JPS62278195A - Diamond synthesis method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a method for synthesizing diamond by chemical vapor deposition.

[Summary of the invention]

The present invention is a diamond synthesis method using chemical vapor deposition, in which a base material made of metal or ceramic is coated with a metal or non-metal having photoelectron emission properties, or particles of the metal or non-metal are attached. This makes it easier to form a diamond synthetic film thereon.

[Conventional technology]

Conventionally, various diamond synthesis methods and devices have been proposed using chemical vapor deposition. As a raw material, a mixed gas of hydrocarbon and hydrogen, a mixture of an organic compound containing a methyl group (gasified or as a liquid) and hydrogen, or a mixture of these with a small amount of inert gas such as argon added is used, and the mixture is decomposed. In addition to heat, energy sources such as electron beams, light, or plasma are known.

FIG. 2 is a system diagram showing a conventional example of a diamond synthesis apparatus using only thermal decomposition. In this figure, (1) is a reactant gas supply device for hydrocarbons and hydrogen or organic compounds and hydrogen, (2) is a heating furnace, (3) is a substrate support, and (4) is a heating furnace.
1 is a reaction tube, (5) is a base material, (6) is a tungsten filament, (7) is an exhaust device, (8) is an exhaust port, ('
Jl, (10), (11)', (12)
indicates a cook. First, the substrate support (
After placing the substrate (5) on the tube (J), the air in the reaction tube (4) is exhausted using the exhaust device (7).

Next, cook (10), (11), (12
) to adjust the concentration and flow rate of the mixed gas and transfer it to the reaction tube (
4), and the inside of the reaction tube (4) is maintained at a predetermined pressure with the cock (9). The mixed gas is introduced from the top of the reaction tube (4), passes through a tungsten filament (6) placed near the substrate support (3), and is supplied to the surface of the substrate (5). When the heating furnace (2) and the tungsten filament (6) are heated to predetermined temperatures, a diamond film is deposited on the surface of the base material (5).

In this case, the pressure inside the reaction tube (4) is not limited to vacuum but can also be normal pressure, but the temperature of the base material is approximately 500 to 900°C.
, the temperature of the tungsten filament is about 2000-2
It is necessary to set the temperature to 300°C.

FIG. 3 is a schematic diagram showing the main parts of a conventional example of a diamond synthesis apparatus using photolysis. In this figure, parts corresponding to those in FIG. 2 are given the same reference numerals, and (14) indicates a light source, and (15) indicates a transparent window.

[Problem that the invention seeks to solve]

All of the conventional diamond synthesis equipment mentioned above
This method deposits a uniform film of diamond on the surface of a flat base material, and is not suitable for coating the surface of wear-resistant tools such as drills and bits with a diamond film or other articles.

[Means for solving problems]

The present invention involves coating a metal or non-metal with photoelectron emitting properties on a base material made of metal or ceramic, or attaching particles of the metal or non-metal to a base material, and then applying light while heating the base material. The above problems were solved by decomposing the reactive gas by irradiating it with

[Effect]

When the above-mentioned method is taken, photoelectrons contributing to the synthesis of diamond are emitted from the surface of the base material by irradiation with light, so that a diamond film covering the surface of the base material is easily deposited.

〔Example〕

FIG. 1 is a schematic sectional view of essential parts showing an example of an apparatus that can be used in the present invention. In this figure, parts corresponding to those in FIGS. 2 and 3 are designated by the same or similar symbols. (2'
) is a heater for heating the base material (5'), (5')
indicates a base material that is an article.

(5') is a bite (cutter tooth) in this example. The base material support stand (3) has holes for erecting a plurality of base materials (5'). In the figure, only 3I161 base materials (5') are shown, but it goes without saying that a larger number may be used. The surface of the base material (5') is covered in advance with a metal or nonmetal layer or particles having photoelectron emission properties.

That is, it is coated or particles are attached in a previous step. A reaction gas is introduced into the reaction chamber (4) from above, and the substrate (5') is irradiated with light while being heated. The wavelength of the light source (14) needs to be appropriately selected depending on the type of photoelectron emitting metal or non-metal. Photoelectron emitting metals and non-gold metals include cesium, barium, rubidium,
Examples include potassium, sodium, lithium, zinc, nickel, platinum, silicon carbide, and magnesium oxide. The light from light # (14) is applied to the base material (5') from above.
When irradiating, the lower part of the base material (5') is not irradiated with much light, but the tip of the cutting tool, which requires the most wear resistance, is irradiated with sufficient light. In addition, the light source (14) is connected to the reaction chamber (4).
) It is even better if it is provided on the side of the base material support stand (3). In this case, the base material support stand (3) may be rotated in the horizontal direction.

(Example 1) Using a mixed gas of acetone and hydrogen as the reaction gas, platinum plating was applied to the substrate, and ultraviolet rays were irradiated while maintaining the substrate temperature at 400 to 500°C.
5 μm thick after 90 minutes and 150 minutes.

Diamond films of 9 μm, 12 μm and 31 μm were produced.

(Example 2) Using a mixed gas of ascent and hydrogen as the reaction gas, galvanizing the base material and irradiating it with ultraviolet rays while maintaining the base material temperature at 150°C, the results were as follows: 30 minutes, 60 minutes, and 90 minutes, respectively.
thickness 2 μm and 6 μm after 150 minutes and 150 minutes.

Diamond films of 9 μm and 15 μm were produced.

(Example 3) Using a mixed gas of ascent and hydrogen as the reaction gas, nickel plating is applied to the base material and the base material temperature is 400 to 500°C.
When irradiated with ultraviolet rays while maintaining the temperature, the thickness was 5 μm after 30, 60, 90, and 150 minutes.

Diamond films of 9 μm, 11 μm and 27 μm were produced.

〔Effect of the invention〕

As explained above, according to the present invention, a diamond film that covers the surface of an article can be easily produced without raising the heating temperature too much.

[Brief explanation of drawings]

Fig. 1 is a schematic sectional view showing an example of an apparatus that can be used in the present invention without showing the main parts, Fig. 2 is a system diagram showing an example of a conventional diamond synthesis apparatus using thermal decomposition, and Fig. 3 is a conventional diamond synthesis apparatus using photolysis. Figure 1 shows a schematic cross-section of the main parts of an example of a diamond synthesis apparatus. (4)... Reaction vessel, (5')... Base material whose surface is covered with a layer or particles of a photoelectron emitting metal or non-metal, (2
')...Heater for heating the base material, (14)...Light source, (15)...Translucent window.

Claims (1)

[Claims] A step of covering the surface of a substrate with a metal or nonmetal layer or particles having photoelectron emission properties, and irradiating light while heating the substrate in a reaction vessel containing the substrate. A method for synthesizing diamond by chemical vapor deposition, comprising the step of irradiating to decompose a reactive gas and depositing diamond on the surface of the base material.