JP5613293B2 - Zygote - Google Patents

Description

  The present invention relates to a joined body, and more particularly to a joined body suitable for a cutting tool.

  Conventionally, as represented by cBN (cubic boron nitride) or diamond cutting tools, cutting tools with high-hardness materials joined to the tip by brazing have been manufactured and used for special steel materials and other various cutting processes. ing.

  Specifically, for example, tools in which cBN and cemented carbide are joined by brazing are manufactured and sold (for example, Non-Patent Document 1). Alternatively, a joined body in which PCD (sintered diamond) or cBN and ceramics or cermet are joined by brazing has been proposed (for example, Patent Document 1 and Patent Document 2). A cutting tool in which a cemented carbide or cermet and high-speed steel or the like are joined by brazing using a Cu brazing material has also been proposed (for example, Patent Document 3).

JP 2002-360008 A Japanese Patent No. 3549424 Japanese Patent Laid-Open No. 11-294058

Issued by Sumitomo Electric Hardmetal Co., Ltd., Igetaroy cutting tool ('07 -'08 general catalog), October 2006, p. L4, Coated Sumiboron series

  However, in many of the brazing materials, a liquid phase appears at about 700 to 800 ° C. For this reason, it has been difficult to use a cutting tool using a joined body by brazing for high-speed cutting or the like that may exceed the aforementioned temperature during cutting. Moreover, the liquid phase produced | generated at the time of brazing oozes and soils a to-be-joined material, and had a bad influence at the time of the process which is a post process.

  Moreover, since the cBN sintered body and the diamond sintered body move back and forth, right and left with respect to the cemented carbide base material and become slanted by the melting of the brazing material, the cBN sintered body for the cemented carbide base material and the like. It was difficult to position the blade, and it was difficult to stabilize the position of the cutting edge with respect to the carbide substrate. For this reason, there existed a problem that the grinding amount and grinding time of to-be-joined materials, such as a cBN sintered compact after joining, increased. In order to cope with this problem, it is necessary to prepare a larger cBN sintered body and diamond sintered body in consideration of the amount of movement of the cBN sintered body and diamond sintered body and the amount of grinding at the time of joining. there were.

  In view of the above problems, the present invention does not reduce the bonding strength of the bonding layer even when the temperature exceeds the temperature at which the brazing material generates a liquid phase during cutting, and the cBN sintered body has a large grinding allowance. It is another object of the present invention to provide a joined body suitable as a cutting tool that does not require the preparation of a diamond sintered body.

As a result of intensive studies, the present inventor has found that the above problems can be solved by the inventions based on the respective technologies described below.
Hereinafter, each technique will be described.

The first technology is
A joined body having a cermet sintered body as a first material to be joined and a cBN sintered body or a diamond sintered body as a second material to be joined, wherein the first material to be joined and the second material to be joined The materials are joined via a joining material that is placed between them and generates a liquid phase at a temperature of more than 800 ° C. and less than 1000 ° C., and the joining is energized while being pressurized at a pressure of 0.1 MPa to 200 MPa. It is a joined body characterized by being performed by heating.

In the first technique , a first material to be joined made of a sintered cermet sintered body and a second material to be joined made of a sintered cBN sintered body or diamond sintered body are between the two. Are joined by a joining material that generates a liquid phase at a temperature exceeding 800 ° C. and lower than 1000 ° C. For this reason, unlike a joined body using a conventional brazing material that generates a liquid phase at a temperature of 800 ° C. or lower, a reduction in joining strength can be suppressed, and a cutting tool suitable for high-speed cutting can be provided.

  In addition, the thickness of the bonding material can be controlled to 30 μm or less, preferably 10 μm or less by energization heating while applying pressure, and the bonding position of the cBN sintered body or diamond sintered body can be made constant with respect to the cermet base material. Since the amount of grinding after joining can be made smaller than in the case of adhesive joining, the amount of movement of the cBN sintered body, the amount of grinding can be designed to the minimum necessary size, and the cBN sintered body etc. can be made small. The usage amount of the cBN sintered body can be suppressed.

  Further, the cermet sintered body has a larger thermal expansion coefficient than the cemented carbide sintered body having a larger thermal expansion coefficient than the cBN sintered body and the diamond sintered body. Therefore, when the cermet sintered body is used as the first material to be joined and the cBN sintered body or the diamond sintered body is used as the second material to be joined, the first material to be joined and the second material to be joined are used. The thermal expansion coefficient difference between the two is larger than when the cemented carbide sintered body is used as the first material to be joined, and cracks due to thermal stress generated in the cooling process after joining are more likely to occur.

However, in the first technique , since joining is performed by energizing and heating while pressurizing at a pressure of 0.1 MPa to 200 MPa, only the peripheral portion of the joint is compared with the conventional brazing joining method or the like. It can be heated in a short time. As a result, it is possible to reduce the generation of thermal stress, suppress the generation of cracks, and stably obtain a high-strength joint.

  Since the cBN sintered body and the diamond sintered body, which are the second material to be joined, are weak against heat and easily decomposed at high temperatures, they are likely to be thermally deteriorated in a short time. For this reason, the first material to be joined and the second material to be joined by brazing joining which requires a long time of 10 minutes or more for joining using a joining material that generates a liquid phase at a temperature exceeding 800 ° C. and less than 1000 ° C. It was difficult to obtain a joined body with the material.

However, in the first technique , the joining is performed by energizing and heating while applying a pressure of 0.1 MPa to 200 MPa between the first material to be joined and the second material to be joined. A strong bond can be obtained in an extremely short time within a few minutes. The preferred energization time is within 1 minute, particularly preferably within 30 seconds. As a result, the cermet is bonded to the cermet using a bonding material that generates a liquid phase at a temperature higher than 800 ° C. and lower than 1000 ° C. without deteriorating the quality of the high-pressure stable material cBN sintered body or diamond sintered body. It becomes possible to do.

If the applied pressure is too small, the contact resistance between the cBN sintered body, the diamond sintered body, and the cermet sintered body, which are the materials to be joined, and the electrode increases, and there is a problem that current does not flow or discharge. . On the other hand, when the applied pressure is too large, there is a problem that the cBN sintered body and the cermet sintered body are deformed. In the first technique , since a preferable pressure is 0.1 MPa to 200 MPa, these problems do not occur and a preferable joined body can be obtained. When the pressure is 1 MPa to 100 MPa, an appropriate contact resistance is obtained, and heat generation at the bonding surface is efficiently performed. Therefore, when the pressure is 10 MPa to 70 MPa, the contact resistance is further appropriate, and the joined body is further deformed. This is more preferable.

  In a tool in which a cBN sintered body and a diamond sintered body containing a metal binder such as Co and / or a sintered body having a cBN content ratio exceeding 70% and a large cBN content ratio are joined to a cermet as a joined body, 1000 ° C. When joining by electric heating is performed at the above temperature, there is a problem that cracks are generated in the cBN sintered body and the diamond sintered body and it is difficult to perform good joining. This is because the difference in thermal expansion coefficient between cBN or diamond and the metal binder is very large, so that the volume expansion of the metal binder is increased by heating at 1000 ° C. or higher, and cracks are generated in the cBN sintered body, or the cBN content is 70%. If the cBN sintered body exceeds 50%, the difference in thermal expansion coefficient from the cermet that is the base material is large, and it is considered that the cBN sintered body is cracked during the cooling process after joining. It is also considered that the metal binder of the cBN sintered body or the diamond sintered body generates a liquid phase at a temperature of 1000 ° C. or higher, and cracks are generated in the cBN sintered body or the diamond sintered body.

However, in the first technique , a bonding material that generates a liquid phase at a temperature lower than 1000 ° C. is used. For this reason, even when a cBN sintered body and a diamond sintered body containing a metal binder such as Co and / or a sintered body with a cBN content rate exceeding 70% and a cBN content rate are joined to a cermet, The heat load applied to the body and the diamond sintered body is smaller than that when bonded at 1000 ° C. or more, and the amount of thermal expansion is also small. Therefore, due to the difference in thermal expansion coefficient between the metal binder or cermet and cBN, diamond. The generated thermal stress is reduced, and it is difficult to introduce cracks into the cBN sintered body and the diamond sintered body, and good bonding can be performed. Moreover, since the metal binder in a cBN sintered compact or a diamond sintered compact does not produce | generate a liquid phase, it can prevent that a crack produces | generates in a cBN sintered compact or a diamond sintered compact.

The second technology is
The bonding material according to the first technique , wherein the bonding material is a bonding material that generates a liquid phase at a temperature of 900 ° C. or higher and lower than 1000 ° C.

In the 2nd technique , since the joining material which produces | generates a liquid phase at the temperature of 900 to 1000 degreeC is used, the tool provided with extremely heat resistance and joining force can be provided.

The third technology is
The first technique or the second technique is characterized in that the first material to be joined generates heat preferentially over the second material to be joined by the energization heating, and is joined. It is a joined body.

In the third technique , the cermet sintered body that is the first material to be joined is heated and joined preferentially over the cBN sintered body and the diamond sintered body that are the second material to be joined. In general, a cBN sintered body or a diamond sintered body has a higher electric resistance than a cermet sintered body. Therefore, during energization heating, the cBN sintered body or diamond sintered body, which is the second material to be joined, is the first object. Heat is generated preferentially over the cermet sintered body, which is a bonding material, and quality degradation (thermal degradation, decomposition, crack generation, etc.) of the cBN sintered body and diamond sintered body may be caused.

  In order to prevent such quality deterioration of the second bonded material, the second bonded material is heated so that the first bonded material generates heat preferentially over the second bonded material during energization heating. It is necessary to devise the bonding material, the arrangement of the bonding material, and the energization method. Specifically, for example, the materials of the electrode in contact with the second bonded material and the electrode in contact with the first bonded material can be changed. By changing the material of the electrode, the amount of current flowing through each of the first material to be bonded and the second material to be bonded is different, so that each heat generation can be controlled. Alternatively, the first material to be bonded may be heated more intensively than the second material to be bonded, and the second material to be bonded may be indirectly heated.

  Thus, by devising the energization path, the first material to be bonded can be preferentially heated over the second material to be bonded. As a result, the cBN sintered body and the diamond sintered body, which are the second materials to be joined, are heated in a short time, specifically within, for example, within 1 minute, preferably within 30 seconds without being heated at a higher temperature than necessary. Since the vicinity of the bonding material can be heated at a high temperature, strong bonding is possible, and cBN is not deteriorated (thermal deterioration, decomposition, crack generation, etc.) without causing quality deterioration of the cBN sintered body or diamond sintered body. Features such as high hardness of the sintered body and the diamond sintered body can be fully utilized.

The fourth technology is
A first technique in which at least one element of the bonding material components is diffused into the first bonded material and / or the second bonded material by energization heating. Or a joined body according to any one of the third techniques .

In the fourth technique , at least one element of the bonding material components is diffused in the first bonded material and the second bonded material, so the first bonded material and the second bonded material. Bonding with the material to be bonded can be performed more efficiently, and a bonded body with higher bonding strength can be obtained.

The fifth technology is
It is no first technology characterized by being bonded using a bonding material which is deformed by electrical heating of the under pressure is a conjugate according to any one of the fourth technical.

In the fifth technique , a bonding material that is deformed by energization heating while applying pressure is used. Therefore, the movement of the substance accompanying the deformation of the bonding material is effective for bonding the interface between the bonded material and the bonding material. Thus, a bonded body with high bonding strength can be obtained. In addition, since the bonding material is deformed in accordance with the shape of the material to be bonded by applying current while heating, the bonding area can be increased, and the effect of improving the bonding strength can be obtained.

The sixth technology is
The bonding material is made of an alloy containing at least one of titanium (Ti), zirconium (Zr), cobalt (Co), nickel (Ni), silver (Ag), and copper (Cu) . The joined body according to any one of the techniques 5 to 5 .

In the sixth technique , Ti, Co, and Ni that are generally used as binder phase components of a cermet sintered body that is a first material to be joined, a cBN sintered body that is a second material to be joined, and a diamond sintered body. Alternatively, since a bonding material made of an alloy containing at least one of Ag, Cu, and Zr that exhibits excellent wettability with a cBN sintered body or a diamond sintered body is used, a bonded body with higher bonding strength can be obtained. Can do.

  Examples of such a bonding material include an Ag—Cu alloy, an Ag—Ti alloy, an Ag—Zr alloy, a Cu—Si alloy, a Cu—Ti alloy, a Cu—Zr alloy, a Ni—Ti alloy, a Ni—Zr alloy, Cu-Mn alloys, Ni-Zn alloys, and solid solutions thereof such as Cu-Ti-Zr alloys, Ag-Cu-Ti alloys, and intermetallic compounds thereof can be used.

  The intermetallic compound may be contained in the bonding material from the beginning. Moreover, the element which comprises an intermetallic compound is contained in another state in the bonding | jointing material, and it may produce | generate by reaction after the completion of joining. When an intermetallic compound is produced by reaction, reaction heat can be used for joining, which is more effective for joining.

The seventh technology is
The bonding material according to the sixth technique , wherein the bonding material contains titanium (Ti).

In the seventh technique , since the material containing Ti used as the binder phase component of the cBN sintered body and the diamond sintered body as the second material to be joined is used as the joining material, Ti in the joining material can be easily obtained. Element diffusion can be performed in the first material to be bonded and the second material to be bonded, and a strong bond can be obtained.

The eighth technology is
At least a portion of the bonding material is a conjugate according to any one of the first technique, characterized in that to generate a liquid phase during electrical heating seventh technical.

In the eighth technique , since at least a part of the bonding material generates a liquid phase during energization heating, the bonded body component easily diffuses into the first bonded material and the second bonded material, A 1st to-be-joined material and a 2nd to-be-joined material can be joined firmly.

The ninth technology is
The bonding material and / or the first nickel contained in the binding phase of the material to be joined (Ni) is, either to no first technique of equal to or less than 30 vol% (volume percent) of the eighth technical It is a joined body of a crab.

In the ninth technique , nickel (Ni) contained in the bonding phase of the bonding material or the first bonded material is set to 30 vol% or less. If this exceeds 30 vol%, the chlorine gas used as the CVD coating material reacts with the bonding material or the first material to be bonded when the bonding body is subjected to CVD coating for the purpose of improving wear resistance. This is because the possibility of abnormal growth of the CVD film is high.

The tenth technology is
The bonding material is either the first technology to the ninth technique, characterized in that provided on the first material to be joined and / or on the surface of the second material to be joined by the plating method It is a joined body as described in above.

In the tenth technique , the bonding material is provided on the surface of the first bonded material or the second bonded material by a plating method. The plating method makes it easier to control the thickness of the bonding material than to apply the bonding material in the form of powder or paste, and can be easily controlled to 50 μm or less. As a result, when energization bonding is performed while applying pressure, the thickness of the bonding material after bonding can be set to 30 μm or less, preferably 10 μm or less, and the bonding quality can be stabilized. Furthermore, when the present technology is applied to mass production of joined bodies, it is easy to automate the process, which is preferable in terms of cost and quality stability.

The eleventh technology
The bonding material is either to no first technique, characterized in that provided on the surface of the first material to be joined and / or the second material to be joined by a physical vapor deposition ninth technical It is a joined body of a crab.

In the eleventh technique , the bonding material is provided on the surfaces of the first bonded material and the second bonded material by physical vapor deposition. The physical vapor deposition method makes it easier to control the thickness of the bonding material than when the bonding material is applied in the form of powder or paste, and can be easily controlled to 50 μm or less. As a result, when energization bonding is performed while applying pressure, the thickness of the bonding material after bonding can be set to 30 μm or less, preferably 10 μm or less, and the bonding quality can be stabilized. Furthermore, when the present technology is applied to mass production of joined bodies, it is easy to mechanize and automate, which is preferable in terms of cost and quality stability. Particularly preferred is the case where the film is formed by sputtering or arc evaporation.

The twelfth technology
The joined body according to any one of the first to eleventh techniques , wherein the joined body is a cutting tool.

In the twelfth technique , since the joined body uses a cermet sintered body as the first joined material and a cBN sintered body or diamond sintered body as the second joined material as the joined materials, A joined body obtained by joining via a material can be suitably used as a cutting tool. Specific cutting tools include, for example, rotary tools such as drills, end mills, and reamers in addition to cutting tips. The tool of the present technology can provide a cutting tool in which the bonding strength of the bonding material does not decrease even in high-speed cutting in which the brazing material has a temperature higher than the temperature at which the brazing material generates a liquid phase.

The present invention is an invention based on the above-described technology.
A joined body having a cermet sintered body as a first material to be joined and a cBN sintered body or a diamond sintered body as a second material to be joined, wherein the first material to be joined and the second material to be joined The materials are joined via a joining material that is placed between them and generates a liquid phase at a temperature of more than 800 ° C. and less than 1000 ° C., and the joining is energized while being pressurized at a pressure of 0.1 MPa to 200 MPa. The joined body is characterized in that the first joined material is heated preferentially over the second joined material by the energization heating and is joined by heating. .

Next, the invention described in claim 2
2. The joined body according to claim 1, wherein the joining material is a joining material that generates a liquid phase at a temperature of 900 ° C. or more and less than 1000 ° C. 3.

Next, the invention according to claim 3
2. The element according to claim 1, wherein at least one element of the bonding material components is diffused into the first bonded material and / or the second bonded material by electric heating. A joined body according to claim 2.

Next, the invention described in claim 4
The bonded body according to any one of claims 1 to 3, wherein the bonded body is bonded using a bonding material that is deformed by energization heating while being pressurized.

Next, the invention according to claim 5 is:
The bonding material is made of an alloy containing at least one of titanium (Ti), zirconium (Zr), cobalt (Co), nickel (Ni), silver (Ag), and copper (Cu). A joined body according to any one of claims 1 to 4.

Next, the invention according to claim 6 is:
6. The joined body according to claim 5, wherein the joining material contains titanium (Ti).

Next, the invention according to claim 7 is:
The bonded body according to any one of claims 1 to 6, wherein at least a part of the bonding material generates a liquid phase during energization heating.

Next, the invention according to claim 8 is:
The nickel (Ni) contained in the binder phase of the bonding material and / or the first bonded material is 30 vol% (volume percentage) or less, according to any one of claims 1 to 7. It is a joined body of description.

Next, the invention according to claim 9 is:
The said joining material is provided on the surface of the said 1st to-be-joined material and / or the said 2nd to-be-joined material by the plating method, The Claim 1 thru | or 8 characterized by the above-mentioned. It is a joined body.

Next, the invention according to claim 10 is:
The said joining material is provided on the surface of the said 1st to-be-joined material and / or the said 2nd to-be-joined material by the physical vapor deposition method, The one in any one of Claim 1 thru | or 8 characterized by the above-mentioned. It is a joined body of description.

Next, the invention of claim 11 is
The joined body according to any one of claims 1 to 10, wherein the joined body is a cutting tool.

  As described above, in the present invention, the cBN sintered body and the diamond sintered body do not cause quality deterioration (thermal deterioration, decomposition, crack generation, etc.) of the cBN sintered body and the diamond sintered body which are high-pressure stable materials. It is possible to provide a tool that can make full use of characteristics such as the high hardness of the body. In particular, it can be suitably provided as a tool such as a wear-resistant tool, a mining / civil engineering tool, a cutting tool, and the like.

  In the present invention, the second material to be bonded can be bonded to the first material to be bonded without necessarily requiring a back metal (a thin cemented carbide layer provided on the opposite side of the cutting surface). However, the joined body of the second material to be joined and the first material to be joined having the back metal is not excluded from the present invention.

  According to the present invention, a cBN sintered body and a diamond sintered body having a large grinding allowance are prepared without decreasing the bonding strength of the bonding layer even when the temperature exceeds the temperature at which the brazing material generates a liquid phase during cutting. Therefore, even if a cBN sintered body or a diamond sintered body that is liable to crack during joining is joined, a joined body suitable as a cutting tool can be provided.

It is a conceptual diagram explaining the one form of electricity supply in electricity supply pressurization joining. It is a conceptual diagram explaining the other form of electricity supply in electricity pressurization joining. It is a conceptual diagram explaining one form in the energization pressurization joining of a rotary tool. It is a conceptual diagram explaining the other form in the electricity pressurization joining of a rotary tool.

Hereinafter, modes for carrying out the present invention will be described based on the following experimental examples . Note that the present invention is not limited to the following embodiments. Various modifications can be made to the following embodiments within the same and equivalent scope as the present invention.

(About energization in energization and pressure bonding)
First, the form of energization in energization and pressure bonding will be described with reference to the drawings.
1. First Form of Energization FIG. 1 is a conceptual diagram illustrating one form of energization in energization / pressure bonding. In FIG. 1, the materials 1 and 3 to be joined are a first material to be joined (cermet sintered body) and a second material to be joined (cBN sintered body or diamond sintered body), respectively. Bonding is performed using the bonding material 2.

  Specifically, the materials to be bonded 1, 3 and the bonding material 2 are sandwiched between electrodes (graphite) 4 and pressurized, and a current is passed through the electrode 4. Since the electrode 4 spans both the material to be bonded 1 and the material to be bonded 3, even if the electric resistance of any of the materials to be bonded is high, the electrode 4 is sufficient for bonding through the material to be bonded having the lower electric resistance. An electric circuit through which a current flows can be formed.

As the bonding material 2, the material shown in claim 1 that generates a liquid phase at a temperature higher than 800 ° C. and lower than 1000 ° C. by energization heating is used. At this time, a material having the characteristics described in claims 4 to 10 is desirable.

  By passing an electric current through the electrode 4, the bonding material 2 generates resistance heat together with the bonded materials 1 and 3, and the bonded materials 1 and 3 are bonded. The material of the two electrodes 4 is of course conductive, but it is desirable that the material does not react with the materials to be bonded 1, 3, and the bonding material 2. However, even if it reacts, the reaction with the electrode can be suppressed by disposing a carbon sheet between each of the materials 1 and 3 to be joined.

2. Second Energization Form FIG. 2 is a conceptual diagram illustrating another form of energization in energization / pressure bonding. In FIG. 2, the divided electrode 5 is in contact with the second material to be bonded 3, and the electrode 4 is in contact with the first material to be bonded 1. By changing the material of the electrode 4 and the divided electrode 5, the electric conductivity and the thermal conductivity can be changed, and different currents can be applied to the first and second bonded materials. It becomes possible, and it becomes possible to change each temperature extremely. Thereby, even to-be-joined material which is easy to cause thermal degradation, it can join, without causing thermal degradation. Furthermore, the pressure applied to the first material to be joined and the second material to be joined can be controlled with high accuracy by dividing the electrodes and pressurizing each electrode independently, thus improving the joining strength. This is preferable.

3. 3rd form of electricity supply FIG. 3: is a conceptual diagram explaining one form at the time of carrying out the electricity pressurization joining of the rotary tool. In FIG. 3, a material to be bonded 1 and a material to be bonded 3 are arranged with a bonding material 2 interposed therebetween, and an electrode 4 is in contact with each material to be bonded. When a voltage is applied between the electrodes, a current flows through the materials 1 and 3 and the bonding material 2 to be bonded by being heated. In order to flow a current sufficient for heating, it is preferable that the electrode 4 and the materials 1 and 3 are in close contact as much as possible. When the material to be bonded 3 is a material having high electrical resistance, it is possible to secure a current path and flow a sufficient current for bonding by adding a material having low electrical resistance to a part of the material to be bonded 3 in advance. It becomes. It is preferable that the electrode 4 and the materials 1 and 3 to be joined are in close contact.

4). 4th form of electricity supply FIG. 4: is a conceptual diagram explaining the other form at the time of carrying out the electricity pressurization joining of a rotary tool. In FIG. 4, a material to be bonded 1 and a material to be bonded 3 are arranged with a bonding material 2 interposed therebetween, and the electrodes are in contact with the respective materials to be bonded. Unlike the case of the third energization mode, the electrodes are divided into an electrode 7 and an electrode 9 that pressurize together with energization, and an electrode 6 and an electrode 8 that mainly energize. Thereby, even if it is the to-be-joined materials 1 and 3 with high electrical resistance, a material with low electrical resistance is added to the to-be-joined materials 1 and 3, and an electric current is preferentially sent from the electrode 6 and the electrode 8 to the part. It becomes possible to perform pressurization and heating only on the necessary portions. The electrode 7 and the electrode 6 and the electrode 9 and the electrode 8 may be in contact with each other. In addition, no current may flow through the electrode 7 and the electrode 9. Furthermore, it is preferable to configure the electrodes 6 and 8 so that the positions and current amounts of the electrodes 6 and 8 can be adjusted independently of each other because changes in shape and characteristics can be accommodated. Further, the materials of the electrodes 6 to 9 may be all the same, partly different, or all different. Or the material may differ only in the part which contacts the to-be-joined materials 1 and 3. FIG.

(About joining by energizing pressure bonding)
Next, energization and pressure bonding using the energization shown in FIGS. 1 to 4 will be described.
The energization conditions are appropriately determined depending on the material to be joined and the material of the joining material, etc., but in order not to cause deformation / melting of the material to be joined and coarsening of the particles other than in the vicinity of the joining material. It is preferably within 1 minute, particularly within 30 seconds.

  As a form of a bonding material for performing energization and pressure bonding, in addition to a method of applying the powder or paste on the surface of the first bonded material or the second bonded material, it is coated by a plating method or a physical vapor deposition method. The method can be adopted. The coating method by plating or physical vapor deposition is easy to handle the material to be bonded after coating the bonding material, which is advantageous for automating the bonding process and easy to control the coating film thickness. It is particularly preferable for stabilization.

  By applying current and heating while applying pressure, the bonding material is easily deformed, adhesion between the bonding material and the material to be bonded is increased, and element diffusion is facilitated. As a result, the bonding strength can be dramatically increased. In particular, when the joined body of the present invention is applied to a cutting tool, for example, a cutting tip, the joining surfaces of the first material to be joined and the second material to be joined are in the vertical and horizontal directions in FIG. There are two directions, and the first material to be bonded and the second material to be bonded need to be firmly bonded in both directions. In such a case, it is preferable to apply pressure from two directions.

  If the applied pressure is too weak, the contact resistance between the electrode and the material to be joined increases, and current cannot flow or discharge occurs, which is inappropriate. Moreover, since a cermet sintered compact will deform | transform if too large, it is unsuitable. In the present invention, 0.1 MPa to 200 MPa is appropriate.

  The bonding atmosphere is preferably performed in vacuum, in an inert gas, or in a reducing atmosphere because both the material to be bonded and the bonding material contain metal. The degree of vacuum is not particularly limited, but is preferably higher than 13.3 Pa (0.1 Torr). Examples of the inert gas include argon, helium, nitrogen, or a mixed gas thereof. Examples of the reducing atmosphere include a gas atmosphere in which hydrogen gas is mixed in a certain proportion with the inert gas, and a method in which heated graphite is installed in the vicinity of the material to be joined.

  As the form of the current to be energized, a direct current and an alternating current can be used as long as a current for allowing the material to be joined and the joining material to be heated to an appropriate temperature can flow. In particular, the DC pulse current can change the peak current value and the ON / OFF ratio of the pulse, so that the instantaneous heating of the bonding interface and the overall temperature control range of the bonded object can be expanded. It is valid.

( Experimental Examples 1-6 and Comparative Examples 1 and 2)
This experimental example and comparative example relate to the relationship between the pressure applied during bonding and the bonding strength, and the relationship between the deformation of the materials to be bonded.
CBN chip with triangular back metal (first bonding material) plated with Ni-7wt% P (melting point: about 900 ° C.) having a thickness of 10 μm on a cermet base metal (first material to be joined) containing counterbore 1 are set as shown in FIG. 1, and 0.05 MPa (Comparative Example 1), 0.1 MPa ( Experimental Example 1), 10 MPa ( Experimental Example 2), 30 MPa ( Experimental Example ) from the vertical direction. 3) Conducting pressure bonding in a vacuum under a state where each pressure of 70 MPa ( Experimental Example 4), 100 MPa ( Experimental Example 5), 200 MPa ( Experimental Example 6), and 250 MPa (Comparative Example 2) was applied, The joined bodies of Experimental Examples 1 to 6 and Comparative Examples 1 and 2 were obtained. Note that graphite was used as an electrode, and a graphite sheet was inserted between the electrode and the material to be joined in order to prevent reaction with the electrode. The energization is performed by a DC pulse current, the pulse current value is 2300 A, the pulse On: Off ratio is 1: 1, the pulse width is 10 ms, the energization time is 10 seconds, the load is 0.98 kN, and the temperature of the bonded body is equal to or higher than the melting point of the bonding material. , Under conditions of less than 1000 ° C. The cermet base metal (first material to be joined) is TiCN-15WC-5Mo ₂ C-3Ni-12Co (material to be joined A) and TiCN-35WC-5Mo ₂ C-3Ni-12Co (material to be joined). B) (both wt%: mass percentage) were used.

  The joining strength (shear fracture strength) of each obtained joined body was measured, and the presence or absence of deformation of each joined material in the vicinity of the joining layer was observed. The results are shown in Table 1.

As shown in Table 1, in the case of a pressure of 0.1 to 100 MPa ( Experimental Examples 1 to 5), the strength equal to that of the conventional brazed product is obtained, and deformation of the joined material is recognized. I can't. In the case of 100 to 200 MPa, no deformation is observed depending on the composition of the materials to be joined. However, when the applied pressure is extremely low (Comparative Example 1), it is not joined, and when a pressure exceeding 200 MPa is applied (Comparative Example 2), the vicinity of the joining layer regardless of the composition of the materials to be joined. The material to be joined has been deformed. As a result, in the present invention, it was confirmed that a preferable pressing force was 0.1 to 200 MPa.

( Experimental example 7)
Next, using a sputtering method, which is a physical vapor deposition method, instead of plating, a 20 μm thick Ti-50 wt% Cu layer (melting point: about 960 ° C.) is applied to cBN (second bonded material) with a back metal. It provided and joined with the cermet base metal (1st to-be-joined material). At this time, as the cermet base metal (first material to be bonded), the material A and the material B to be bonded were used, and the bonding conditions were the same as those in Experimental Example 3. As a result, it was confirmed that cBN and cermet were joined without a gap through the Ti—Cu layer. This is presumably because a liquid phase was generated during bonding. The bonding strength was 220 MPa for the material A to be bonded and 290 MPa for the material B to be bonded.

Next, each of the joined bodies in Experimental Example 3 and each joined body in Experimental Example 7 using A and B as the first material to be joined is ground using a diamond grindstone, and then a known CVD method is used. Then, TiCN was coated with a thickness of 5 μm at a coating temperature of 870 ° C., and the state of growth of the CVD film was observed. As a result, in the bonded body of Experimental Example 3 in which the bonding material was Ni-P, abnormal growth of the CVD film was observed regardless of the type of the first bonded material. On the other hand, in the joined body of Experimental Example 7 in which the joining material was Ti—Cu instead of Ni—P, abnormal growth of the CVD film was not seen regardless of the type of the first joined material.

( Experimental example 8)
Next, a material (bonding material) obtained by dissolving 50 vol% Cu-25 vol% Ti-25 vol% Zr powder (melting point about 850 ° C.) with a solvent is used as a cermet base metal (bonded material A: first bonded material). This was applied, set with a cBN chip without back metal (second material to be joined), and energized and pressure bonded under the same energizing conditions as in Experimental Example 3. The joint strength of this joined body was 290 MPa, and it was confirmed that it had a strength equivalent to that of a conventional brazed product. A dense Cu—Ti—Zr layer having a thickness of 20 μm was observed at this joined portion, and it was confirmed that the Cu—Ti—Zr powder was melted or sintered.

( Experimental example 9)
Next, based on the experimental example 8, for the purpose of shortening the energization time, the joining condition was obtained by changing the energization time among the conditions shown in the experimental example 8. As a result, when the energization time was changed from 10 seconds in Experiment Example 8 to 8 seconds, good joining was possible at a current 100A larger than the current value (2300A) shown in Experiment Example 8. Further, when the energization time was 6 seconds, good bonding was possible by further increasing the pulse current by 100 A.

( Experimental example 10)
Next, in order to join the back surface of cBN (second material to be joined) with high accuracy, the joining was performed while applying pressure from two directions. As in the previous examples, the vertical pressure was applied with the upper and lower electrodes, and the load was applied separately from the side so that the cBN could be pressurized in the horizontal direction. In addition, the to-be-joined material A was used as a 1st to-be-joined material. The same Ni-P plated cBN with back metal as used in Experimental Example 3 was used, and the bonding was performed with a pulse current of 4000 A, a pulse On: Off ratio of 1: 4, and an energization time of 10 seconds.

  As a result, not only the bottom surface of cBN but also the back surface was bonded to the cermet base metal via the Ni-P layer. The bonding strength at this time was 360 MPa, and higher strength was obtained as compared with the case where pressure was applied only in the vertical direction.

( Experimental example 11)
Next, among the electrodes to be energized and pressurized, the upper electrode is divided, and the electrode for pressing the cermet base metal (bonded material A: first bonded material) and cBN without back metal (second bonded material) are used. The material of the electrode to be pressurized was changed. Thereby, the electric current which flows into an electrode changes, and the electric current value which flows into a cermet base metal and cBN also changes. As a result, each temperature can be changed extremely, and the temperature of cBN in which deterioration is a concern at high temperatures can be lowered.

  The electrode for energizing and pressing the cermet base metal was graphite, and the electrode for energizing and pressing cBN was hBN. hBN is an electrically insulating material, and almost no current flows. As cBN, 69 vol% Ag-26 vol% Cu-5 vol% Ti (melting point: about 820 ° C.) coated by 40 μm by sputtering was used. When an experiment was performed with a pulse current of 3000 A, a pulse On: Off ratio of 1: 2, a pulse width of 10 ms, an energization time of 10 seconds, and a load of 0.98 kN, cBN could be joined without thermal degradation. This is presumably because almost no current flowed through the cBN, the cBN itself did not generate Joule heat, and the cermet base metal was preferentially heated so that it could be joined without raising the temperature of the cBN. The bonding strength was 250 MPa, which was equivalent to that of a conventional brazed product.

( Experimental example 12)
A joined body was obtained in the same manner as in Experimental Example 11 except that the upper electrode was an undivided electrode. The joint strength of the obtained joined body was 290 MPa, which was equal to or higher than that of the conventional brazed product and higher than the joint strength in Experimental Example 11. However, some cracks occurred in the cBN of the obtained bonded body, and quality degradation due to heat was observed.

From the results of Experimental Example 11 and Experimental Example 12, by controlling the power supply to the cBN (second bonded body) and preferentially heating the cermet (first bonded body), cBN (first bonded body). It was confirmed that a bonded body having a high bonding strength without thermal deterioration of the second bonded body) can be obtained.

( Experimental example 13)
Next, instead of the insulating hBN shown in Experimental Example 11, the material of the electrode that pressurizes cBN (second bonded material) is made conductive. At this time, the material which has electrical conductivity higher than the electrical conductivity of the electrode which pressurizes a cermet base metal (1st to-be-joined material) was used. As a result, the current flowing through the cermet base metal and the cBN can be changed. The current flowing through the cermet base metal heats the base metal near the cBN, and the current flowing through the cBN can preferentially heat the bonding material.

  Specifically, the cermet base metal was set to about 2000 A, and cBN was set to about 1000 A (current is an estimated value), and energization and pressure bonding was performed. At this time, the difference between the counterbore depth and cBN height of the cermet base metal was 0.1 mm, and by using the divided electrodes, it was possible to pressurize both the cermet base metal and the cBN even if the gap was large. As a result of energization, it was possible to perform bonding firmly without deteriorating cBN.

DESCRIPTION OF SYMBOLS 1 1st to-be-joined material 2 Joining material 3 2nd to-be-joined material 4, 6, 7, 8, 9 Electrode 5 Divided electrode

Claims (11)

A joined body having a cermet sintered body as a first material to be joined and a cBN sintered body or a diamond sintered body as a second material to be joined, wherein the first material to be joined and the second material to be joined The materials are joined via a joining material that is placed between them and generates a liquid phase at a temperature of more than 800 ° C. and less than 1000 ° C., and the joining is energized while being pressurized at a pressure of 0.1 MPa to 200 MPa. A joined body characterized in that the first joined material is heated preferentially over the second joined material by the energization heating and is joined by heating .   The joined body according to claim 1, wherein the joining material is a joining material that generates a liquid phase at a temperature of 900 ° C or higher and lower than 1000 ° C. By electrical heating, at least one element of the bonding material component is claim 1, characterized in that it is an element diffused into the first material to be joined and / or the second material to be joined or The joined body according to claim 2 . The bonded body according to any one of claims 1 to 3 , wherein the bonded body is bonded using a bonding material that is deformed by energization heating while being pressurized. The bonding material is made of an alloy containing at least one of titanium (Ti), zirconium (Zr), cobalt (Co), nickel (Ni), silver (Ag), and copper (Cu). The joined body according to any one of claims 1 to 4 . The joined body according to claim 5 , wherein the joining material includes titanium (Ti). The joined body according to any one of claims 1 to 6 , wherein at least a part of the joining material generates a liquid phase during energization heating. The nickel (Ni) contained in the binder phase of the bonding material and / or the first bonded material is 30 vol% (volume percentage) or less, according to any one of claims 1 to 7. The joined body described. The said joining material is provided on the surface of the said 1st to-be-joined material and / or the said 2nd to-be-joined material by the plating method, The Claim 1 thru | or 8 characterized by the above-mentioned. The joined body. The said joining material is provided on the surface of the said 1st to-be-joined material and / or the said 2nd to-be-joined material by the physical vapor deposition method, The one in any one of Claim 1 thru | or 8 characterized by the above-mentioned. The joined body described. The joined body according to any one of claims 1 to 10 , wherein the joined body is a cutting tool.

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