JPH1015791A - Method for polishing diamond, method for producing grinding wheel used in the method and polishing apparatus using the method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a diamond polishing method, a grinding wheel and a polishing apparatus which enable high speed polishing. SOLUTION: Oxide powder including at least one kind of transition metal element, alkali metal element or alkali earth metal element is supplied to the surface of a diamond 1 to be polished, while the diamond is heated nearly to the phase transformation point of the oxide to polish the surface of the diamond.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for polishing diamond, a method for manufacturing a grindstone used in the method, and a polishing apparatus using the method.

[0002]

2. Description of the Related Art Diamond is attracting attention as an optical material because it is coated with a cutting tool by utilizing its high hardness, or because it has excellent translucency in the infrared and ultraviolet regions.

[0003] However, because of its high hardness, polishing is extremely difficult, and various polishing methods have been proposed in the past. Among them, a typical one is a physical polishing using a skiff machine, a diamond grinding wheel, a laser or the like. Method or a thermochemical reaction method using an iron plate (Japanese Unexamined Patent Publication
-7075945).

[0004]

SUMMARY OF THE INVENTION Among these methods,
When a skiff machine or a diamond grinding wheel is used, diamond is required as a processing material, and when a high energy beam such as a laser is used, there is a drawback that energy efficiency is low due to high transmittance of diamond. Further, in the polishing method utilizing the thermochemical reaction, there is a problem that it is extremely difficult to improve the polishing rate because the diffusion of carbon from the diamond to the polishing plate is utilized.

The present invention has been made in view of the above circumstances, and has as its object to provide a diamond polishing method, a grindstone and a polishing apparatus capable of high-speed polishing.

[0006]

A first feature of the present invention is as follows.
While supplying an oxide powder containing at least one transition metal element, alkali metal element, or alkaline earth metal element to the surface of a diamond to be polished, in the vicinity of a phase transformation point of the oxide in an atmosphere containing oxygen. And polishing the surface of the diamond.

A second feature of the present invention is that a polishing plate made of an oxide containing at least one transition metal element, alkali metal element or alkaline earth metal element is brought into contact with the surface of diamond to be polished, A diamond polishing method characterized in that the diamond and the polishing plate are relatively rotated while being heated to near the phase transformation point of the oxide in an atmosphere containing oxygen to polish the diamond surface. It is in.

A third feature of the present invention is that a step of heating an oxide containing at least one transition metal element, alkali metal element or alkaline earth metal element to a polishing temperature or higher in an oxygen atmosphere, A cooling step of cooling the oxide to room temperature in an oxygen atmosphere to obtain a grindstone made of an oxide containing at least one transition metal element, alkali metal element, or alkaline earth metal element. In a method of manufacturing a whetstone.

A fourth feature of the present invention is that a polishing plate made of an oxide containing at least one transition metal element, an alkali metal element or an alkaline earth metal element and a diamond to be polished are applied to the polishing plate. A supporting means for supporting the diamond or the polishing plate, and a rotating means for rotating the polishing plate; and supplying oxygen to a region where the diamond is brought into contact with the polishing plate while the region is in contact with the oxide phase. A heating means for heating to a vicinity of the transformation point, wherein the diamond surface is polished.

A fifth feature of the present invention is that a polishing plate made of an oxide containing at least one transition metal element, alkali metal element or alkaline earth metal element is brought into contact with the surface of diamond to be polished, While relatively rotating the diamond and the polishing plate, it was heated to near the phase transformation point of the oxide in an atmosphere containing oxygen to press the polishing plate against the diamond surface, thereby polishing. A diamond polishing method characterized in that:

Transition metal elements such as manganese (Mn), iron (Fe), and cobalt (Co); magnesium (Mg);
An oxide or composite oxide containing at least one alkali metal element such as barium (Ba) or calcium (Ca) or an alkaline earth metal element acts as a catalyst for generating active oxygen under a high-temperature and low-pressure atmosphere. ,
As shown in FIG. 2, it was discovered that carbon in diamond reacts with active oxygen, and polishing proceeds at high speed and efficiently, and this was done by paying attention to this. Desirably, polishing is performed in the vicinity of a phase transformation that releases oxygen, such as a reaction from Mn ₂ O ₃ to Mn ₃ O ₄ , for example.
As shown in (1), a state in which active oxygen is easily released can be created, and the polishing rate can be further improved.

Furthermore, after oxidizing the metal oxide at a high temperature equal to or higher than the polishing temperature, the metal oxide is cooled to room temperature in an oxygen excess atmosphere, whereby a metal oxide containing more active oxygen can be obtained. Further high-speed polishing is possible by using a metal oxide.

The oxide may be supplied as a powder to the polishing area, or may be used as a polishing plate in contact with the diamond surface.

According to this structure, the reaction between the active oxygen released from the metal oxide and the carbon of the diamond causes
Very high-speed polishing can be performed.

[0015]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 shows a diamond polishing apparatus according to a first embodiment of the present invention. This apparatus is an apparatus used for polishing a relatively small diamond 1 and has Mn ₂
The polishing plate 2 made of the oxide is brought into contact with the diamond 1 while supplying the O ₃ powder P. The heating temperature of the polishing plate 2 is 900, which is the phase transformation temperature of Mn ₂ O ₃ to Mn ₃ O ₄ . The polishing is performed while the polishing plate is heated to ℃. That is, the apparatus comprises a polishing plate 2, a heater 3 for heating the polishing plate, a rotary motor 4 for rotating the diamond, a pressing plunger 5 for pressing the diamond 1 toward the polishing plate, And a moving stage 6 for transferring the diamond 1 to be formed.
Here, the temperature of the polishing plate 2 is always detected by the thermocouple 8, and the heat source 7 for the heater is controlled by the temperature controller 9.
, So that the polishing plate has a desired temperature. Reference numeral 10 denotes a diffusion pump, which can control the inside of the vacuum chamber 11 to a desired reduced pressure state.

The diamond 1 to be polished here is formed on a {111} plane of a single-crystal silicon substrate of 10 mm × 10 mm by plasma CVD under the following conditions, with a thickness of about 50 μm and a surface roughness of about 3.0 μm Rmax. Diamond film. The film forming conditions CH ₄ 2 sccm and H ₂ 2
The substrate was formed at a substrate temperature of 850 ° C. and a film formation time of 100 hours using a source gas composed of a mixed gas of 00 sccm.

Next, the diamond 1
The method for polishing the surface will be described. First, the diamond 1 to be polished is attached to the rotary motor 4 and the chamber 1
1 is reduced to 0.5 Pa using the diffusion pump 10. Then, the heat source 7 for the heater is controlled by the temperature controller 9, and the polishing plate is heated by the heater 3 so that the temperature of the polishing plate becomes 500 to 1000 ° C.

In this state, while moving horizontally in the moving stage 6, the Mn ₂ O ₃ powder P is moved toward the polishing region.
While pressing, the diamond 1 is pressed by the pressing plunger 5 toward the polishing plate.

As described above, in a low-pressure and high-temperature atmosphere, by supplying active oxygen from a metal oxide, carbon and oxygen in diamond react with each other to evaporate into carbon monoxide or carbon dioxide, and extremely high speed is obtained. , And a smooth surface can be obtained.

In the above-described embodiment, the polishing is performed while applying pressure. However, mechanical polishing by applying pressure is not required, and good polishing can be achieved without mechanical polishing.

Next, a second embodiment of the present invention will be described.

In the first embodiment of the present invention, the polishing is performed while supplying the metal oxide powder. In this embodiment, as shown in FIG. 4, the polishing plate 12 is made of Co _0.63 Fe _2.37 O _4.
It is characterized by comprising a metal oxide. That is, a Co _0.63 Fe _2.37 O ₄ ceramic plate is 760 mH
It was formed by cooling from 1200 ° C. to room temperature in g of oxygen and had a surface roughness of about 0.5 μmRmax. The other parts were formed in exactly the same manner as in the first embodiment. The same portions are denoted by the same reference numerals, and description thereof will be omitted.

Next, a method of polishing the same diamond 1 as used in the first embodiment using this apparatus will be described.

First, the diamond 1 to be polished is attached to the rotary motor 4, and the pressure in the chamber 11 is reduced to 0.5 Pascal using the diffusion pump 10. Then, the heat source 7 for the heater is controlled by the temperature controller 9,
The polishing plate 12 is heated by the heater 3 so as to be at a temperature of 500 to 1000 ° C.

In this state, the diamond 1 is pressed against the polishing plate 12 by the pressing plunger 5 while moving in the horizontal direction on the moving stage 6.

In this way, polishing is achieved at a very high speed.

FIG. 5 shows the result of measuring the polishing rate while changing the temperature of the polishing plate. From this result, it can be seen that there is a point where high-speed polishing is possible at around 900 ° C., which is the phase transformation point.

Next, a third embodiment of the present invention will be described. In this example, as shown in FIG. 6, the apparatus for polishing a large diamond 1 is characterized in that the diamond 1 is placed on a heater 3 for heating and the polishing plate 2 is rotated. Things. Here, the CoFe ₂ O ₃ ceramic plate is 760 mH in the same manner as in the second embodiment.
What was formed by cooling from 1300 ° C. to room temperature in g of oxygen was used as a polishing plate 2, and mounted on a rotation motor 4.
The other parts were formed in exactly the same manner as in the first embodiment. Again, the same parts are given the same symbols,
Description is omitted.

Next, a method for polishing the same diamond 1 as used in the first embodiment using this apparatus will be described.

First, the diamond 1 to be polished is placed on the heater 3, the polishing plate 12 is attached to the rotary motor 4, and the chamber 11 is
Reduce pressure to 0.5 Pascal using. Then, the heater heat source 7 is controlled by the temperature controller 9, and the diamond 1 is heated by the heater 3 so that the temperature of the diamond 1 becomes 500 to 1000 ° C.

In this state, the polishing plate 12 is moved horizontally by the moving stage 6 while the pressing plunger 5 is moved.
Is pressed toward the diamond 1.

In this way, polishing is achieved at a very high speed.

FIG. 7 shows the result of measuring the relationship between the polishing plate temperature and the polishing rate at this time. Here, the curve a is the result of using the CoFe ₂ O ₃ ceramic plate of the embodiment of the present invention.
For comparison, the curve b shows the relationship between the polishing plate temperature and the polishing rate when an Fe plate is used as the polishing plate. These comparisons also show that extremely high-speed polishing can be achieved when the metal oxide of the present invention is used.

Although a CoFe ₂ O ₃ ceramic plate or the like is used in the above embodiment, the metal oxide can be selected as appropriate, and it is desirable to select a metal oxide having a phase transformation point in the polishing temperature range. The metal oxide to be used can be made into an oxygen-rich state by performing a heat treatment in an atmosphere higher than the oxygen partial pressure at the time of polishing.

[0036]

As described above, according to the present invention, it is possible to perform high-speed polishing while oxidizing diamond using a metal oxide as a catalyst.

[Brief description of the drawings]

FIG. 1 is a diagram showing a diamond polishing apparatus according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating the principle of the diamond polishing method of the present invention.

FIG. 3 is a diagram illustrating the principle of the diamond polishing method of the present invention.

FIG. 4 is a diagram showing a diamond polishing apparatus according to a second embodiment of the present invention.

FIG. 5 is a diagram showing a relationship between a temperature and a polishing rate in the apparatus.

FIG. 6 is a diagram showing a diamond polishing apparatus according to a third embodiment of the present invention.

FIG. 7 is a comparative diagram showing a relationship between a temperature and a polishing rate in the apparatus.

[Explanation of symbols]

1 Diamond P Mn ₂ O ₃ powder 2 polishing plate 3 heater 4 rotary motor 5 pressurization plunger 6 moving stage 7 the heat source 8 thermocouple 9 Temperature controller heater 10 diffusions pumps 11 vacuum chamber 12 polishing plate

Claims (5)

[Claims] An oxide powder containing at least one transition metal element, alkali metal element or alkaline earth metal element is supplied to the surface of diamond to be polished in an atmosphere containing oxygen. A diamond polishing method characterized in that the diamond surface is polished by heating to the vicinity of the phase transformation point. 2. A polishing plate made of an oxide containing at least one transition metal element, alkali metal element, or alkaline earth metal element is brought into contact with the surface of a diamond to be polished. A diamond polishing method, wherein the diamond is heated to about the phase transformation point of the oxide in an atmosphere containing oxygen while relatively rotating the diamond. 3. A step of heating an oxide containing at least one transition metal element, alkali metal element, or alkaline earth metal element to a polishing temperature or higher in an oxygen atmosphere, and heating the oxide in an oxygen atmosphere. A method for producing a grindstone comprising an oxide containing at least one transition metal element, alkali metal element, or alkaline earth metal element, comprising a cooling step of cooling to room temperature. 4. A polishing plate made of an oxide containing at least one transition metal element, alkali metal element or alkaline earth metal element, and a support for supporting diamond to be polished so as to abut the polishing plate. Means for rotating the diamond or the polishing plate; heating for heating the region to a vicinity of a phase transformation point of the oxide while supplying oxygen to a region where the diamond is in contact with the polishing plate. Means for polishing the diamond surface. 5. A polishing plate made of an oxide containing at least one transition metal element, alkali metal element or alkaline earth metal element is brought into contact with the surface of a diamond to be polished, and the diamond and the polishing plate are brought into contact with each other. While relatively rotating, heated to near the phase transformation point of the oxide in an atmosphere containing oxygen, pressing the polishing plate against the diamond surface, and polished diamond, characterized in that Polishing method.