JPH1067597A - Method for producing diamond thick film and probe for measuring instrument having contact made of this diamond thick film - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To realize an inexpensive bore gauge measurement probe having excellent durability and reliability. SOLUTION: A diamond thick film is manufactured by a combustion flame method. A step of separating the internal flame 14 from the external flame 15 in the combustion flame, a step of irradiating the substrate 11 having a concave surface on which the diamond thick film is formed with the internal flame 14 separated from the external flame 15, To allow the diamond thick film formed on the substrate 11 to be spontaneously peeled off by allowing it to cool naturally. The concave surface of the substrate 11 is formed so as to be a female mold with respect to the surface shape of the diamond thick film to be formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a probe for a measuring instrument such as a bore gauge having improved durability and reliability suitable for measurement of a mold or the like made of cemented carbide, and a diamond used for a contact of the probe. The present invention relates to a method for manufacturing a thick film.

[0002]

2. Description of the Related Art A bore gauge is usually used when a dimension is previously adjusted to a micrometer or a ring gauge (hole gauge) having a known inner diameter, and the dimension is compared with a hole diameter of a workpiece. For example, when measuring a hole diameter of 10 mm, first, the bore gauge 21 shown in FIG.
Between the contact 25 of the measurement probe 24 and the bore gauge 2
Adjust the scale of 1 to ± 0μm and set the dial mounting screw 22
Tighten for initial setting.

At the time of initial setting, the grip handle 23 is held by hand, and the measuring probe 24 is pressed and shrunk with a finger, and then gently inserted into the measuring hole of the object M to be measured. In this case, the measurement probe 24 is slightly shaken so as not to be twisted, and the bore gauge 21 is shaken.
After stabilizing the dial pointer, reading is made by reading the indicated value on the scale. When the measurement probe 24 is shaken to stabilize the dial gauge pointer, the contact 25 slides on dust and chips remaining on the inner wall of the measurement hole. It is required to be an excellent material.

Conventional bore gauge contacts include tool steel (J
Those cured H _RC 55 to 65 by heat-treating IS SKS31 etc.), or the like that has been subjected to hard chromium Tetsukin is used in the steel. Hv1400-1 as a special product
Cemented carbide chips having a hardness of 800 have been used.

[0005] However, the contact using the tool steel as described above has low wear resistance and corrosion resistance, and is easily worn or corroded early. Although the wear resistance of cemented carbide alloys is slightly improved due to its high hardness, unevenness and wear scars are inevitable when used in the measurement of cemented carbide dies. As it reduces the reliability of the bore gauge. For this reason, a flat measurement surface such as an anvil of a myrometer has a higher hardness (Hv 2000 to 1000).
No. 0) has been proposed as a ceramic or diamond (for example, Japanese Patent Application Laid-Open No. 63-65064 and Japanese Utility Model Application Laid-Open No. 3-52601). However, since the contact of the bore gauge has a curved surface, it has been substantially impossible to grind ceramics or diamond into this curved shape in industrial production. Therefore, in the process of manufacturing a cemented carbide mold, the measurement probe having a contact made of cemented carbide is worn out in a short time and then replaced with a new one. Has been consumed.

On the other hand, since diamond is an allotrope of carbon that is stable under ultrahigh pressure, it is considered that diamond is naturally formed under the ultrahigh pressure and high temperature of the deepest. It has been synthesized under an ultrahigh pressure of 5 GPa or more even by an artificial method. On the other hand, in recent years, using a hydrocarbon gas such as methane gas as a raw material, the raw material gas is decomposed and excited by means of high-frequency discharge or the like, and diamond is synthesized in a gaseous phase in a range of about 1/1000 to several atmospheres. A possible way is being developed.

As such a method, for example, a thermal CVD method (JP-A-58-91100), a plasma CVD method (JP-A-58-135117, JP-A-58-1104)
No. 94 each publication), an ion beam method, a laser CVD method, a combustion flame method and the like are known. Also, JP-A-4-305279
Japanese Patent Application Laid-Open Publication No. H11-209,199 discloses a CVD diamond-coated ultrasonic probe tip. Since this CVD diamond has a low film-forming rate and a strong adhesive force to a substrate, there is a problem that it takes time to peel off the substrate from the substrate and adhere to the probe. Alternatively, a probe or a contact coated with a diamond thin film is disclosed in JP-A-63-281030 and JP-A-2-186203. The diamond film formation by the CVD method disclosed herein is effective for the thickness (5 to 10 μm) of the insulating coating film having good thermal conductivity. However, for the production of a relatively thick and inexpensive diamond thick film having a thickness of 50 μm or more where mechanical wear resistance is required as in the present invention, it is industrially suitable because the film forming speed is low. Hard to say.

On the other hand, a diamond synthesis method using a combustion flame (Yoichi Hirose, Noriaki Kondo, Proceedings of the 35th Federation of Applied Physics Related Lectures, p. Vol. 9 p
840, 1988, and Japanese Patent Application Laid-Open No. 1-282193) is a diamond synthesis method near atmospheric pressure. According to these methods, high-speed synthesis of diamond is realized at low cost because the concentration of radicals and ions is high.

[0009]

Various methods for producing a curved surface plate of diamond have been studied so far, but there are problems in terms of high cost, rough surface properties, small adhesive force, etc. It was not suitable for use. Specifically, JP-A-60-141697, JP-A-1-138110
And Japanese Patent Application Laid-Open No. 1-138111 disclose methods of forming a diamond self-solid by a gas phase method. However, these methods are not suitable for forming a diamond thick film thick enough to be self-solid. There is a disadvantage that it takes a long time of several days to several weeks.

Further, CVs disclosed in these publications, such as a hot filament method, a high frequency method, a microwave method, etc.
The diamond film formed by the method D has a problem that the adhesion to the substrate is weak for use as a tool, but too strong to separate from the substrate as a self-solid. Therefore, in these patents, the diamond film formed on the substrate is separated and acquired with considerable labor such as cooling once and heating again, or melting the metal substrate with a strong acid. Therefore, the curved diamond plate obtained by the method disclosed in the above-mentioned publication is not particularly economical when applied to a bore gauge measuring probe, and is practically impossible to realize.

In view of the above circumstances, the present invention provides a method for manufacturing a diamond thick film which can realize an inexpensive bore gauge measurement probe which is excellent in durability and reliability in order to fundamentally solve the conventional problems, and this diamond thickness. An object of the present invention is to provide a probe for a measuring instrument having a contact made of a membrane.

[0012]

A method for producing a diamond thick film according to the present invention is a method for producing a diamond thick film by a combustion flame method, comprising the steps of separating an internal flame from an external flame in a combustion flame. Irradiating the inner flame separated from the outer flame to a substrate having a concave surface on which a diamond thick film is formed, and the thickness of the diamond formed on the substrate by allowing the substrate to cool naturally. And a step of spontaneously removing the film.

The method for producing a diamond thick film according to the present invention is a method for producing a diamond thick film by a combustion flame method, comprising the steps of separating an internal flame from an external flame in a combustion flame; Irradiating the inner flame separated from the outer flame to a substrate having a concave surface on which is formed, irradiating the substrate and the inner flame with a plasma of Freon gas; Allowing the diamond thick film formed on the substrate to peel off naturally by allowing it to cool.

Further, in the method for manufacturing a diamond thick film according to the present invention, the concave surface of the substrate is formed so as to be a female mold with respect to the surface shape of the diamond thick film to be formed.

In the method for producing a diamond thick film according to the present invention, the substrate may be made of molybdenum, silicon,
Tungsten, iron, nickel, copper, tantalum, chrome,
It is formed of titanium, graphite, tungsten carbide, titanium nitride, titanium carbide, silicon carbide, alumina, sialon, cermet, or a mixture or compound thereof.

Further, in the method of manufacturing a diamond thick film according to the present invention, the substrate surface having the concave surface on which the diamond thick film is formed is coated with an impurity which inhibits diamond film formation. Also,
In the method for producing a thick diamond film according to the present invention, the impurity is an organic compound or a mixture of an organic compound and a pigment. Further, in the method for producing a diamond thick film according to the present invention, the organic compound is silicone grease, glycerin or benzene, and the mixture of the organic compound and the pigment is magic ink, paint, butter, loin, fat, machine oil, heavy oil. Or kerosene.

Further, the probe for a measuring instrument according to the present invention comprises:
According to another aspect of the present invention, there is provided a contact having a diamond thick film manufactured by any of the above methods.

According to the present invention, in particular, in a bore gauge measuring probe having a hemispherical contact, the contact portion of the contact with the object to be measured is preferably 10 μm or more and 2 mm in thickness.
The following measurement probe of a bore gauge made of a diamond curved plate is obtained. The diamond curved surface plate is formed of a diamond thick film formed on a substrate having a concave surface which becomes a female type with respect to the spherical surface of the contactor by a combustion flame method including an internal flame in which an external flame is separated. The curved plate of the diamond thick film created by the combustion flame method is obtained by spontaneously exfoliating the substrate by cooling it naturally to room temperature after it is made by the combustion flame method.
In addition, the substrate can be reused many times in the manufacture of the second and subsequent diamond thick film curved plates.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a method for manufacturing a diamond thick film according to the present invention and a measuring instrument probe having a contact made of the diamond thick film according to the present invention will be described below with reference to the drawings.

In this embodiment, it is assumed that the method of the present invention is applied to form the contact (see FIG. 4) of the bore gauge measuring probe described above. That is, here, the contact 1 is attached to the outer peripheral portion of the measurement probe 2 as shown in FIG. 1, and the diamond thick film manufactured by the method of the present invention is used as the contact 1.

According to the method of the present invention, a diamond thick film is produced by a combustion flame method. The main steps are a step of separating an internal flame from an external flame in a combustion flame, and a method of forming a diamond thick film on a substrate having a concave surface. On the other hand, the method includes a step of irradiating the inner flame separated from the outer flame, and a step of spontaneously removing the diamond thick film formed on the substrate by allowing the substrate to cool naturally.

The diamond thick film that is the object of the present invention is:
The bore gauge measurement probe 2 has a curved surface so as to be in contact with the object to be measured. The diameter of the diamond thick film is 0.99 mm or more and 50 cm or less, the radius of curvature of the curved surface is 0.99 mm or more and 10 m or less, and the thickness is 10 μm or more and 2 mm or less.
A preferable range is 0 μm or more and 1 mm or less. When the thickness of the diamond thick film is less than 1 μm, the diamond film does not become a continuous diamond film, and when it exceeds 1 mm, the economical efficiency is unnecessarily deteriorated.

In the method of the present invention, the combustion flame method is used as described above. For example, the deposition rate of a diamond thick film by thermal CVD is 0. In contrast to several μm / h, the film formation rate by the combustion flame method is several tens to several hundred μm / h, which is 100 times or more.
For inexpensive applications such as the bore gauge measuring probe 2 as in this example, the combustion flame method is most suitable for forming a diamond thick film.

Here, when the internal flame separated from the external flame is used as the combustion flame for synthesizing the diamond thick film (see Japanese Patent Application Laid-Open No. 2-19694), the combustion reaction is stabilized, so that the diamond flame of the same standard is used. The film can be mass-produced with good reproducibility. It is also effective to stabilize the flame by using a flat flame conditioned with hydrogen gas whose burning rate is lower than that of acetylene (combustion and flame, vol 9,
no.3 & 4, p239, 1992). In order to further improve the film forming speed, the inner flame flow is disturbed to always bring the active species into contact with the substrate surface (Japanese Patent Laid-Open No. 6-002933), or the pressure of the film forming atmosphere is reduced to 0.1. It is effective to set the pressure in a range from atmospheric pressure to 20 atmospheric pressure.

On the diamond growth surface, hydrogen terminates the bond of the surface carbon atom. The terminal hydrogen is extracted by active hydrogen atoms in the inner flame, and diamond grows while repeating the bonding of carbon in the inner flame to vacant bonds at this time. Here, if an appropriate amount of halogen such as fluorine, chlorine, bromine, and iodine is present, the terminal hydrogen extraction reaction is promoted, and diamond grows at a lower substrate temperature at a higher speed. Therefore, adding a gas containing these halogen atoms to the internal flame is also effective for high-speed synthesis.

For example, Japanese Patent Application Laid-Open No. 2-208291 discloses that addition of a halogen gas to a fuel gas increases the temperature of the flame and the concentration of C radicals, thereby improving the diamond film formation speed by the combustion flame. I have. In this method, flame irradiation cannot be sustained for a long time so that the added halogen gas corrodes the inside of the burner and a diamond thick film can be formed, and the effect of the halogen addition is to contribute to the reaction between gases in the flame. There is. In fact, it is to promote the hydrogen extraction reaction on the diamond growth surface. The present inventors have conducted intensive studies based on these facts, and as a result, the halogen atom is given in the form of a less reactive compound,
It has been newly found that a method of decomposing the compound in the vicinity of the combustion flame to diffuse halogen atoms to the substrate surface is effective.

In the method of the present invention, a substrate having a concave surface on which a diamond thick film is formed is irradiated with an internal flame separated from an external flame. The radius of curvature of a contact portion of a bore gauge measurement probe, which is currently widely used, with an object to be measured is a curved surface of several mm to several cm. To obtain a diamond with such a curved surface,
A thick diamond film is formed by a combustion flame method on a substrate having a concave surface which becomes a female type with respect to a convex surface (male type) of a measurement probe.

As the substrate material having the concave surface, molybdenum, silicon, tungsten, iron, nickel, copper,
Tantalum, chromium, titanium, graphite, tungsten carbide,
Titanium nitride, titanium carbide, silicon carbide, alumina, sialon, cermet, and mixtures or compounds thereof are used.

As a result of the inventor's diligent research, the diamond thick film formed on the substrate by the combustion flame method transfers the back surface (boundary surface side with the substrate) even to the minute shape of the substrate. It has been found that if the substrate is a mirror surface, the back surface of the diamond thick film is also a mirror surface.

Further, in the method of the present invention, the diamond thick film formed on the substrate is spontaneously peeled off by allowing the substrate to cool naturally. This is because, when the diamond thick film formed on the substrate is cooled to room temperature after being formed by the combustion flame, the adhesive force to the substrate is weak enough to easily peel off from the difference in thermal expansion coefficient with the substrate material, Therefore, they have found that it is possible to produce a diamond thick film any number of times using the same substrate, and have completed the present invention. The coefficient of linear thermal expansion α of diamond is about 2.3 × 10 ⁻⁶ , which is smaller than the coefficient of thermal expansion of the substrate material described above (3.3 × 10 ^{−6 to} 33 × 10 ⁻⁶ ). In addition, if the substrate surface is coated in advance with an impurity that inhibits diamond film formation to a thickness of about 0.1 μm to several tens μm, peeling of the formed diamond thick film becomes easier. Specific examples of the impurities include organic compounds such as silicone grease, glycerin, and benzene, magic inks that are mixtures of organic compounds and pigments, paints, butter, loin, fat, machine oil, heavy oil, kerosene, and the like. .

The diamond thick film formed by the above process is used by being attached to a measurement probe 2 of a bore gauge as shown in FIG. This mounting method is a method of physically fixing, such as caulking, screwing, nailing, and intermolecular adhesion between mirror surfaces, or by interposing an intermediate substance between the measurement probe main body and the diamond thick film. There is a way to fix.

Examples of the intermediate material in the latter method include a brazing alloy, a brazing alloy, a solder, an inorganic adhesive, an organic adhesive and the like. As the brazing alloy, any of the currently known brazing alloys can be applied, and among them, a high melting point brazing alloy is particularly desirable. For example, TiCu sill (4.5% Ti, Cu
(26.7%, the remaining Ag, melting point 840-850 ° C.) in an inert atmosphere results in a good brazing alloy. Pa3 published in U.S. Pat. No. 4,414,178
0%, Cr 10%, B 3%, the remaining Ni alloy is 9
Brazing can be performed well in the range of 80 to 1100 ° C. Also, Au 20%, Ni 10%, Pa 5% Mn 8%, which are disclosed in U.S. Pat. No. 4,527,998,
The remaining Cu alloy composition can be used because it has a liquidus in a wide temperature range of 90 to 1000 ° C.

Measuring probe 24 of conventional bore gauge 21
Among them, the hardness of the carbide contact having the highest hardness is Hv180.
On the other hand, the hardness of the contact 1 to which the curved plate of the diamond thick film is bonded is Hv10000. Further, the surface of the curved diamond plate is a smooth mirror surface. When a mold made of cemented carbide was measured using this bore gauge, the wear and damage of the contact did not occur, and on the other hand, accurate measurement could be repeated without damaging the mold.

[0034]

Next, specific examples of the method of the present invention will be described. (Embodiment 1) FIG. 2 shows a schematic configuration of an apparatus for manufacturing a diamond thick film according to Embodiment 1. In the figure, a substrate 1
For 1, a molybdenum plate having a size of 20 mm × 20 mm and a thickness of 5 mm was used. At the center of this molybdenum plate, a radius of 2
A depression corresponding to a 0.8 mm depth of a 0.8 mm sphere was processed and formed, and the surface was mirror-finished. Each of the two substrates was bonded with a silver paste to a water cooling box 12 in an apparatus having two gas welders 13 shown in FIG. Tinder diameter 1mm
Acetylene gas in each of the two gas welders 13.
5 liter / min, oxygen gas 2.0 liter / min
Was supplied and ignited, and the generated internal flame 14 was brought into contact with the center of the molybdenum substrate 11. The outer flame 15 is discharged outside the apparatus.

While maintaining the substrate surface temperature at 800 to 1000 ° C., the inner flame 14 is continuously irradiated under atmospheric pressure,
An m-thick synthetic diamond layer was created. Five hours later, the irradiation of the internal flame 14 was terminated, and the mixture was allowed to cool naturally. As a result, a diamond concave thick film having a diameter of 3.5 nm is formed around the depression of each substrate 11, and when this peripheral portion is gently pressed with a piece of paper, it is peeled off from the molybdenum substrate, and two autostereoscopic diamond thick films are formed. Obtained at the same time.

A curved plate (diameter: 2.9 mm, radius of curvature: 2 mm, thickness: 0.2 mm) of a diamond thick film obtained by removing the peripheral edge portion of 0.3 mm from the thick film has a convex surface as shown in FIG. Bore gauge measurement probe 2
Was mounted by TiCu-sil brazing. When a mold made of cemented carbide was measured using this bore gauge, the wear and damage of the contact did not occur, and on the other hand, accurate measurement could be repeated without damaging the mold.

(Embodiment 2) FIG. 3 shows a schematic configuration of an apparatus for manufacturing a diamond thick film according to Embodiment 2. In the figure, a silicon carbide plate having a size of 20 mm × 20 mm and a thickness of 5 mm was used for substrate 11. At the center of the silicon carbide plate, a dent corresponding to a sphere having a radius of 1.5 mm and a depth of 0.6 mm was formed by working, and the surface was mirror-finished. This substrate 11 was bonded to a water cooling box 12 in the apparatus shown in FIG. 3 with a silver paste. Acetylene gas 2.8 liter / min, oxygen gas 2.3
The premixed gas at 1 liter / min was supplied and ignited, and the generated internal flame 14 was brought into contact with the center of the silicon carbide substrate. The external flame 15 is discharged to the outside of the apparatus via the valve 18.

Further, the inner flame 14 and the substrate 11 are shown in FIG.
As shown in FIG. 2, a chlorofluorocarbon gas (CF) using helium gas as a carrier from the fluorocarbon plasma supply pipe 16 in the horizontal direction
The plasma of 4) was simultaneously irradiated. A high-frequency coil is wound around the Freon plasma supply pipe 16 and a power supply 17 (50
(kHz, 1.5 kV). In this case, while maintaining the surface temperature of the substrate 11 at 900 ° C., irradiation with the internal flame 14 and Freon plasma was continued at 2 atm, and a synthetic diamond layer having a thickness of 50 μm was formed. One hour later, the irradiation of the internal flame 14 was terminated, and the mixture was allowed to cool naturally. As a result, a diamond concave plate having a diameter of 2.4 mm is formed around the substrate depression, and when this peripheral portion is gently pressed with a piece of paper, the diamond concave plate is peeled off from the silicon carbide substrate, and a self-stereoscopic thick diamond film is obtained. Was.

The above operation was performed twice to remove a 0.2 mm peripheral portion of these thick films, thereby obtaining a diamond thick film curved plate (diameter 2.0 mm, radius of curvature 1.5 mm, thickness 5 mm).
0 μm) were mounted on the measurement probe 2 of the bore gauge in such a manner that the organic adhesive was used as the intermediate layer, with the convex surface facing up as shown in FIG. When a mold made of cemented carbide was measured using this bore gauge, the wear and damage of the contact did not occur, and on the other hand, accurate measurement could be repeated without damaging the mold.

[0040]

As described above, according to the present invention, a curved plate made of a thick diamond film can be easily manufactured in a short time. Accordingly, in addition to the diamond curved plate being formed at a high speed, there is no need to dissolve the substrate with an acid or to remove the diamond plate by applying force to remove the diamond plate from the concave curved substrate.
Furthermore, since the surface of the removed diamond curved plate is a mirror surface, it is not necessary to separately polish the surface. Accordingly, there is an advantage that a diamond curved plate that can be bonded to a curved bore gauge measurement probe can be manufactured at extremely low cost.

[Brief description of the drawings]

FIG. 1 is a schematic view of a tip portion of a probe for bore gauge measurement according to the present invention.

FIG. 2 is a diagram showing a schematic configuration of a diamond synthesizing apparatus used in a first embodiment of the present invention.

FIG. 3 is a diagram showing a schematic configuration of a diamond synthesizing apparatus used in a second embodiment of the present invention.

FIG. 4 is a front view showing a configuration of a bore gauge.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Contact 2 Bore gauge measurement probe 11 Substrate 12 Water cooling box 13 Gas welder 14 Inner flame 15 Outer flame 16 Freon plasma supply pipe 17 AC power supply 18 Valve

Claims (8)

[Claims] 1. A method for producing a diamond thick film by a combustion flame method, comprising the steps of: separating an internal flame from an external flame in a combustion flame; Irradiating the inner flame separated from the outer flame, and naturally spontaneously exfoliating the diamond thick film formed on the substrate by naturally cooling the substrate. Method for producing a thick diamond film. 2. A method for producing a thick diamond film by a combustion flame method, comprising the steps of: separating an inner flame from an outer flame in a combustion flame; Irradiating the inner flame separated from the outer flame; irradiating the substrate and the inner flame with a plasma of Freon gas; and forming the substrate on the substrate by allowing the substrate to cool naturally. And a step of spontaneously removing the diamond thick film. 3. The diamond thick film according to claim 1, wherein the concave surface of the substrate is formed to have a female shape with respect to the surface shape of the diamond thick film to be formed. Production method. 4. The substrate is made of molybdenum, silicon, tungsten, iron, nickel, copper, tantalum, chromium, titanium, graphite, tungsten carbide, titanium nitride, titanium carbide, silicon carbide, alumina, sialon, cermet, or a mixture thereof. 4. The method for producing a diamond thick film according to claim 1, wherein the method is formed of a compound. 5. 5. The method according to claim 1, wherein the surface of the substrate having a concave surface on which the diamond thick film is formed is coated with an impurity that inhibits diamond film formation.
5. The method for producing a diamond thick film according to any one of 4. 6. The method for producing a diamond thick film according to claim 5, wherein the impurity is an organic compound or a mixture of an organic compound and a pigment. 7. The organic compound is silicone grease, glycerin or benzene, and the mixture of the organic compound and the pigment is a magic ink, paint, butter, loin,
7. The method for producing a diamond thick film according to claim 6, wherein the method is fat, machine oil, heavy oil, or kerosene. 8. A probe for a measuring instrument having a contact made of a diamond thick film manufactured by the method according to claim 1. Description: