JP2001179504A - Hard carbon film-coated tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hard carbon film-coated tool capable of realizing a coated tool superior in both of abrasion resistance and slidability, by coating the tool with a hard carbon film including proper amounts of diamond superior in the crystalline property and the abrasion resistance and graphite superior in slidability with high adhesiveness, and remarkably elongating the life of the tool in comparison with a conventional one. SOLUTION: In this tool coated with a hard carbon film including diamond, both of diamond where the maximum structural coefficient TC (hkl) is TC (400) and hexagonal graphite satisfying that the strongest peak of an X-ray diffraction is (008) face index, are included in the hard carbon film.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a tool coated with a hard carbon film.

[0002]

2. Description of the Related Art With the recent increase in hardness and weight of workpieces, there is an increasing trend to use cutting tools and wear-resistant members coated with a diamond film having high hardness and high thermal conductivity. In particular, diamond-coated tools are promising for processing aluminum alloys and graphite materials, and are being actively studied. In general, these diamond films are prepared by using a raw material gas containing carbon such as hydrocarbons as a hot filament (Japanese Patent Laid-Open No.
91100), microwave plasma, etc.
10494), and a film is formed on the substrate surface by causing a reaction.

[0003] Although the diamond film formed by the chemical vapor deposition (CVD) method has a high hardness, it is (11)
The 1) plane and the (220) plane are oriented in a direction parallel to the surface of the base, and the surface of the film has large irregularities, and thus has a drawback of poor slidability. Further, the (111) plane has a disadvantage that it is easily cleaved. On the other hand, in Japanese Patent Publication No. 7-13298, the edge portion is a facet-shaped polycrystalline material having an average particle diameter of 0.1 μm or more, and an area of 50% or more of the surface has less cleavage (100) or ( 110) A diamond-coated cutting tool characterized by having a crystal face is disclosed. Further, an attempt has been made to reduce unevenness on the film surface and obtain a smooth film by making amorphous carbon, graphite, hydrogen, or the like other than diamond in the hard film. For example, Japanese Patent Application Laid-Open No. Sho 60-71597 discloses a sliding mechanism component having a hard carbon film made of a mixed crystal of diamond and hexagonal graphite on a sliding surface. However, these methods do not consider the crystallinity and orientation of diamond and hexagonal graphite and the adhesion between the two materials, and when used as a tool,
There was a disadvantage that the wear resistance was poor.

[0004]

In view of the above-mentioned drawbacks of the conventional diamond-coated tools, the problem to be solved by the present invention is to provide a diamond having excellent crystallinity and abrasion resistance and excellent slidability. Both graphites have good adhesion to each other and are coated with an appropriate amount of a hard carbon film to provide a coated tool with excellent wear resistance and sliding properties. Another object of the present invention is to provide a hard carbon film coated tool having a long tool life.

[0005]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, have found that the organization coefficient TC
By coating a hard carbon film containing both diamond having the largest TC (400) in (hkl) and hexagonal graphite having the strongest X-ray diffraction peak (008) plane index, The present inventors have found that a tool having cutting durability characteristics can be realized, and have reached the present invention.

That is, the present invention relates to a hard carbon film-coated tool coated with a diamond-containing hard carbon film,
Diamond having the largest TC (400) among the texture coefficients TC (hkl) and the strongest peak of X-ray diffraction are (008)
A tool coated with a hard carbon film, characterized by containing both hexagonal graphite having a plane index. The diamond having the highest TC (400) in the texture coefficient TC (hkl) and the hexagonal graphite having the strongest X-ray diffraction peak having the (008) plane index contain both diamond, so that the excellent resistance to diamond is obtained. It is judged that excellent tool characteristics having both abrasion and excellent sliding characteristics of graphite are realized.

Here, the texture coefficient TC (hkl) is defined by the following equation. TC (hkl) = 4 × {I (hkl) / I ₀ (hkl)} / [{I (111) / I ₀ (111)} + {I (311) / I ₀ (311)} + {I ( 400) / I ₀ (400)} + {I (331) / I ₀ (331)}] (1) where (hkl) = (111), (311), (40)
0) and (331) I (hkl) are (h) of the diamond film.
It is the measured X-ray diffraction intensity from the (kl) plane. I ₀ (hkl)
Is the JCPDS file No. 6-0675 (Powder Di
ffractionFile Published by JCPDS International Cen
ter for Diffraction Data), and represents the X-ray diffraction intensity from the (hkl) plane of isotropically oriented diamond powder particles. TC (hkl) defined by Equation 1
Indicates the relative intensity of the measured X-ray diffraction peak intensity from the (hkl) plane of the diamond film. The larger the TC (hkl) value, the stronger the (hkl) plane is oriented in the tangential direction to the substrate surface. It shows. The diamonds are (111), (220), (311), (400),
Five X-ray diffraction peaks of (331) are observed.
The X-ray diffraction peak of (20) (2θ = 75.30 °) has a WC
(200) peak (2θ = 75.51 °), and was not used in the calculation of the texture coefficient TC (hkl) in Expression 1.

[0008] The diamond component contained in the hard carbon film of the present invention has a TC of the texture coefficient TC (hkl).
Since (400) is the largest, (10)
0) The crystal plane is oriented in the tangential direction of the substrate, the cleavage of the crystal grains is small, the surface is flat, and it is judged that it has excellent wear resistance. At the same time, since the strongest peak of the X-ray diffraction contains hexagonal graphite having a (008) plane index, it is determined to have excellent slidability. Moreover, the hard carbon film of the present invention is expected to have an excellent bonding force between the diamond component and the hexagonal graphite component for the reasons described below, and as a result, both the wear resistance and the sliding property are excellent. Is determined to be.

FIG. 2 illustrates a unit cell of diamond. Cubic structure, lattice constant is 0.35667n
m. FIG. 2 shows that diamond has two carbon atoms at the position of the (400) plane, that is, at the position of the distance between the planes of 0.08916 nm. One feature of the present invention is that the (400) X-ray diffraction peak intensity is strong.

FIG. 3 shows hexagonal graphite (JCPDS).
File No. 23-64 and 25-284), and the lattice constant is a ₀ = 0.2456n
_{m, c 0 = 0.6696nm (File} No.25-
284) or a ₀ = 0.2463 nm, c ₀ = 0.6
714 nm (File No. 23-64). The actual length of the C-axis of the hexagonal graphite depends on the degree of crystallinity and the disorder of the orientation of the layer, and is 0.6696 to 0.688.
nm. Tables 1 and 2 respectively show the JCPDS F
ile No. It is a part extracted from (002-8) of the standard X-ray diffraction intensity with respect to each plane index of hexagonal graphite shown in 23-64 and 25-284. From Tables 1 and 2, the X-ray diffraction intensity IG of (008) was obtained.
(008) is the X-ray diffraction intensity IG of (002) (002)
It can be seen that the ratio is 1/10 to 1/100.

[0011]

[Table 1]

[0012]

[Table 2]

As can be seen from FIG. 3, the fact that the (008) plane of hexagonal graphite is oriented in the tangential direction to the substrate surface is the same as the orientation of the (002) plane. , IG (008) / IG (002) is always 0.1 to 0.01. However, in the case of the product of the present invention, IG (008) ≫IG (002). Although the reason is not clear, it is considered that the probability that atoms are present at the position of the (008) plane of hexagonal graphite, that is, at the position of 0.08370 nm between planes is high.

As described above, according to the present invention, both the hexagonal graphite component and the diamond component contained a distance between planes of 0.08370 nm and 0.08 nm.
Since there is a high probability that atoms exist at the position of 8916 nm, it is considered that there is some interference such as atom sharing between the two, and there is a possibility that a strong bonding force exists between the two. Is determined. As can be seen from the above discussion, the hexagonal graphite having the strongest (008) X-ray diffraction peak in the present invention has an interplanar distance of 0.08370.
As long as it is a graphite-based substance having an X-ray diffraction peak intensity in the vicinity of nm, it is apparent that it is not absolutely necessary to use hexagonal graphite.

At the same time as the above, the coated tool of the present invention has a (008) X-ray diffraction peak intensity of hexagonal graphite which is 0.1 to 3 times that of diamond (400) X-ray diffraction peak.
Preferably, the ratio is 0.15 to 2.5 times, more preferably 0.35 to 2 times. The ratio of the (008) X-ray diffraction peak intensity of hexagonal graphite to the (400) X-ray diffraction peak intensity of diamond is IG (008) / ID (400) of 0.1 to
3, the diamond component having excellent wear resistance and the graphite component having excellent slidability are contained in appropriate amounts, and the balance between wear resistance and slidability is excellent, and excellent tool durability characteristics are obtained. It is determined that it has been realized. When the X-ray diffraction peak intensity ratio IG (008) / ID (400) is less than 0.1 times, the content of hexagonal graphite is small, and the sliding characteristics are inferior. There is a disadvantage that the hardness is reduced and the wear resistance is reduced. Further, the X-ray diffraction peak intensity ratio IG (008) / ID
When (400) is 0.15 to 2, the wear resistance and sliding resistance are well balanced, and a longer tool life is obtained. When (400) is 0.35 to 2, the longest tool life is obtained. Can be

Further, in the coated tool of the present invention, at least one of carbides, nitrides and carbonitrides of metals belonging to the group IVa, Va and VIa of the periodic table and Fe, Ni, Co,
It is more preferable that the substrate is a cemented carbide consisting of at least one of W, Mo, and Cr. Further, the carbide of W, a nitride, and at least one of carbonitrides are made of Co, and It is most preferable to use a cemented carbide having a carbide, nitride, or carbonitride component of a Group IVa, Va, or VIa metal in the periodic table of 1% by mass or less as the base. By using the cemented carbide as a base, the toughness, hardness and heat resistance of the entire coated tool of the present invention are improved in a well-balanced manner, and it is judged that good cutting durability characteristics are realized as the coated tool. In addition, at least one of carbides, nitrides, and carbonitrides of W is composed of Co, and IV of the periodic table excluding W is included.
The adherence between the cemented carbide substrate and the hard carbon film is increased by using a cemented carbide having a carbide, nitride, or carbonitride component of a, Va, or VIa group metal of 1% by mass or less as a substrate. , It is determined that better tool durability characteristics have been realized.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below in more detail with reference to a hard carbon film coated end mill which is a typical example of a hard carbon film coated tool in the present invention.

In the coated tool of the present invention, the X-ray diffraction peak of diamond is identified by using the X-ray diffraction data of the above-mentioned JCPDS file (File No. 6-0675). Is the same as the file No. Performed using data of 25-284.

In order to manufacture the coated tool of the present invention, a hot filament chemical vapor deposition method (hot filament CVD method), a microwave CVD method, an rf plasma CVD method, an ECR plasma CVD method, or the like can be used. The application is not limited to a solid end mill type cutting tool, but may be an end mill type cutting tool using a throw-away insert, a milling tool, or a turning tool. Further, a wear resistant material, a mold, a molten metal part, or the like coated with a hard carbon film may be used.

In the coated tool of the present invention, the component of the hard carbon film is not limited to carbon. As long as the effects of the present invention are not lost, unavoidable additives and impurities such as Co and W may be contained, for example, up to about several mass%.

[0021]

EXAMPLES Next, the coated tool of the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples.

(Example 1) WC: 94% by mass, Co: 6
% By mass, and a ball end mill type cemented carbide substrate for a cutting tool (diameter 6 m) manufactured by sintering in the same lot.
m, two blades) and a rectangular parallelepiped substrate for X-ray diffraction measurement (5 × 5 × 1
0 mm ³ ) was set in a furnace, and a hard carbon film having a thickness of about 8 μm was formed on those surfaces by hot filament CVD. That is, by passing an electric current through a tungsten filament disposed around the end mill, the tungsten filament is heated to about 2,500 ° C., and the CH ₄ / H ₂ ratio is adjusted to 0.5 to 0.5 ° C.
10% to 150 cm ³ / m 3% mixed gas of CH ₄ and H ₂
in, and a film was formed at a pressure of 1.33 to 13.3 kPa and a substrate temperature of 900 to 1200 ° C.

FIG. 1 is a representative X-ray diffraction pattern of the product of the present invention prepared under the conditions of Example 1. The X-ray diffraction pattern of the hard carbon film formed on the surface of the rectangular parallelepiped substrate was measured using an X-ray diffractometer (RU-200BH) manufactured by Rigaku Denki Co., Ltd.
2θ−θ using α1 ray (λ = 0.15405 nm)
It was measured by the scanning method. The measurement range of 2θ is 10 to 145
In °, noise (background) was removed by software built into the device. Table 3 shows the 2θ value and X-ray diffraction intensity of the hard carbon film of the product of the present invention obtained from the X-ray diffraction pattern of FIG. The value of X-ray diffraction intensity is shown.

[0024]

[Table 3]

Table 4 shows the measured values of the diamond components in Table 3 and the TC (hkl) value obtained from Equation 1.

[0026]

[Table 4]

FIG. 1 and Tables 3 and 4 show that the hard carbon film of the present invention is composed of diamond and hexagonal graphite, and the peak at which the texture coefficient TC (hkl) of diamond is the maximum is (400). It can be seen that (008) is the strongest in hexagonal graphite. Further, the X-ray diffraction peak intensity IG of (008) of hexagonal graphite
(008) is 0.51 times the X-ray diffraction peak intensity ID (400) of diamond (400).

Table 5 shows the results of X-ray diffraction measurement of the tool coated with the hard carbon film produced in Example 1.

[0029]

[Table 5]

In each of the samples, TC (400) was the largest in the texture coefficient of diamond. From these results,
In the product of the present invention, any of the hard carbon films has a texture coefficient TC (4
It can be seen that (008) is composed of diamond having the maximum value and (008) being hexagonal graphite having the strongest value. The X-ray diffraction peak intensity IG (008) of (008) of hexagonal graphite is (400) of diamond.
X-ray diffraction peak intensity ID (400) of 0.05 to 3.
It turns out that it is 72 times.

The product of the present invention is in the range of 900 to 1200 ° C.
As the substrate temperature is increased by IG (008) and TC (4
00) and the film forming gas within the range of 0.5 to 3%.
CH _Four/ H_TwoID (400) increases as ratio decreases
Was.

Table 5 summarizes the results of evaluating the tool life of the product of the present invention. The tool life was indicated by the length of cutting the graphite material under the following conditions using each of the three manufactured invention products until the flank wear of the cutting edge of the outer peripheral edge reached 0.05 mm. . Work material Graphite (Hs105) Tool shape Ball nose end mill (6φ, 2 flutes) Tool rotation speed 7958 rotations / min Cutting speed 150 m / min Feed speed 398 mm / min (0.025 mm / tooth) Cutting 0.5 mm Cutting oil Abrasion resistance of the tool can be evaluated at an early stage by using a graphite material having a Shore hardness Hs of 105 and hard as a work material without using it. The flank wear was measured using a stereo microscope with a magnification of 100 and a slide table with a resolution of 1 μm.

From Table 5, it can be seen that all of the products of the present invention have a long cuttable length of 5 m or more and have an excellent tool life. The (008) X-ray diffraction peak intensity IG (008) of hexagonal graphite is (400) X of diamond.
When the diffraction intensity is 0.1 to 3 times the line diffraction peak ID (400), the cutting length is as long as 10 m or more, excellent tool life is obtained, and IG (008) / ID (400) is 0.15 to 2.0.
In the case of No. 5, the cuttable length is as long as 15 m or more, and a more excellent tool life can be obtained, and IG (008) / ID (40
When 0) is 0.35 to 2, the cuttable length is 18 m or longer, which is the longest, indicating that the best tool life can be obtained.

(Comparative Example 1) In a hard carbon film, TC
Diamond with the largest (400) and X of (008)
Contains both graphite, which has the strongest line diffraction intensity
To determine the effect of tooling on tool life
A ball end having the same composition and shape as in Example 1
Cemented carbide substrate for mill-type cutting tools (diameter 6 mm, 2 pieces
Blade) and rectangular parallelepiped substrate for X-ray diffraction measurement (5 × 5 × 10 m
m³) Is set in the furnace, and heat filament
Hard carbon film of about 8μm thickness is formed
did. Tungsten filament to about 2,300 ° C
Heat and add 4% CH _FourAnd H_TwoMixed gas
Is 150cm³/ Min, at a pressure of 13.3 kP
a, A film was formed at a substrate temperature of 800 ° C.

The prepared hard carbon film of Comparative Example 1 was made of TC
(111) is composed of the largest diamond,
No hexagonal graphite peak was observed.

The tool life was evaluated under the same conditions as in Example 1 using each of the three cutting tools manufactured under the conditions of Comparative Example 1. As a result, the wear amount of the outer edge reached 0.05 mm within 3 m. It was found that the tool life was shorter than the product of the present invention, and the tool was inferior.

Example 2 WC: 95.5% by mass, C
o: A scare end mill type cemented carbide substrate for cutting tools (diameter 6 mm, two blades) having a composition of 4.5% by mass was set in a furnace, and the surface thereof was about 8 μm by hot filament CVD. A hard carbon film having a thickness was formed. That is,
By passing a current in a tungsten filament which is disposed around the end mill, which was heated to about 2,500 ° C., this CH ₄ / H ₂ ratio of 0.5% to 3% of CH ₄ and H ₂
Flowing a mixed gas of only 10~150cm ³ / min, pressure 1.33～13.3KPa, substrate temperature 900-120
A film was formed at 0 ° C.

An X-ray diffraction pattern of the manufactured product of the present invention was measured under the same conditions as in Example 1 using the flat portion at the tip of the edge of the scare end mill as a sample surface. Since the flat part at the tip of the cutting edge of the scare end mill has a small area, the part other than the flat part is removed by processing as much as possible, and by covering it with vinyl tape, it is devised so as not to affect the X-ray diffraction pattern as much as possible.

Table 6 shows typical measurement results of X-ray diffraction peaks of diamond contained in the hard carbon film of the present invention, measured by the above method.

[0040]

[Table 6]

From Table 6, it can be seen that the hard carbon film of the present invention has the largest texture coefficient TC (400) compared to diamond (008).
It can be seen that the X-ray diffraction intensity is composed of both hexagonal graphite having the maximum intensity. The hexagonal graphite (008) X-ray diffraction peak intensity IG (008) of diamond (400) is the X-ray diffraction peak intensity ID (40) of diamond (400).
0) is 1.57 times as large.

Table 7 shows the results of X-ray diffraction measurement of the tool coated with the hard carbon film produced in Example 2.

[0043]

[Table 7]

As in Example 1, in all samples, the texture coefficient of diamond was TC (400) and TC (hkl)
Medium and maximum. From these results, it can be seen that all the hard carbon films of the present invention are composed of diamond having the largest texture coefficient TC (400) and hexagonal graphite having the strongest (008).

The tool life of the product of the present invention was evaluated under the following conditions using each of the three manufactured products of the present invention. Work material Al-11 mass% Si alloy Tool shape Scare end mill (6φ, two blades) Tool rotation speed 7958 rotations / min Cutting speed 150 m / min Feed speed 477 mm / min (0.03 mm / blade) Depth of cut 0.1 mm No cutting oil was used. The tool life was indicated by the length of cutting until the flank wear of the cutting edge reached 0.05 mm, as in Example 1.

Table 7 also shows the tool life. From this, it can be seen that all of the products of the present invention have a long cuttable length of 20 m or more and have an excellent tool life. The (008) X-ray diffraction peak intensity IG (008) of hexagonal graphite is (400) X-ray diffraction peak intensity ID (4) of diamond.
00), the cutting length is as long as 30 m or more, excellent tool life is obtained, and IG (008) / I
When D (400) is 0.15 to 2.5, the cuttable length is 4
0m or more, longer tool life is obtained,
When G (008) / ID (400) is 0.35 to 2, the cuttable length is as long as 50 m or more, and it can be seen that a particularly excellent tool life can be obtained.

(Comparative Example 2) In a hard carbon film, TC
Diamond with the largest (400) and X of (008)
In order to clarify the effect on the tool life due to the presence or absence of both graphite having the strongest line diffraction intensity, a cemented carbide for a Scare end mill type cutting tool having the same composition and shape as in Example 2 The substrates were set in a furnace, and their surfaces were coated with about 8 μm by hot filament CVD.
A hard carbon film having a thickness of m was formed. The tungsten filament is heated to about 2,300 ° C., and a mixed gas of CH ₄ and H ₂ having a CH ₄ / H ₂ ratio of 0.4% is added to the tungsten filament at 150 cm ³ / m
in, at a pressure of 13.3 kPa, and a substrate temperature of 800 ° C.
Was formed.

The hard carbon film of Comparative Example 2 was made of TC
Although (400) contained the largest diamond component, no hexagonal graphite peak was observed.

The tool life was evaluated under the same conditions as in Example 2 using each of the three cutting tools manufactured under the conditions of Comparative Example 2, and as a result, the wear of the outer edge reached 0.05 mm within 10 m. It was found that the tool life was shorter than that of the product of the present invention, and the tool was inferior.

[0050]

As described above, according to the present invention, it is possible to realize a hard carbon film-coated tool having both good wear resistance and good sliding properties and excellent tool durability.

[Brief description of the drawings]

FIG. 1 shows an example of an X-ray diffraction pattern of a tool coated with a hard carbon film of the present invention.

FIG. 2 is an explanatory view showing a unit cell of diamond.

FIG. 3 is an explanatory view showing a unit cell of hexagonal graphite.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3C046 FF03 FF12 4G077 AA03 AB08 BA03 DB07 HA13 TA03 TA04 4K030 AA10 AA17 BA28 CA03 FA01 FA10 HA14 JA13 JA20 LA22

Claims (2)

[Claims] 1. A hard carbon film-coated tool coated with a diamond-containing hard carbon film, wherein the hard carbon film has the highest TC (400) among the texture coefficients TC (hkl) and the strongest X-ray diffraction. A hard carbon film-coated tool containing both hexagonal graphite whose peaks are (008) plane index. 2. The hard carbon film-coated tool according to claim 1, wherein the hexagonal graphite has an X-ray diffraction peak intensity of (008) plane index of diamond which is 0% of an X-ray diffraction peak intensity of (400) plane index of diamond. A tool coated with a hard carbon film, characterized in that the tool is 1 to 3 times.