JPH05171464A - Oxidation method - Google Patents

Abstract

PURPOSE:To enable the oxidation of a metal combined with a low m.p. material, to shorten the time required to oxidize a material of large volume and to attain a uniform thickness of an oxidized film and a uniform oxidized region by colliding fine particles having heat resistance at above the oxidation temp. of the surface of the material to be oxidized against the surface. CONSTITUTION:Fine particles 2 of 0.1-5mum particle diameter are made collid against the surface 1S of a metal body 1 to be oxidized as shown by an arrow (k). By this collision, the kinetic energy of the fine particles 2 is transformed into heat energy and the surface 1S is instantaneously heated to about >=200 deg.C and oxidized. At this time, the oxidized surface 1S is instantaneously cooled by oxygen-contg. atmospheric gas and the oxidation is carried out while keeping the entire metal at such a relatively low temp. as the room temp.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oxidation method for oxidizing the surface of an oxide such as a metal, and more particularly to a novel oxidation method for bombarding fine particles to perform oxidation.

[0002]

2. Description of the Related Art In the case of oxidizing the surface of a metal, a method of heating the temperature of the metal to about 100 to 200 ° C. or more in the atmosphere has been conventionally adopted. However, this oxidation method by heating has the following problems.

First, when the oxide to be oxidized has a composite structure of a metal and a low melting point material such as plastic, it is not possible to raise the temperature to perform the oxidation treatment, and the oxide to be oxidized having a large volume is If the time for raising and lowering the temperature is long, and if there is a difference in temperature between the oxides, the oxide film thickness will vary, and if there is processing strain or stress on the surface of the oxides, only this part will occur. However, there is a problem in that it is apt to be intensively oxidized from the surface to a deep depth, variations occur in the thickness of the oxidized portion and its oxide film, and it is not possible to oxidize locally.

[0004]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems in the conventional oxidation method by proposing a completely new oxidation method to the conventional heating oxidation method as described above. That is, it enables oxidation of a metal having a composite structure with a low-melting-point material, shortens the oxidation time for a material with a large volume, avoids variations in oxide film thickness and oxidation region, and locally as necessary. Be able to oxidize.

[0005]

The oxidation method according to the present invention is as shown in FIG.
The fine particles 2 having heat resistance equal to or higher than the oxidation temperature are bombarded and oxidized on the surface 1S to be oxidized.

Further, according to another oxidation method of the present invention, in the above-mentioned oxidation method, the particle diameter of the fine particles 2 is 0.1 to 5 μm.
m.

Still another oxidation method according to another aspect of the present invention is the above-mentioned oxidation method, in which the fine particles 2 are bombarded in an atmosphere containing oxygen.

Further, another oxidation method according to another aspect of the present invention uses particles containing oxygen atoms as the fine particles 2 in the above-mentioned oxidation method.

Furthermore, according to another oxidation method of the present invention, the impact velocity of the fine particles 2 is set to 10 to 100 m / sec.

[0010]

As described above, the oxidation method according to the present invention adopts a novel method of heating the oxide to be oxidized, which is completely different from the conventional method. It utilizes that the surface can be oxidized.

As shown in FIG. 1, the kinetic energy of the fine particles 2 is converted into thermal energy by applying the fine particles 2 to the surface 1S of the oxide 1 to be oxidized as shown by an arrow k, so that the oxide 2 is oxidized. The surface of No. 1 is instantaneously heated to a temperature of about 200 ° C. or higher to be oxidized. At this time, the oxidized surface 1S that has been oxidized is instantaneously cooled by the atmospheric gas, and oxidation is performed while the temperature of the entire metal is kept at a relatively low temperature of about room temperature.

When the particle size of the fine particles is less than 0.1 μm, such oxidation is less likely to occur and the processing time is unnecessarily prolonged, and when the particle size exceeds 5 μm, the particles are too large. The surface may be roughened due to unevenness formed on the surface. In the oxidation method according to another aspect of the present invention, since the particle size of the fine particles is set to 0.1 to 5 μm, it is possible to oxidize with good productivity and without damaging the oxidized surface 1S.

Further, in the oxidation method according to another aspect of the present invention, the fine particles are collided in oxygen gas. By doing so, for example, as shown by an arrow m in FIG. Oxygen molecules in the oxygen gas surrounding the are supplied to the heat generating portion due to the collision of the fine particles 2, so that the oxidized surface 1S of the oxide 1 can be efficiently oxidized.

Further, in the oxidation method according to another aspect of the present invention, by using particles containing oxygen atoms as the fine particles 2, oxygen is generated in the heat generating portion due to the impact of the fine particles 2.
It is liberated from itself and the oxidized surface 1S of the oxide 1 can be efficiently oxidized.

Furthermore, according to another oxidation method of the present invention, the impact velocity of the fine particles 2 is set to 10 to 100 m / sec. This is because when the impact velocity is less than 10 m / sec, heat generation due to impact of fine particles hardly occurs, and therefore the oxidation velocity is extremely slow, and when it exceeds 100 m / sec,
This is due to the fact that the surface 1S to be oxidized of the oxide 1 may be damaged, particles may be attached or embedded, and the surface 1S to be oxidized may be contaminated. Then, it was confirmed that by selecting the impact velocity as described above, it is possible to oxidize reliably with good productivity and without causing inconvenience such as stain.

[0016]

EXAMPLES An example of the oxidation method of the present invention will be described in detail below with an apparatus for carrying out the method.

FIG. 2 is a schematic configuration diagram of an example of an apparatus for carrying out the oxidation method of the present invention. An air compressor 101 for supplying compressed air and compressed air sent from the air compressor 101 as indicated by an arrow a. It is composed of a mixing chamber 102 for mixing fine particles, a blast chamber 103 for injecting the fine particles to the oxide together with the compressed air, and an air blower 104 for collecting and sucking the fine particles from the blast chamber 103.

An air supply pipe 55 is led out from the air compressor 101, and the air supply pipe 55 is further branched into a first supply pipe 56 and a second supply pipe 57, which are connected to the mixing chamber 102, respectively. Has been done. An adjusting valve 58 for adjusting the pressure of the compressed air supplied to the mixing chamber 102 and an electromagnetic valve 59 for controlling the supply of the compressed air to the mixing chamber 102 are provided in the middle of the air supply pipe 55. An adjusting valve 60 that adjusts the flow rate of the compressed air to the second supply pipe 57 is provided in the middle of the second supply pipe 57.

On the other hand, a supply unit 11 for the fine particles 2 is provided above the mixing chamber 102, and the lid body 1 of the supply unit 11 is provided.
2 is opened to supply the fine particles 2.
The bottom of the supply unit 11 has a conical slope,
An inlet 11a to the mixing chamber 102 is provided in the central portion, and a conical supply valve 13 that fits into the inlet 11a is provided. The supply valve 13 is provided so as to penetrate through the central portion of the lid body 12 described above, and the coil spring 1 is provided between the lid portion 12 and the locking portion 13 a provided at the base end portion thereof.
4 is urged upward in FIG.
Therefore, normally, the peripheral surface of the conical portion 13b is the inlet port 11a.
When the supply valve 13 is pressed against the above-mentioned coil spring 14 as necessary, the conical portion 13b is released from the close contact state with the inlet 11a, and the supply The fine particles 2 in the portion 11 are made to fall into the mixing chamber 102.

The mixing chamber 102 is constructed as a cylindrical container in which the fine particles 2 are stored. The bottom portion thereof is conically inclined toward the bottom surface, and the bottom surface has a disk-shaped filter 16, for example, a porous plate having innumerable fine pores formed by sintering metal powder, a so-called cermet. Is provided. Then, the compressed air supplied to the first supply pipe 56 of the air compressor 101 as shown by the arrow b is introduced between the fine particles 2 in the mixing chamber 102 via the filter 16.

A plurality of vibrating means 17 are provided on the conical slope around the filter 16 described above. The vibrating means 17 is composed of, for example, a pair of upper and lower piezoelectric elements and electrodes, is composed of a so-called bimorph, is arranged in an annular shape so that its free end faces above the filter 16, and the base end portion of the mixing chamber 102. It is fixed to a conical slope. The vibrating means 17 can vibrate its free end in the vertical direction by applying a predetermined AC voltage, for example, and mechanically disperse the fine particles 2 as indicated by an arrow d, while compressing air from the filter 16. An air vibrator effect of stirring and mixing can be added.
The frequency of the applied AC voltage is, for example, 200 to 40.
A high frequency of about 0 Hz may be used, and it is desirable that the resonance frequency be substantially equal to the resonance frequency of the bimorph. Furthermore, it is more effective if the phases of the vibrations of the vibrating means 17 adjacent to each other are reversed.

In this example, a rubber sheet 18 is attached to cover the half of the vibrating means 17 on the proximal end side, and the fine particles 2 enter below the vibrating means 17 to prevent vibration. I try to prevent it.

At the center of the above-mentioned filter 16, a delivery pipe 19 penetrating the bottom of the mixing chamber 102 is erected so that its tip end 19a opens into the mixing chamber 102. The fine particles 2 which are agitated and dispersed by compressed air are sent out. The second supply pipe 5 described above is provided in the middle of the delivery pipe 19.
The tip portion 7a of 7 is inserted, and the negative pressure generated by the air flow of the compressed air supplied by the second supply pipe 57 as indicated by the arrow e sucks the fine particles 2 into the delivery pipe 19. , Mixed with compressed air and sent out. The delivery pipe 19 is connected to a tubular delivery pipe 20 that extends to the blast chamber 103. A nozzle 20a is provided at the end of the blast chamber 103 and a vibration means is provided in the middle thereof. 21 is provided to prevent the discharged fine particles 2 from accumulating in the middle of the discharge pipe 20, and the fine particles 2 are smoothly discharged together with the compressed air as shown by arrows f and g.

The delivery pipe 20 is made of, for example, a flexible tube such as a urethane tube, a nylon tube, and a vinyl tube, and is arranged so as to be gently bent while avoiding sharp bending. Further, the connecting portion of the pipes 19 and 20 has a structure that prevents air from being trapped by avoiding a step or the like, so that clogging due to the volume of fine particles is prevented.

On the bottom surface of the mixing chamber 102, an air outlet 22 is formed around the delivery pipe 19, and a part of the compressed air supplied from the first supply pipe 56 is the air. Gush from the outlet 22
At the entrance of the delivery pipe 19, that is, near the tip portion 19a,
As shown by the arrow d, a turbulent air flow is generated and the fine particles 2 are strongly stirred.

Furthermore, inside the mixing chamber 102, there is provided a stirring mechanism 24 in which a rotating shaft 23 is fixed to the bottom surface of the supply valve 13. The stirring mechanism 24 is composed of an arm portion 24a extending from the rotating shaft 23, a frame body 24b made of a thin metal wire, so-called wire, etc., and a brush 24c provided along the lower edge of the frame body 24b. By driving the rotating shaft 23, it has a function of crushing the aggregate of the fine particles 2 aggregated in the mixing chamber 102.

A dust collector 25 is provided above the delivery pipe 19 in the mixing chamber 102, and a bottom portion of the dust collector 25 faces the tip portion 19a of the delivery pipe 19. The powder collecting recess 25a is provided in a trapezoidal cross section. A filter 25b made of a porous material is provided in the upper half of the dust collector 25, and is connected to the exhaust fan 104 via the outlet pipe 26. This derivation pipe 2
A solenoid valve 27 for adjusting the flow and amount of waste is provided in the middle of 6.
Also, an exhaust amount adjusting valve 28 is provided.

The blower 104 has a filter 29 and a suction fan 30 inside which sucks air from the outlet pipe 26 through the filter 29 and exhausts it from an exhaust port 31. Therefore, the exhaust gas from the inside of the mixing chamber 102 is cleaned by the filter 29 and discharged to the outside. The fine particles removed by the filter 29 are stored in the dust collecting portion 32 provided below the filter 29.

Further, a moisture absorbing means 33 such as silica gel and a heating means 34 such as a heater are provided above the mixing chamber 102, and a heating means 35 such as a heater is wound around the mixing chamber 102, for example. The fine particles 2 in the mixing chamber 102 are kept dry to prevent agglomeration.

On the other hand, the blast chamber 103 is provided with a rotary table 37 on which the oxide 36 is placed so as to face the nozzle 20a. The rotary table 37 is rotated by a motor 38, and the fine particles ejected as shown by an arrow h are reflected by the table 37 so that, for example, the side surface of the oxide 36 is carelessly processed. It has a mesh shape in order to prevent it from falling.

The periphery of the turntable 37 is covered with an intake box 39 so as to prevent scattering of fine particles into the blast chamber 103. If the fine particles are scattered in the blast chamber 103, the fine particles may leak to the outside when, for example, an operator opens the blast chamber 103, and the efficiency of collecting the fine particles is reduced.

The bottom of the blast chamber 103 is also conical, and a return pipe 40 is provided so that the collected fine particles are sent to the above-mentioned supply unit 11, for example, the lid 12 of the supply unit 11. It is connected to one end. Similarly, the intake box 39 also has a conical bottom portion, is provided with a return pipe 41, and is connected to a midway portion of the return pipe 40 so that fine particles from the return pipe 41 are sent to the supply unit 11. Further, the vibrating means 42 made of a bimorph or the like is provided at the bottom of the blast chamber 103, as in the above-mentioned mixing chamber 102, so that the falling fine particles are quickly discharged by air vibration.

An exhaust pipe 43 is provided at the other end of the lid body 12, that is, at the end opposite to the one end to which the return pipe 40 is connected with the supply valve 13 interposed therebetween to control the flow of exhaust gas. It is connected to the blower 104 via the electromagnetic valve 45.
Further, a cylindrical partition plate 44 is hung inside the lid body 12, and the fine particles collected from the blast chamber 103 to the supply unit 11 via the return pipes 40 and 41 are bypassed by the partition plate 44. By passing through the same, it is roughly classified according to the same principle as the cyclone,
Housed inside. The unnecessary air is discharged from the air blower 104 through the exhaust pipe 43.

The operation mode of the oxidizing device having the above-mentioned structure will be described.

First, the compressed air sent from the air compressor 101 is divided into the first supply pipe 56 and the second supply pipe 57, and the compressed air divided into the first supply pipe 56 is supplied to the filter 16 or. It flows into the mixing chamber 102 from the air outlet 22. At this time, when the compressed air passes through the fine particles 2, the fine particles 2 are agitated by a so-called air vibrator effect, and a part of the fine particles 2 is fed by the dust collecting recess 25a of the dust collector 25 and the vicinity of the inlet or tip portion 19a of the pipe 19. Collected in.

During this stirring, mechanical dispersion is also performed by the vibrating means 17, and the above-mentioned air vibrator effect is effectively maintained. Further, the electromagnetic valve 27 provided in the middle portion of the outlet pipe 26 connected to the dust collector 25 and the electromagnetic valve 45 provided in the middle portion of the exhaust pipe 43 connected to the lid 12 of the supply unit 11 are fixed. The opening and closing states are controlled so as to be opposite to each other in a cycle, and the fine particles 2 in the mixing chamber 102 are further disturbed by the pressure difference due to these opening and closing operations. At this time, the displacement control valve 2
When the amount of exhaust gas from the inside of the mixing chamber 102 is reduced by 8 to a certain amount, the above-mentioned pressure difference becomes small, and the fine particles 2 are almost constantly injected even if a periodic opening / closing operation is performed.

On the other hand, the compressed air diverted by the second supply pipe 57 is sent straight to the sending-out pipe 19, and a negative pressure is generated by the air flow, so that the fine particles 2 collected near the tip portion 19a are sucked in. ,
In the delivery pipe 19, it is mixed with compressed air.

Then, this mixture of compressed air and fine particles is jetted from the nozzle 20a through the delivery pipes 19 and 20, and is sprayed on the surface to be oxidized of the oxide 36 to be oxidized. The used fine particles are the return pipe 40,
It is returned to the supply unit 11 via 41 and reused.

Oxidation was performed using a metal as the oxide 1 using the above-mentioned apparatus. Changes in the surface state of the oxide 1 at this time are shown in the schematic linear enlarged cross-sectional views of FIGS.

First, as shown in FIG. 3A, the resist 3 is patterned into a desired pattern by applying photolithography or the like to a portion on the surface 1S to be oxidized of the oxide 1 which is not oxidized.

On the surface 1S to be oxidized of the oxide 1 to be oxidized by the above-mentioned device, for example, 1 μm having a particle size of 0.1 to 5 μm.
m is ceramics made of alumina, silicon carbide, boron carbide, boron nitride, etc., or glass such as quartz glass, soda glass, lead glass, etc., or metal such as iron, stainless steel, chromium, etc. A material having heat resistance equal to or higher than the oxidation temperature, for example, fine particles 2 made of silicon carbide in this case is bombarded as shown by an arrow i. The impact velocity at this time is 10 to 100 m / sec, for example, 50 m.
/ Sec. Oxidized surface 1S contacted with fine particles 2 is oxidized, and at the same time, microscopic disturbance occurs in the crystal structure due to the impact of fine particles 2, and as shown in FIG. 3B, several hundred Å to 1000
The convex portion 4 is formed by a slight bulge having a height of about Å.

Then, when the impact of the fine particles 2 is continued, the convex portions 4 are gradually scraped off, and as shown in FIG.
S is flattened.

When the impact of the fine particles 2 is further continued, as shown in FIG. 3D, the oxidized surface is shaved and the recess 5 is formed. Therefore, the oxidation treatment is performed in the above-mentioned FIG. 3B or FIG.
In this state, the impact of the fine particles 2 is stopped.

Although air was used as the atmosphere gas at this time, the fine particles 2 may be bombarded in an inert gas such as N ₂ or Ar, and O ₂ gas may be used at a required ratio. It is possible to easily control the film thickness of the oxide film by mixing it in the inside and adjusting the mixing ratio. Further, by colliding the fine particles in the atmosphere of only the inert gas, it is possible to perform the oxidation while removing the dirt on the surface 1S to be oxidized.

Next, FIGS. 4 and 5 show the results of surface analysis before and after oxidation of the oxide to be oxidized by such a method. In each of the figures, the analysis results by AES (Auger electron spectroscopy) are shown, and the horizontal axis shows the depth from the surface to be oxidized. In this case, NiP was used as the oxide to be treated, and untreated N cut out from the same lot with a diameter of 2.5 inches was used.
The iP and the NiP after the oxidation treatment were measured. 4 and 5, the solid line o is oxygen, and the solid line m ₁
Indicates the relative intensity of Ni, and the solid line m ₂ indicates the relative intensity of P. FIG. 4 shows an untreated surface, and FIG. 5 shows the above-mentioned conditions, that is, fine particles of silicon carbide having a particle size of 1 μm, at a speed of 50 m / sec.
The surface to be oxidized after being subjected to an oxidation treatment by being impacted for a minute is shown.

As can be seen from FIG. 4, although a spontaneously-generated oxide film can be seen on the surface of the sample to be oxidized before oxidation, almost no oxygen component can be seen at a certain depth or more. On the other hand, in the oxide to be oxidized after the oxidation treatment shown in FIG. 5, a certain amount of oxygen component is seen up to a considerable depth, and it can be seen that the oxide is certainly oxidized.

As described above, according to the oxidation method of the present invention, the surface to be oxidized can be surely oxidized to a predetermined depth. At this time, since heating is not performed unlike the conventional method, it is possible to oxidize at room temperature, and it is possible to locally oxidize only a required portion by providing a required mask layer.

In the present embodiment, the oxidation treatment of the oxide to be made of the metal has been described. However, the exposure of the low melting point material to other composite materials such as the metal and the low melting point material is also exposed. It is possible to oxidize only a predetermined portion by bombarding fine particles such as by covering the portion to be covered with a required mask layer, and it is possible to apply the present invention to an oxidizing method for oxidization of various other materials. it can.

Also, when oxidizing an oxide having a large heat capacity, such as a metal having a relatively large volume, only the surface of the oxide is locally heated in the method of the present invention.
Oxidation can be performed in a relatively short processing time.

Further, even when there is a slight temperature difference on the oxide, the oxide film thickness is almost constant, and when the oxide is a metal sample and the surface thereof has a processing strain or stress. The oxidation treatment can be performed with a substantially constant film thickness without intensively oxidizing this portion. For example, in the conventional method, when processing strain occurs at a depth of about several μm from the surface, only this portion is oxidized over a depth of several μm. It was possible to form an oxide film with a uniform film thickness even on the surface to be oxidized where processing strain occurred.

The thickness of the oxide film to be oxidized can be controlled by properly controlling the particle size of the fine particles, the impact velocity, and the impact time without being limited to the above-mentioned embodiment, and the atmosphere can be controlled. The thickness of this oxide film can also be controlled by changing the oxygen concentration in the gas.
Compared with the conventional method, there is an advantage that the film thickness can be controlled easily and the film thickness can be made uniform.

[0052]

As described above, according to the oxidation method of the present invention, an oxide film having a uniform film thickness can be reliably formed locally at a required portion only at a room temperature by a completely new method which has never been used. be able to.

Since the oxidation treatment can be locally performed, the oxidation treatment can be performed on the composite material with the low melting point material, and the oxide to be oxidized having a large heat capacity can be oxidized. Also in this case, the oxidation can be performed in a relatively short treatment time.

Further, even when there is a slight temperature difference on the oxide to be oxidized, the oxide film thickness is almost constant, and when the oxide is a metal sample and there is processing strain or stress on its surface. The oxidation treatment can be performed with a substantially constant film thickness without intensively oxidizing this portion.

Further, the thickness of the oxide film on the surface of the oxide can be controlled by changing the particle size of the fine particles, the impact velocity, the impact time, or the oxygen concentration in the atmosphere gas, which is in comparison with the conventional method. Thus, the film thickness can be easily controlled and the film thickness can be made uniform.

[Brief description of drawings]

FIG. 1 is a schematic diagram illustrating an example of an oxidation method of the present invention.

FIG. 2 is a schematic diagram showing an example of an apparatus for carrying out the present invention.

FIG. 3 is a schematic cross-sectional view showing a change in the surface state of an oxide to be oxidized.

FIG. 4 is a diagram showing an analysis result of a sample before oxidation treatment by Auger electron spectroscopy.

FIG. 5 is a diagram showing an analysis result by Auger electron spectroscopy of a sample after an oxidation treatment by the oxidation method of the present invention.

[Explanation of symbols]

 1 Oxidized 1S Oxidized surface 2 Fine particles

Claims (5)

[Claims] 1. A method for oxidizing, characterized in that fine particles having heat resistance equal to or higher than an oxidation temperature are bombarded against an oxidized surface to oxidize the surface. 2. The oxidation method according to claim 1, wherein the particle size of the fine particles is 0.1 to 5 μm. 3. The oxidation method according to claim 1, wherein the impact of the fine particles is performed in an atmosphere containing oxygen. 4. The oxidation method according to claim 1, wherein particles containing oxygen atoms are used as the fine particles. 5. The impact velocity of the fine particles is 10 to 100 m.
/ Sec is set, The oxidation method of Claim 1 characterized by the above-mentioned.