JP2987955B2 - Diamond or diamond-like carbon coated hard material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diamond-coated hard material having a diamond or diamond-like carbon coating layer having high adhesion strength to a substrate.

[0002]

2. Description of the Related Art Diamond has extremely high hardness, is chemically stable, and has many excellent properties such as high thermal conductivity and sonic transmission speed. As the hard material coated with diamond or diamond-like carbon, for example, the following materials are widely used. Since it hardly reacts with Al, Cu, various light metals used in practical use, or their alloys, these alloys can be cut at high speed and have a very good finished surface. Tools, for example cutting tools such as throw-away tips, drills, microdrills, end mills. Various wear-resistant tools such as bonding tools that have high wear resistance and enable long-time machining with high dimensional accuracy. Various mechanical parts including heat sinks. Various diaphragms including speakers. Various electronic components.

[0003] Among the methods for producing artificial diamond, methods for forming a diamond coating layer from a gas phase include a microwave plasma CVD method, an RF-plasma CVD method,
Numerous methods such as EA-CVD method, induced magnetic field μ-wave plasma CVD method, RF thermal plasma CVD method, DC plasma CVD method, DC plasma jet CVD method, filament thermal CVD method, and combustion method are known. It is a powerful method of material production.

[0004]

However, many diamond-coated hard materials have insufficient adhesion strength between the base material and the diamond coating layer, so that the life of the diamond-coated layer is often extended by peeling of the diamond coating layer. One of the major reasons for this is that diamond has no wettability with other substances because it does not have any substance and an intermediate layer. In order to obtain a diamond-coated hard material having high adhesion strength, a method of selecting a substrate having the same coefficient of thermal expansion as diamond (Japanese Patent Publication No. 61-291493,
a sintered body mainly composed of i ₃ N ₄ and a sintered body mainly composed of SiC), and a metal which adversely affects the formation of a diamond coating layer on the surface of a substrate is removed by etching. A method of increasing the generation density of diamond nuclei on the surface of a base material (Japanese Unexamined Patent Publication No. Hei 1-2201475 discloses that the surface of a cemented carbide is etched with an acid solution to remove the Co metal component and suppress the graphitization of diamond nuclei. (In Japanese Patent Application Laid-Open No. 61-124573, the surface of the substrate is damaged by diamond abrasive grains or a grindstone to increase the nucleation density of diamond on the surface of the substrate.)
However, at present, the adhesion strength is insufficient. An object of the present invention is to solve these problems and to provide a diamond-coated hard material having excellent adhesion strength.

[0005]

SUMMARY OF THE INVENTION As mentioned above, diamond is extremely chemically stable and does not produce any substances and intermediate compounds. For this reason, when producing a diamond-coated hard material having excellent adhesion strength, it is necessary to create a state in which the diamond-coated layer and the substrate are joined by some physical strong force. In order to realize this, the present inventor created a state in which a convex portion having high adhesion strength was mechanically or chemically produced on the surface of the substrate, and a diamond coating was applied to the surface of the substrate. It has been found that when a layer is formed and the projections are made to penetrate into the diamond coating layer, the adhesion strength between the diamond coating layer and the substrate becomes extremely high. It is considered that this is because the contact area between the diamond coating layer and the base material was increased, and the convex portions had an anchoring effect on the diamond coating layer, so that the diamond coating layer was hardly peeled off.

[0006] The irregularities described herein are not macroscopic irregularities formed by (1) diamond grinding stones, (2) scratching treatment with diamond abrasive grains, etc., but are irregularities in a minute section. -At the substrate interface, the reference length was a minute section such as 50 µm. The irregularities within this reference length. The present inventors have created various concavities and convexities, and as a result, within a reference length of 50 μm, the surface roughness at the substrate interface is 0.5 to 30 μm in Rmax, and the projections are diamond. It has been found that a state in which 0.2 μm or more penetrates into the coating layer increases the adhesion strength. This surface roughness is observed after lapping the cross section of the substrate after diamond coating,
A photograph is taken, and the surface roughness (Rmax) of the coated substrate is determined based on the boundary between the interface between the diamond coating layer and the substrate.

Here, in the early stage of coating, in order to promote the generation of diamond nuclei on the entire surface of the chip, it is desirable to carry out a commonly-used scratching treatment with diamond abrasive grains. At this time, in the method of physically pressing and scratching the abrasive grains, since the produced convex portion may be broken or broken, the present base material and the diamond abrasive grains are mixed with a solvent such as water, ethyl alcohol, acetone or the like. It is desirable to perform a damaging treatment by applying ultrasonic vibration to the solution. The scratched or damaged only process, uniformly generated diamond nuclei throughout partial non protrusions and projections of the substrate surface. This makes it possible to create a state in which the protrusions have penetrated the diamond coating layer.

As a specific method of forming irregularities on the substrate, a method of depositing columnar crystals and / or needles on the surface of the substrate, a method of removing a binder which is easily etched by etching, a method of applying a mask to the substrate, and then etching the substrate. Then, a method of removing the mask An appropriate method is selected according to the base material, such as a method of physical processing using a laser or the like. Is a method of subjecting the substrate to any heat treatment to allow free growth of columnar crystals or needle-like crystals on the surface of the substrate component and / or accelerating the generation of secondary crystals. This method is effective for a material composed of a hard phase and a binder phase having different corrosiveness to the above. The method is to provide a mask in an arbitrary pattern using a photomask and then remove the mask by etching.

[0009] As the material constituting the convex portion, silicon nitride crystal, crystal containing silicon nitride, sialon, silicon carbide, a substance containing silicon carbide, tungsten, carbide or carbonitride of tungsten, tungsten and one or more of 2
It is selected from the group consisting of carbides or carbonitrides of at least one kind of metal and substances containing these. It is preferable that the substance forming the uneven portion is formed of the same material integrally with the base material, and the same material may have a different composition.

FIG. 1 schematically shows the state of the interface between the diamond and / or diamond-like carbon coating layer and the substrate according to the present invention. That is, although macroscopic undulation is recognized at the interface, this is regarded as a pseudo straight line as shown in FIG. 2 and Rmax is calculated.

In any case, when the reference length is set to 50 μm at the interface between the diamond and / or the diamond-like carbon coating layer and the base material, when the reference length is 50 μm, It is necessary that the surface roughness at the interface of the base material is 0.5 to 30 μm in Rmax, and the protrusion has a penetration length of 0.2 μm in the diamond coating layer.
It is preferable to invade with m or more. When the surface roughness at the interface of the base material was 0.5 or less in Rmax, no improvement in the adhesion strength was observed, and when it exceeded 30 μm, a decrease in the adhesion strength was observed. Also, the maximum penetration depth of the projection is 0.2
When it is less than μm, the adhesion strength is not substantially changed.

The substrate is made of cemented carbide, cermet, Al ₂ O
_3. Any hard material such as various ceramics such as silicon nitride and silicon carbide can be used. Among them, in particular, a compound of Ti and / or a substance containing a compound of Ti, such as silicon nitride, silicon carbide, titanium carbide, titanium nitride, and titanium carbonitride, carbide of tungsten and / or carbide of tungsten alloy and / or It was also found that when there is unevenness due to a substance containing these, high adhesion strength is exhibited. Furthermore, the shape of the projection has an aspect ratio of 1.
In the case of 5 or more columnar crystals or needle-like crystals,
It was also found that the adhesion strength was further increased.

Regarding the thickness of the diamond coating layer, when the coating thickness is 0.1 μm or less, no improvement in various properties such as abrasion resistance is recognized by the coating layer, and even when the coating layer having a thickness of 200 μm or more is formed, the performance is no longer large. 0.1 μm to 200 μm is desirable because no improvement in the thickness is observed.

The description so far has focused on the case where the coating layer is diamond. However, when the diamond coating layer contains diamond-like carbon and other diamonds having a crystal structure, and when these single layers are used. Alternatively, even in the case of a multi-layer structure or more, the same effect can be obtained. The same effect can be obtained when the diamond coating layer or the diamond-like carbon coating layer contains different kinds of atoms such as boron and nitrogen. Next, the present invention will be described specifically with reference to examples.

[0015]

EXAMPLES As a base material, a silicon nitride-based ceramic (concrete) was used.
Typically Si_ThreeN_Four-4wt% Al _TwoO_Three-4wt% Zr
O_Two-3wt% Y_TwoO_Three) Is a slot of SPG422
A way chip was prepared. 1800
C, 5 atm N_TwoHeat treatment in gas atmosphere for 30 minutes
As a result, the chip surface has a minor axis of 2 μm and a major axis of 8 μm.
m, silicon nitride columnar crystals and needle-like crystals with an aspect ratio of 4
Crystals formed. This chip is used for a 2 g particle size of 8 to 16 μm.
Throw in ethyl alcohol with diamond abrasive grains,
Ultrasonic vibration was applied for 15 minutes. Made in this way
The chip is mounted on a 2.45 GHz microwave plasma CVD device.
And heated to 1000 ° C, and the total pressure was 80 Torr.
For 8 hours in a mixed plasma of 2% hydrogen and methane
To produce a diamond-coated cutting tip with a layer thickness of 10 μm
did. Also, for comparison, heat treatment with the same shape and the same composition
Was not performed, and columnar crystals of silicon nitride existed on the surface.
A comparative chip with a diamond coating layer
Got ready. (No ultrasonic treatment was applied to the comparison chip
In this test, the coating deposited on the surface of the substrate
The layer is coated with a diamond coating by Raman spectroscopy.
Was confirmed.

Using these cutting tips, work material: Al-24 wt% Si alloy (block material) Cutting speed: 400 m / min Feed: 0.1 mm / rev. Cutting: Intermittent cutting was performed under the condition of 0.5 mm, and after 3 minutes and 10 minutes, the flank wear amount, the cutting blade wear state, and the welded state of the work material were observed. In observation of the cutting edge 10 minutes after the start of cutting, the amount of flank wear was 0.03 mm.
And normal wear, and almost no welding of the work material was observed. On the other hand, in the comparative tip, cutting start 3
In the cutting edge observation after a minute, a large peeling of the diamond coating layer was observed, and the flank wear amount was also 0.12 mm.
Cutting was stopped because the work material was also largely welded.

After cutting and lapping the chip after the cutting test, the interface between the substrate and the diamond coating layer was observed with an optical microscope. As a result, in the cutting tip of the present invention, columnar crystals of silicon nitride had a maximum diameter of 3 μm in the diamond coating layer. It penetrated at a depth, and within a reference length of 50 μm, the microscopic surface roughness was 3 to 5 μm in Rmax. In the comparative chip, no columnar crystal of silicon nitride was present at the interface between the substrate and the diamond coating layer, and no penetration of the substrate into the diamond coating layer was observed.

Example 2 A silicon carbide whisker ceramic (specifically, Al ₂ O ₃ -35 vol% SiC whisker 5 wt%) was used as a base material.
ZrO ₂ ) was used to produce a throwaway chip having a shape of SPG422. This chip is brought into contact with molten NaOH,
By etching, the chip surface has a minor axis of 1μ.
m, needle-like crystals of silicon carbide whiskers having a major axis of 8 μm were exposed. This chip was thrown into ethyl alcohol together with 2 g of diamond abrasive grains having a particle size of 8 to 16 μm, and subjected to ultrasonic vibration for 15 minutes. The chip manufactured in this manner was heated to 1000 ° C. using a 2.45 GHz microwave plasma CVD apparatus, and was held for 8 hours in a mixed plasma of 2% hydrogen-methane at a total pressure of 80 Torr. A diamond-coated cutting tip having a layer thickness of 8 μm was produced. Also, for comparison, a comparative chip was prepared in which a diamond coating layer was provided on a chip having no needle-like crystal of silicon carbide whiskers on the surface because the etching treatment was not performed with the same shape and the same composition. No sonication was performed). In this test, it was confirmed that the coating layer deposited on the surface of the substrate was a diamond coating layer by Raman spectroscopy.

Using these cutting tips, work material: Al-24 wt% Si alloy (block material) Cutting speed: 400 m / min Feed: 0.1 mm / rev. Cutting: Intermittent cutting was performed under the condition of 0.5 mm, and after 3 minutes and 10 minutes, the flank wear amount, the cutting blade wear state, and the welded state of the work material were observed. In observation of the cutting edge 10 minutes after the start of cutting, the flank wear was 0.05 mm.
And normal wear, and almost no welding of the work material was observed. On the other hand, in the comparative tip, cutting start 3
In the cutting edge observation after a minute, a large peeling of the diamond coating layer was observed, and the flank wear amount was also 0.16 mm.
Cutting was stopped because the work material was also largely welded.

After cutting and lapping the chip after the cutting test, the interface between the substrate and the diamond coating layer was observed with an optical microscope. As a result, in the cutting tip of the present invention, silicon carbide whiskers were applied to the diamond coating layer at a maximum of 3.5 μm. It penetrated at a depth, and at the interface, the microscopic surface roughness within a reference length of 50 μm was 4 to 5 μm in Rmax. In the comparative chip, no silicon carbide whiskers were present at the interface between the substrate and the diamond coating layer, and no penetration of the substrate into the diamond coating layer was observed.

Example 3 JIS-K10 cemented carbide (specifically, WC
(-5% Co) to form a throwaway chip having a shape of SPG422. This chip is mirror-finished and then laser-processed. (1) Grooves having a depth of 3.0 μm and a width of 1.5 μm are formed into a lattice shape at intervals of 2 μm. The chips (1) and (2) of the present invention in which the grooves were processed into a lattice shape at 3 μm intervals were produced. In each case, the calculated microscopic Rmax is 3, 6 μm. In the same manner as described above, this chip is
And the mixture was poured into ethyl alcohol together with the diamond abrasive grains, and subjected to ultrasonic vibration for 15 minutes. Using a known hot filament CVD method on the surface of the chip thus produced, a reaction tube container: a quartz tube having a diameter of 200 mm Filament material: Metal W Filament temperature: 2400 ° C. Distance between filament and chip surface: 7.0 mm Pressure: 100 Torr Atmospheric gas: H ₂ -1.5% CH ₄ gas Time: 7 hours A 6 μm diamond coating layer was formed.
For comparison, a comparative chip having a diamond coating layer provided on a chip having the same shape and the same composition but not subjected to the laser processing was prepared (the comparative chip was not subjected to ultrasonic treatment). In this test, it was confirmed that the coating layer deposited on the surface of the substrate was a diamond coating layer by Raman spectroscopy.

Using these cutting tips, work material: Al-12 wt% Si alloy (round bar) Cutting speed: 1000 m / min Feed: 0.15 mm / rev. Cutting: Intermittent cutting was performed under the condition of 1.5 mm, and after 5 minutes and 30 minutes, the amount of flank wear, the state of wear of the cutting blade, and the state of welding of the work material were observed. In (4) to (4), when the cutting edge was observed 10 minutes after the start of cutting, the flank wear amounts were 0.02 and 0.03, respectively, indicating normal wear, and almost no welding of the work material was observed. . On the other hand, in the comparative tip, when the cutting edge was observed 5 minutes after the start of cutting, a large peeling of the diamond coating layer was observed, the flank wear was 0.24 mm, and the work material was also largely welded. Ceased.

After cutting and lapping the chip after the cutting test, the interface between the base material and the diamond coating layer was observed with an optical microscope. It penetrates at a depth of 3 μm, and the microscopic surface roughness within the 50 μm reference range is 2.8 and 6.1 μm in Rmax, respectively.
It was confirmed that the value was almost the same as the value measured before coating. In the comparative chip, no intrusion into the diamond coating layer of the base material and the presence of irregularities were not observed.

[0024]

It can be seen that the diamond and / or diamond-like carbon-coated hard material of the present invention has better peeling resistance as compared with the conventional diamond and / or diamond-like carbon-coated hard material. The methods in Examples 1 and 2 are surface treatments that make use of the characteristics of the base material. However, since the method in Example 3 is a method excellent in applied power regardless of the base material, silicon carbide,
Even when various ceramics mainly composed of Al ₂ O ₃ , cermets and the like are used as base materials, good results can be obtained.
Can be expected enough. In this embodiment, the case of the cutting tool has been introduced. However, it can be expected that good results can be obtained also when applied to a wear-resistant tool such as a TAB tool or a mechanical part. In addition, it can be applied to end mills, drills, drills for drilling printed circuit boards, and reamers.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram schematically showing a state of a coating layer-substrate interface of the present invention.

FIG. 2 is an explanatory diagram in which the state shown in FIG. 1 is simulated as a straight line.

──────────────────────────────────────────────────続 き Continuation of front page (51) Int.Cl. ⁶ identification code FI C30B 29/04 C30B 29/04 P Q (58) Field surveyed (Int.Cl. ⁶ , DB name) C23C 16/00-16 / 56 C23C 14/00-14/58 C01B 31/06 C04B 41/87 C30B 29/04

Claims (8)

(57) [Claims] 1. A coated hard material formed by forming a diamond and / or diamond-like carbon coating layer on the surface of a hard material, wherein (1) microscopic unevenness is present on the surface of the base material, and (2) convex portions. Has a reference length of 50 μm at the diamond and / or diamond-like carbon coating layer-substrate interface.
when the m, Ri 0.5~30μm der surface roughness in the reference length is at Rmax, (3) diamond and / or diamond-like carbon
At least 0.2 μm of protrusions penetrate into the coating layer
Ri, (4) and the shape of the invading material, the aspect ratio is 1.
A diamond or diamond-like carbon-coated hard material having a columnar shape of 5 or more . 2. The method according to claim 1, wherein the surface of the hard material has diamond and
// Coating formed by forming diamond-like carbon coating layer
In the hard material, (1) microscopic unevenness is present on the surface of the base material, and (2) the projection is formed of diamond and / or diamond.
The reference length is 50 μm at the interface between the carbon coating layer and the substrate.
m, the surface roughness within this reference length is Rmax
Is 0.5 to 30 m, (3) diamond and / or diamond-like carbon-coated layer, contact convex portion is at least 0.2μm intrusion
Ri, (4) and wherein the to holder Iyamondo or diamond-like carbon-coated hard material that shapes of the invading material is needle-shaped. 3. The diamond or diamond-like carbon-coated hard material according to claim 1, wherein the projection is a crystal and / or a sialon containing a silicon nitride crystal and / or a silicon nitride. 4. The diamond or diamond-like carbon-coated hard material according to claim 1, wherein the projections are made of silicon carbide and / or a substance containing silicon carbide. 5. The method according to claim 1, wherein the convex portions are (1) tungsten, (2) a carbide or carbonitride of tungsten, (3) a carbide or carbonitride of tungsten and one or more other metals, and (4) 3. The diamond or diamond-like carbon-coated hard material according to claim 1, wherein the hard material is composed of at least one material selected from the group consisting of substances containing these. 6. A hard material comprising: (1) a cemented carbide;
-Met, (3) Al ₂ O ₃ , silicon nitride, silicon carbide, etc.
Of various ceramics, or (4) a composite material of
A die according to any one of claims 1 to 5, wherein
Hard material coated with diamond or diamond-like carbon. 7. Diamond or diamond-like carbon
An object that forms irregularities at the boundary between the coating layer and the substrate
The quality is the same material as the substrate.
Item 7. A diamond or a diamond according to any one of Items 1 to 6.
Hard carbon-coated hard material. 8. Diamond or diamond-like carbon
An object that forms irregularities at the boundary between the coating layer and the substrate
It is the same material as the base material, but with a different composition.
The die according to any one of claims 1 to 7, wherein
Hard material coated with diamond or diamond-like carbon.