JPH0480379A - Ornament having hard transparent film on surface and its production - Google Patents

Abstract

PURPOSE:To obtain an ornament having a hard transparent film on its surface having wear resistance, corrosion resistance and light transmittance by depositing an aluminum oxide of an amorphous structure by MO-CVD method on the surface of a metallic substrate, etc., under specified conditions. CONSTITUTION:An amorphous Al2O3 is formed by MO-CVD method on the surface of a metallic substrate or a metallic substrate subjected to decorative surface treatment such as gold plating. The MO-CVD is performed in an inert gas atmosphere and/or reduced pressure at 300-450 deg.C to deposit an org. aluminum compd. such as aluminum acetylacetate and water vapor. Thereby, the obtd. ornament has wear resistance and corrosion resistance without losing the color tone of the metallic substrate or colored surface thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to decorative accessories having a hard transparent film on the surface and a method for manufacturing the same, and more specifically, to a decorative accessory having a hard transparent film on the surface and a method for manufacturing the same. By applying a hard aluminum oxide film with a highly transparent amorphous structure to the colored surface of a metal substrate that has undergone surface treatment such as anodic oxidation coloring or stainless steel oxidation coloring, the surface of the metal substrate or the metal substrate This invention relates to decorative accessories that have strength, corrosion resistance, and abrasion resistance without impairing the tint of the colored surface. The present invention relates to a gas phase synthesis method M O-CV D
(metal lie organo-chemi
The present invention also relates to a method for manufacturing such jewelry, which comprises depositing aluminum oxide in an amorphous structure onto the surface of a metal substrate by a cal vapor deposition method.

Conventional Technology Decorative accessories are manufactured from various metals and are used in a solid state, or are plated with gold, silver, anodized (for example, titanium), colored by oxidation (for example, stainless steel), etc. It is ready for use after surface treatment.

For example, in the case of titanium coloring treatment and stainless steel coloring treatment (e.g. ink-based), the thickness of the colored film obtained is quite thin, and although hardening treatment is performed by heat treatment and chemical treatment, Because it is disadvantageous in terms of wearability,
Top coatings of transparent paints have been applied by electrodeposition or spray coating methods. If a transparent paint is used, the color tone of the underlying colored film will not be impaired, but it will be insufficient in terms of abrasion resistance and corrosion resistance, and furthermore, since it is a paint coating, it has a strong image of being a cheap product.

Furthermore, gold plating, silver plating, etc. have poor abrasion resistance and low hardness, so they tend to be easily scratched and reduce commercial value. Furthermore, silver plating has a problem with corrosion resistance, and is particularly prone to clouding of the surface.

In order to compensate for these drawbacks, it has been proposed to apply transparent ceramic films such as aluminum oxide, spinel, silicon oxide, i-carbon, etc. However, in all cases, interference colors appear or a slightly black or gray coloration occurs. Because of this, it has the disadvantage that it impairs the color tone of the underlying colored surface (colored film), and currently it is not applied to decorative items where luxury and beauty are essential.

As mentioned above, the hard transparent film of aluminum oxide produced by the conventional technology has poor transparency.Furthermore, we believe that the aluminum oxide film produced by the conventional technology has problems in strength and corrosion resistance. It has been found that aluminum coatings are not suitable for decorative items.

We have intensively studied the above-mentioned defects of the aluminum oxide film according to the prior art and investigated the causes thereof, and as a result, we have discovered that these defects are caused by the crystallinity of the aluminum oxide film.

We further developed our research and found that by adopting an amorphous aluminum oxide film instead of the conventional crystalline aluminum oxide film, significant improvements in transparency, corrosion resistance, and strength were achieved. I discovered that.

Furthermore, an aluminum oxide film with an amorphous structure is produced by MO-CVD from a mixture of an organoaluminum compound and water vapor in an inert gas atmosphere and/or under reduced pressure at a relatively low temperature in the range of about 300 to 450°C. It has also been discovered that it can be deposited onto the surface of a substrate. This vapor deposition method involves appropriately arranging the workpiece and an organo-aluminum compound (e.g. aluminum acetylacetonate) on a base in a closed chamber, and forming an inert gas (e.g. N2, Ar) atmosphere in the chamber. Alternatively, it can be carried out by applying reduced pressure (for example, a vacuum degree of 10'rorr), heating the base to a temperature of about 300 to 450° C., and introducing water vapor into the chamber.

In this way, the organoaluminum compound and water vapor react, and aluminum oxide having an amorphous structure can be easily deposited onto the surface of the workpiece. Note that when the workpiece is silver, it is preferable to use reduced pressure and an inert gas atmosphere in combination in order to prevent oxidation. For other metals, satisfactory results can be obtained using only an inert gas atmosphere.

Translucency between the amorphous aluminum oxide film according to the present invention and the crystalline aluminum oxide film of the prior art,
A comparison of corrosion resistance, strength and hardness is as follows.

ωTranslucent crystalline aluminum oxide has crystals that grow in columnar shapes, so
Light scattering occurs at grain boundaries, which impairs translucency. The most common aluminum oxide crystals also exhibit birefringence (a different index of refraction depending on the orientation of the crystal), which further adversely affects transparency.

On the other hand, amorphous aluminum oxide does not have grain boundaries, so light scattering does not occur. It is also isotropic. Therefore, it has physical properties that are advantageous for translucency.

(b) Corrosion resistance Even if crystalline aluminum oxide has strong corrosion resistance within the crystal grains, it is easy for corrosion to progress because atoms are missing or certain atoms are arranged in relatively large numbers at the grain boundaries. . Furthermore, microcracks occur at grain boundaries, propagate, and easily allow corrosive substances to enter.

On the other hand, since aluminum oxide having an amorphous structure has no grain boundaries, the above-mentioned undesirable phenomenon is unlikely to occur.

(c) Strength In crystalline aluminum oxide, as mentioned earlier, columnar crystals grow side by side, so defects occur between crystal grains and cracks are likely to occur. There are also linear or planar lattice defects within the crystal grains. All of these have an adverse effect on strength and toughness.

On the other hand, aluminum oxide with an amorphous structure has excellent strength and toughness because it has no linear or planar defects, although it has a few point defects.

(→Hardness There is virtually no difference in the hardness of both crystalline and amorphous aluminum oxides.

Example The present invention will be explained in more detail below using Examples.

Example 1 Numerous watch sides made of brass as a core material were plated with nickel (5 μ) and Au-Ni alloy (23K) (0
, 2-0.3μ) flash plating was applied.

Half of the watch sides plated in this way were plated using aluminum acetylacetonate and water vapor.
An amorphous structure Ag2O3 was vapor-deposited using the O-CVD method (nitrogen atmosphere width approximately 400°C). The thickness of this film is 2
．． It was 0μ. Through this film, the underlying Au-Ni
The color tone unique to alloy plating (23K) could be observed without being impaired.

A wristwatch was assembled using five watch sides that had only been subjected to the above plating treatment and five watch sides that had been subjected to plating treatment and amorphous Ag2O3 vapor deposition treatment.

Five testers wore a (plated) watch and a (plated/deposited) watch on their left and right wrists, and carried out continuous mobile phone comparison tests on a daily basis.

On average of the 5 testers, the plated watch will last about 1 month (
After 22 days at the earliest and 35 days at the longest, the underlying nickel plating became exposed. However, for watches that are plated and vapor-deposited, all testers tested
No surface abnormalities were observed even after several years.

Example 2 5cm x 5em made from stainless steel 5US304 material
A flat test piece was coated with bright Ag plating (3μ thick), and an amorphous structure A (t 20 s) was evaporated to a thickness of 1.0 μm using the same MO-CVD method as in Example 1. A film was formed while maintaining the color tone.

A half-immersion test (25°C, 24 hours) was conducted on a test piece that had been vapor-deposited with amorphous aluminum oxide and a test piece that had only Ag plating but was not vapor-deposited in artificial sweat with the following composition. Sulfur discoloration was observed overall in the test piece that was only Ag plated but not vapor-deposited, but no abnormality was observed in the test piece that was vapor-deposited with A,020s.

Composition of artificial sweat Food Salt sodium sulfide Urine ammonia water Sugar milk acid 1g of the above with distilled water 9.9g/(1 0.8g/β L, 7g/1 0.18cc/R 0.22g/# 1.1 cc/ρ shall be.

Example 3 A 5cm x 5cm flat test piece made of titanium material was colored by electrolytic coloring in a phosphoric acid solution, and 0.0% of AlI2O3 having an amorphous structure was applied thereon by the same MO-CVD method as in Example 1. It was deposited to a thickness of 5μ.

When tested by rubbing the test piece with the abdomen of the thumb in the palm of one hand, the colored film by electrolytic coloring was 5 to 6.
It peeled off just by rubbing twice, but the Aρ203 vapor deposited film
Even after 00 times or more of rubbing, there was no abnormality and the color tone of the colored film was maintained as it was.

Example 4 5 cm X made of stainless steel 5US304 material
A 5 am flat test piece was immersed and colored in a chromic acid solution, and A11203 having an amorphous structure was coated on it to a thickness of 3 μm using the same MO-CVD method as in Example 1.
was deposited on. In this way, the test piece with the vapor-deposited Aρ203 film and the test piece with only the chromic acid coloring treatment but without the vapor-deposited film were tested using felt cloth under a load of 250 g.
A reciprocating abrasion test was conducted using 5 test pieces (each using 5 test pieces). None of the former five test pieces with evaporated film showed any abnormality even after being used over 2,000 times, but the latter test piece without evaporated film showed abrasion of the colored film after an average of 396 times (minimum 370 times, maximum 422 times). was recognized.

Effects of the Invention As described above, the present invention achieves various favorable effects by using an aluminum oxide film having an amorphous structure.

When the present invention is applied to colored film products made of stainless steel, titanium, etc., it is possible to impart abrasion resistance, corrosion resistance, translucency, etc. without impairing the value of the product as a decorative item. In addition, as for gold-plated products, the abrasion resistance can be greatly improved even with very thin plated products of around 0.2μ, making it possible to significantly reduce costs (the amount of precious metal for plating can be reduced). ). The corrosion resistance of metal products such as silver-plated products that change color when left indoors or outdoors can be improved without losing their unique color tone. Therefore, the commercial value of each product as a decorative item can be significantly improved.

[Brief explanation of drawings]

The attached figure is an electron diffraction photograph of aluminum oxide with an amorphous structure according to the present invention. No Lawe spots were observed, indicating that the material was amorphous. The conditions for forming this film were: Reactive gas source: AN (02C5H7) 30 steam gas source heating temperature = 350°C, substrate temperature 2350°C. Electron diffraction was performed using a JEM-200B transmission electron microscope manufactured by JEOL Ltd. at an accelerating voltage of 200 kV. Moreover, this film had the following physical property values. Optical constants 1.60-0.00i (wavelength 546.1nm) Specific resistance (frequency 0.01Hz) 2 x 1012 ohm e cm (film thickness > 200na+)

Claims (1)

[Claims] 1. A decorative accessory characterized in that a transparent film of aluminum oxide having an amorphous structure is applied on the surface of a metal base material or on the surface of a metal base material that has been subjected to a decorative surface treatment. 2. Decorative surface treatment is gold plating, silver plating,
The accessory according to claim 1, which is colored by anodic oxidation of titanium or colored by oxidation of stainless steel. 3. The accessory according to claim 1 or 2, wherein the aluminum oxide film having an amorphous structure has a thickness within a range of 0.1 to 5 microns. 4. 4. The accessory according to claim 1, wherein the aluminum oxide film having an amorphous structure is formed by MO-CVD, a vapor phase synthesis method. 5. On the surface of a metal base material or on the surface of a metal base material that has been subjected to a decorative surface treatment, a temperature within the range of 300 to 450 ° C. is applied under an inert gas atmosphere and/or under reduced pressure by the MO-CVD method. 1. A method for producing decorative jewelry having a hard transparent film on its surface, comprising depositing aluminum oxide in an amorphous structure from a mixture of an organoaluminum compound and water vapor.