JPS6326356A - Formation of film - Google Patents

Abstract

PURPOSE:To improve the density and adhesion of a film formed on a substrate and to prolong the service life of the resulting tool by placing a prescribed electrically conductive member between an electrode for electric discharge and the substrate and by sticking an ionized metal and an ionized gas to the substrate to form a film of a compound of them. CONSTITUTION:An electrically conductive member 8 having voids through which ions can pass and kept at positive potential is placed between an electrode 5 for electric discharge and a substrate 3 in a reaction furnace 1. Electric discharge is caused between the electrode 5 and a metal 6 in a crucible 4 to generate plasma of a reactive gas introduced into the furnace 1. The metal 6 evaporated by irradiation with electron beams 7 is passed through the plasma and stuck to the substrate 3 together with the reactive gas ionized by the discharge. A film of a compound produced by the reaction of ions of the metal with ions of the reactive gas is formed on the surface of the substrate 3.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention involves forming a reactive gas plasma by discharging a discharge electrode, and passing a metal vaporized by an electron beam through the plasma. The present invention relates to a so-called activated reaction vapor deposition method in which ionized metal and reactive gas ions are attached to the surface of a substrate, and the surface of the substrate is coated with a film of a compound produced by the mutual reaction of these ions.

[Conventional technology]

Conventionally, when manufacturing carbide tools such as cutting tools and wear-resistant tools, titanium carbide, titanium nitride,
The activation reaction vapor deposition method described above is used to deposit and form a hard fractured film of titanium carbonitride, etc. For example, to explain the formation of a nitride film by way of example, the method shown schematically in Fig. 2 is as follows. As shown in the illustration, the reactor]
Introduce nitrogen gas 2 into the reactor 1 to increase the atmospheric pressure inside the reactor 1]
A DC voltage of several tens of volts was applied to the discharge electrode 5 placed between the base 3 and the water-cooled copper crucible 4, which were placed facing each other in the reactor 1. is applied to the metal titanium 6 held in the crucible 4.
and the discharge electrode 5 to generate a plasma of nitrogen gas 2 between the discharge electrode 5 and the crucible 4, while irradiating the all-class titanium 6 with an electron beam 7. This is melted and evaporated, and the evaporated titanium is passed through the plasma to be ionized, and then deposited on the substrate 3 maintained at a negative potential of 0 to 500 volts, and
Ions (nitrogen atomized) are also attached to the substrate 3 by the discharge, and a nitrogen-rich titanium film produced by the reaction between these titanium ions and nitrogen ions is deposited and formed on the surface of the substrate 3.

[Problem that the invention seeks to solve]

In this film formation method, when the metal melted and vaporized by electron beam irradiation passes through the plasma of the reaction gas, not all of it is ionized, but some of it is activated. Metal particles and particles that are still in an atomic state are also generated, and these non-ionized metal particles are also deposited on the substrate, and a compound film containing these particles is formed on the substrate surface. It has the drawbacks of poor adhesion to the substrate and poor film quality, and therefore, for example, carbide tools coated with the above-mentioned hard coating have poor wear resistance and short tool life. Ta.

[Findings based on research]

Therefore, as a result of various studies to solve these problems, the inventors of the present invention found that (1) the discharge electrode and the substrate have a large number of penetrating gaps that allow the passage of ions; When a conductive member, such as a stainless steel wire mesh, is interposed while maintaining a positive potential, activated metal particles and metal particles in an atomic state among the metals evaporated by the electron beam are transferred to the conductive member. Selective adhesion, with only ionized metals adhering to the substrate.

(2) A compound film (hereinafter also referred to as a vapor deposited film) that is formed only from particles that have been substantially heated up generally has excellent adhesion to a substrate and is dense in film quality. We have found that wear resistance is improved in carbide tools coated with a hard coating having the following properties.

[Means for solving problems]

This invention was invented based on the above knowledge, and aims to improve the adhesion and density of a vapor deposited film deposited on the surface of a substrate in the active f-hybrid reaction vapor deposition method. generating a discharge between a discharge electrode disposed between the base body and the crucible and the metal held in the crucible to form a plasma of the reaction gas introduced into the reactor; , the metal is irradiated with an electron beam to melt and evaporate the metal, and the evaporated metal is passed through the plasma to be ionized and then deposited on the substrate, and the reactive gas ionized by the discharge is also ionized on the substrate. In the method of forming a broken membrane of a compound produced by the reaction of these metal ions and reactive gas ions on the surface of the substrate, the method comprises: having a large number of penetrating voids that allow the passage of the ions; A conductive member maintained at a positive potential is interposed between the discharge electrode and the substrate, and ions (non-heated evaporated metal) are attached to the conductive member, and the ions are guided out of the reaction system. It is characterized by this.

[Detailed description of the invention]

As shown in FIG. 1, the method of this invention has a large number of penetrating gaps between the discharge electrode 5 and the base 3 through which ionized particles can pass, and a conductive conductor maintained at a positive potential. The conductive member 8 is characterized by the interposition of a conductive member 8, which is evaporated by the irradiation of the electron beam 7, and is then combined with the activated particles of the metal that passed through the plasma. Since the particles that are still in the atomic state are selectively attached and guided out of the dino reaction system, only those with large kinetic energy among the ionized particles pass through the gap in the conductive member 8 and form the substrate 3. adheres to the surface of

This conductive member can be any material that has a large number of holes through which ions can pass and is made of a conductive material, but it is usually made of steel or mild steel. A wire mesh or grid is preferably used, and not only one but more than one electrically conductive member can be used.

If the voids in such a wire mesh or lattice are too large, activated metal particles and metal particles in the atomic state will not be removed sufficiently, while if the voids are too small, even sufficiently ionized particles will be repelled by the positive potential. Since the passage of ionized particles is obstructed, the size of the void is generally preferably 10 to 50.
In addition, it is preferable that the linear and band-shaped materials that make up the wire mesh or lattice be as thin as possible, but considering mechanical strength,
It is generally advantageous for the width or width and thickness to be between 1 and 5 meters.

To extract only ions by this conductive member, it is typically maintained at a positive potential of 1 to 30 volts by a DC power source.

For other parts, for example, as discharge electrodes, conventionally used electrodes such as molybdenum electrodes can be used, and in carrying out this invention, the same conditions as conventional ones, such as titanium nitride coating For vapor deposition, a substrate potential of 20 to -1500 volts, a discharge electrode potential of several tens of volts, a furnace pressure of 10-2 to 10-4 Torr, and a furnace temperature of 300 to 800°C are used. It is convenient.

For example, when this invention is used to manufacture a cemented carbide tool whose surface is coated with a hard coating, a cemented carbide such as WCC cemented carbide is used as the base material, and Ti, Ti, By using metals such as Zr, Hf, V, Ta, Si, etc., and nitrogen, acetylene, methane, propane, ammonia, oxygen, -acid fcarbon, etc. as reaction gases, titanium nitride, charcoal (titanium, titanium carbonitride) can be produced. ,
One or more hard coatings of titanium carbonitride oxide, zirconium carbonate, etc. can be deposited on the surface of the substrate, optionally via a metal component.

〔Example〕

Next, the present invention will be explained by taking as an example the production of a cutting tool coated with a hard coating and comparing it with a comparative example.

Example 1 In the apparatus shown in FIG. 1, a cylindrical reactor 1 having an outer diameter of 1300 mm, a water-cooled copper crucible 4 having a ridge of 100 A', and dimensions: 20 mm x 150 wn x
Discharge electrode 5 with three throats and mesh size: 15mm
X15+nm, wire diameter: 2 mm, and dimension: 150
A vapor deposition apparatus equipped with a stainless steel wire mesh 8 of +mn×150 mm was used, and SNP made of 5KH51 was used as a substrate
A 432 type chip was used, and the reaction conditions were: furnace temperature: 500°C, furnace pressure = 5 x 1O-4 Torr, nitrogen atmosphere and substrate potential: Q 500 volts, discharge electrode potential: ■ 50 volts, wire mesh potential: ■ Adopts 25 volts and deposits titanium nitride with a thickness of 9-2/Jm on the surface of the chip, and for comparison, the device shown in FIG. 2 is different only in that it does not include the wire mesh 8. Inventive coated chip 1 and comparative coated chip 1 were prepared, respectively, by depositing the same thickness of titanium nitride coating on the same chips as described above using a method and reaction conditions similar to those described above.

Next, to examine the wear resistance of these coated chips.

Work material: SN0M8 (JIS) (hardness: HRC250
) round bar, cutting speed: 60 m/m? A continuous cutting test was conducted under the following conditions: depth of cut: 185 doors, feed rate: 0.1 k/rev, , and the cutting time until the flank wear width reached 0.3 ran, that is, the life was measured. As a result, the following results were obtained.

Life (mm) Front flank Outer flank - 10 - Invention coated chip 124.0 500 Comparative coated chip 1 30 100 Example 2 The reactant gas was a mixed gas of nitrogen and acetylene, and the substrate was a JISM 20 equivalent. J made of cemented carbide
A chip in the form of IS 5NP432 was used, and the reaction conditions were: furnace pressure fJ: 5 x 10 = 4 Torr, furnace temperature: 600°C, substrate potential = 0500■, discharge electrode potential 2050V, and wire mesh potential: 20■. Thickness =
Inventive coated chips 2 and comparative coated chips 2 were each produced having a 2 pm carbonitride titanium coating.

Next, in order to examine the wear resistance of these coated chips, the following materials were used: Work material: Nickel chromium molybdenum steel, JISSNCM
439 (hardness: HB250) round bar, cutting speed: ] 30 rn/min, depth of cut:]
Continuous cutting tests were carried out under the conditions of 5mm, feed: 0.32g/rev, and the cutting time until the flank wear width of the cutting edge reached 0.3mm, that is, the life, was measured. The following results were obtained.

Flank wear life (Dragon) Invention coated tip 2 20° Comparative coated tip 2 30 [Effects of the invention] As is clear from the results obtained in the examples, the cutting tip coated with the hard coating according to the present invention It can compete with cutting chips coated by conventional methods and has a much longer lifespan, which indicates that the present invention can form a deposited film with significantly improved wear resistance due to significantly increased adhesion and film density. It shows.

As is clear from the above explanation, according to the present invention, a compound film with excellent adhesion and a dense film quality can be deposited and formed on the surface of a substrate, making it possible to form a deposited film with excellent durability. Therefore, for example, in a carbide tool coated with a hard coating, its wear resistance can be improved and the tool life can be extended.

[Brief explanation of drawings]

FIGS. 1 and 2 are explanatory diagrams showing an overview of the apparatus used to carry out the method of the present invention and the conventional method, respectively. In the figure]...reactor,
2... Reactive gas, 3 - Substrate, 4...
- Crucible, 5... Electrode for discharge, 6... Metal, 7... Electron beam, 8... Wire mesh.

Claims (1)

[Claims] A reaction gas is introduced into the reactor by causing an electric discharge between a discharge electrode placed between a base and a crucible that are arranged to face each other in the reactor, and the metal held in the crucible. While forming a plasma, the metal is irradiated with an electron beam to melt and evaporate the metal, and the evaporated metal is passed through the plasma to be ionized and then deposited on the substrate, and the metal is ionized by the plasma, and the metal is ionized and attached to the substrate by the electric discharge. In a method in which an ionized reactive gas is also attached to the substrate and a film of a compound generated by the reaction between these metal ions and the reactive gas ions is formed on the surface of the substrate, a large number of A conductive member having a through gap and maintained at a positive potential is interposed between the discharge electrode and the base, and non-ionized evaporated metal is adhered to this conductive member. The method for forming a film, characterized in that the film is guided out of the reaction system.