount of an organic binder shall be 100 volume% or less of the volume of the space | gap produced when a tap mold is filled with SiC powder and metal Si powder. When an organic binder exceeding 100% by volume of the void volume is added, the porosity of the porous sintered body is lowered, and the passage of condensation polymerization water generated by the condensation polymerization reaction of the organic binder is reduced. Therefore, the condensation polymerization water in the molded body suddenly undergoes volume expansion during the binder removal treatment, and there is a risk that cracks will occur. Moreover, since the reaction production amount of SiC also increases, the SiC filling rate of the SiC / Si composite material increases.

  The molded body that has been subjected to binder removal treatment is subjected to deoxygenation treatment in a deoxidation step to obtain a porous sintered body. The deoxygenation treatment is held in a vacuum atmosphere at, for example, a temperature range of 1300 to 1410 ° C. for 5 to 20 hours. More preferably, baking is performed in a vacuum atmosphere at a temperature range of 1350 to 1410 ° C. for 15 to 20 hours. Note that the pressure of the sintering atmosphere is not limited and can be any pressure from reduced pressure, normal pressure to several atmospheric pressure, but normal pressure is preferable from the viewpoint of cost.

The porous sintered body obtained by firing has a large number of pores of 5 to 20 μm, and the porosity is 40 to 50%. In addition, you may grind a porous sintered compact by a mechanical means as needed. If the porous sintered body is formed in a predetermined shape in advance, the obtained SiC / Si composite material becomes a near net, and processing required for making the final shape can be reduced.

  Then, the obtained porous sintered body is impregnated with dissolved metal Si in the impregnation step. The impregnation treatment is preferably performed by a non-pressure permeation method, but may be performed by other methods such as a pressure permeation method. When performing non-pressure permeation, for example, it is heated to 1550 ° C. in a vacuum atmosphere, and further heated to 1645 ° C. in an inert gas atmosphere, and held for 10 hours, more preferably 20 to 30 hours. A part of the metal Si reacts with the carbon component remaining in the porous sintered body to generate SiC, but most of the metal Si impregnates the pores.

  Thereby, a SiC / Si composite material having a low SiC filling rate of 20 to 50% by volume can be obtained. In addition, you may grind a SiC / Si composite material by a mechanical means as needed.

  As described above, by adding the metal Si powder to the molding material containing the SiC powder and the organic binder in advance, the initial filling rate of SiC in the molded body is lowered. Along with this, the porous sintered body obtained by sintering the molded body has a low SiC filling rate and is excellent in strength without increasing pores. And by impregnating this porous sintered body with metal Si, a SiC / Si composite material having a low SiC filling rate can be obtained. By increasing the addition amount of the metal Si powder, the SiC filling rate can be 20 to 50% by volume.

  If the amount of the organic binder added is increased without adding metal Si powder to the molding material, the porosity of the porous sintered body is too large and there is a problem in strength, and the SiC / Si composite that is the final product The SiC filling rate of the material was practically limited to 50% by volume. In the present invention, the metal Si powder is mixed in the molding material in advance to prevent the porosity of the porous sintered body from becoming excessively high, thereby solving this problem.

  Hereinafter, the present invention will be described in detail with specific examples and comparative examples of the present invention.

  In Examples 1 to 10 and Comparative Example 1, first, as raw material powder, SiC powder (# 800, average particle size 17 μm, GP # 800 manufactured by Shinano Electric Smelting Co., Ltd.) and metal Si powder (average particle size 10 μm, Fukuda Metal Foil Powder Industry Co., Ltd. Si-S-10 μm) was prepared. Moreover, the phenol resin (OI-305A by Dainippon Ink and Chemicals, Inc.) was prepared as an organic binder. The average particle size ratio of the metal Si powder to the SiC powder is 10/17.

  Then, the addition amount of SiC powder is 100 parts by weight, the addition amount of metal Si powder is the weight part shown in Table 1, and phenol with respect to the volume of voids formed in the mold when the SiC powder and metal Si powder are tapped. With the addition amount of the resin as the volume% shown in Table 1, these were mixed and put into a mold, and a square plate-like molded body having a side of 200 mm and a thickness of 10 mm was produced at a molding pressure of 2.94 MPa.

  And the obtained molded object was heated in the temperature range of 250-1000 degreeC with the temperature increase rate of 28 degreeC / hr in the vacuum atmosphere, and the binder removal process was performed. Then, the temperature range of 1300-1410 degreeC was heated with the temperature increase rate of 22 degreeC / hr in the vacuum atmosphere, the sintering process was performed, and the porous sintered compact was obtained.

  Then, the obtained porous sintered body is brought into contact with Si heated to a melting point or higher (manufactured by Nippon Denko Co., Ltd.), held in an inert gas atmosphere at a temperature of 1645 ° C. for 24 hours, and melted Si and A SiC / Si composite material was produced by reacting carbon contained in the porous sintered body to form SiC, and simultaneously impregnating Si with pores.

  And the bulk density of the center part and four corner | angular parts of the obtained SiC / Si composite material was measured, respectively, and the SiC filling rate and its standard deviation were calculated | required from the measurement result. The results are summarized in Table 1, and the relationship between the metal Si addition amount and the SiC filling rate is shown in FIG.

  When the addition amount of the metal Si powder was 0 part by weight as in Comparative Example 1, the SiC filling rate of the obtained SiC / Si composite material was 59.1% by volume, greatly exceeding 50% by volume. The standard deviation of the SiC filling rate was 0.61% by volume.

  When the addition amount of the metal Si powder was 10 parts by weight and 20 parts by weight as in Examples 1 and 2, the SiC filling rate of the obtained SiC / Si composite material was 54.4% by volume and 52.1% by volume, respectively. %, Exceeding 50% by volume. The standard deviation of the SiC filling rate was 0.21% by volume and 0.28% by volume, respectively, and the variation of the SiC filling rate was smaller than that of Comparative Example 1.

  As in Examples 3, 4, 5, 6, 7, 8, 9, and 10, the addition amount of the metal Si powder was 30 parts by weight, 35 parts by weight, 40 parts by weight, 44 parts by weight, 52 parts by weight, 66 parts by weight. , 80 parts by weight, 94 parts by weight, the SiC filling rate of the obtained SiC / Si composite material is 47.1% by volume, 46.4% by volume, 44.5% by volume, 41.9% by volume, It became 39.5 volume%, 35.7 volume%, 33.2 volume%, 29.9 volume%, and became 50 volume% or less. The standard deviation of the SiC filling rate was 0.29 to 0.57% by volume, and the variation of the SiC filling rate was equal to or less than that of Comparative Example 1.

  And as shown in FIG. 1, it turned out that the SiC filling rate of a SiC / Si composite material falls, so that the addition amount of metal Si powder increases. From this, it is estimated that if 130 parts by weight of metal Si powder is added to 100 parts by weight of SiC powder, the SiC filling rate in the SiC / Si composite material is about 20% by volume.

  Further, as Comparative Example 2, SiC / Si was used in the same manner as in Example 5 except that carbon beads (average particle size 6 μm, ATNo. 40-C manufactured by Oriental Sangyo Co., Ltd.) were used instead of metal Si powder. A composite material was prepared. The SiC filling rate obtained from the bulk density measurement result of the obtained SiC / Si composite material was 70.9% by volume, greatly exceeding 50% by volume.

  As Comparative Example 3, the SiC / Si composite material was prepared in the same manner as in Example 5 except that the addition amount of the phenol resin was 120% by volume of the void volume generated in the mold when the SiC powder was tapped. Produced. However, cracks occurred in the molded body during press molding.

  Furthermore, as Example 11, as SiC powder, ESK Ceramics GmbH & Co. A SiC / Si composite material was produced in the same manner as in Example 5 except that GC # 180 (# 180, average particle size 88 μm) manufactured by (Germany) was used. At this time, the average particle diameter ratio of the metal Si powder to the SiC powder was 10/88, which was 1/2 or less. The SiC filling rate obtained from the measurement result of the bulk density of the obtained SiC / Si composite material was 59.1% by volume and exceeded 50% by volume.

  As Example 12, as a metal Si powder, M.I. Si. A SiC / Si composite material was produced in the same manner as in Example 5 except that 600 (average particle diameter of 3 μm) was used. At this time, the average particle diameter ratio of the metal Si powder to the SiC powder was 3/17, which was 1/2 or less. In this case, the SiC filling rate obtained from the measurement result of the bulk density of the obtained SiC / Si composite material was 55.1% by volume and exceeded 50% by volume. The results of Examples 5, 11, and 12 are summarized in Table 2.

Claims (1)

On the Si C or Ranaru ceramic powder and an organic binder, the average particle diameter ratio is 1/2 to 2 in a by sintering a compact molded mixture was added S i or Ranaru metal powder to the ceramic powder To obtain a porous sintered body having a porosity of 40 to 50%, and impregnating the porous sintered body with the same kind of metal as the metal powder, so that the ceramic filling rate is 20 to 50% by volume. A manufacturing method for manufacturing a ceramic composite material ,
The method for producing a metal-ceramic composite material , wherein the addition amount of the organic binder is 20 to 30% by volume of the void volume generated when the ceramic powder and the metal powder are tapped into a mold .

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