JPH07187862A - Oxide ceramic substrate coated with hard carbon-containing film and its production - Google Patents

Abstract

PURPOSE:To improve adhesion by forming an N ion implanted layer in the surface part of an oxide ceramic substrate by irradiation with N ions and coating the outside of the N ion implanted layer with a hard carbon-contg. film. CONSTITUTION:An oxide ceramic substrate of Al2O3, SiO2 or ZrO2 is washed with a neutral surfactant and acetone and put in a vacuum vessel. This vessel is evacuated to a high vacuum of about <=2X10<-6>Torr and gaseous N. as an ion source is introduced and ionized. The surface of the substrate is irradiated with about 1X10<15>-1X10<17> N ions per 1cm<2> under 0.2-20keV ion acceleration energy to form an ion implanted layer in the surface. Hydrocarbon such as methane is then introduced, plasma is generated by supplying high-frequency power and the hydrocarbon is thermally decomposed in the plasma to form a hard carbon-contg. film excellent in adhesion. The outside of the ion implanted layer is coated with the film and the objective oxide ceramic substrate is obtd.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate made of an oxide ceramic used in various machine parts, etc., which are required to have wear resistance and slidability with other members. The present invention relates to a film coated with a hard carbon-containing film and a method for producing the same.

[0002]

2. Description of the Related Art Alumina (Al ₂ O ₃ ) and silicic acid anhydride (SiO ₂ ) which are excellent in such properties are used for component bases which are required to have abrasion resistance and slidability with other members. It has been proposed to employ an oxide ceramic such as zirconium oxide (ZrO ₂ ) as a material for the component substrate. Further, in order to further improve the above-mentioned various properties, it has been proposed to coat the substrate made of the oxide ceramic with a hard carbon-containing film.

However, since the hard carbon-containing film has a high hardness and generates an excessive internal stress during the film formation, the film has a poor adhesion to the substrate. In addition, the hard carbon-containing film thus formed has a decrease in adhesiveness over time and peeling occurs. Therefore, silicon (S) which has a large bonding strength between the base and the hard carbon-containing film and has relatively good adhesion to the oxide ceramic base, and which has relatively good adhesion to the hard carbon-containing film.
It has been attempted to form an intermediate film containing i) or a metal such as titanium (Ti).

[0004]

However, the interlayer film is chemically stable in an environment of normal temperature and humidity, and the adhesion between the substrate and the hard carbon-containing film is maintained. In an environment such as wet or water, a metal such as Si or Ti contained in the intermediate film is easily oxidized, and the intermediate film and the hard carbon-containing film are easily peeled off. The use environment of the oxide ceramic substrate is limited.

Therefore, the present invention is an oxide ceramic substrate coated with a hard carbon-containing film, the hard carbon-containing film being coated on the substrate with good adhesion, and not only under a normal temperature and normal pressure environment but also at a high temperature. It is an object of the present invention to provide an oxide ceramic substrate coated with a hard carbon-containing film that is difficult to be peeled off for a long period of time even in a high-pressure environment or in water, and a method for producing the same.

[0006]

Means for Solving the Problems The inventors of the present invention have conducted extensive research to solve the above problems and found that the hard carbon-containing film is formed on the nitride ceramic substrate with good adhesion. Based on the above findings, the present invention provides an oxide ceramic substrate coated with a hard carbon-containing film, which has a nitride layer of the partial material on the surface portion of the substrate, the outside of which is coated with the hard carbon-containing film. A substrate and a method for manufacturing the same, wherein a layer in which nitrogen ions are implanted is formed on a surface portion of the substrate by irradiating the oxide ceramic substrate with nitrogen ions, and thereafter, the ion A method of forming a hard carbon-containing film on the outside of an injection layer is provided.

Materials for the oxide ceramic substrate include alumina (Al ₂ O ₃ ) and silicic anhydride (Si).
O ₂ ), zirconium oxide (ZrO ₂ ), titanium oxide (TiO ₂ ), zinc oxide (ZnO), barium titanate (BaTiO ₃ ), and the like, and combinations thereof. The method of the ion source used in the nitrogen ion irradiation is not particularly limited, and for example, a high frequency type, a Kauffman type, a bucket type and the like can be considered.

Further, nitrogen gas (N ₂ ) or the like can be considered as a source gas for generating nitrogen ions. In the nitrogen ion irradiation, the ion acceleration energy is 0.2 ke.
V to 20 keV is desirable, 0.2 keV
If it is smaller, nitrogen ions will not be implanted inside the substrate, and
If it is higher than keV, damage to the substrate increases, which is not preferable, and the adhesion between the hard carbon-containing film and the substrate decreases conversely.

The nitrogen ion irradiation dose is 1 × 10 ¹⁵ io.
ns / cm ² to 1 × 10 ¹⁷ ions / cm ² is preferable, and if the irradiation dose is smaller than 1 × 10 ¹⁵ ions / cm ^{2, the} effect of implanting nitrogen ions becomes insufficient and 1 × If it is higher than 10 ¹⁷ ions / cm ² , the damage to the substrate becomes large, which is not preferable, and the adhesive force between the hard carbon-containing film and the substrate is decreased.

In the nitrogen ion irradiation, the number of nitrogen ions reaching the substrate can be monitored by an ion current measuring device, for example, a Faraday cup equipped with a secondary electron suppressing electrode.
The angle of incidence of nitrogen ions on the substrate is not particularly limited as long as the intended ion-implanted layer can be obtained. As the method for forming the hard carbon-containing film, the raw material gas containing carbon element is thermally decomposed on the surface of the substrate heated to an appropriate temperature due to resistance and the decomposition product is used to form a film on the substrate.
A VD method, a plasma CVD method in which the raw material gas is turned into plasma by applying electric power, and a film is formed on a substrate under the plasma can be considered.

As the raw material gas which is pyrolyzed or turned into plasma to form the hard carbon-containing film, methane (CH ₄ ), acetylene (C ₂ H ₂ ), benzene (C ₆
Hydrocarbon compounds such as H ₆ ) can be used.

[0012]

The hard carbon-containing film-coated substrate according to the present invention has a nitride layer on the surface of the substrate. Therefore, the hard carbon-containing film is coated on the nitride layer with good adhesion, and at room temperature and normal pressure. Not only in the environment but also in a high-temperature and high-pressure environment or in water, it is difficult to peel for a longer period than before.

According to the method of the present invention, first, the oxide ceramic substrate is irradiated with nitrogen ions to form a layer into which nitrogen ions have been implanted, and a hard carbon-containing film is formed thereon. To be done. According to the substrate of the present invention thus formed, the adhesion between the hard carbon-containing film and the oxide ceramic substrate is good, and the good adhesion is maintained thereafter.

The reason why the film adherence is good in the substrate according to the method of the present invention and it is difficult to change and decrease with time is that the nitrogen ions injected into the surface portion of the oxide ceramic substrate have oxygen atoms and other atoms due to the acceleration energy. Break the bond of
The oxygen atoms are replaced by nitrogen atoms to modify the surface portion of the substrate into a nitride ceramic, and contaminants attached to the substrate surface are removed by nitrogen ion irradiation to clean the surface on which the hard carbon-containing film is formed. It is thought that it is because it will be converted.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a cross-sectional view of an oxide ceramic substrate coated with a hard carbon-containing film according to one embodiment of the present invention, and FIG. 2 shows a schematic structure of a film forming apparatus used in the method for manufacturing the substrate shown in FIG. It is a thing. The apparatus shown in FIG. 2 is provided with a vacuum container 1 in which an electrode 2 which also serves as a substrate holder for mounting a film formation substrate S is provided. The electrode 2 is normally grounded or a negative voltage is applied, but it is grounded here. Further, a heater 21 for heating the substrate S placed thereon to a film forming temperature is additionally provided. The heater 21 is separated from the holder 2 when the substrate S is heated by radiant heat.

The high-frequency antenna 3 is a power-applying electrode for applying high-frequency power to the film-forming gas introduced between it and the electrode 2 to turn it into plasma. In the illustrated example, a high-frequency power source is supplied via a matching box 4. 5 are connected. To the vacuum container 1, an exhaust device 6 is further connected by piping, and a film supply source gas supply unit 7 for film formation is also connected by piping. The gas supply unit 7 includes one or more mass flow controllers 711, 712, ... And open / close valves 721, 7
.., which are connected via 22 ...

An ion source 8 is installed so as to face the electrode 2 which also serves as a substrate holder, and an ion current measuring device 9, here a Faraday cup, is arranged near the electrode 2.
According to this plasma CVD apparatus, the substrate S to be film-formed is placed on the electrode 2 in the vacuum container 1, the inside of the container 1 is set to a predetermined vacuum degree by the operation of the exhaust device 6, and the substrate 1 is ionized. The source 8 emits nitrogen ions 8a. The irradiation energy of nitrogen ions is preferably about 0.2 keV to 20 keV, and the irradiation dose is 1 × 10 ¹⁵ ions / cm ² to
It is preferably about 1 × 10 ¹⁷ ions / cm ² .
The ion irradiation amount is monitored by an ion current measuring device 9, here, a Faraday cup.

Next, a film forming gas containing a carbon element is introduced into the vacuum container 1 from the gas supply unit 7. Further, high-frequency power is applied to the high-frequency antenna 3 from the power supply 5 through the matching box 4, the gas introduced thereby is turned into plasma, and under this plasma, the nitrogen ions of the substrate S are hardened on the surface of the substrate S. A carbon-containing film is formed.

By the film-forming operation described above, as shown in FIG. 1, the layer S in which nitrogen ions are implanted into the surface portion of the substrate S.
1 is formed and the outside thereof is coated with the hard carbon film S2. The hard carbon-containing film formed in this example is not diamond, but is a diamond-like carbon-containing film, and is a transparent or semitransparent film having high hardness, chemical stability, electrical insulation and the like.

Although the nitrogen ion irradiation and the film formation by plasma are performed in the same vacuum container 1 here, they may be performed in different vacuum containers. Next, a specific example of the method for manufacturing a substrate of the present invention by the film forming apparatus shown in FIG. 2 and an oxide ceramic substrate coated with a hard carbon film obtained by the method will be described.

20 mm made of alumina (Al ₂ O ₃ )
A substrate S having a size of 20 mm and a thickness of 2 mm was thoroughly washed with a neutral surfactant and acetone, and then placed on the electrode 2 serving also as a substrate holder.

Next, the inside of the container 1 is set to a vacuum degree of 2 × 10 ^-6 Torr, and N ₂ gas having a purity of 5N (99.999%) is introduced into the ion source 8 until the inside of the container 1 becomes 5 × 10 ^-5 Torr. And ionize it, and direct the ions 8a toward the substrate S,
Irradiation was performed at an angle of 0 ° with respect to the normal line standing on the substrate S. Five substrates S were prepared and sequentially replaced, and only the acceleration energy of the ions 8a was 0.2 keV, 1.0 keV, 5.0.
keV, 10.0 keV, 20.0 keV,
Other conditions were the same, and ion irradiation was performed. The ion irradiation dose was 5 × 10 ¹⁵ ions / cm ^{2 in} all cases.

Next, for each substrate S that has been subjected to ion irradiation,
The inside of the container 1 is set to a vacuum degree of 5 × 10 ⁻⁶ Torr or less, and CH ₄ is supplied from the gas supply unit 7 to the inside of the container 1 at 1 × 10 ⁻³ Torr.
At a flow rate of 2 sccm, and at the same time, a high frequency power source 5 applies a high frequency power having a frequency of 13.56 MHz and a power of 1 kW to generate a hard carbon film S2 on the substrate S having the nitrogen ion implantation layer S1 under the generated plasma. Was formed. The film thickness of the film S2 was 500 nm. In Comparative Example 1, the nitrogen ion irradiation was not performed, and the hard carbon film S2 was formed on the substrate S under the same conditions as in Example 1 except for the above.

As Comparative Example 2, using the film-forming apparatus shown in FIG. 4, a T film was formed between the substrate s and the hard carbon film s2 shown in FIG.
An example of forming the substrate s having the intermediate film s1 made of i will be described below. The apparatus shown in FIG. 4 includes an evaporation source 10 in place of the ion source 8 in the apparatus shown in FIG. 2, a film thickness monitor 11 in place of the ion current / current measuring device 9, and a crystal oscillator type film thickness monitor here. The other configuration is the same as that of the device shown in FIG.

20 mm made of alumina (Al ₂ O ₃ )
A substrate s having a size of 20 mm and a thickness of 2 mm was sufficiently washed on its surface with a neutral surfactant and acetone, and then placed on the electrode 2. Next, the inside of the container 1 was evacuated to a vacuum degree of 5 × 10 ⁻⁶ Torr, and Ti pellets 1 having a purity of 4N (99.99%)
0a was vapor-deposited on the substrate s by using the evaporation source 10 which heats and vaporizes the vapor deposition material by the electron beam (EB), and the Ti intermediate film s1 having a film thickness of 50 nm was formed on the substrate s.

Further, a hard carbon film s2 having a film thickness of 500 nm was formed thereon under the same conditions as in the above embodiment. next,
An experiment for evaluating the adhesion between the hard carbon film and the substrate was conducted on the substrates according to the above-mentioned Examples, Comparative Examples 1 and 2, as follows. The substrate after film formation is kept in warm water at 80 ° C. for 24 hours, and the state of the surface of the hard carbon film is visually observed.
The film adhesion before and after the hot water treatment was evaluated by measuring the load (scratch load) at which the hard carbon film peels off by the scratch test method.

The results are shown in Tables 1 and 2.

[0028]

[Table 1]

[0029]

[Table 2]

As shown in Table 1, in the substrate according to the example, no peeling of the hard carbon film observed with the naked eye was observed even after the substrate was kept in warm water at 80 ° C. for 24 hours, whereas in Comparative example 1
Peeling occurred on the substrate according to Example 1 and the substrate according to Comparative Example 2.
Although not shown in Table 1, peeling did not occur in the substrate formed by performing the nitrogen ion irradiation and the hard carbon film formation in different vacuum containers, as in the case of the substrate according to the example.

Further, as shown in Table 2, according to the scratch test, no peeling of the film S2 occurs even with a load of 120 g before the hot water treatment in any of the ion acceleration energies of the substrate S according to the example, and after the hot water treatment. Acceleration energy 0.2 keV
Although the film S2 peeled off at a load of 80 g, the peeling did not occur at a load of 120 g at an acceleration energy of 5.0 keV or more. On the other hand, in Comparative Example 1, peeling occurred with a load of 60 g even before the hot water treatment, and peeling occurred with a load of 20 g after the hot water treatment. Further, in Comparative Example 2, a load of 120 is applied before the hot water treatment.
Although the peeling of the film s2 did not occur even with g, the peeling occurred with a load of 60 g after the hot water treatment.

Although not shown in Table 2, a substrate formed by performing nitrogen ion irradiation and forming a hard carbon film in different vacuum chambers also gave the same results as the substrate according to the above-mentioned embodiment. From the above results, by forming the layer S1 in which nitrogen ions are implanted on the surface portion of the oxide ceramic substrate S, the hard carbon film S2 having good adhesion is formed, and the film S2 is formed in high temperature water. It can be seen that peeling does not occur even when kept in the environment, and the adhesive force is maintained. On the other hand, when the hard carbon film S2 is formed on the substrate S without forming the nitrogen ion-implanted layer S1, the film adhesion is weak and the adhesion is further reduced by the hot water treatment. It is understood that when the Ti intermediate film s1 is formed between the hard carbon film s2 and the hard carbon film s2, the adhesive force after the film formation is good, but the adhesive force is reduced by the hot water treatment.

[0033]

According to the present invention, there is provided an oxide ceramic substrate coated with a hard carbon-containing film, the hard carbon-containing film being coated on the substrate with good adhesion, not to mention under normal temperature and normal pressure environment. It is possible to provide an oxide ceramic substrate coated with a hard carbon-containing film that is unlikely to be peeled off in a high temperature and high pressure environment or in water for a long period of time, and a method for producing the same.

Further, when the ion acceleration energy is controlled to about 0.2 keV to 20 keV in the nitrogen ion irradiation, the film adhesion becomes more appropriate.

[Brief description of drawings]

FIG. 1 is an enlarged cross-sectional view of a part of a substrate according to an embodiment of the present invention.

FIG. 2 is a diagram showing a schematic configuration of an example of a film forming apparatus used for manufacturing the substrate shown in FIG.

FIG. 3 is a partial enlarged cross-sectional view of an example of an oxide ceramic substrate coated with a conventional hard carbon-containing film.

FIG. 4 is a diagram showing a schematic configuration of an example of a film forming apparatus used for manufacturing the base body shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vacuum container 2 Substrate holder and ground electrode 21 Heater 3 High frequency antenna 4 Matching box 5 High frequency power supply 6 Exhaust device 7 Gas supply section 8 Ion source 8a Nitrogen ion 9 Ion current measuring instrument 10 Evaporation source 10a Evaporation substance 11 Film thickness monitor S, s Substrate S1 Nitrogen ion implantation layer S2, s2 Hard carbon-containing film s1 Intermediate film

Claims (3)

[Claims] 1. An oxide ceramic substrate coated with a hard carbon-containing film, wherein the substrate surface portion has a nitride layer of the substrate surface portion material, the outside of which is coated with the hard carbon-containing film. An oxide ceramic substrate coated with a hard carbon-containing film. 2. An oxide ceramic substrate is irradiated with nitrogen ions to form a layer into which nitrogen ions have been implanted on the surface of the substrate, and then a hard carbon-containing film is formed outside the ion-implanted layer. A method for producing an oxide ceramic substrate coated with a hard carbon-containing film, comprising: 3. The method for producing an oxide ceramic substrate coated with a hard carbon-containing film according to claim 2, wherein the ion acceleration energy is controlled to 0.2 keV to 20 keV in the nitrogen ion irradiation.