JPH05339755A - Structure of coating film for accessory - Google Patents

Abstract

PURPOSE:To prevent cracks in a hard carbon layer for a metal accessory by forming a laminated film consisting of a hard carbon layer, hard transparent glass layer, and silica directly on the surface of a metal accessory or with a hard base layer interposed. CONSTITUTION:A base layer 2 comprising a Ti film and Si film is formed by electron beam vapor deposition or the like on the surface of an accessory made of metal such as stainless steel, iron steel, super hard allay, copper alloy, and light alloy. Then, a hard carbon layer 3 is formed on the base layer 2 by using a hydrocarbon gas such as methane as the reaction gas, and further the accessory is dipped in a mixture colloid liquid of sodium silicate and silica soln., drawn from the liquid, heated and dried to form a hard transparent glass layer 4. Then, a soln. of partially hydrolyzed ethylsilicate is applied, dried, and baked to from the uppermost layer 5 of silica. Thus, the obtd. accessary has no crack in the hard carbon layer 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating structure for an accessory such as a watch case.

[0002]

2. Description of the Related Art Generally, jewelry such as a watch case has a titanium nitride layer on the surface of a base material such as a stainless steel material, a steel material, a super hard material, a copper alloy material, and other non-metal materials, and a black coating on the base material. There are many commercially available products in which a hard carbon layer having a color tone is provided to improve wear resistance. But,
Such a configuration has a very high hardness of the hard carbon layer, so that if a defect such as a crack or peeling occurs even at one place,
It had the drawback of rapidly expanding to the next flaw, which significantly reduced the commercial value.

[0003]

In view of this point, the present invention has an object to prevent defects of cracking in an accessory having a hard carbon layer on its surface.

[0004]

[Means for Solving the Problems] The above problem is a hard carbon layer formed on the surface of a substrate such as stainless steel material, steel material, cemented carbide material, copper alloy material or other non-ferrous metal material directly or through an underlayer. And a hard transparent glass protective layer and a top layer made of silica derived from alkyl silicates of alkyl silicate are sequentially laminated on the protective layer.

To obtain the coating structure of the present invention, 20 to 21% by weight of SiO _{2 is} added to the hard carbon layer formed on the substrate.
After applying a treatment solution prepared by diluting a colloidal solution containing Na ₂ O in an amount of 3.8 to 4.4% by weight with pure water 4 to 12 times, and drying by heating to form a hard transparent glass protective layer on the surface. Further, a partial hydrolysis solution of an organic silicic acid ester is applied to the surface of the layer and heated and baked to form the uppermost layer made of silica.

This hard transparent glass protective layer is not a conventional colloidal solution prepared by mixing sodium silicate and silica gel as it is, but 4 to 1 with pure water from which carbon dioxide gas is completely removed.
A 2-fold diluted colloidal solution containing 1.7 to 5.0 wt% SiO ₂ and about 0.3 to 1.0 wt% Na ₂ O is applied by a dipping method or spraying.
It is formed by heating and baking at 150 to 300 ° C. for 30 to 120 minutes. The thickness of this protective layer is about 0.5-
5 mm is preferable.

Further, the surface of this layer is coated with a partially hydrolyzed solution of alkyl silicate and heated and baked to give about 0.5
An uppermost layer made of thin silica having a thickness of about 3 μm is formed.

The partially hydrolyzed solution of alkyl silicate has the following formula R ¹ _n Si (OR) _4-n (wherein R is selected from a lower alkyl group, R ¹ is a methyl group or a phenyl group, and n is 0, 1, 2 or 3
Is. ) It is prepared by partially hydrolyzing an organic silicic acid alkyl ester represented by. In this case, the most preferable one is ethyl silicate type.

The concentration of the partially hydrolyzed liquid is about 20-40% by weight. The solution is applied by the usual method 150-
After heating and drying at a temperature of 300 ° C. for 30 to 120 minutes, baking is performed to form a silica layer having a desired thickness. Since the thickness of this uppermost layer is 1 to 3 μm and the hardness is 9H, it is not sufficient to prevent scratches, but defects such as cracks do not occur due to the double structure with the underlying hard glass protective layer. A surface layer is formed.

[0010]

EXAMPLES Hereinafter, examples will be described in detail.

(Embodiment 1) A titanium alloy watch case 1 which is an accessory is washed and set in a vacuum tank of an ion plating apparatus which is dry plating. After evacuating the inside of the vacuum chamber, introducing argon gas and maintaining it at 1 × 10 ⁻⁵ Torr,
Argon ions are ionized with a negative potential of 50 V and an anode current of 40 A to bombard the surface of the watch case. Next, the base layer 2 including the titanium coating and the silicon coating is formed. The evaporation source metal titanium is irradiated with an electron beam generated at an appropriate accelerating voltage, a titanium film is formed with the generated titanium vapor to a thickness of 0.5 μm, and the evaporation source silicon is irradiated with the electron beam. A silicon film is formed to a thickness of 0.5 μm by the generated silicon vapor. Next, methane gas, which is a hydrocarbon gas, is introduced into the vacuum layer, and the mixed gas with the argon gas is kept at 1 × 10 ⁻³ Torr as a reaction gas. Next, irradiating the metal titanium of the evaporation source with an electron beam generated at an appropriate acceleration voltage,
A hard carbon coating 3 is formed on the surface of the underlayer 2 to a thickness of 1 μm.

Next, the watch case 1 having the hard carbon film 3 formed thereon is washed. On the surface of the hard carbon coating 3, a mixed colloidal solution of sodium silicate containing 20% by weight of SiO ₂ and 4.0% by weight of Na ₂ O and silica sol,
The watch case 1 is immersed in pure water from which carbon dioxide gas has been removed by a factor of about 6 and then dried at about 200 ° C. for about 60 minutes to obtain a hard transparent glass protective layer 4 of about 2.0 μm. It was Further, a 60% by weight solution of a partial hydrolyzate of ethyl silicate was diluted to about 30% by weight and dip-coated on the surface of the hard transparent glass protective layer 4, dried and baked at a temperature of about 250 ° C. for about 60 minutes. Then, the uppermost layer 5 having a thickness of about 2.5 μm was formed.

(Embodiment 2) A watch band made of stainless steel (SUS304 or SUS316), which is an accessory, is set in the vacuum chamber of the ion plating apparatus in the same manner as in Embodiment 1, and the surface is bombarded and cleaned. An underlayer of a titanium film having a thickness of 0.3 μm and a silicon film having a thickness of 0.5 μm was formed, and a hard carbon film having a thickness of 1 μm was further laminated on the surface of the underlayer. next,
On the surface of the hard carbon layer, a hard transparent glass protective layer having a thickness of about 2.0 μm and an uppermost layer made of silica having a thickness of about 2.5 μm were formed.

(Embodiment 3) A nickel-palladium plating film is formed by wet plating, and a titanium film and a silicon film are formed by ion plating on the surface of a brass watch case which is an accessory. The thickness of each coating is 0.3μ for nickel-palladium coating.
m, titanium coating 0.5 μm, silicon coating 0.5 μm
m. Then, in the same manner as in Example 1, 1
A μm hard carbon coating was laminated.

Next, the watch case 1 having the hard carbon film formed thereon is washed. 20 on the surface of this hard carbon coating
Formed on the surface of the watch case by diluting a mixed colloidal solution of sodium oxalate and silica sol containing only wt% SiO ₂ and 4.0 wt% Na ₂ O about 10 times with pure water without carbon dioxide. It was made to adhere to the surface of the hard carbon layer by spray method. Then, this was dried at about 150 ° C. for about 90 minutes to obtain a hard transparent glass protective layer having a thickness of about 1.0 μm.
Next, a 60% by weight solution of a partial hydrolyzate of ethyl silicate was diluted to about 30% by weight and applied on the surface of this hard transparent glass protective layer by a spray method, followed by ethyl acetate at a temperature of about 150 ° C. for about 100 minutes. The silicate was baked to obtain a 2.5 μm thick top layer.

The silicon coating formed on the lower surface of the hard carbon layer in the above embodiment is for improving the adhesion between the hard carbon coating and the coating formed on the base of the accessory or the surface of the accessory. Further, as a metal having the same effect as that of the silicon film, there is germanium or the like.
Further, the titanium coating formed between the base of the accessory and the silicon coating and the nickel-palladium plated coating formed between the base of the accessory and the titanium coating are also for improving the adhesion. When the base material is a super hard material such as dungsten carbide and tantalum carbide, a hard carbon coating can be directly formed on the surface of the base material without forming the underlayer. Further, although the silicon coating, the hard carbon coating and the like were formed by ion plating which is dry plating, it goes without saying that they may be formed by dry plating such as sputtering and vapor deposition.

(Comparative Example 1) For comparison, an accessory made of stainless steel (SUS304 or SUS31) is used for comparison.
After cleaning the watch case of 6) in the same manner as in Example 1, the watch case is set in the vacuum chamber of the ion plating apparatus, and the surface is subjected to bombard cleaning. After that, an underlayer of a titanium film having a thickness of 0.5 μm and a silicon film having a thickness of 0.5 μm was formed, and a hard carbon film having a thickness of 1 μm was further laminated on the surface of the underlayer.

Next, various tests were conducted on the coatings formed on the surfaces of the jewelry manufactured in Examples 1 to 3 and the jewelry manufactured by the conventional method for comparison.

Table 1 shows the results of a scratch test conducted to examine the adhesion of the hard carbon coating. (Test method) An accessory is fixed to a mounting table (test piece fixing base), and a diamond terminal having a tip of 50 μm is applied with a load perpendicularly to the coating surface of the accessory, and thereafter,
The stage is moved 10 mm at a speed of about 75 mm / min. After the test, the peeling of the hard carbon coating formed on the surface of the accessory was evaluated by a symbol.

The hard carbon coating having the coating structure of the present invention did not peel at a load of 600 grams, whereas the hard carbon coating having the conventional coating structure had peeling at a load of 500 grams.

[0021]

[Table 1]

Next, Table 2 shows the result of examining the progress of peeling of the hard carbon coating by the drop test. The hard carbon coating of the accessory manufactured in Examples 1 to 3
As a comparative example, the hard carbon coating of the accessory manufactured by the conventional method was peeled off by a scratch test, and then the accessory was dropped onto a concrete surface from a certain height to examine the progress of peeling of the hard carbon coating.

The hard carbon coating having the coating structure of the present invention showed no increase in peeling at a height of 5 m, whereas the hard carbon coating having the conventional coating structure had peeling at a height of 2 m. Expansion was seen. That is, according to the present invention, by the hard transparent glass protective layer formed on the surface of the hard carbon coating and the uppermost layer made of silica, even if a part of the hard carbon coating is peeled off, it is possible to prevent further expansion. it can.

[0024]

[Table 2]

As other tests, a. Moisture resistance test and b. An artificial sweat test was conducted, but neither peeling nor rusting was observed in the hard carbon coating of the jewelry manufactured in Examples 1 to 3 and the hard carbon coating of the jewelry manufactured by the conventional method for the comparative example. .. The conditions of the humidity resistance test and artificial sweat test are shown below. I. Humidity resistance test The state was examined by holding the sample for 24 hours under an atmospheric condition of room temperature of 60 ° C. and relative humidity of 95%. B. Artificial sweat test The resistance was examined by immersing in an aqueous solution of the following components at 30 ° C for 48 hours. << Aqueous solution component >> NaCl: 9.9 g / l, Na ₂ S:
0.8 g / l, (NH ₂ ) ₂ CO: 1.7 g / l, CH ₃
CHOHCOOH: 1.7 g / l, and NH ₄ OH: 0.
2 ml / l

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view of an embodiment of the present invention.

[Explanation of symbols]

 1 Watch Case 2 Underlayer 3 Hard Carbon Coating 4 Hard Transparent Protective Layer 5 Top Layer

Claims (1)

[Claims] 1. A stainless steel material, a steel material, a cemented carbide material,
A hard carbon layer formed on the surface of a substrate such as a copper alloy material or other non-ferrous metal material directly or through an underlayer, a hard transparent glass protective layer formed on the surface of the hard carbon layer, and the hard transparent glass protective layer A coating structure for an accessory, which comprises a laminated film with an uppermost layer made of silica derived from alkyl silicates formed on the surface of the body.