JP2007092091A - Hard film coated sintered member, and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hard film coated sintered member capable of realizing a tough hard film coated on a base material formed of a sintered body to prolong the lifetime. <P>SOLUTION: Any one of a ceramic film, a BCN-based super-hard material film, and a mixed film of metal and ceramic is coated on a surface of a base material formed of the sintered body, and has a dislocation structure having the dislocation density of the uniformly distributed, straight dislocation being 1×10<SP>4</SP>to 9×10<SP>10</SP>cm<SP>-2</SP>in a range of tens of μm or under from the interface of the base material formed of the sintered body. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to a hard film-coated sintered member and a method for producing the same, and more specifically, a hard film having a high hardness is coated on the surface of a sintered substrate such as cemented carbide, cermet or ceramic sintered body. And a method for manufacturing the same.

Conventionally, titanium nitride (TiN), titanium carbonitride (TiCN), titanium carbide (TiC), chromium nitride (CrN), aluminum titanium nitride (TiAlN), aluminum oxide (Al ₂ O ₃ ), diamond-like carbon (DLC) or other hard film is coated by chemical vapor deposition (hereinafter abbreviated as CVD), physical vapor deposition (hereinafter abbreviated as PVD) or plasma CVD. Based on various characteristics such as wear resistance, sliding characteristics, decoration, corrosion resistance, and heat resistance of hard films, the hard film coated sintered member consists of cutting tools, wear resistant tools, molds, automotive engine parts, Machine-related parts such as bearing sliding members, corrosion-resistant parts, heat-resistant parts such as gas turbine blades, electrical parts such as hard disks and magnetic heads, and sports parts such as golf heads It has been widely used.

By the way, especially when utilizing the above-mentioned hard film coated sintered member as a machine-related part, the hard film itself is fragile and there is a problem in the adhesion between the sintered body base material and the hard film. For this reason, once micro damage occurs in the hard film, the hard film is rapidly peeled off from the sintered base material, and as a result, machine-related parts are rapidly worn and their life is shortened. There was a problem.

Therefore, conventionally, after coating a hard layer on the surface of a cemented carbide substrate, a shot is projected to improve wear resistance and fracture resistance, or after coating the surface of a cemented carbide member with a hard layer. A metal, glass or ceramic shot having a particle size of 10 to 1000 μm is projected at a projection speed of 140 to 500 m / s to improve fracture resistance and wear resistance.
JP-A-2-254144 Japanese Patent No. 3232778

  However, the conventional method for strengthening a hard film in a cemented carbide base material configured as described above can provide sufficient fracture toughness, wear resistance, fatigue strength, thermal shock resistance, thermal fatigue resistance, or sliding characteristics. There was a problem that the service life was still short.

The present invention has been made in view of the above circumstances, and its object is to harden a hard film coated on a sintered body base material and to extend its life, and to manufacture the same. It is to provide a method.

As a result of intensive studies on the hard film-coated sintered member, the present inventors have improved the fracture toughness, wear resistance, fatigue strength, thermal shock resistance, thermal fatigue resistance or sliding characteristics of the hard film-coated sintered member. The ceramic film formed on the surface of a substrate made of a sintered body such as cemented carbide, cermet or ceramic sintered body by chemical vapor deposition method (CVD method), physical vapor deposition method (PVD method) or plasma CVD method After coating the surface of the sintered base material as a hard film, either a BCN-based ultra-hard material film or a metal / ceramic mixture film, the hardness of the sintered base material coated with the hard film is A spherical injection material having a particle size of 10 to 100 μm lower than that of the hard film is injected under predetermined injection conditions to form dislocations on the substrate side of the hard film-sintered substrate interface. We have found that the method is very effective.
The hard film-coated sintered member thus obtained has a dislocation structure in which the dislocation density of uniformly distributed linear dislocations is 1 × 10 ^{4 to} 9 × 10 ¹⁰ cm ^−2. It was generated in the range of several tens of μm or less from the interface.

In order to achieve the above object, the hard film-coated sintered member according to the first aspect of the present invention provides a hard film with a high hardness on the surface of a substrate made of a sintered body such as cemented carbide, cermet or ceramic sintered body. A hard film-coated sintered member formed by coating, wherein a ceramic film, a BCN ultra-hard material film, or a mixed film of metal and ceramic is coated on the surface of the sintered body substrate as the hard film. And having a dislocation structure in which the dislocation density of uniformly distributed linear dislocations is 1 × 10 ^{4 to} 9 × 10 ¹⁰ cm ⁻² within a range of several tens of μm or less from the base material interface of the sintered body. It is characterized by.

  According to a second aspect of the present invention, there is provided a method for producing a hard film-coated sintered member comprising: a hard substrate having a high hardness is coated on a surface of a substrate made of a sintered body such as cemented carbide, cermet or ceramic sintered body. A method of producing a hard film-coated sintered member comprising a ceramic film, a BCN-based ultra-hard material film, a metal-ceramic mixture film on the surface of the sintered base material, and a chemical vapor deposition method. (CVD method), physical vapor deposition method (PVD method) or plasma CVD method coated as the hard film, the sintered body coated with the hard film, the hardness is lower than that of the hard film and A spherical propellant having a particle size of 10 to 100 μm is sprayed under predetermined spraying conditions to form dislocations on the substrate side of the hard film-sintered substrate interface, thereby improving the film adhesion strength. Fracture toughness, wear resistance, fatigue strength, thermal shock resistance, To improve the fatigue resistance or sliding characteristics, characterized in that to extend the life.

The hard film in the present invention includes titanium nitride (TiN), titanium carbonitride (TiCN), titanium carbide (TiC), chromium nitride (CrN), aluminum titanium nitride (TiAlN), aluminum oxide (Al ₂ O ₃ ), It consists of one kind of single layer or a laminate of two or more layers formed of a hard material such as diamond-like carbon (DLC) or a mixture containing this hard material.

In addition, the hard film-coated sintered member of the present invention has a dislocation structure in which the dislocation density of uniformly distributed linear dislocations is 1 × 10 ^{4 to} 9 × 10 ¹⁰ cm ^−2. It has a range of several tens of μm or less from the material interface. The dislocation density is preferably 1 × 10 ^{4 to} 9 × 10 ¹⁰ cm ⁻² , and preferably 1 × 10 ^{5 to} 9 × 10 ⁹ cm ⁻² . If the dislocation density is less than 1 × 10 ⁴ cm ⁻² , no further improvement in the strength and toughness of the hard film can be obtained, and if it exceeds 9 × 10 ¹⁰ cm ⁻² , the hard film tends to break due to stress concentration. In addition, the high toughness of the hard film cannot be maintained, and the hard film is peeled off or damaged.
However, the dislocation density is a value measured by a transmission electron microscope.

In addition, the injection material in the present invention is preferably as close to a true sphere as possible, and a ceramic material having a lower hardness than the hard film is particularly preferable. And as a particle size of an injection material, several micrometers-500 micrometers are preferable, and 10-100 micrometers is especially suitable. Specific examples of the propellant include zircon, mullite, zirconia, alumina, silicon nitride, and silicon carbide.

In addition, the jetting speed of the propellant in the present invention is preferably 20 to 150 m / s. If it is less than 20 m / s, the toughness of the hard film cannot be obtained, and if it exceeds 150 m / s, chipping of the hard film becomes remarkable and peeling of the hard film occurs.
In addition, the spray density in the present invention is preferably 0.03 to 100 g / cm ² . If it is less than 0.03 g / cm ² , the toughness of the hard film cannot be obtained, and if it exceeds 100 g / cm ² , chipping of the hard film becomes significant, and peeling of the hard film occurs.
In addition, the jetting time in the present invention is preferably 0.1 to 20 seconds / cm ² . If it is less than 0.1 sec / cm ² , the toughness of the hard film cannot be obtained, and if it exceeds 20 sec / cm ² , the chipping of the hard film becomes significant, and peeling of the hard film occurs.

As apparent from the above description, the invention of claim 1 is a hard film coating obtained by coating a surface of a sintered body such as cemented carbide, cermet or ceramic sintered body with a hard film having high hardness. It is a sintered member, and any one of a ceramic film, a BCN-based ultra-hard material film, and a mixed film of metal and ceramic is coated on the surface of the sintered base as the hard film and is uniformly distributed. This type of conventional dislocation structure having a dislocation density of linear dislocations of 1 × 10 ^{4 to} 9 × 10 ¹⁰ cm ⁻² is within a range of several tens of μm or less from the base material interface of the sintered body. Compared with the hard film-coated sintered member, the hard film becomes tough and has excellent practical effects such as a significant increase in life.

According to a second aspect of the present invention, there is provided a hard film-coated sintered member obtained by coating a surface of a sintered body such as cemented carbide, cermet or ceramic sintered body with a hard film having a high hardness. A ceramic vapor deposition method (CVD method), a physical vapor deposition method (PVD), or any one of a ceramic film, a BCN ultra-hard material film, and a metal / ceramic mixture film is formed on the surface of the substrate made of the sintered body. Method) or plasma CVD method as the hard film, and the sintered base material coated with the hard film has a spherical shape having a hardness lower than that of the hard film and a particle size of 10 to 100 μm. The injection material is injected under predetermined injection conditions to form dislocations on the substrate side of the hard film-sintered substrate interface to improve the film adhesion strength, thereby providing fracture toughness, wear resistance, fatigue Improved lifespan by improving strength, thermal shock resistance, thermal fatigue resistance or sliding characteristics Therefore, not only the hard film but also the fracture toughness on the base side of the hard film-sintered base material interface is greatly improved, and the interface of the sintered base material is plastic together with the hard film. Since the adhesive strength between the hard film and the base material is enhanced by deformation, excellent practical effects such as a significant increase in the life of the hard film-coated sintered member are obtained.

The characteristics of the hard film coated sintered member produced by applying the present invention were examined as follows. First, a thin film sample for TEM observation was prepared with a focused ion beam device (Hitachi F-2000), and the structure was observed with a transmission electron microscope (TEM) and JEOL-200CX (pressurized voltage 200 kV) manufactured by JEOL Ltd. went. The dislocation density is obtained by calculating the length of dislocation per unit volume. Specifically, (1) the thickness of the thin film sample is measured, and (2) a TEM observation image of the place where the dislocation density is measured is obtained. (3) The dislocation density was measured through a process of measuring the length of dislocations contained in the unit area from the TEM observation image.

In addition, the characteristics of the hard film coated sintered member produced by applying the present invention were evaluated as follows. That is, after the surface of the test piece of the hard film-coated sintered member was polished with various diamond polishing papers such as # 600, # 1000, and # 3000 by the fracture toughness test method (IF method) specified in JIS R 1607 Sequential polishing with 1 μm and 1/4 μm diamond suspensions, followed by testing the Vickers indenter with an optimal indentation load selected from 1 kgf, 2 kgf, 5 kgf, 10 kgf, 30 kgf, and 50 kgf based on the specimen material After pressing into the surface of the piece for 15 seconds, the crack length generated from the four corners of the indentation formed by the indentation of the Vickers indenter is measured. Then, to obtain a toughening effect of the hard film by the equation of α = Ca / C _b.
Here, α is the crack length reduction rate (−), C _b is the crack length (μm) before toughening, and C _a is the crack length (μm) after toughening. It shows that the toughening effect is larger as the value of α is smaller than 1.

The end surface of a cylindrical test piece with a diameter of 10 mm and a height of 10 mm made of cemented carbide K10 as a sintered base material is polished to a mirror finish to a surface roughness of 0.2 S or less, and then the finished surface In addition, a TiN (silicon nitride) film, a TICN (titanium carbonitride) film, a TIAlN (aluminum titanium nitride) film, a CrN (chromium nitride) film, an Al ₂ O ₃ (aluminum dioxide) film, etc. by PVD and CVD methods A single-layer hard film having a thickness of 5 μm is coated, and a spray material such as alumina, silicon nitride, zircon or mullite having an average particle diameter of 100 μm, 50 μm, 20 μm, etc. Inject for a predetermined time from the vertical direction at the injection pressure and various injection speeds, and then observe the sample surface on which the injection material was injected under the accelerating voltage of 200 kV with the transmission electron microscope described above. And give a Rutotomoni observation image, then, obtain the dislocation density by measuring the length of dislocations contained in the unit area from the observed image. Next, a Vickers indenter is pushed into the surface of the sample onto which the spray material has been sprayed to form an indentation, and subsequently, the crack length generated from the four corners of the indentation is measured. Then, by the above equation of α = Ca / C _b, to obtain a toughening effect of the sample. The results are shown in Table 1.
Note that the crack length reduction rate α decreases as the dislocation density of the hard film in the crystal of the structure of the sintered body base material increases, and the fracture toughness of the hard film-coated sintered member tends to be improved.

Table 1 shows the following. All the test pieces to which the present invention is applied have a crack length reduction rate α of less than 1. This is because, in the vicinity of the interface between the hard film and the sintered base material, plastic deformation is caused in the structure of the sintered body base material through the hard film by precision machining injection, and in the crystal of the structure. This is because the dislocation was introduced and the fracture toughness of the hard film and the base material made of a sintered body immediately below the hard film was improved. In particular, the chromium nitride film of Example 6 has been improved by significant toughening.

After polishing the end face of the test piece made of cemented carbide K10 as the sintered base material and mirror-finishing it to a surface roughness of 0.2S or less, CrN (chromium nitride) with a thickness of 3 μm on the finished surface A silicon nitride propellant having an average particle diameter of 50 μm and a hardness of 1400 HV is applied to the surface of the sample coated with the PVD method and coated with a chromium nitride film from the vertical direction at an injection speed of 60 m / s and an injection density of 10 g / cm ^2. Next, in order to evaluate the adhesion of the chromium nitride film to the cemented carbide K10 and the wear resistance of the chromium nitride film, a scratch test and a ball-on-disk wear test were performed. Show.

  Table 2 shows the following. In Example 13, the load critical load at which cracks occur in the chromium nitride film by the scratch test is about 1.4 times larger than that in Comparative Example 4, and when the chromium nitride film is completely peeled by the scratch test. The load critical load is also 1.5 times larger than that of Comparative Example 4. This is because the chromium nitride film is improved in fracture toughness by the injection of the spray material, and the interface of the cemented carbide K10 is plastically deformed together with the chromium nitride to improve the bonding strength with the chromium nitride and is hard. In the vicinity of the interface between the film and the sintered compact substrate, precision processing injection causes plastic deformation of the structure in the sintered compact substrate via the hard film, and dislocations are introduced into the crystals of the structure. This is because the fracture toughness of the hard film and the substrate made of a sintered body immediately below the hard film was improved.

In Example 13, the wear area of the test piece is about 20% smaller than that of Comparative Example 4. As is clear from the scratch test results, the test piece of Example 13 can have a larger critical load than that of Comparative Example 4 at which cracks are generated and the chromium nitride film is peeled off. It is thought that the wear due to the peeling of the chromium film was reduced and the wear resistance was improved.

A cylindrical specimen having a diameter of 10 mm and a height of 10 mm was used for the scratch test, and a flat specimen having a length of 50 mm, a width of 50 mm, and a thickness of 8 mm was used for the ball-on-disk wear test.
The scratch test was performed by loading a diamond indenter having a tip radius of 200 μm at a load speed of 200 N / min and a scratch speed of 10 mm / min.
The wear test conditions were as follows: a tribometer tester using a SiC ball having a diameter of 6.35 mm as a stationary counterpart, a load of 10 N, a rotation radius of 3.0 mm, a rotation speed of 10.0 cm / s, and a wear area of 60 It was calculated by measuring the cross-sectional shape of the wear scar after 1,000 rotations.

A silicon nitride injection material having an average particle diameter of 50 μm was injected at an injection speed of 100 m / s and an injection density of 5 g / cm ² on a Kyocera insert chip (PVD cermet PV7020, tool part number: TPMT110308GP) coated with a hard film. Insert inserts that do not inject silicon nitride injection material on CNC lathes, cut chromium molybdenum steel (SCM415) at a cutting speed of 170 m / min and feed speed of 0.25 mm / rev, and investigate the life of each. As a result, the insert tip injected with the silicon nitride injection material was able to cut 900 chrome molybdenum steels, but only 300 insert tips that were not injected with the silicon nitride injection material could be processed. . The wear resistance of the insert tip was improved by the injection of the silicon nitride injection material.

A Fujikoshi-made aqua drill coated with a hard film and injected with an alumina injection material having an average particle diameter of 50 μm at an injection speed of 60 m / s and an injection density of 15 g / cm ² ; As a result of drilling in carbon steel (S53C) with a cutting speed of 80 m / min, feed rate of 0.24 mm / rev, and a hole depth of 23 mm, and investigating the life of each, injection of alumina The drill that injected the material was capable of drilling 1260 carbon steels, but 720 drills that did not spray the alumina injection material began to flash. The lifetime of the drill was increased by 175% by the injection of the alumina injection material.

An injection material made of silicon nitride having an average particle diameter of 50 μm is applied to a die for punch die made of carbide V30 coated with a 3 μm thick titanium nitride film by PVD method at an injection speed of 80 m / s and an injection density of 30 g / cm ² . As a result of cold forging the cap hole-shaped automotive part (material: SCR416) with a diameter of 20mm using the sprayed one and the punch mold that does not inject the silicon nitride propellant, the lifespan was compared. The mold in which the spray material was injected had a healthy titanium nitride film even after 200,000 shots or more, but the mold in which the silicon nitride spray material was not sprayed was damaged by peeling off the titanium nitride film after 15,000 shots. . When the silicon nitride spray material was sprayed, the lifetime of the titanium nitride film was extended 13 times or more.

An alumina injection material having an average particle diameter of 100 μm is applied to a die die for cemented carbide V30 coated with a 3 μm thick TiCN film by the PVD method at an injection speed of 80 m / s and an injection density of 5.0 g / cm ² . As a result of cold forging 40 mm diameter joint automobile parts (material: SCR416) using the injected one and a die mold that does not inject the alumina injection material, Although the TiCN film was sound even when the injected mold was 240,000 shots or more, the TiCN film peeled off after 80,000 shots of the mold that did not inject the alumina injection material. When the alumina injection material was injected, the life of the TiCN film was extended by more than three times.

Claims (3)

A hard film-coated sintered member formed by coating a surface of a substrate made of a sintered body such as cemented carbide, cermet or ceramic sintered body with a hard film having high hardness,
Dislocation density of linear dislocations in which a ceramic film, a BCN ultra-hard material film, or a metal / ceramic mixture film is coated on the surface of the sintered body substrate as the hard film and distributed uniformly A hard film-coated sintered member having a dislocation structure of 1 × 10 ^{4 to} 9 × 10 ¹⁰ cm ⁻² on the surface within a range of several tens μm or less from the base material interface of the sintered body . A method for producing a hard film-coated sintered member formed by coating a surface of a sintered body such as cemented carbide, cermet or ceramic sintered body with a hard film having high hardness,
Any one of a ceramic film, a BCN-based ultra-hard material film, and a metal / ceramic mixture film is formed on the surface of the sintered body substrate by chemical vapor deposition (CVD), physical vapor deposition (PVD), or plasma CVD. The spherical base material having a hardness lower than that of the hard film and having a particle diameter of 10 to 100 μm is coated on the sintered base material coated with the hard film by the method. Injecting under injection conditions to form dislocations on the substrate side of the hard film-sintered substrate interface to improve film adhesion strength, thereby providing fracture toughness, wear resistance, fatigue strength, thermal shock resistance A method for producing a hard film-coated sintered member, which improves heat fatigue resistance or sliding characteristics and extends the life. In the manufacturing method of the hard film covering sintered member according to claim 2,
The hard film is characterized in that the spraying conditions of the spray material are a spray speed of 20 to 150 m / s, a spray density of 0.03 to 100 g / cm ² , and a spray time of 0.1 to 20 seconds / cm ^2. A method for producing a coated sintered member.