JPH083732A - Production of golden ornament - Google Patents

Abstract

PURPOSE:To provide a method for producing golden ornaments by the vapor deposition of a gold alloy by which a change of color tone between batches for vapor deposition is suppressed and the gold alloy as an evaporating source can be repeatedly utilized any number of times without requiring total exchange after a prescribed number of repetition. CONSTITUTION:The compsn. of a gold alloy in a crucible is calculated from vapor deposition time and the reduction of the gold alloy and the compsn. of a gold alloy added to the crucible is determined. A gold alloy having the determined compsn. is added to the crucible by an amt. equal to the reduction and it is used for subsequent vapor deposition.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a golden ornament such as a watch case, a band, a ring, a necklace, glasses, a bracelet, a door knob, a handle and a writing instrument.

[0002]

2. Description of the Related Art Conventionally, when a gold alloy film is formed by vapor deposition as a finish color tone for gold ornaments, a gold alloy with an initial charge composition is added in an amount equal to the evaporated weight of the gold alloy in the crucible. Was there.

[0003]

However, in the conventional manufacturing method, when the vapor deposition process is repeatedly performed as shown in the change 2 of the gold alloy composition in the conventional manufacturing method of FIG. The alloy composition was gradually changing. This is Au
This is because the evaporation rates of the element and the additive element are different. For this reason, there is a drawback that the color difference between the color tone of the golden ornament obtained by the vapor deposition process and the target color tone becomes gradually larger. Further, the gold alloy in the crucible needs to be completely replaced after a predetermined number of treatments, which is economically problematic. An object of the present invention is to newly devise a method for manufacturing a golden ornament to solve such a conventional problem, and to realize a method for manufacturing a golden ornament whose color tone is always stable.

[0004]

In order to solve the above problems, the composition of the gold alloy to be added is changed in accordance with the composition of the gold alloy remaining in the crucible after the vapor deposition process.

[0005]

In the manufacturing method of the above-mentioned golden ornament,
As seen in the gold alloy composition change 1 in the production method of the present invention, the gold alloy composition at the start of vapor deposition is constant,
The color tone of gold ornaments is stable. Therefore, the difference in color tone is reduced and the yield is improved. Further, in the production method of the present invention, the gold alloy in the crucible can be repeatedly used any number of times, which is advantageous in terms of production cost.

[0006]

EXAMPLES The present invention will be described below based on examples. First, 60.0 g of a gold alloy having a composition of Au-3.0 wt% Fe was put in a graphite crucible and placed in a processing apparatus. Next, the washed golden ornamental fabric was mounted in the processing apparatus, and the inside of the chamber was evacuated to 1 × 10 ⁻⁴ Torr. Subsequently, the pressure in the chamber was adjusted to 8 × 10 ⁻⁴ Torr by introducing Ar gas. Au-
The Fe alloy was melted and vaporized by an electron beam of 9.5 kV and 280 mA, and the vaporized Au alloy was deposited on the fabric of the golden ornament. The processing time was 8 minutes. As a result of this vapor deposition process, a gold alloy layer of about 0.1 μm was formed on the fabric of the golden ornament. The gold alloy remaining in the crucible is 4
It was 9.8g.

Prior to the next vapor deposition process, the composition of the gold alloy added to the crucible was calculated by the method shown below. From the time of vapor deposition and the weight of the gold alloy remaining in the crucible (1)
As a result of calculating the evaporation rate by the formula, av = 2.95 × 1
It became 0 ^-2 kg · m ^-2 s ^-1 . av = Md / (s · t) (1) av: evaporation rate [kg · m ⁻² s ⁻¹ ] Md: evaporation weight [kg] s: surface area of evaporation source [m ² ] t: evaporation time [ sec]

The relationship between the evaporation rate av and the surface temperature T of the evaporation source is expressed by equation (2). In the case of Au-Fe alloy, a
= 28.28, b = 1.24 × 10 ⁻² , and T≈2000K. T≈ (ln (av) + a) / b (2) T: evaporation source surface temperature [K]

Then, the Fe concentration in the gold alloy in the crucible was calculated by the equation (3). γ = 0.35. As a result, χ _f ≈ 11.13 at% ≈ 3.43 wt%. 1n (l _f / L _s ) = {1 / α ₁₂ -1)} {1h (x _f / x _s ) α ₁₂ 1n (1-x _s ) / (1-x _f )} ・ ・ ・ (3) L _f : amount of charged gold alloy [mol] L _s : residual amount of gold alloy [mol] χ _s : mole fraction of Fe in charged alloy χ _f : mole fraction of Fe in final gold alloy α ₁₂ : relative Volatility α ₁₂ = P _Au / (γP _Fe ) γ: Average activity coefficient P _Au , P _Fe : Saturated vapor pressure [Pa] of a single element at temperature T [K]

As a result of obtaining the composition of the gold alloy to be added by the equation (4), it was χ _a = 3.10 at% = 0.90 wt%. As a result, 0.10 g of pure iron and 10.1 g of pure gold were added to the gold alloy in the crucible, and the evaporation source gold alloy weight was 6%.
It was used as the second vapor deposition treatment as 0.0 g. χ _a = (L _s χ _s −L _f χ _f ) / (L _s −L _f ) ... (4) χ _a : mole fraction of Fe in the gold alloy to be added

The same operation as above is performed 10 times in succession,
The color tone of the obtained vapor-deposited gold alloy layer was measured with a color difference meter.
As a light source of the color difference meter, D65 defined by ASTM was used.
The viewing angle of the light source was 2 °. The color difference between the gold alloy film obtained in the first treatment and the gold alloy film obtained in the tenth treatment is the difference in lightness dL ^* = 0.9, the difference in chromaticity da ^* =-0.6, the difference in chromaticity db.
^* =-2.0. This is a value that is difficult to identify with the naked eye. In the conventional manufacturing method, dL ^* = 4.3, da ^*
= −2.1, db ^* = − 4.1, and the decrease in saturation was also apparent by the naked eye.

[0012]

As described above, according to the present invention, the color tone of the gold-colored ornament obtained by the vapor deposition process is always stable, so that the reprocessing rate is lowered due to the difference in color tone, which leads to cost reduction. Further, the gold alloy of the vapor deposition source can be repeatedly used any number of times without replacing it after a predetermined number of times, which is effective not only from an economical point of view but also from the viewpoint of effective utilization of resources.

[Brief description of drawings]

FIG. 1 is a diagram showing changes in the gold alloy composition in the production method of the present invention and changes in the gold alloy composition in the conventional production method.

[Explanation of symbols]

 1 Gold alloy composition change in the production method of the present invention 2 Gold alloy composition change in the conventional production method

Claims (2)

[Claims] 1. A method of manufacturing a gold-colored ornament in which a gold alloy is melted and vaporized by an electron gun to form a gold-deposited film, by changing the gold alloy composition consisting of additional gold and an additive element in a crucible, an evaporation source. A method for producing a golden ornament, characterized in that the gold alloy composition is constant. 2. The gold and the additional element added to the crucible are the evaporation rate and surface temperature of the vapor deposition source, the concentration of the additional element in the gold alloy,
The method for producing a gold-colored ornament according to claim 1, wherein the mole fraction of the additional element in the gold alloy to be added is calculated and determined.