JPH08972B2 - Ion mixing method and apparatus - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a novel coating technique, and more particularly, to an ion mixing method and an apparatus therefor for forming a coating excellent in corrosion resistance and wear resistance at a low temperature.

[Conventional technology]

It has long been practiced to form a coating on the surface of structural members in order to improve the corrosion resistance and wear resistance of structural members.
This coating can be formed by plating, spraying, CVD, PVD
The method (ion plating method, ion beam spattering method) or ion mixing method is used. However, these have advantages and disadvantages, and the plating method and the thermal spraying method have problems such as adhesion to a substrate and internal defects. CV
Since the method D is processed at high temperature, it has good adhesion to the substrate,
Deformation of the base material becomes a problem. Furthermore, because it is processed at high temperature,
The crystal grains of the coating become large.

Further, in the ion plate ink method or the ion beam sputtering method, the ionized atoms are deposited on the base material with a kinetic energy of several eV to several hundred eV and are hardly injected into the base material. It was not sufficient in terms of adhesion. Furthermore, the ion mixing method deposits a substance on the surface of the base material, infiltrates the vapor deposition material into the base material by a rare gas ion species of several hundred KeV or more, and then removes the remaining deposited film by a chemical method. However, a large amount of heteroatoms can be injected near the surface of the substrate, but it is difficult to maintain a constant mixing ratio with the constituent atoms of the substrate. Therefore, the reliability of corrosion resistance and wear resistance was not sufficient. Also,
Since the kinetic energy of several hundred KeV is converted into thermal energy, the temperature of the base material becomes high, the base material is not deformed or altered, and the crystal grains become coarse.

On the other hand, there has been proposed a film forming method by a so-called dynamic mixing method in which a certain substance is vapor-deposited on the surface of a substrate and at the same time rare gas ions are injected to form a film on the surface of the substrate. For example, JP-A-60-169559 proposes a method for forming a boron nitride film by this method. This method uses a substance containing boron as an evaporation source, and forms a boron nitride film on the surface of a substrate by accelerating gas ions that act on boron of the evaporation source to form a film of boron nitride to several tens KeV. Is. Although a boron nitride film can be formed by controlling the vapor deposition amount of boron and the injection amount of ionic species by this method, no consideration is given to the control of the crystal grain size and crystal growth of the film. That is, the compound coating has different properties depending on the growth of crystals, the size of crystal grains, etc., and these must be controlled in order to obtain a good quality coating.

Further, Japanese Examined Patent Publication No. 61-57904 discloses an ion plating method for nitrogen ions.

[Problems to be solved by the invention]

The characteristics of corrosion resistance and wear resistance vary greatly depending on the crystal growth of the coating and the size of the crystal grains, and it is important to form a coating that controls these. That is, in order to improve the corrosion resistance and wear resistance, the growth of the coating must be equiaxed and the crystal grains must be fine. The above publication does not describe them at all.

An object of the present invention is to provide an ion mixing method and apparatus for forming a film of equiaxed crystal grains having a fine grain size.

[Means for solving problems]

The present invention provides an ion mixing method of injecting ions, which react with a metal vapor to form a non-metal compound, by ion plating to form the non-metal compound layer on the surface of the member to be treated. The metal vapor is deposited on the surface of the member to be processed provided directly above the evaporation source of the metal vapor while being differentially moved, and the ions are horizontally irradiated and injected into the surface of the member to be processed. Ion mixing method.

In particular, in a member having a non-metal compound layer on the surface of a metal member, the non-metal compound layer is formed via a mixture layer of the metal member and the non-metal compound, and the crystal grains of the compound layer are equal to each other. It has axial crystals and the grain size of the crystal grains is
This is to enable formation of a film having a thickness of 0.01 to 0.5 μm.

In view of the above circumstances, the inventors of the present invention have conducted various investigations, and as a result, control of the incident angle of ions to be implanted with the base material and precession injection of the incident ions to form compounds such as nitrides, oxides, and carbides. It was found that a film with fine crystal grains can be formed by equiaxed crystals.

According to the present invention, the raw material of the film to be formed is deposited on the substrate by vapor deposition or sputtering, and at the same time, the ionic species containing at least the reactive ionic species to be formed are precessed at an angle with the substrate. To irradiate the substrate
By forming a film of nitride, oxide, or carbide of equiaxed and fine crystal grains on the base material, a member excellent in corrosion resistance and wear resistance can be obtained.

Further, in the ion beam mixing apparatus for injecting the ions of the present invention by an ion plating to form the non-metallic compound layer on the surface of the member to be processed, a rotating holder for setting the member to be processed is provided, The holder is installed right above the evaporation source of the metal vapor and is inclined at a predetermined angle with respect to the horizontal implantation of the ions, and the angle changes with the rotation. Is equipped with a mechanism for precession, which is an ion beam mixing apparatus.

[Function] In the corrosion-resistant and wear-resistant member obtained by the method of the present invention, a mixed layer composed of the components of the base material and the coating film is formed between the base material and the coating film (nitride, oxide, carbide or a mixture thereof). Therefore, there is no clear boundary between the substrate and the coating, and the adhesion of the coating is excellent. That is, the accelerated reactive ion species are injected into the base material, and at the same time, the base material is sputtered and the component particles of the base material are ejected. A layer is formed on the surface of the base material in a state in which the particles of the base material thus ejected are mixed with the adhered particles formed by the vapor deposition method. Further, in some cases, the vapor deposition particles that collide with the reactive ion species while reaching the surface of the base material are accelerated to form a compound and bite into the base material. In such a state, a mixed layer is formed between the base material and the coating film. However, this mixed layer has a certain thickness, and when the thickness of the coating becomes thick, the accelerated reactive ion species are not injected into the vicinity of the surface of the base material and gradually become only the coating component from the surface of the base material. On the other hand, in the formation of this compound film, the accelerated reactive ion species collide with the substrate or the film and stop. The accelerated kinetic energy of the ion species is converted into thermal energy, so that high heat is generated.
A compound is formed by the adhered particles formed by vapor deposition or sputtering by the heat and the reactive ion species. However, the high temperature part is extremely only the surface layer, and the low temperature can be maintained. If the material changes or deforms due to heat storage, the base material may be cooled or the reactive ion species may be intermittently injected, if necessary. On the other hand, when heat is stored and the temperature of the substrate becomes high, the formed compound is recrystallized and the crystal grain size becomes coarse, so that the desirable coating film of the present invention cannot be formed. Therefore, the crystal grain size of the present invention 0.01 ~ 0.05
In order to obtain a film having a thickness of μm, the temperature needs to be lower than the recrystallization temperature.

As a method of forming the compound layer, it is desirable to simultaneously perform the formation of the adhered particle layer and the injection of the reactive ion species. Can be formed. However, it is necessary to consider the thickness of the deposited particle layer and the acceleration voltage of the reactive ion species.

Next, it is a method to obtain fine crystal grains with equiaxed crystal. In order to form a film of equiaxed crystal, the reactive ion species to be injected are injected horizontally and the evaporation source is provided directly below the member to be treated. It is necessary to give a precession motion to the processed member.
That is, since the ion beam has a straight traveling property, when the ion beam is injected from a certain direction at a certain angle, the crystal grows in the direction in which the beam is incident to form a resinous crystal film. On the other hand, when the injection is performed while precessing at an angle, the injection direction is not constant, so that an equiaxed film is formed. The implantation angle of the reactive ion species is preferably 25 ° to 60 ° in order to form a good quality film. When the angle is less than 25 °, the incident angle is too small, the adhesion strength of the coating is lowered, and the spatter caused by the reactive ion species becomes severe, and the coating formation rate is also lowered. Further, at 60 ° or more, perfect equiaxed crystals are not formed, and crystals having directionality coexist, which is not preferable. Preferably
30 ° to 50 ° is good. This angle changes with rotation, and the changing angle is preferably 10 to 45 °. Rotation speed is 2
20 RPM is preferable, and 5 to 15 RPM is particularly preferable.

The crystal grain size of the coating is preferably 0.01 μm to 0.5 μm. Abrasion resistance tends to improve as the crystal grain size decreases, but corrosion resistance tends to decrease. That is, in general, the grain boundaries are innately corroded and the corrosion progresses. Therefore, when the crystal grains are small, the crystal grains fall off quickly and the corrosion progresses quickly. On the other hand, in the case of wear, when the crystal grains are small, the bond between the crystal grains becomes strong,
It becomes difficult for crystal grains to fall off due to friction. In the experiments conducted by the present inventors, it was found that when the crystal grain size was 0.01 μm or less, the corrosion resistance was significantly reduced, and when the crystal grain size was 0.5 μm or more, the wear was severe. Desirably 0.05-0.3
μm is preferred. As mentioned above, in order to obtain such crystal grains, it is necessary to perform the treatment at a recrystallization temperature or lower,
When the temperature is higher than the recrystallization temperature, the formed film is recrystallized and the crystal grains become large, so that the wear resistance decreases. Therefore, the film forming treatment temperature was set to the recrystallization temperature or lower. It is preferable to perform the treatment at a temperature not higher than the recrystallization temperature and at a temperature at which the base material is not deformed or deteriorated.

Next, for the film to be formed on the base material, a compound having excellent corrosion resistance and wear resistance such as nitrides, oxides and carbides,
It may be used as necessary, or a mixture of these compounds may be synthesized as needed. In short, it is only necessary to extract and synthesize the required compound according to the purpose and form a film to use.

The coating film formed by the method as described above has excellent adhesion due to the presence of the mixed layer, is free from deformation of the base material and material change due to the low temperature treatment, and is suitable for use as a corrosion resistant and wear resistant member.

Fe, Cu, Al, Ni, Co, Zr, Ti as metal parts
A system member is used.

Si, Ti, V, Cr, Zr, Nb, Mo, Hf, Ta, W, Al for non-metallic compound layer
It is preferable to use at least one of nitrides, carbides and oxides of at least one of the above.

Embodiment 1 FIG. 1 is a system configuration diagram of an ion beam mixing apparatus of the present invention.

The gas to be injected from the gas cylinder 10 is the ion source 2
And is horizontally injected into the sample 16 provided on the rotating sample holder 3 together with the ion beam 1. At the same time, the metal vapor 4 is put into a crucible 17 provided directly below the sample holder 3 and is formed by an electron beam evaporator 14, and a shutter 5 is formed.
It is opened and closed by Sample holder 3 is cooling water 6
It is cooled by the rotation of the ion beam 1 and is rotated in the direction shown in the figure, and is inclined with respect to the horizontal incident direction of the ion beam 1, and its angle is changed as indicated by an arrow 18 with the rotation. In addition, the device of the present invention is a pure water cooling device 8,
Gas controller 9, power supply 11, beam extraction GTO switch,
A vacuum pump 13, a vacuum container 7, and a film thickness monitor 15 are provided.

Hereinafter, a nonmetallic compound layer was formed using the above-mentioned apparatus.

Aluminum alloy JIS 2024 alloy (100mm × 1
(00 mm × 5 mm), attach it to a water-cooled holder that can adjust the rotation and angle in the vacuum container, evacuate the container to 10 ^-6 Torr or less, and then inject Ti ions on the substrate while implanting nitrogen ions, The compound coating was formed to a thickness of about 3 μm. The film forming conditions are vapor deposition rate: 9Å / s, accelerating voltage: 20 Kv, and nitrogen ion implantation amount: 5 × 10 ¹⁷ pieces / cm ² / min. The incident angle between the reactive ion species and the sample is in the range of 20 ° to 90 °. Two types of film formation are performed: one that changes the angle while rotating the water-cooled holder (precession swing motion) and one that does not rotate. Ivy. Further, oxygen ions and carbon ions were implanted while depositing Ti under the same method and conditions as described above to form a TiO ₂ and TiC coating film with a thickness of about 3 μm. Corrosion test pieces, wear test pieces and SEM sample test pieces were taken from these samples.

A typical SEM observation of the film (TiN) formed by the method of the present invention was performed. The reaction ion species are adjusted so that the incident angle to the water-cooled holder with the base material attached is 30 to 50 °, and a film is formed while rotating the water-cooled holder. It was injected into the base material.

For those that do not rotate, the incident angle between the reactive ion species and the substrate is
The film was formed without rotating the water-cooled holder at 90 °. That is, the incident angle of the reactive ion species is constant and the incident angle is one direction.

The coating film formed by the method of the present invention is equiaxed and formed of fine crystal grains, and there is almost no gap between the crystal grains. On the other hand, it can be seen that the film formed by the conventional method is a columnar crystal that grows in the direction of implantation of the reactive ion species, has coarse crystal grains, and has a gap between the crystal grains. From the results of SEM observation, it was confirmed that TiO ₂ and TiC had similar results. Therefore, it is possible to judge which of the corrosion resistance is better just by comparing these photographs. That is, when there is a gap between the crystal grains, the corrosive liquid enters the gap to promote the corrosion. Therefore, it is desirable to minimize the gap between crystal grains.

FIG. 2 shows typical results of a corrosion test and an abrasion test of the TiO ₂ film formed. Corrosion test at room temperature 0.1 mol / l
The corrosion weight loss was obtained by immersing in salt water. In addition,
The corrosion test piece was prepared by forming a TiO ₂ film on the entire surface.
The abrasion test uses a pin-disk type tester and the friction rate is 1
0m / s, load: 5kg, lubricating oil: turbine oil # 140, lubricating oil flow rate: 3
0cc / min, partner material: Carbide. The amount of wear is shown as a relative ratio when the amount of wear when the crystal grain size is 0.5 μm is 1.

As is clear from FIG. 2, in the corrosion test, the corrosion weight loss tends to increase when the crystal grain size is 0.01 μm or less. On the other hand, in the wear test, the wear amount tends to increase when the crystal grain size is 0.5 μm or more. In most commonly used materials, corrosion resistance and wear resistance are often used synergistically. Therefore, a material having good corrosion resistance and wear resistance is desirable. The present inventors limited the crystal grain size to a range of 0.01 μm to 0.5 μm as a range having good corrosion resistance and wear resistance, but if either one is good, it is limited to these limits. No need. In addition, TiN, Ti
Similar results were obtained with the C film.

Example 2 Under the same method and conditions as in Example 1, nitrogen ions were implanted while depositing Ti on a SUS304 substrate to form a TiN film of about 0.3 μm.
Formed to a thickness of. This sample was subjected to composition analysis in the depth direction from the surface by means of Auger electron spectroscopy while performing argon sputtering. As a comparative material, TiN with a film thickness of 0.3 μm is formed on the SUS304 substrate by the ion plating method.
What formed the film was used. The surface of each of these SUS304 base materials was lapped before forming a film.

FIG. 3 shows the results of Auger electron spectroscopy analysis, with the horizontal axis representing the spatching etching time (minutes) and the vertical axis representing the peak intensity ratio (IΣ
3 is a graph showing the relationship with / ΣI). As is clear from FIG. 3, the material of the present invention has a TiN coating formed on its surface,
The composition of the coating gradually decreases in the vicinity of the base material, and the width of the portion where the base material composition gradually increases increases. On the contrary, the width of the film formed by the ion plating method is narrow. It is considered that this narrow width portion is due to the unevenness of the substrate surface, and it is considered that there is no mixed layer. However, in the material of the present invention, even if this width is subtracted, there is an overlapping portion of the composition of the coating film and the substrate, but this portion is a mixed layer, and there is no clear boundary between the coating film and the substrate. It can be seen that there is no adhesiveness.

Example 3 Example 1 using SS41 material (φ20 mm × 3 mm) as a base material
Ni, Ni, CrN, BN, Si ₃ N ₄ , and AlN coatings were deposited to a thickness of about 2.5 by implanting nitrogen ions while depositing Ti, Cr, B, Si, and Al under the same method and conditions.
μm formed. In addition, oxygen ions were implanted while depositing Al and Si to form an Al ₂ O ₃ and SiO ₂ coating film of about 2.5 μm. The incident angles of the reaction ions to the base material were 75 ° and 35 °, and those with an incident angle of 75 ° were 35 ° without rotating the water-cooled target.
Processed by spinning. These samples in 5% NaCl solution
After immersion for 100 hours, the adhesion strength of the coating was measured using a tensile tester. In addition, the comparative materials were those injected from one direction at a constant incident angle of 75 ° and TiN by the ion plating method.
A film having a thickness of about 2.5 μm was used.

Table 1 shows the adhesion strength test results of the base material and the coating film after being immersed in a 5% NaCl aqueous solution for 100 hours. As is clear from Table 1, all the coating films formed by the method of the present invention were peeled off from the adhesive (epoxy resin type) and showed a strength equal to or higher than that of the adhesive. In comparison with these, the films formed by the ion plating method and the conventional method, which are comparative materials, both showed low values of 5 kg / mm ² or less. As described above, it is considered that the coating film formed by the conventional method has a gap between crystal grains, and the NaCl aqueous solution permeates through the gap to corrode the interface with the base material to lower the strength.

As described above, it can be seen that the material of the present invention has excellent corrosion resistance and good adhesion to the substrate.

Example 4 An alumina plate (15 mm × 15 mm × 1 mm) was used as a base material,
Under the same method and conditions as in Example 1, while depositing Ti, nitrogen ions were implanted at an incident angle of 20 ° to 90 ° on the substrate to form a TiN coating film. The sample holder was rotated during the coating process. Crystal growth of these samples was observed by SEM. In addition, a tensile test was conducted to measure the adhesion strength of these samples.

Table 2 shows the SEM observation results and the adhesion strength test results.
As is clear from Table 2, when the incident angles of the reactive ion species are 70 ° and 80 °, crystal growth is a mixture of equiaxed crystals and columnar crystals, and at 90 °, only columnar crystals are grown. In addition, the adhesion strength test result shows that the adhesion strength is relatively low at 6 kg / mm ² at 20 °, but it is 10 kg / mm ² or more at 30 ° to 90 ° and peels off from the adhesive surface of the adhesive, Remarkably high. The present inventors limited the incident angle of the reactive ion species to 25 ° to 60 ° from the viewpoint of adhesion strength and crystal growth.

As described above, the incident angle of the reactive ion species is 25 ° to 60 °.
By forming the film within the range, it is possible to form a film having equiaxed crystal and good adhesion.

[Effect of the Invention] According to the present invention, it is possible to form a film of equiaxed and finely crystalline equiaxed crystal having a mixed layer between a base material and a film, which is an optimum film for corrosion- and wear-resistant members. Corrosion- and wear-resistant members with characteristics that are not seen are obtained.

[Brief description of drawings]

FIG. 1 is a system configuration diagram of an ion beam mixing apparatus showing an embodiment of the present invention, FIG. 2 is a graph showing the relationship between the crystal grain size of the coating and the amount of corrosion and wear resistance, and FIG. It is a graph which shows a spectroscopic analysis result. 1 ... Ion beam, 2 ... Ion source, 3 ... Rotating sample holder, 4 ... Metal vapor, 5 ... Shatter, 6 ... Cooling water, 7 ... Vacuum container.

Claims (6)

[Claims] 1. An ion mixing method for injecting ions, which react with a metal vapor to form a non-metal compound, by ion plating to form the non-metal compound layer on the surface of the member to be treated. While precipitating the metal vapor, the metal vapor is deposited on the surface of the member to be treated provided directly above the evaporation source of the metal vapor, and the ions are horizontally irradiated and injected into the surface of the member to be treated. Characteristic ion mixing method. 2. The ion mixing method according to claim 1, wherein the deposition of the metal vapor and the implantation of the ions are alternately performed. 3. The precession movement is to install the member to be processed in a holder tilted with respect to the ion implantation direction, and rotate the holder while changing the tilt angle of the holder. The ion mixing method according to item 1 or 2. 4. The inclination angle is 25 degrees to 60 degrees with respect to the ion implantation direction, the angle changing angle is 10 degrees to 45 degrees, and the rotation speed is 5 to 20 minutes per minute. The ion mixing method according to claim 3, wherein the method is rotation. 5. The ion mixing method according to claim 1, wherein the non-metallic compound layer is formed below the recrystallization temperature of the non-metallic compound while cooling the member to be treated. . 6. A surface of a member to be treated is irradiated with ions, which react with metal vapor to form a non-metallic compound, by an ion source,
In the ion beam mixing apparatus for forming the non-metal compound layer on the surface of the member to be processed, a rotating holder for installing the member to be processed is provided, and the rotating holder is installed directly above the evaporation source of the metal vapor, and A mechanism that is inclined at a predetermined angle with respect to the horizontal irradiation of the ions, the angle of the rotary holder changes with the rotation, and the rotary holder precesses. Ion beam mixing equipment.