JP2019070183A - Sintered body, joined body including the sintered body, and production method of sintered body - Google Patents

Abstract

To produce, without cost increase, a sintered body capable of obtaining high bond strength with another member, while having high strength.SOLUTION: A sintered body 2 according to the present invention is formed by subjecting base powder containing metal powder having a higher melting point than copper as a main component to compression molding and sintering. The base powder contains flat copper powder 1 which has a flat shape, and the sintered body contains a solid solution 9 formed by solid-dissolving the flat copper powder 1 into the metal powder which is the main component at the time of sintering.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a sintered body, a joined body containing the sintered body, and a method of manufacturing the sintered body.

  Conventionally, in the field of powder metallurgy, manufacture of a metal material (sintered body) strengthened by sintering a green compact obtained by compression molding of a raw material powder containing metal powder in a high temperature furnace Has been done. Since this technology enables mass production in the so-called near net shape, it is applied to many fields such as machine parts. In particular, in the automotive field, since excellent mechanical properties (especially mechanical strength) are required, adoption of a high-strength sintered body for the automotive field has been studied and actually adopted.

  On the other hand, in recent years, weight reduction of automobile parts is required, and in order to realize this, compounding of a conventional sintered body and a lightweight body is being studied. As a method for this compounding, insert molding, adhesion, etc. are known. Specifically, for example, Patent Document 1 discloses that the resin is solidified in a state in which the resin (molten resin) before solidification enters the pores existing on the surface of the sintered body, and the resin that has entered the pores and A composite of a sintered body and a resin body has been proposed which can exhibit an anchoring effect. Alternatively, in Patent Document 2, the laser light is irradiated from the first member side in a state where the adhesive sheet is provided between the first member such as resin having transparency and the second member such as metal. The method of fuse | melting an adhesive sheet and joining a 1st member and a 2nd member is proposed.

Unexamined-Japanese-Patent No. 2003-239976 Patent No. 4771371 gazette

  However, although the technology described in Patent Document 1 can be applied to so-called low density sintered bodies (sintered bodies having a relative density of less than 80%), medium density structures (relative density of 80% or more) or high In the case of a density sintered body (sintered body having a relative density of 90% or more), since the number of pores on the surface is relatively small, in the case of a sintered body having a conventional structure, an anchor utilizing surface open holes I can not expect much effect. Further, in the bonding technology described in Patent Document 2, when the metal body as the second member is a high density sintered body, the adhesion between the sintered body and the adhesive layer is relatively reduced, It is difficult to obtain high bonding strength. For example, high bonding strength can be obtained by bonding after performing a predetermined surface treatment on the surface of a sintered body, but this leads to an increase in the number of man-hours and hence an increase in cost, so it is suitable as a manufacturing technology for mass-produced products. It can not be said.

  In view of the above situation, the present invention is to solve the problem of manufacturing a sintered body capable of obtaining a high bonding strength with other members while having high strength without increasing the cost.

  The solution to the above problems is achieved by the sintered body according to the present invention. That is, this sintered body is a sintered body obtained by compression molding and sintering a raw material powder containing a metal powder having a melting point higher than that of copper as a main component, and the raw material powder has a flat shape. It is characterized in that it contains a copper powder and contains a solid solution in which the flat copper powder forms a solid solution in the metal powder during sintering.

  The present inventors pay attention to the copper powder generally used in producing a sintered body, and reduce the strength of the sintered body by controlling the shape of the copper powder and the sintering temperature conditions. It has been found that copper powder can function as a kind of surface pore-forming agent without The present invention has been made based on this finding, and a flat powder is formed on a raw material powder of a sintered body obtained by compression molding and sintering a raw material powder containing a metal powder having a melting point higher than that of copper as a main component. It was made to contain copper powder, and it was made for the sintered compact to contain the solid solution which solid copper powder becomes a solid solution in the metal powder of the main ingredients at the time of sintering. By forming the sintered body in this way, the flat copper powder in the raw material powder moves to the vicinity of the boundary between the mold and the raw material powder during compression molding of the raw material powder (especially when filling the mold), As a result, flat copper powder covers the green compact surface with high probability. In other words, the ratio of the flat copper powder in the surface layer (for example, the region from the surface of the green compact to a depth of 20 to 150 μm) is higher than that of the center of the green compact. Therefore, copper is dissolved in the metal powder of the main component at the time of sintering of the green compact to form a solid solution, so copper existing in the surface layer portion as compared with the central portion disappears and the sintered body There are voids on the surface. Therefore, even when the relative density of the sintered body is high, it is possible to form more pores on the surface due to the solid solution of copper compared with the inside, thereby providing excellent anchor effect while having high strength. It becomes possible to make it express. In addition, since it is possible to form many pores on the surface only by using a copper powder generally used for this kind of sintered body, it is possible to use a flat copper powder other than copper powder. For points, the conventional method can be applied as it is. Therefore, it becomes possible to mass-produce the sintered compact which can express the outstanding anchor effect, without causing a significant cost up.

  In the sintered body according to the present invention, the aspect ratio of the flat copper powder, which is a value obtained by dividing the maximum longitudinal dimension of the flat copper powder by the maximum thickness dimension of the flat copper powder, is 10 or more and 200 or less. And preferably 13 or more and 160 or less. The maximum longitudinal dimension referred to here means the circumscribed circle diameter of the flat copper powder as shown by the symbols L and t in FIG. 1, respectively, and the maximum thickness dimension is the maximum in the thickness direction of the flat copper powder. Means a value.

  By using flat copper powder having such a shape (aspect ratio), the flat copper powder in the raw material powder moves to the vicinity of the boundary between the mold and the raw material powder during compression molding of the raw material powder, with higher probability. The compacted powder surface can be covered with flat copper powder. Therefore, it is possible to form many pores on the surface of the sintered body by solid solution of copper at the time of sintering, and it is possible to express a more excellent anchor effect.

In the sintered body according to the present invention, the apparent density of the flat copper powder may be 0.2 g / cm ³ or more and less than 1.4 g / cm ³ , preferably 0.5 g / cm ³ or more. And 1.0 g / cm ³ or less.

  By using flat copper powder having such an apparent density and shape, flat copper powder in the raw material powder moves to the vicinity of the boundary between the mold and the raw material powder during compression molding of the raw material powder, which is higher The powder compact surface can be covered with flat copper powder with probability. Therefore, it is possible to form many pores on the surface of the sintered body by solid solution of copper at the time of sintering, and it is possible to express a more excellent anchor effect.

  In the sintered body according to the present invention, the ratio of the flat copper powder to the raw material powder may be 0.5 wt% or more and less than 10.0 wt%.

  By setting the compounding ratio of the flat copper powder to 0.5 wt% or more, preferably 1.0 wt% or more, the above-described precipitation action on the surface of the green compact and the formation of pores due to solid solution at the time of sintering The effects can be enjoyed effectively. In addition, by suppressing the compounding ratio of the flat copper powder to less than 10 wt%, excessive formation of pores on the surface of the sintered body can be suppressed, and the number and size (surface area, depth) appropriate for expression of the anchor effect And so on) can be formed.

  In the sintered body according to the present invention, the relative density may be 80% or more. The relative density here is a value obtained by dividing the density of a sintered body measured according to the Archimedes method according to JIS Z 2501: 2000 by the true density of the raw material powder of the sintered body ( It refers to the weight ratio).

  By setting the relative density of the sintered body to 80% or more in this way, it is possible to ensure the mechanical strength that the sintered body should have as a machine component, for example. Further, according to the present invention, even in the case of a sintered body having a relative density of 80% or more, many pores can be formed on the surface for the reason described above. Therefore, the sintered body itself can not only obtain excellent mechanical strength, but can also exhibit excellent anchor effect with other members to obtain high bonding strength.

  In the sintered body according to the present invention, the metal powder of the main component may be iron-based powder. The term "iron-based" as used herein means not only pure iron but also iron-based alloys. Moreover, pure iron here is industrial pure iron, and may contain unavoidable impurities.

  Since the melting point of iron (1535 ° C.) is higher than the melting point of copper (1084 ° C.), the range of possible sintering temperatures in the case of using iron-based powder as the main component is higher than the melting point of copper (e.g. 1350 ° C.). On the other hand, the temperature range in which copper can form a solid solution with iron is 1200 to 1400 ° C. Therefore, according to the combination of the iron-based powder as the main component of the raw material powder and the flat copper powder, copper can be dissolved in iron relatively easily while appropriately sintering iron as the main component. Sintering conditions (in particular, sintering temperature conditions) can be set. Moreover, since iron-based powder is also a powder used widely in the field of powder metallurgy as copper powder (flat copper powder), a sintered body can be used without applying cost increase by applying conventional techniques. It becomes possible to mass-produce.

  As described above, since the sintered body according to the present invention exhibits an excellent anchor effect with other members, for example, the first member formed of this sintered body, and the sintering It is possible to suitably provide as a joined body including a second member fixed to the first member in a state where a part of the hole is formed in the surface of the body.

  Alternatively, the sintered body according to the present invention includes a first member formed of the sintered body, and a second member fixed to the first member via the adhesive layer, and the adhesive layer is It is also possible to provide as a joined body in which the second member is joined to the first member in a state in which a part thereof is in the pores formed in the surface of the sintered body.

  Moreover, the solution of the above-mentioned subject is achieved also by the manufacturing method of the sintered compact concerning the present invention. That is, this manufacturing method is a method of manufacturing a sintered body obtained by compression molding and sintering a raw material powder containing a metal powder having a melting point higher than copper as a main component, and the raw material powder has a flat shape. It is characterized in that it contains flat copper powder and causes the flat copper powder to form a solid solution in the metal powder of the main component during sintering.

  As described above, according to the method for producing a sintered body according to the present invention, the flat copper powder in the raw material powder is a mold and the raw material powder at the time of compression molding of the raw material powder as in the sintered body according to the present invention. It moves to the vicinity of the boundary, and the ratio of flat copper powder in the surface layer portion is higher than that of the center portion of the green compact. Therefore, copper forms a solid solution in the metal powder of the main component at the time of sintering of the green compact to form a solid solution, so copper which is present in the surface layer disappears and pores are generated on the surface of the sintered body. . Therefore, even when the relative density of the sintered body is high, it is possible to form more pores due to the solid solution of copper on the surface than in the inside, thereby achieving an excellent anchor effect while having a high density. It becomes possible to make it express. In addition, since it is possible to form many pores on the surface only by using a copper powder generally used for this kind of sintered body, it is possible to use a flat copper powder other than copper powder. For points, the conventional method can be applied as it is. Therefore, it becomes possible to mass-produce the sintered compact which can express the outstanding anchor effect, without causing a significant cost up.

  As described above, according to the present invention, it is possible to manufacture a sintered body capable of obtaining high bonding strength with other members while having high strength without increasing the cost.

They are a side view (upper side) and a top view (lower side) of flat copper powder concerning the present invention. It is the figure which planarly viewed the surface of the sintered compact concerning this embodiment. It is an expanded sectional view of the surface layer part of the sintered compact containing the surface shown in FIG. It is a side view of the zygote of a sintered compact and a lightweight object concerning this embodiment. It is a principal part expanded sectional view of the joined body shown in FIG. (A) The surface image of the sintered compact which concerns on the comparative example 1, (b) It is the surface image of the sintered compact which concerns on Example 1. FIG. (A) The surface image of the sintered compact which concerns on the comparative example 2, (b) It is the surface image of the sintered compact which concerns on Example 2. FIG. (A) It is a cross-sectional image of the sintered compact which concerns on the comparative example 1, (b) It is a cross-sectional image of the sintered compact which concerns on Example 1. FIG. (A) It is a cross-sectional image of the sintered compact which concerns on the comparative example 2, (b) It is a cross-sectional image of the sintered compact which concerns on Example 2. FIG.

  Hereinafter, an embodiment of the present invention will be described.

  The sintered body according to the present invention comprises a predetermined metal powder as a main component, and is formed by compressing and sintering a flat-shaped copper powder, that is, a raw material powder containing flat copper powder. The details of the composition of the raw material powder, mixing, compacting and sintering will be described below in this order.

[Composition of raw material powder]
Any metal powder can be used as the metal powder that is the main component of the raw material powder, as long as it is a metal having a melting point higher than that of copper. Furthermore, when it is essential to sinter metal powders of the main component, the temperature range in which the green compact containing the metal powder as a main component can be sintered is a temperature range in which copper can be dissolved during sintering. Any metal powder can be used as long as it overlaps with. Iron-based powder can be mentioned as an example of the metal powder which satisfies the above conditions. In addition, there is no particular limitation on the method of producing the metal powder of the main component, for example, one obtained by applying known powder production technology such as mechanical alloying method or reduction method including atomizing method such as gas atomizing method It is possible.

  Further, the particle size distribution of the metal powder of the main component is not particularly limited, as long as the relative density (for example, 80% or more by weight ratio) can be obtained so as to show mechanical strength usable as a mechanical part. The particle size distribution in this case is 50 to 200 μm in terms of an average particle size.

  Further, the metal powder which is the main component of the raw material powder is not limited to only one type, for example, pure iron powder and stainless steel powder (ferrous powder and ferric powder), or pure iron powder and It is also possible to use two or more types of metal powder as a main component, such as pure copper powder (iron-based powder and copper-based powder which is not flat copper powder) having a smaller degree of flatness than flat copper powder. In this case, it may be considered that the same amount of both types of metal powder is contained, or the most amount of either type of metal powder is contained and the other type of metal powder is secondly contained, etc. .

  As flat copper powder contained in the raw material powder, at least a part of the copper powder contained in the raw material powder may move to the vicinity of the boundary between the mold and the raw material powder during compacting, in other words, onto the molding surface of the mold. Insofar, the size or degree of flatness is arbitrary. As an example, when flat copper powder 1 has a shape as shown in FIG. 1, one having a maximum longitudinal dimension L of 10 μm or more and 100 μm or less, preferably 20 μm or more and 80 μm or less can be used is there. Further, flat copper powder 1 having a maximum thickness dimension t of 0.25 μm or more and 5.0 μm or less, preferably 0.5 μm or more and 3.0 μm or less can be used. However, it is important that the aspect ratio of flat copper powder 1, which is a value obtained by dividing the maximum longitudinal dimension L by the maximum thickness dimension t, is larger than that of the metal powder of the main component (aspect ratio). And 200 or less, more preferably 13 or more and 160 or less.

Also, the apparent density of the flat copper powder, and a 0.2 g / cm ³ or more but less than 1.4 g / cm ³ can be used, preferably at 0.5 g / cm ³ or more and 1.0 g / The thing of cm ³ or less is usable. The definition of the apparent density conforms to the definition of JIS Z 8901.

  The method for producing flat copper powder is optional, and for example, a flat copper powder produced by atomization may be flattened by crushing.

  The ratio (blending ratio) of the flat copper powder having the above characteristics to the raw material powder is set to, for example, 0.5 wt% or more and less than 10.0 wt%. Among these, 1.0 wt% or more is more preferable about a lower limit, and 8.0 wt% or less is more preferable about an upper limit.

  Moreover, you may add substances other than the metal powder and flat copper powder of a main component to raw material powder. For example, one or two or more solid lubricants such as graphite and molybdenum disulfide may be added in order to reduce the sliding resistance with the mold at the time of compacting.

  The raw material powder of the above composition is as uniform as possible by, for example, adding the metal powder and flat copper powder as main components and the above-mentioned additives as necessary to a known mixer such as a V-type mixer and mixing them. It can create a dispersed state.

Compacting
After obtaining the uniformly dispersed raw material powder in this way, the raw material powder is filled in a predetermined area (cavity) of the molding die. Thereafter, the raw material powder is compressed by performing cold pressing under a predetermined condition, for example, by a uniaxial pressing method, and is formed into a green compact having a predetermined shape. At this time, it is preferable to appropriately set compression molding conditions (for example, the filling amount of the raw material powder, the upper dead point position of the upper punch, etc.) so that the relative density of the finally obtained sintered body is 80% or more. .

  In this compacting process, the flat copper powder contained in the raw material powder has a smaller apparent density (smaller average particle diameter) and a relatively higher degree of flatness than the metal powder as the main component. Therefore, flat copper powder is likely to precipitate (move) in the vicinity of the molding surface, for example, when filling the cavity. In addition, flat copper powder easily adheres to the molding surface. As a result, the proportion of flat copper powder is relatively high at the surface of the green compact obtained by compression molding or in the vicinity thereof (surface layer portion), and is low at the central portion.

  In addition, the method of compacting is arbitrary, and it is also possible to apply shaping | molding methods other than the uniaxial pressing mentioned above. Specifically, it is also possible to apply a forming method using a multi-axis CNC press or a forming method using cold isostatic pressing (CIP). Also, not limited to cold press molding, warm press molding in which powder compacting is performed in a state where a mold and a raw material powder are heated, and mold lubrication in which press molding is performed in a state where a lubricant is held on the surface of the mold. Molding may be applied. Further, the material of the molding die is not particularly limited. The molding surface of the molding die may be coated with a hard film containing various nitride films such as diamond like carbon (DLC), CrN, TiN, TiAlN and the like.

[Sintering]
The green compact is sintered by applying a predetermined heat treatment using a heating device such as a furnace. Here, the maximum temperature during sintering (so-called sintering temperature) is set based on the melting point of the main component metal powder. On the other hand, in the present invention, the maximum temperature at the time of heating is set within a temperature range in which the flat copper powder constituting the green compact together with the metal powder of the main component can form a solid solution in the metal powder. That is, while the metal powders of the main component are joined by sintering, the maximum temperature at the time of sintering is set so that the flat copper powder forms a solid solution in the metal powder of the main component. In the present embodiment, the maximum temperature during sintering is set to 1200 to 1300 ° C. ([melting point × 80 to 85%] ° C. of the metal powder of the main component). As a result, the metal powders of the main component are bonded together to form a sintered body, and the flat copper powder in the green compact is solid-solved in the metal powder of the main component to form a solid solution. Since the flat copper powder consisting of a copper structure is mainly dispersed on the surface of the green compact and in the vicinity thereof (surface layer portion), when solid solution occurs as described above, the copper structure of the surface layer disappears, and instead A void is created. Therefore, as shown in FIG. 2, on the surface 3 of the sintered body 2, the pores 4 already opened at the stage of the green compact and the pores 5 newly formed after sintering due to the solid solution of copper. And are mixed. In this case, for example, as shown in FIG. 3, the sintered body 2 has the metal structure 7 of the main component and the copper structure 8 having a flat shape, and particularly in the surface layer portion 6, the metal structure 7 of the main component is copper. It has a solid solution 9 formed as a solid solution. In this case, the pores 5 generated at the time of sintering due to the solid solution of copper often exist adjacent to the solid solution 9. In the present embodiment, although a sintered body as a final product is completed by sintering, it is needless to say that another heat treatment may be performed after sintering if necessary. Alternatively, processing other than heat treatment (such as dimension correction processing such as sizing) or post-processing such as washing may be performed.

  Thus, according to the sintered body 2 of the present invention, the flat copper powder 1 in the raw material powder moves to the vicinity of the boundary between the mold and the raw material powder during compression molding of the raw material powder, and the center of the green compact is obtained. The proportion of the flat copper powder 1 in the surface layer portion is higher than that of the portion. Therefore, copper forms a solid solution in the metal powder of the main component at the time of sintering of the green compact to form a solid solution 9, so that a large amount of copper in the surface layer portion 6 disappears and the surface 3 of the sintered body 2 is Holes 5 are generated. Therefore, even when the relative density of the sintered body 2 is high (80% or more), many pores 5 can be formed on the surface 3 due to the solid solution of copper compared with the inside. Therefore, for example, as shown in FIG. 4, it is considered to manufacture a joined body 12 formed by joining the sintered body 2 and the lightweight body 10 formed of a light metal such as aluminum via the adhesive layer 11. The part 11a of the adhesive layer 11 enters the holes 4 and 5 formed on the surface 3 of the sintered body 2 by heating, for example (see FIG. 5). Therefore, by solidifying the adhesive layer 11 including the part 11a in this state, the part 11a of the adhesive layer 11 and the holes 4 and 5 are engaged, and the anchor effect can be exhibited. As a result, it is possible to obtain high bonding strength between the sintered body 2 and the adhesive layer 11 while having high density, and it is possible to increase the bonding strength between the sintered body 2 and the lightweight body 10. Moreover, since it is possible to form many pores 5 on the surface 3 only by using copper powder (flat copper powder 1) used widely for sintered body 2, flat copper powder can be formed into copper powder. The conventional method can be applied as it is, except that 1 is used. Therefore, it becomes possible to mass-produce the sintered compact 2 which can express the outstanding anchor effect, without causing a significant cost up. As a result, it is possible to manufacture a joined body 12 of the sintered body 2 and the lightweight body 10 having high bonding strength.

  As mentioned above, although one Embodiment of this invention was described, the manufacturing method of the sintered compact concerning this invention, the joined body containing this sintered body, and a sintered compact is not limited to the form of the said illustration, This invention Of course, any form can be taken within the scope of the invention.

  For example, in the above embodiment, as a joined body of a sintered body and a lightweight body, one integrated between a sintered body and a light metal body via an adhesive layer is exemplified, but of course the joined body according to the present invention Is not limited to this. For example, the sintered body and the resin material may be integrated by insert molding of a resin material having the sintered body as an insert. In this case, the resin material is integrated in a state in which a part of the resin material is intruded into the pores formed on the surface of the sintered metal material. The point is that the sintered metal material and the dissimilar material are integrated in a state in which a part of the dissimilar material to be joined of the sintered metal material enters the pores provided on the surface of the sintered metal material.

  Of course, the sintered body according to the above description is not necessarily limited to the use for bonding with different materials, and can also be used for bonding with the same materials. Moreover, it is widely applicable to the machine component of various uses as a sintered compact single body or a joined body. Further, the shape of the sintered body alone or the bonded body is not particularly limited. Therefore, of course, the present invention is applied to all mechanical parts having various shapes such as a rectangular plate shape, a disk shape, and a cylindrical shape.

  Hereinafter, examples for demonstrating the utility of the present invention will be described.

(Preparation of primary test piece)
First, while using pure iron powder as metal powder which is a main component of raw material powder, using copper powder and using graphite and a wax lubricant as a solid lubricant, Examples 1 to 3 and Comparative Examples 1 to 1 The primary test pieces (all were sintered bodies) according to No. 3 were produced. At this time, electrolytic copper powder CE-15 (apparent density: 1.4 to 1.6 g / cm ³ ) manufactured by Fukuda Metal Foil & Powder Industry Co., Ltd. is used as a copper powder in Comparative Examples 1 to 3 as an example. In 1-3, flat copper powder MS-800 (apparent density: 0.5 to 1.0 g / cm ³ ) manufactured by the same company was used. The maximum longitudinal dimension L of the flat copper powder used here is 20 to 80 μm, and the maximum thickness dimension t is 0.5 to 3.0 μm (aspect ratio L / t = 13.3 to 160). The addition amount of each copper powder is 1.0 wt% (Comparative Example 1, Example 1), 5.0 wt% (Comparative Example 2, Example 2), 8.0 wt% (Example 3), 10.0 wt% It was made into four levels of (comparative example 3). The pure iron powder, the copper powder, the graphite, and the solid lubricant were mixed for 40 minutes in a V-type mixer manufactured by Tsurui Rikakai Kikai Co., Ltd. for any of the comparative examples and the examples to obtain a raw material powder. Thereafter, a molding die made of alloy tool steel SKD11 was used to form a green compact having a predetermined shape, here, a plate-like shape, by uniaxial pressing using a floating die method. The molding conditions were room temperature at 980 MPa. At this time, the dimension of the green compact obtained in the longitudinal direction was 60 mm, the dimension in the width direction was 12 mm, and the dimension in the thickness direction was 2 mm.

The green compact obtained as described above was heated to 1250 ° C. in a pusher furnace and held for 90 minutes. Thereby, the green compact was sintered to prepare a primary test piece (sintered body). The sintered density of each primary test piece is shown in Table 1. Here, the sintering density is the density of the sintered body measured by the Archimedes method.

(Observation of the surface)
In addition, the surface and cross section of each primary test piece were observed with a digital microscope VHX-5000 manufactured by Keyence Corporation, and a surface image and a cross-sectional image were obtained by photographing. As a representative example, the surface image of the primary test piece according to Comparative Example 1 is shown in FIG. 6 (a), and the surface image of the primary test piece according to Example 1 is shown in FIG. 6 (b). The surface image of the primary test piece is shown in FIG. 7 (a), and the surface image of the primary test piece according to the second embodiment is shown in FIG. 7 (b). Further, FIG. 8A shows a cross-sectional image of the primary test piece according to Comparative Example 1, and FIG. 8B shows a cross-sectional image of the primary test piece according to Example 1. The cross-sectional image of the piece is shown in FIG. 9 (a), and the cross-sectional image of the primary test piece according to the second embodiment is shown in FIG. 9 (b).

(Measurement of surface porosity)
Moreover, the surface porosity of each primary test piece was measured by performing predetermined | prescribed image processing with winROOF of Mitani Corporation about each acquired surface image. The surface porosity of each primary test piece is shown in Table 1.

(Evaluation of base material strength)
In addition, cylindrical sintered metal materials are produced under the same composition and conditions as in Examples 1 to 3 and Comparative Examples 1 to 3, and the strength (base material strength) of these cylindrical sintered metal materials is measured according to JIS Z 2507. It evaluated based on the measurement result of the crushing strength implemented based on the above. This test was conducted under stroke control using a universal testing machine. The stroke speed at the time of the test was 0.1 mm / min. Here, the radial crushing strength means the strength of the cylindrical sintered metal material determined by a constant method from the radial crushing load, and the radial crushing load compresses the cylindrical sintered metal material in two planes parallel to the axis and causes cracking. Refers to the load at which The base material strength of each primary test piece is shown in Table 1.

(Preparation of test piece)
Next, a test piece (joined body) was produced by joining a lightweight body test piece (secondary test piece) as a dissimilar material to the primary test piece obtained as described above. Specifically, a primary test piece and a secondary test piece (here, A5052 as an aluminum material) both having a plate shape are prepared, and one longitudinal end of the primary test piece and one longitudinal end of the secondary test strip are It piled up and heated to 150 degreeC by the hot press in the state which interposed the 80-micrometer-thick heat adhesive film in the piled part. Thereby, a primary test piece and a secondary test piece were mutually fixed via the heat bond film, and the test piece (joined body) was produced. The adhesion area at this time was 50 mm ² .

(Evaluation of bonding strength)
Moreover, the joint strength of the test piece which concerns on Examples 1-3 and Comparative Examples 1-3 was measured by the shear tension test according to ISO19095-3, and was evaluated. This test was conducted under stroke control using a universal testing machine. The stroke speed at the time of the test was 10 mm / min. The bonding strength of each test piece is shown in Table 1.

  Next, evaluation results will be described.

(Effect of shape of copper powder on bonding strength)
As can be seen from Table 1, when the shape of the copper powder is a general-purpose shape, that is, a spherical or nearly spherical shape (in the case of Comparative Examples 1 to 3), overall bonding is performed regardless of the amount of copper powder added. The intensity showed a low value. On the other hand, when the shape of the copper powder has a flat shape (in the case of Examples 1 to 3), the bonding strength as a whole shows a higher value than in the case where the copper powder has a general spherical shape. . The results (Table 1) also show that flat copper powder was used in the same compounding amount, in which the surface porosity was higher in the case of always using flat copper powder than in the case of using general-purpose spherical copper powder (Table 1). It confirms that it shows higher bond strength. From the above results, by using a copper powder having a predetermined shape (flat shape) as a pore forming agent on the surface of a sintered body, it is possible to obtain high bonding strength with other members while having high density. It turned out that a sinter which can be produced can be manufactured.

(Effect of blending amount of flat copper powder on bonding strength)
In addition, as can be seen from Table 1, when general-purpose spherical copper powder was used (Comparative Examples 1 to 3), the sintering density decreased as the compounding amount of the copper powder was increased. Moreover, even if the compounding amount increased, the bonding strength remained generally low. On the other hand, when flat copper powder was used (Examples 1-3), even if the compounding quantity of the said copper powder increased, the fall of sintering density was hardly seen. Also, it was found that higher bonding strength can be obtained by increasing the compounding amount to a certain extent (when the composition is increased to about 8.0 wt% in the composition of this example).

1 Flat copper powder 2 Sintered body 3 Surface 4 hole (present at the time of green compact)
5 Holes (formed by solid solution during sintering)
6 surface portion 7 metal structure 8 copper structure 9 solid solution 10 light weight body 11 adhesive layer 11 a part 12 joined body

Claims (9)

A sintered body obtained by compression molding and sintering a raw material powder containing a metal powder having a melting point higher than that of copper as a main component,
The raw material powder contains flat copper powder having a flat shape,
A sintered body containing a solid solution in which the flat copper powder forms a solid solution in the metal powder of the main component at the time of sintering.   The sintered body according to claim 1, wherein the aspect ratio of the flat copper powder, which is a value obtained by dividing the longitudinal direction dimension of the flat copper powder by the thickness direction dimension of the flat copper powder, is 10 or more and 200 or less. The sintered compact according to claim 1 or 2 whose apparent density of said flat copper powder is 0.2 g / cm ² or more and less than 1.4 g / cm ² .   The sintered compact according to any one of claims 1 to 3, wherein a proportion of the flat copper powder in the raw material powder is 0.5 wt% or more and less than 10.0 wt%.   The sintered body according to any one of claims 1 to 4, which has a relative density of 80% or more.   The sintered compact according to any one of claims 1 to 5, wherein the metal powder of the main component is an iron-based powder.   The first member formed of the sintered body according to any one of claims 1 to 6, and the first member in a state in which a part of the first member is intruded into the pores formed on the surface of the sintered body. And a second member fixed to the member.   A first member formed of the sintered body according to any one of claims 1 to 6, and a second member fixed to the first member via an adhesive layer, A bonding body in which the bonding layer bonds the second member to the first member in a state where a part of the bonding layer is in a void formed in the surface of the sintered body. A method for producing a sintered body, comprising compression molding a raw material powder containing a metal powder having a melting point higher than that of copper as a main component, and sintering the raw material powder,
The raw material powder contains flat copper powder having a flat shape,
The manufacturing method of the sintered compact which makes the said flat copper powder the solid solution in the metal powder of the said main component at the time of the said sintering.