JP3554119B2 - Hard carbon film coated member - Google Patents

Description

【００４３】
表１の結果によれば、Ｈ_１ ／Ｈ_２ が０．０５以上、Ｈ_１ ＜Ｈ_２ ＜Ｈ_３ を満足する硬質炭素膜を形成した本発明の試料は、いずれも強酸溶液に対しても全く腐食が認められず、優れた耐食性を示し、また、アレルギー源金属の溶出は検出限界以下であった。しかも、密度も３．１ｇ／ｃｍ^３ 以上の高密度を有していた。
【００４４】
また、比較例として従来のＴｉＣ基サーメットでは、強酸に対して０．５時間で表面が白く変色し、アレルギー源金属の溶出が確認された。また、マイクロ波ＣＶＤ法等で作製された試料Ｎｏ．９の部材や、成膜条件によってＨ_１ ／Ｈ_２ の比率が０．０５よりも小さい試料Ｎｏ．１、２、９、１０の部材では、いずれも試験後の膜表面に腐食によると思われる１０〜１０００μｍのスポットが多数観察され、腐食が局所的に進行したことがわかり、その結果、微量のアレルギー源金属の溶出が確認された。
【００４５】
また、上記と同様にして、作製した部材を入れた容器内に４０％ＮａＯＨ溶液のアルカリ溶液を８０ｍｌ注ぎ込み、４０℃で４８時間放置後の腐食の状態を観察した結果、試料Ｎｏ．１７のＴｉＣ基サーメットからなる容器では、全面に腐食が見られたが、それ以外の試料Ｎｏ．１〜１６についてはほとんど変化は見られなかった。
【００４６】
【発明の効果】
以上詳述したように、本発明の硬質炭素膜被覆部材は、強酸や強アルカリとの接触においても局所的な腐食等の進行を抑制し長期にわたり優れた耐食性を発揮することができる。その結果、海水や汗等との接触においても、基体中のアレルギー源金属の溶出を防止することができる。これにより、人の肌と接触する、特に装飾用部材の長期にわたる安全性および信頼性を高めることができる。
【図面の簡単な説明】
【図１】本発明における硬質炭素膜（試料Ｎｏ．３）のラマン分光スペクトルチャート図である。
【図２】比較例における硬質炭素膜（試料Ｎｏ．９）のラマン分光スペクトルチャート図である。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an improvement in a member coated with a hard carbon film, in particular, a member used for decoration, such as a watch exterior part, a necklace, a piercing, an eyeglass frame, and a fishing tackle.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, members used for decoration, such as watch exterior parts such as watch cases and bands, and necklaces, earrings, and eyeglass frames are generally processed from natural minerals. However, since the decorative member is directly in contact with a person or exposed to seawater, rain, or the like, excellent scratch resistance and corrosion resistance to sweat and the like are required.
[0003]
In response to such demands, recently, ceramics such as colored alumina ceramics and colored zirconia ceramics, and carbides and nitrides such as WC, TiC and TiN have been sintered together with iron group metals such as Ni and Co. 2. Description of the Related Art Sintered alloys such as hard alloys and cermet alloys exhibiting gold or silver are known.
[0004]
On the other hand, it has been proposed to coat various substrates with the most chemically stable diamond in order to enhance the wear resistance and the like. This diamond film is formed as a thin film on the surface of various substrates by, for example, thermal CVD, microwave plasma CVD, or the like.
[0005]
[Problems to be solved by the invention]
However, these sintered alloys contain iron group metals such as Ni and Co as constituents, but these metal elements are eluted as free metals due to sweat or the like, and these metals contact the skin by contact with the skin. There is a concern that allergies such as inflammation may occur, and regulations on elution of these allergic sources are being strengthened in Japan and overseas.
[0006]
Then, in preventing such elution of allergic sources, it can be expected to prevent elution by coating with a diamond film or the like. However, although the diamond film formed by the thermal CVD method or the microwave CVD method has excellent abrasion resistance, crystal grains are large, grain boundaries exist between the crystals, and voids and the like are present in the film. Exists. Therefore, when exposed to seawater, sweat, or the like for a long time, the allergic source in the base may be eluted.
[0007]
In addition, the conventional diamond film needs to be mirror-finished for decoration since the surface has irregularities due to the self-shape of large crystal grains. However, there is a problem that the diamond film itself has a very high hardness and is difficult to process.
[0008]
Accordingly, the present invention provides a hard carbon film-coated member that has excellent corrosion resistance to a member containing an allergen-source metal and has no elution of the allergen-source metal, and is particularly suitable for decoration. It is the purpose.
[0009]
[Means for Solving the Problems]
The present inventors have conducted intensive studies on a method for solving the above-mentioned problem, and found that the surface of a substrate containing a total of 1% by weight or more of a metal that causes metal allergy of Ni, Co, and Cr was placed on a surface of a Raman spectrum. , 1160 ± 40 cm ⁻¹ , 1340 ± 40 cm ⁻¹ and 1500 ± 60 cm ⁻¹ , and the strongest peak intensity among the peaks existing at 1160 ± 40 cm ⁻¹ is H ₁ , 1340 ± 40 cm ^{− The} peak intensity having the highest intensity among the peaks existing in No. ¹ is H ₂ , and the peak intensity having the highest intensity among the peaks existing at 1500 ± 60 cm ⁻¹ is H _3, and is expressed as H ₁ / H _2. and the peak intensity ratio is 0.05 or _more, by coating the hard carbon film which satisfies a relation of _{H 1 <H 2 <H 3} , the objective reaches Found is that by, leading to the present invention.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
The hard carbon film-coated member according to the present invention is suitably used particularly as a decorative member that can directly touch human skin, such as a watch exterior part, a necklace, a piercing, an eyeglass frame, a button, and a broach.
[0011]
The substrate used in the present invention is a substrate containing 1% by weight or more of a metal causing a metal allergy (hereinafter, referred to as an allergen metal). Specifically, Ni, Co, Cr, Al, Mn, Fe, Rh, Pd, and the like are reported as allergen metals, but in the present invention, the total of these metals is 1% by weight or more. The substrate. In particular, it is effective for substrates in which the content of Ni, Co, and Cr is 1% by weight or more.
[0012]
Examples of such a substrate include a cemented carbide containing a hard phase mainly composed of TiC, TiCN, TiN, and WC and a binder phase composed of an iron group metal such as Ni or Co at about 1 to 20% by weight, a TiC-based cermet. And sintered alloys such as TiCN-based cermet and TiN-based cermet. The hard phase component includes, in addition to the above main components, carbides, nitrides, carbonitrides, and the like of metals of Groups 4a, 5a, and 6a of the periodic table such as Ti, Zr, Ta, V, Nb, and Cr. In some cases.
[0013]
In addition, as the substrate, other than the above sintered alloy, ceramic materials such as alumina ceramics, zirconia ceramics, and alloys containing gold, silver, copper, and the like containing the above-mentioned allergen metal in an amount of 1% by weight or more, Further, there may also be mentioned a base body plated with noble metal, and a base body plated with Ni or the like as an underlayer.
[0014]
According to the present invention, the surface of the above substrate is coated with a hard carbon film containing diamond.
[0015]
Conventionally, a generally known diamond film is known to be formed by a thin film forming method such as a thermal CVD method or a microwave CVD method. Such a diamond film is usually made of high-purity diamond, It has a structure in which carbon atoms are bonded by SP ³ hybridization. Particularly, those having a peak only at 1340 ± 40 cm ⁻¹ in the Raman spectroscopy spectrum are often used. In addition, a diamond film having a broad peak near 1500 to 1600 cm ^-1 in addition to the above-mentioned peak containing carbon having a graphite structure bonded by SP ² hybridization is known in part. Also, this diamond film has large irregularities on the surface after film formation due to the crystal shape of the diamond due to large diamond crystal grains, and therefore, there are grain boundaries between crystals, and a large amount of voids are present inside the thin film. Exists.
[0016]
On the other hand, the hard carbon film according to the present invention is mainly composed of diamond, but has peaks at least at 1340 ± 40 cm ⁻¹ , 1160 ± 40 cm ⁻¹ and 1500 ± 60 cm ⁻¹ in the Raman spectrum. Things. Of the above peaks, the peak at 1340 ± 40 cm ⁻¹ indicates a diamond crystal peak, the peak at 1500 ± 60 cm ⁻¹ indicates the presence of an amorphous carbon phase, and the peak at 1160 ± 40 cm ⁻¹ indicates a diamond precursor or polyene. It is considered to indicate the existence of a structure, and is meant to be formed by extremely fine crystals. Therefore, the hard carbon film of the present invention is formed of a crystal having a very fine diamond crystal and an average particle diameter of 1 μm or less, and a dense film having almost no voids in the film.
[0017]
As described above, the hard carbon film itself is very dense, has almost no grain boundary components, and has no voids in the film. Since there is no local erosion of the crystal grain boundaries and excellent corrosion resistance, it is possible to prevent the allergen source metal in the base from eluting to the member surface.
[0018]
In addition, since this hard carbon film has excellent flatness without irregularities due to the diamond crystal's own shape as in the prior art, there is no need to process the surface, and even when a smooth mirror surface is processed, a short time is required. It also has the advantage that it can be processed easily. Further, when the hard carbon film is formed on the predetermined substrate surface, a smooth and dense film surface conforming to the substrate surface shape can be formed on the substrate surface of any shape, and excellent corrosion resistance is required. It can be formed with high smoothness on the member surface.
[0019]
The peak intensity in the Raman spectrum of the hard carbon film in the present invention will be specifically described. As shown in FIG. 1, the hard carbon film of the present invention has peaks at least at 1340 ± 40 cm ⁻¹ and 1160 ± 40 cm ⁻¹ . 1160 peak intensity of ± 40 cm ^-1 is to draw oblique lines between positions 1100 cm ^-1 and 1700 cm ^-1, this as a baseline, the high peak intensity of most intense among the peaks present in 1160 ± 40 cm ^-1 H _1, 1340 when the high peak intensity of most intense among the peaks and with _{H 2} present in ± 40 cm _^-1, the peak intensity ratio represented by H 1 / _{H 2} is 0.05 or more, preferably, 0.2 It is important that it is ~ 1.0.
[0020]
If the peak intensity ratio is less than 0.05, diamond crystal grains grow too large, voids are generated in the film, or the surface roughness of the film increases, so that local corrosion easily proceeds. On the other hand, if the peak intensity ratio is too large, the ratio of diamond crystals decreases, resulting in a decrease in film strength. The peak intensity ratio represented by H ₁ / H ₂ is desirably 1.0 or less.
[0021]
Further, as shown in FIG. 1, the Raman spectroscopy spectrum has a peak at 1500 ± 60 cm ⁻¹ , and when the highest peak intensity among the peaks in the region is H ₃ , H ₁ <H It is desirable that the relationship of ₂ <H _{3 be} satisfied. This peak indicates an amorphous phase existing between the diamond crystals. However, the intensity of H ₃ is low, and when H ₁ > H ₃ or H ₂ > H ₃ , the denseness of the film is reduced. In this case, a problem occurs that the allergen metal is eluted.
[0022]
According to the hard carbon film-coated member of the present invention, the hard carbon film is dense, so that even when the film thickness is small, it is possible to prevent the elution of the allergen metal in the substrate, If the thickness is too thin, the strength of the film itself will be reduced, and the film may crack when subjected to an impact. Therefore, the thickness is preferably 0.5 μm or more. Further, from the viewpoint of manufacturing cost, the thickness is desirably 20 μm or less.
[0023]
According to the hard carbon film-coated member of the present invention, in order to enhance the adhesion to the substrate, an intermediate layer composed of at least a composite of diamond and metal carbide is interposed between the substrate and the hard carbon film. Thereby, a hard carbon film having extremely good adhesion can be formed.
[0024]
The reason why the adhesion strength between the hard carbon film and the base material is improved by the interposition of the intermediate layer is considered as follows. Atoms are bonded by intervening electrons, but in general, electrons are shared by both atoms rather than ionic bonds in which electrons between atoms are present on one side and are electrically connected. A covalent bond has a stronger binding force. Diamond has a strong bonding force because it is constituted by a covalent bond of carbon. Therefore, in order to improve the adhesion strength between diamond and a different compound, it is considered that a covalent compound having a similar bonding mode is desirable. Also, it is considered that a compound containing carbon which is a component of diamond has better consistency. There are many metal carbides, and most of them are mainly ionic bonds. The covalent carbide includes silicon carbide and boron carbide, but silicon carbide is most desirable in the decorative covering member of the present invention.
[0025]
By forming such an intermediate layer containing a mixture of metal carbide and diamond between the hard carbon film and the substrate, the adhesion strength between the hard carbon film and the substrate is improved. In addition, the diamond and the metal carbide do not exist in a layer-separated state, but have a structure in which the metal carbide surrounds the diamond. This improves the adhesion.
[0026]
As a method for producing a hard carbon film in the present invention, a so-called plasma CVD method or a thermal CVD method in which plasma is generated by microwave or high frequency to form a carbon film on a predetermined substrate surface has conventionally been used as a means for generating a diamond film. The filament method is the mainstream. However, in the plasma CVD method, an area where a film can be formed is small because a plasma generation region is small, and an area where a film can be formed is generally about 20 mm in diameter, and its application as a processing member is limited. Further, when the pressure is too high or the plasma density is too low, and the substrate has a complicated structure or a curved surface structure, uniform plasma along the structure cannot be obtained, and the film thickness distribution becomes uneven. Prone.
[0027]
On the other hand, in the hot filament CVD method, the filament is liable to be cut, and it is necessary to set the filament in accordance with the shape of the substrate in order to suppress the variation in the film thickness. I have.
[0028]
On the other hand, according to the so-called electron cyclotron resonance plasma CVD method in which a magnetic field is applied to the plasma generation region in the plasma CVD method, high-density plasma can be obtained under low pressure (1 torr or less). It can be uniformly generated in a wide area, and a film can be uniformly formed in an area about 10 times as large as that of a normal plasma CVD method.
[0029]
Therefore, here, the electron cyclotron resonance plasma CVD method (ECR plasma CVD method) will be described as an example. In this method, a reaction gas is introduced into a reaction furnace in which a predetermined base is installed, and simultaneously a microwave of 2.45 GHz is introduced. At the same time, a magnetic field of a level of 875 Gauss or more is applied to this region. As a result, the electrons generate cyclotron motion based on the cyclotron frequency f = eB / 2πm (where m: mass of electrons, e: charge of electrons, B: magnetic flux density). When this frequency coincides with the microwave frequency (2.45 GHz), it resonates and electrons are remarkably absorbed by the microwave energy, accelerated, collide with neutral molecules, cause ionization, and generate high-density plasma. Become like At this time, the temperature of the substrate is set at 150 to 1000 ° C., and the furnace pressure is set at 1 × 10 ^{−2 to} 1 torr.
[0030]
According to this method, the components and the like of the hard carbon film to be formed are changed by changing the substrate temperature, the furnace pressure, and the reaction gas concentration during the film formation. Specifically, as the pressure in the furnace increases, the region of the plasma decreases, and the growth rate of the film decreases, but the crystallinity tends to improve. Also, when the concentration of the reaction gas increases, the size of the particles constituting the film tends to decrease, and the crystallinity tends to deteriorate. Specifically these conditions by controlled appropriately as described in the examples below, it is possible to control the H _{1 /} H ₂ ratio described above.
[0031]
In the above-described film forming method, when producing the decorative covering member of the present invention, hydrogen and a carbon-containing gas are used as source gases in forming the hard carbon film. Examples of the carbon-containing gas used include, for example, alkanes such as methane, ethane, and propane; alkenes such as ethylene and propylene; alkynes such as acetylene; aromatic hydrocarbons such as benzene; cycloparaffins such as cyclopropane; And cycloolefins such as cyclopentene. In addition, oxygen-containing carbon compounds such as carbon monoxide, carbon dioxide, methyl alcohol, ethyl alcohol and acetone, and nitrogen-containing carbon compounds such as mono (di, tri) methylamine and mono (di, tri) ethylamine are also used as carbon source gases. Can be used. These can be used alone or in combination of two or more. Further, in order to form an intermediate layer composed of a mixture of diamond and silicon carbide as described above, after performing a diamond nucleation treatment as desired, hydrogen, a carbon-containing gas and a silicon-containing gas are introduced as reaction gases. . Examples of the silicon-containing gas include halides such as silicon tetrafluoride, silicon tetrachloride, and silicon tetrabromide, oxides such as silicon dioxide, mono (di, tri, tetra, penta) silane, and mono (di). Silane compounds such as (tri, tetra) methylsilane and silanol compounds such as trimethylsilanol. These can be used alone or in combination of two or more.
[0032]
As described above, the hard carbon film of the present invention is mainly composed of diamond having a fine grain structure, and is dense and free from defects such as voids on the film surface and inside, and also has excellent smoothness on the film surface. It is. Therefore, when this hard carbon film is formed on the surface of a member that comes into contact with the human skin, high corrosion resistance can be imparted. In particular, while preventing the occurrence of local corrosion to voids or the like due to sweat or acid rain, sweat and acid It is also possible to prevent the rain film from remaining in voids and recesses.
[0033]
Further, by interposing an intermediate layer containing at least diamond and metal carbide between the member surface and the hard carbon film, the adhesion of the hard carbon film to the substrate can be increased. Peeling from the substrate can be prevented.
[0034]
【Example】
(Example)
In an oven at electron cyclotron resonance plasma CVD device, a cemented carbide as the substrate (80 wt% WC-10 wt% Co-10 wt% Ni), TiC-based cermet (80 wt% TiC-15 wt% _{Cr 2 C} 2 - A 100 ml container made of any one of 5 wt% Ni) and a TiN-based cermet (85 wt% TiN-15 wt% Ni) was installed.
[0035]
The mixture was treated with a gas of H ₂ 297 sccm and CH _{4 3} sccm at a gas concentration of 1%, a substrate temperature of 650 ° C., and a furnace pressure of 0.1 torr for 1.5 hours to generate diamond nuclei. Using H ₂ gas, CH ₄ gas and Si (CH ₃ ) ₄ gas as the gas,
H ₂ 297 sccm
CH _{4 3} sccm
Si (CH ₃ ) ₄ 0.3 sccm
At a gas concentration of 1%, a substrate temperature of 650 ° C., and a furnace pressure of 0.05 torr by applying a magnetic field having a maximum intensity of 2 kGauss by an electron cyclotron resonance (ECR) plasma CVD method to obtain a microwave output of 3.0 KW. The film was formed under the conditions for 5 hours to form an intermediate layer having an average film thickness of 0.8 μm in which diamond and silicon carbide were mixed on the inner surface of the container.
[0036]
In Table 1, the sample No. For 4, an intermediate layer formed _H 2 300 sccm
Si (CH ₃ ) ₄ 0.3 sccm
An intermediate layer made of silicon carbide was formed in a thickness of 1 μm in exactly the same manner as described above except that the gas ratio was set to the above, and the evaluation was performed in the same manner.
[0037]
Next, a film was formed on the intermediate layer using H ₂ gas, CH ₄ gas, and CO ₂ gas having a purity of 99.9% or more at a gas ratio, a gas concentration, a substrate temperature, and a furnace pressure shown in Table 1. Was performed to form a 2 μm hard carbon film on the inner surface of the container.
[0038]
Against the formed hard carbon film, subjected to Raman spectrum analysis of the film surface, draw a line between positions 1100 cm ^-1 and 1700 cm ^-1 from the Raman spectrum chart, which was the baseline, 1160 ± 40 cm ^- the peak intensity of the maximum peak present the peak intensity of the maximum peak present in ¹ to _H 1, 1340 ± 40cm ^-1 as _{H 2,} was calculated intensity ratio expressed by H 1 / _{H 2.} Further, the peak intensity having the highest intensity among the peaks in the region of 1500 ± 60 cm ⁻¹ was defined as H _3, and the magnitude relation between H ₁ , H ₂ and H ₃ was shown. In Table 1, Sample No. 3 and Sample No. The charts for No. 9 are shown in FIGS. Note that an Ar laser (oscillation line 488.0 nm) was used as a laser as an oscillation source in the Raman spectroscopic analysis. Further, the film alone was taken out, and the density of the film was measured by a flotation method using a specific gravity solution of thallium formate aqueous solution.
[0039]
Next, 80 ml of a 45% hydrofluoric acid solution was poured into a container having an inner surface coated with a hard carbon film, and left at a temperature of 40 ° C. for 48 weeks. The film surface after standing was observed with a binocular microscope, and the state of corrosion is shown in Table 1. Further, the amount of metal eluted into the solution was measured by the ICP method, and the results are shown in Table 1.
[0040]
(Comparative Example 1)
The same corrosion test as in Example 1 was performed using a TiC-based cermet that did not cover the hard carbon film. 17 is shown.
[0041]
(Comparative Example 2)
Using the TiC-based cermet used in the examples as a substrate, an intermediate layer was formed by microwave CVD at a gas concentration of 1%, a substrate temperature of 950 ° C., and a furnace pressure of 30 torr for 3 hours. After the film formation, the sample Nos. Under the conditions shown in FIG. 9, a 1 μm hard carbon film was formed. On the other hand, the same corrosion test as in Example 1 was performed. The results are shown in FIG.
[0042]
[Table 1]

[0043]
According to the results shown in Table 1, the samples of the present invention in which a hard carbon film satisfying H ₁ / H ₂ of 0.05 or more and satisfying H ₁ <H ₂ <H ₃ were all resistant to a strong acid solution. No corrosion was observed, excellent corrosion resistance was shown, and the elution of allergic metal was below the detection limit. In addition, the density was as high as 3.1 g / cm ³ or more.
[0044]
As a comparative example, in the case of a conventional TiC-based cermet, the surface turned white in 0.5 hours against a strong acid, and the elution of allergen metal was confirmed. In addition, the sample No. manufactured by the microwave CVD method or the like. Sample No. 9 and a sample No. 9 in which the ratio of H ₁ / H ₂ is smaller than 0.05 depending on the film formation conditions. In each of the members 1, 2, 9, and 10, a large number of spots of 10 to 1000 μm, which are considered to be caused by corrosion, were observed on the film surface after the test, and it was found that the corrosion had locally progressed. Elution of allergen metal was confirmed.
[0045]
In the same manner as described above, 80 ml of a 40% NaOH alkali solution was poured into the container containing the produced members, and the state of corrosion after being left at 40 ° C. for 48 hours was observed. In the container made of the TiC-based cermet of No. 17, corrosion was observed on the entire surface. For 1-16, little change was seen.
[0046]
【The invention's effect】
As described in detail above, the hard carbon film-coated member of the present invention can suppress the progress of local corrosion and the like even in contact with a strong acid or strong alkali, and can exhibit excellent corrosion resistance over a long period of time. As a result, even in the case of contact with seawater, sweat, or the like, elution of the allergen source metal in the base can be prevented. Thereby, the long-term safety and reliability of the decorative member that comes into contact with the human skin, in particular, can be enhanced.
[Brief description of the drawings]
FIG. 1 is a Raman spectrum chart of a hard carbon film (sample No. 3) according to the present invention.
FIG. 2 is a Raman spectrum chart of a hard carbon film (sample No. 9) in a comparative example.

Claims (1)

Peaks at 1160 ± 40 cm ⁻¹ , 1340 ± 40 cm ^−1, and 1500 ± 60 cm ⁻¹ in Raman spectroscopy on the surface of a substrate containing a total of 1% by weight or more of metals that cause metal allergy of Ni, Co and Cr. Among the peaks present and present at 1160 ± 40 cm ⁻¹ , the highest peak intensity is H ₁ , and the highest one of the peaks present at 1340 ± 40 cm ⁻¹ is H ₂ , 1500 ± 60 cm ^−. when a strong peak intensity of most intense among the peaks present was _{H 3} in _^1, a peak intensity ratio represented by H 1 / _{H 2} is 0.05 or _more, the relationship of _{H 1 <H} 2 _{<H 3} A hard carbon film-coated member for decoration characterized by being coated with a hard carbon film satisfying the following.

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