JPS6327320B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for producing artificial diamond by precipitation.

In the past, many methods have been proposed as methods for producing synthetic diamonds, among them, for example, JP-A-58
A method using a thermionic emissive material, such as that described in Japanese Patent No. 91100, is attracting attention because it allows stable operation with a relatively simple device.

The method using this thermionic emitting material includes, for example, the first
Using the apparatus shown in the schematic cross-sectional view in the figure, a reaction mixture gas mainly composed of hydrocarbons and hydrogen, which is introduced through a reaction gas introduction pipe b opening at the upper part of a quartz reaction vessel a, is heated. It flows downward through a filament c made of metal tungsten as an electron emitting material and a material e to be treated held on a support d, and is exhausted from a reaction gas exhaust pipe f, during which time the atmospheric pressure in the reaction vessel a is maintained at 1 to 1 While maintaining the temperature at 300 torr, the filament C is heated to 1500 to 2500°C to activate the reaction mixture gas and to heat the surface of the material to be treated, which is placed at a predetermined interval below, at a temperature of 300 to 1300°C.
The artificial diamond is precipitated and generated on the surface of the material to be treated 5 by heating the material to a temperature within the range of .degree. C. and carrying out a reaction for a predetermined period of time in this state.

However, in this method using a thermionic emitting material, the number of diamond crystal nuclei precipitated on the surface of the material to be treated at the initial stage of the reaction is small, and on the other hand, diamond grows around these crystal nuclei and takes on a film-like appearance. Therefore, a considerable reaction time was required to deposit and form an artificial diamond film having a predetermined thickness.

Therefore, from the above-mentioned viewpoint, the present inventors conducted research to increase the number of diamond crystal nuclei that precipitate on the surface of the treated material at the initial stage of the reaction, and found that artificial diamond If the surface is activated by ion etching prior to the formation of a precipitate, the formation of diamond crystal nuclei that precipitate at the early stage of the reaction will be significantly promoted, resulting in rapid precipitation formation. They obtained the knowledge that it is possible to precipitate artificial diamonds at high speeds.

The present invention provides an artificial diamond precipitation generation device developed based on the above knowledge, which comprises a reduced pressure reaction vessel partitioned into an upper chamber where diamond precipitation is performed and a lower chamber where ion etching is performed. and the upper chamber is equipped with a reaction gas inlet pipe, and the lower chamber is equipped with a reaction gas discharge pipe, a shutter that can be opened and closed to partition the reduced pressure reaction container into an upper chamber and a lower chamber, and an upper chamber of the reduced pressure reaction container. and a lifting device for moving the material to be processed up and down across the lower chamber; a heating device for heating the material to be processed in the lower chamber; and a device for ion etching the surface of the material to be processed in the lower chamber. A necessary glow discharge generator, a thermionic emitting material provided at a position facing the surface of the material to be treated that has moved into the upper chamber of the reduced pressure reaction vessel, and a thermion emitting material provided along the outer periphery of the lower chamber of the reduced pressure reaction vessel via a gate valve. An apparatus for precipitating and producing artificial diamonds is characterized by comprising: a vacuum charging chamber and a vacuum extraction chamber that are connected to each other.

Next, the apparatus of the present invention will be specifically described by way of examples with reference to the drawings.

Embodiment FIG. 2 shows a device according to the invention in a schematic cross-sectional view. As shown in the figure, the quartz reduced pressure reaction vessel 1 includes an upper chamber 1A for depositing diamond on the surface of the material S to be treated, and a lower chamber 1B for performing ion etching on the surface of the material S to be treated.
The upper chamber 1A is divided into two parts by a shutter 2 which can be opened and closed, and the upper chamber 1A is filled with a reaction mixture gas mainly consisting of hydrocarbons and hydrogen for producing diamond precipitation, and Ar gas for ion etching treatment in a reduced pressure reaction vessel. A reaction gas introduction pipe 3 is provided for introducing the reaction gases into the chamber 1, and a reaction gas discharge pipe 4 for discharging these reaction gases is provided in the lower chamber.

Further, in the lower chamber 1B of the reduced pressure reaction vessel 1, a heating device 6 for heating the material to be processed S placed on a support material 5 made of a plate material, a grid material, or a net material, and A lifting device 7 is provided for vertically moving the material S together with the supporting material between the upper chamber 1A (position indicated by the two-dot chain line in the figure) and the lower chamber 1B (position indicated by the solid line in the figure). is connected to a high frequency power source or a DC power source 8 as a device for generating glow discharge necessary for ion etching the surface of the material S to be processed.
In addition, in order to make the reaction uniform, a mechanism for rotating the lifting device 7 may be provided as necessary.

Further, in the upper chamber 1A of the reduced-pressure reaction vessel 1, a metal tungsten material, for example, is placed opposite to the surface of the treated material S on the support material moved into the upper chamber for diamond precipitation. A thermoelectron emitting material 9 made of a filament made of aluminum or the like is provided.

Furthermore, the reduced pressure reaction vessel 1 is provided with a line along the outer periphery of the lower chamber 1B for loading and unloading the treated material S placed on the support material 5 into the reduced pressure reaction vessel 1. In this case, a reduced pressure charging chamber 10 and a reduced pressure extraction chamber 11 for constantly maintaining the inside of the reduced pressure reaction vessel in a reduced pressure state are connected via gate valves 12 and 13, and the reduced pressure charging chamber 10 and The reduced pressure extraction chamber 11 has a gas exhaust pipe 14,
15, and airtight lids 10A, 11A, and each of the airtight lids 10A, 11A includes a charging rod 16 for moving the material S on the support material 5 into the reduced pressure reaction container, and a charging rod 16 for moving the material S on the support material 5 into the reduced pressure reaction container. , a take-out rod 17 is provided for taking it out.

Since the device of this invention has the above structure,
First, open the airtight lid 10A of the reduced pressure charging chamber 10,
The supporting material 5 carrying the material to be treated S is loaded therein, the sealing lid 10A is closed, and the gas is exhausted from the gas exhaust pipe 14 to reduce the pressure in the depressurized charging chamber to 1×10 ^-2 torr or less. After that, the gate valve 12 is opened, and the support material 5 carrying the material to be treated S is moved by the charging rod 16 onto the heating device 6 provided in the lower chamber of the reduced pressure reaction vessel 1, which is already in a reduced pressure state. With the gate valve 12 and shutter 2 closed, Ar gas is introduced into the reduced pressure reaction vessel 1 through the reaction gas introduction pipe 3, and exhausted through the reaction gas exhaust pipe 4 to maintain the atmospheric pressure at 0.1 to 300 torr. While reducing the pressure, the material to be treated S on the support material 5 is heated to 400 to 500°C by the heating device 6, and a direct current is applied to the surface of the material to be treated S by applying it to the glow discharge generator 8. When glow discharge is generated, the surface of the material S to be treated is ion-etched by this direct current glow discharge and becomes significantly activated.Then, the shutter 2 is opened and the material S to be treated is supported by the lifting device 7. The material 5 is moved into the upper chamber 1A, and stopped at a position where the distance between the thermionic emitting material 9 and the surface of the material S to be treated is 30 to 50 mm, and the temperature of the thermionic emitting material 9 is set to 1500 to 50 mm.
In a state heated to 2500°C, a reaction mixture gas consisting mainly of hydrocarbons and hydrogen is introduced from the reaction gas introduction pipe 3, and during this time the reaction mixture gas is activated by the thermionic radiation material 9, and the reaction mixture gas is Since the surface of the material S is heated to a temperature of 300 to 1300°C, artificial diamonds are precipitated and formed on the surface of the material S to be treated at a significantly high precipitation rate. After depositing on the surface of the material S, the material S to be processed is lowered to the initial loading position in the lower chamber 1B, the shutter 2 is closed, the gate valve 13 is opened, and the material S to be processed, together with the supporting material 5, is transferred to the vacuum extraction chamber 11. Removal rod 1 attached to the airtight lid 11A of
At 7, the reduced pressure extraction chamber is evacuated from the reduced pressure reaction vessel 1 through the gas exhaust pipe 15 and is in a reduced pressure state.
11, open the sealing lid 11A with the gate valve 13 closed, and take out the workpiece S on which artificial diamond has been precipitated on the surface together with the support material 5. It will be done.

Now, using the apparatus of the present invention described above, ion etching treatment using Ar is carried out on a tungsten carbide-based cemented carbide (Co: 6
Weight %, WC: remainder) cutting throw-away chip, atmospheric pressure in the reduced pressure reaction vessel 1: 1×10 ^-3 torr, heating temperature of the material to be processed S by the heating device 6: 500°C, power to the high frequency power source 8 Applied power: 300W (Frequency:
13.56MHz), treatment time: 10 minutes, and after the reaction mixture gas composition: volume ratio, H ₂ /CH ₄ =
100/1, Distance between filament 9 made of metal W as thermionic emitting material and surface of treated material S: 40 mm, Atmospheric pressure in reduced pressure reaction vessel 1: 10 torr, Heating temperature of filament 9: 2000°C, Reaction time : When artificial diamond was precipitated and formed under the following conditions for 6 hours, an average layer thickness of 3 μm was formed on the surface of the treated material S.
An artificial diamond film was formed.

On the other hand, when an artificial diamond film was directly precipitated and formed under the above conditions without performing the above ion etching process, an artificial diamond film with an average thickness of only 1.5 μm could be formed. .

As described above, according to the apparatus of the present invention, the surface of the material to be treated is ion-etched before artificial diamond is precipitated and generated on the surface of the material to be treated, so that the rate of precipitation and formation of diamond crystal nuclei at the initial stage of the reaction is reduced. is significantly promoted, and this brings about industrially useful effects such as making it possible to precipitate artificial diamond at an extremely high precipitate formation rate.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view showing a conventional artificial diamond precipitation generating device, and FIG. 2 is a schematic cross-sectional view showing the artificial diamond precipitation generating device of the present invention. In the drawings, 1... reduced pressure reaction vessel, 1A...
Upper chamber, 1B...lower chamber, S...material to be treated, 2...
... Shutter, 3 ... Reaction gas introduction pipe, 4 ... Reaction gas discharge pipe, 5 ... Support material, 6 ... Heating device, 7
... Lifting device, 8 ... High frequency power supply, 9 ... Thermionic radiation material, 10 ... Reduced pressure charging chamber, 11 ... Reduced pressure extraction chamber, 12, 13 ... Gate valve, 14, 15 ...
...Gas exhaust pipe, 10A, 11A...Sealing lid, 16
...Charging rod, 17...Ejecting rod.

Claims (1)

[Scope of Claims] 1. A reduced pressure reaction vessel partitioned into an upper chamber where diamond precipitation is performed and a lower chamber where ion etching is performed; the upper chamber is equipped with a reaction gas introduction pipe, and the lower chamber is equipped with a reaction gas introduction pipe. a shutter that is equipped with a discharge pipe and can be opened and closed to partition the reduced pressure reaction container into an upper chamber and a lower chamber; a lifting device that moves the material to be treated up and down across the upper and lower chambers of the reduced pressure reaction container; and the lower chamber. a heating device for heating the material to be processed located in the lower chamber, a glow discharge generating device necessary for ion etching the surface of the material to be processed located in the lower chamber, and the material to be processed moved into the upper chamber of the reduced pressure reaction vessel. a thermionic emitting material provided at a position facing the surface of the depressurized reaction vessel, and a depressurized charging chamber and a depressurized extracting chamber connected via a gate valve along the outer periphery of the lower chamber of the depressurized reaction vessel. Artificial diamond precipitation generation device.