JPH06262405A - Coating part for tool - Google Patents

Abstract

PURPOSE:To improve the adhesive property and the durability of the film, and obtain the excellent surface hardness by forming the film containing cubic tungsten carbide by the specified composition of the specified film thickness on the surface of the base material of grinding and polishing tools. CONSTITUTION:A film containing cubic tungsten carbide with less residual stress is formed on the surface of the base material 8 by preheating the base material 8 in a vapor phase reaction device 1 provided with a plasma generating means (work coil) 6, and cooling means such as a preheating means and a circulating cooling jacket, generating tungsten carbide by the vapor phase reaction in the thermal plasma 7, and executing the rapid cooling. A coating parts excellent in the adhesive property, the durability and the surface hardness can be obtained by containing 30vol.% or more of cubic tungsten carbide in this formed film, and setting the film thickness in the range of 0.5-100mum to form the film on the surface of grinding or polishing tools.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cubic tungsten carbide coated component for a cutting tool or an abrasive tool, and more specifically, a coating containing cubic tungsten carbide is formed on the surface of a substrate. Of coated parts for tools in.

[0002]

2. Description of the Related Art In general, tungsten carbide exists in a limited region with hexagonal tungsten carbide represented by WC or W ₂ C according to the W-C binary system equilibrium diagram.
_1-x (In the formula, x is 2,380 ± 30 ° C. to 2,747 ± 1
Cubic tungsten carbide represented by 0.3 to 0.4) at 2 ° C.

The former hexagonal tungsten carbide has various forms from powders to coatings. Of these, there are many proposals for tool parts in which the base material is coated with hexagonal tungsten carbide, and a typical one is the Japanese Patent Publication No.
No. 9-39242, Japanese Patent Publication No. 59-39243 and Japanese Patent Publication No. 61-46550.

Among these, Japanese Examined Patent Publication No. 61-46550 discloses a coated tool component having a coating layer made of one or more of tungsten and tungsten carbide and having a layer thickness of 5 to 1,000 μm.

Further, Japanese Patent Publication No. 59-39242 discloses a titanium carbide layer and Japanese Patent Publication No. 59-39243 discloses a nickel alloy layer as an intermediate layer. Similarly, a layer made of at least one of tungsten and tungsten carbide is used. Thickness 5
Disclosed is a coated tool part having a coating layer of 1,000 μm.

The coating layer of tungsten carbide in these coated tool parts uses tungsten halide,
It is formed by a chemical vapor deposition method and is made of hexagonal tungsten carbide. Such coated tool parts are
When the temperature is raised to several hundred degrees in the air, the coating layer of hexagonal tungsten carbide is easily oxidized and peeled off from the surface, so that the heat resistance of the tool is limited.

On the other hand, Japanese Patent Laid-Open No. 1-115810 discloses
A method of making a fine powder of cubic tungsten carbide is disclosed. In this method, a tungsten oxide powder or a tungsten carbonyl powder is introduced into plasma together with a mixed gas of hydrogen and hydrocarbon, and a highly pure cubic tungsten carbide powder is obtained by a gas phase reaction. Even if an attempt is made to form a cubic tungsten carbide coating on the surface of the substrate by this method, a complete coating is not formed, and even if the coating is formed, residual stress occurs between the coating and the substrate after cooling, Since the coating film cracks, it is of little practical value.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems and to provide a coating having excellent adhesion and durability and having a surface hardness suitable for a cutting tool or an abrasive tool. Is to provide a coated part in which the surface of a substrate is formed.

[0009]

Means for Solving the Problems The inventors of the present invention have made extensive studies on a method of forming a film of cubic tungsten carbide on the surface of various base materials, and as a result, the plasma generation means, the preheating means and the circulation cooling jacket have been investigated. A film containing cubic tungsten carbide with little residual stress on the surface of the base material when the base material is preheated in a gas phase reactor equipped with various cooling means, tungsten carbide is generated by a gas phase reaction in plasma, and rapidly cooled. A composite having a coating of a specific film thickness containing cubic tungsten carbide in a specific content, which is formed in this manner, as a coated part for a cutting tool or an abrasive tool. The inventors have found that they have suitable properties and have completed the present invention.

That is, the coated part for a cutting tool or polishing tool of the present invention has a film thickness of 0.5 to 100 μm containing 30% by volume or more of cubic tungsten carbide on the surface of the base material.
Is present.

The base material of the coated component of the present invention includes metals (including semimetals) and alloys (including cermets).
Alternatively, any of ceramics sintered bodies may be used.
Since a preheat of 0 ° C. or higher is required, one having a melting point of 1,300 ° C. or higher, preferably 1,600 ° C. or higher is used. In addition, a substance having a high thermal conductivity is particularly preferable in terms of cooling efficiency for cooling the film when forming the coating film.

Preferred metals or semimetals for the substrate include B, Si, Ti, Zr, Hf, V, Nb, Ta,
Cr, Mo, W, Re, Th, Ru, Rh, Os, Ir
And high melting point metals or semi-metals such as Pt and Ti and M because they have excellent adhesion to the coating film.
Metals that easily form carbides, such as o and W, are particularly preferable.

Preferred alloys or cermets as the base material are high speed steels such as tungsten type and molybdenum type; WC-Co type, WC-TiC-Co type and WC-Ti.
Cemented carbide such as C-TaC-Co system; and TiC group,
Examples include cermets such as Ti (C, N) groups. As a ceramics sintered body preferable as a base material, Al ₂ O _{3 is used.}
System, oxide systems such as ZrO ₂ system; and Si ₃ N ₄
A system, a SiC system, etc. are preferable. Of these, carbide-based and non-stoichiometric compounds that form carbides or alloys containing non-stoichiometric compounds, cermets and ceramics sintered bodies are particularly preferred because of their excellent adhesion to the coating film. preferable.

The coating formed on the surface of the coated component of the present invention contains 30% by volume or more, preferably 50% by volume or more of cubic tungsten carbide. If the content of cubic tungsten carbide is less than 30% by volume, sufficient hardness cannot be obtained. The remaining component contained in the coating film is at least one of hexagonal tungsten carbide (WC, W ₂ C), tungsten and carbon which are by-produced during the gas phase reaction. To increase the wear resistance of the coating, tungsten is 10% by volume.
Hereinafter, the carbon content is preferably 5% by volume or less.

The film thickness is 0.5 to 100 μm, preferably 5 to 50 μm. If the film thickness is less than 0.5 μm,
No improvement in wear resistance and tool life can be obtained. On the other hand, if the film thickness exceeds 100 μm, the wear resistance and life expectancy corresponding to the increase cannot be expected, and since the film acts as a heat insulating layer, the film formation time becomes long, and high-speed cutting and Not only is heat buildup in the composite part during polishing unfavorable, it also increases the cost of forming the coating.

In the coated component of the present invention, for example, when the base material is an oxide-based ceramics sintered body, in order to improve the adhesion between the base material and the coating, the base material is cemented carbide. In the case of or cermet, an intermediate layer may be formed between the base material and the surface coating, if necessary, in order to prevent the binding metal in the base material from evaporating. The intermediate layer is preferably made of a carbide, a metal that easily forms a carbide, or a non-stoichiometric compound that easily reacts with carbon in order to improve the adhesion between the intermediate layer and the surface coating. Examples of such an intermediate layer include metals of group 4a, 5a or 6a of the periodic table; silicon; Carbonitrides or oxycarbonitrides; or solid solutions of these are used, specifically, Si, T
i, Zr, Hf, V, Nb, Ta, Cr, Mo and W
Metal or semi-metal such as; SiC, TiC, ZrC,
(Ti, Zr) C, HfC, VC, NbC, TaC, C
Carbides such as r ₃ C ₂ , Mo ₂ C and WC (hexagonal tungsten carbide); AlN, Si ₃ N ₄ , TiN,
(Ti, Al) N, ZrN, (Ti, Zr) N, Hf
Nitride such as N, VN, NbN and TaN; Ti
Carbonates such as (C, O); Nitride oxides such as Ti (N, O) and (Ti, Al) (N, O); (Ti,
Carbonitrides such as Al) (C, N) and Ti (C, N)
N, O) and (Ti, Al) (C, N, O) carbonitride oxides; or their solid solutions with each other. Further, such an intermediate layer may be a single layer or a plurality of layers.

Thickness of the intermediate layer (total thickness in the case of multiple layers)
Is 20 μm or less, preferably 0.5 to 10 μm. If the thickness exceeds 20 μm, peeling is likely to occur, and the above-mentioned effects of providing the intermediate layer cannot be expected to be improved, resulting in an increase in cost.

The shape of the coated part of the present invention can be any shape suitable for a cutting or polishing tool. The coating may be formed on all of its surfaces, some of the surfaces,
Alternatively, it may be formed at a part of the site. Further, the intermediate layer, which is provided as necessary, may be provided on all the surfaces or portions forming the coating film, or may be provided on a part thereof.

Such a coated component can be manufactured, for example, as follows. That is, first, a base material or a base material on which an intermediate layer is previously formed, if necessary, is heated to 1,000 ° C. or higher, preferably from 1,200 to
Preheat to 1,700 ° C. Then, the base material is placed in a tail flame portion of a thermal plasma such as a high frequency plasma or a direct current plasma, a tungsten source and a hydrocarbon are supplied, and a gas phase reaction is performed. Argon is usually used as the plasma gas. The plasma temperature is usually 6,000 ° C or higher, preferably 7,000 to 11,000 ° C.

As the tungsten source, in addition to tungsten, tungsten trioxide, hexagonal tungsten carbide,
Mention may be made of tungsten compounds such as tungsten carbonyl, with tungsten trioxide being preferred. It is also preferable that these are supplied as powder. The hydrocarbon may be a saturated hydrocarbon such as methane, ethane, propane or butane, or an unsaturated hydrocarbon such as ethylene, propylene, butylene or acetylene, or a mixture thereof. The supply ratio of both is preferably in the range of 0.5 to 20 as C / W atomic ratio, and more preferably in the range of 1 to 10.

The vapor-phase reaction product is deposited on the surface of the base material, and the base material is rapidly cooled to prevent decomposition of the formed cubic tungsten carbide coating. Cooling rate is 10 ⁶
The range of 10 ⁷ K / s is preferred. By such a method, a coated component having a coating film containing 30% by volume or more of cubic tungsten carbide on the surface of the base material can be obtained.

[0022]

EXAMPLES The present invention will be described in more detail with reference to Examples and Comparative Examples. The invention is not limited by these examples.

FIG. 1 shows a conceptual diagram of a vertical cross section of a film forming apparatus using high frequency thermal plasma, which is used for manufacturing the coated part of the present invention. A raw material supply port 2 and a plasma gas introduction port 3 are provided above the reactor 1. After exhausting gas from the exhaust system connection hole 4 to reduce the pressure in the system 1, plasma gas is introduced from 3 and the work plasma 6 connected to the high frequency power source 5 forms the thermal plasma 7. The base material 8 is placed on a sample stage 9 equipped with a height adjusting device for preheating the base material 8 by the heat of the tail flame portion 7a of 7 and inserting it into the 7a; and a water circulation cooling device. The height adjusting device described above holds 8 at a suitable position outside 7a so that it is preheated to a desired temperature without melting or thermal deformation,
Preheat. Then, 8 is inserted into an appropriate position in 7a by a height adjusting device, a raw material is supplied from 2 to perform a gas phase reaction, and 8 is cooled by a cooling device in 9 to contain cubic tungsten carbide. The reaction product is deposited on the surface of 8 to form a film.

Example 1 On the sample table 9, a commercially available Si ₃ N ₄ based sintered body (J
IS standard SNMN 120408) is placed and the reactor 1 is set to 10 ^-3 Torr.
After the pressure was reduced to 1, Ar gas was introduced through the inlet 3 and the pressure was maintained at 1 atm. Ar gas was introduced at a total inflow rate of 50 liters / min, and a high frequency of 3 MHz and an output of 10 kW was applied to generate plasma in the plasma torch part above the reactor. H ₂ gas flow rate of 2,000 ml / m
While introducing in, the high frequency output was increased to 13kW. In this state, the base material is preheated to 1,650 ° C., and WO ₃ powder having an average particle size of 50 μm and CH ₄ are mixed with CH ₄ / WO.
_Under the conditions of a ₃ molar ratio of 8 and a WO ₃ powder supply rate of 200 mg / min, 2 was introduced into the reactor 1 to cause a gas phase reaction and the substrate 8 was rapidly cooled to form a film on the surface of the substrate. Then, the present invention product 1 was produced.

WF was added to the same Si ₃ N ₄ based sintered body as above.
Comparative product 1 was prepared by forming a coating film of hexagonal tungsten carbide by a chemical vapor deposition (CVD) method using ₆ , CH ₄ and carrier gas H ₂ .

The invention product 1 and the comparative product 1 thus obtained were subjected to film thickness measurement, composition ratio analysis, surface hardness measurement and dry turning test as follows. It was

(1) Film thickness: By microscopic observation of the cross section. (2) Composition ratio: The crystal structure was analyzed by X-ray diffraction.
That is, the ratio of the strength of the strongest line of each crystal and the sum of the strength of the strongest line of all the crystals was defined as the ratio of that crystal. (3) Hardness: Measured with a Vickers hardness meter. (4) Dry turning test: A dry turning test was conducted under the conditions shown in Table 1, and the cutting times until the average flank wear amount reached 0.3 mm were compared.

[0028]

[Table 1]

Table 2 shows the results of the film thickness, composition ratio, hardness and dry turning test for the product 1 of the present invention and the comparative product 1. However, the results of the turning test are shown as a relative ratio with the cutting time of the comparative product 1 obtained as described above being 1.

[0030]

[Table 2]

Example 2 Commercially available cemented carbide as a base material (JIS standard K10 equivalent product)
Was used to form a coating film on the surface of a substrate in the same manner as in the product 1 of the present invention of Example 1 except that the supply rate of WO ₃ powder and the treatment time were changed as shown in Table 3. Items 2-10
Was produced.

For comparison, comparative products 2 to 11 were prepared as follows. Comparative product 2: The conditions were the same as those of the product 2 of the present invention except that the treatment time was 5 seconds. Comparative products 3 to 11: Under the same conditions as in Comparative product 1 of Example 1,
The treatment time was adjusted to form a conventional tungsten carbide coating film having a film thickness approximately corresponding to the film thicknesses of the products 2 to 10 of the present invention.

For the products 2 to 10 of the present invention and the comparative products 2 and 3, the film forming conditions, and the film thickness, composition ratio, hardness and dry turning test results obtained in the same manner as in Example 1 are shown in Table 3. Shown in. However, the results of the turning test are shown as a relative ratio with the cutting time of the comparative product 3 obtained as described above being 1.

[0034]

[Table 3]

Example 3 As a base material, as shown in Table 4, commercially available Al ₂ O ₃ -based ceramic sintered bodies, ZrO ₂ -based ceramics sintered bodies, Ti (C, N) -based cermets, and Cemented carbide (JIS standard P30 equivalent product) is used, and the thermal plasma CVD method (used to form the coating of the products 1 to 10 of the present invention in Examples 1 and 2) on the surface of each substrate, CV.
The intermediate layers shown in Table 4 were formed by the D method and the ion plating (IP) method, respectively. Using the substrate thus obtained with the intermediate layer formed, the same procedure as in Example 1 of the present invention 1 except that the WO ₃ powder supply rate was 120 mg / min and the treatment time was 12 minutes Then, a coating film was formed on the surface of the intermediate layer to produce the products 11 to 14 of the present invention.

The products 11 to 1 of the present invention thus obtained
Table 4 shows the thickness and composition of the intermediate layer and the coating, and the surface hardness of the coating, which were obtained by the same method as in Example 1 for Sample No. 4. Further, a scratch test of the products 11 to 14 of the present invention was carried out with a scratch hardness tester to determine the maximum load that the coating film and / or the intermediate layer can withstand without peeling. The results are shown in Table 4.

[0037]

[Table 4]

Example 4 Using commercially available W, Mo and Ti plate materials as base materials,
The gas phase reaction was performed in plasma in the same manner as in the product 1 of the present invention of Example 1 to form a coating film containing cubic tungsten carbide on each base material to manufacture products 15 to 17 of the present invention.

For comparison, similar W, Mo and Ti
Using each of the plate materials as a base material, CVD was performed in the same manner as in the comparative product 1 of Example 1 to form a hexagonal tungsten carbide coating film on each base material, and comparative products 12 to 14 were manufactured.

The products 15 to 1 of the present invention thus obtained
7 and comparative products 12 to 14 were each used as a lapping machine (lapping machine), and a polishing test (lapping process) was performed using a cemented carbide as a work material to compare the lives of the product of the present invention and the comparative product. Material of the base material of the products 15 to 17 of the present invention;
Table 5 shows the composition ratio and hardness; and the relative ratio of the lifespan to the corresponding comparative product using the same substrate.

[0041]

[Table 5]

[0042]

As is apparent from the above examples, the coated parts for tools obtained by the present invention have a cubic tungsten carbide coating on the surface of the base material, and the surface hardness and durability thereof are high. Because it is excellent, it is extremely useful as a cutting tool and an abrasive tool.

[Brief description of drawings]

FIG. 1 is a conceptual diagram of a cubic tungsten carbide film manufacturing apparatus used in an example.

[Explanation of Codes] 1 Reactor 2 Raw material supply port 3 Plasma gas inlet port 4 Exhaust system connection port 5 High frequency power supply 6 Work coil 7 Thermal plasma 7a Plasma tail flame section 8 Base material 9 Sample stage

(72) Inventor Hiroaki Kurita 1-7 Tsukagoshi, Sachi-ku, Kawasaki-shi, Kanagawa Prefecture Toshiba Tungaloy Co., Ltd. Company (72) Inventor Kenzo Fukuda 1-1 Higashi, Tsukuba-shi, Ibaraki Institute of Industrial Science and Technology, Institute of Materials Engineering (72) Inventor Tetsuya Kameyama 1-1-1 East, Tsukuba-shi, Ibaraki Institute of Materials Engineering and Technical Research (72) Inventor Akihiro Motoe 1-5-1, Kannondai, Tsukuba City, Ibaraki Prefecture

Claims (2)

[Claims] 1. A coated part for a cutting tool or an abrasive tool, wherein a coating film containing 30% by volume or more of cubic tungsten carbide and having a film thickness of 0.5 to 100 μm is present on the surface of a base material. 2. A metal of Group 4a, 5a or 6a of the Periodic Table; Silicon; Periodic Table 4 between the substrate and the coating.
a, 5a or 6a group metal, silicon or aluminum carbide, nitride, carbonate, oxynitride, carbonitride or oxycarbonitride; or a single layer or a multi-layer comprising at least one of solid solutions thereof. 2. The coated component according to claim 1, wherein an intermediate layer having a total layer thickness of 20 μm or less is present.