JPH058266B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a gold alloy that is colored bright black and a method for coloring the same, which is related to the manufacture of precious metal ornaments.

<Prior art> In the field of precious metal accessories, gold products are defined by the Karat Law, and in Japan, processed products made of 18-karat gold with a gold content of 75% by weight account for more than 90% of the products in circulation. There is. It is believed that 18 karat gold has become popular because it has the most stable mechanical, physical, and chemical properties, is easy to process, and can be easily applied to changes in hue. And 18
The concept that the hue of karat gold was golden has long been fixed, but in recent years, consumers' needs for precious metal ornaments made of gold alloys have diversified, and efforts have been made to make them more colorful and make the most of their designs. I'm getting old.

Currently, the hues used in gold alloy products are:
Au-Ag alloy is pale green-yellow, Au-Ag-Cu alloy is yellow, Au-Au alloy is red, and Au-Cu-Ni alloy is pale yellow-white. By combining these colors, colorful processing is possible. It was considered a good item. Very recently, it has become possible to change the color by adding purple from Au-Al alloy and yellow-green from Au-Cd alloy.

<Problem to be solved by the invention> However, as mentioned above, the five colors of white, yellow, red, purple, and yellow-green have limitations in creating multicolor designs for decorative items, and colored Au other than the above There is currently a demand for the development of alloys, especially black gold alloys that have an extremely good contrast with the gold color that is consumed in large quantities.

<Means for Solving the Problems> The present invention has been proposed in view of the above, and includes: (A) pure gold (Au) or gold containing 38% by weight;
In the above, a gold alloy containing one or more of silver (Ag), nickel (Ni), and platinum group elements (Pt, Pd, Rh, Ir, Ru, Os), and (B) 3 to 30% of the total amount 20% by weight copper (Cu), 3-20% iron (Fe) based on the total amount, cobalt (Co) 3-20% by weight based on the total amount, titanium 1-10% by weight based on the total amount An alloy consisting of one or more of (Ti), and the total amount of elements other than gold does not exceed 62% by weight, the above (A), (B), and (C) 0.5 to 5% by weight based on the total amount % of zinc (Zn), and in which the total amount of elements other than gold does not exceed 62% by weight, is placed in the atmosphere or in an oxidizing atmosphere higher or lower than the atmospheric oxygen partial pressure at a temperature below the melting point of the alloy. Gold colored in a brilliant black, characterized by being heat treated in an alloy and then air-cooled, water-cooled or oil-cooled to form a black oxide layer on the whole or part of the surface layer of the processed alloy product. It concerns alloys and their coloring methods.

Silver (Ag), nickel (Ni), and platinum group elements (A) in each of the above alloys are additive elements for adjusting the gold grade and mechanical properties. In general, gold alloy ornaments with the lowest gold content of 38% by weight are commercially available, so this may be used.

In addition, copper (Cu), iron (Fe), cobalt (Co), and titanium (Ti) in (B) are used to form a black selective oxide film, and the total amount is 62
If the weight percentage is exceeded, the gold quality will be low and the value as a gold (alloy) product will be low. Furthermore, if the content of copper (Cu), iron (Fe), or cobalt (Co) is less than 3% by weight, the color becomes gray or gray-black, and the black color with high decorative value does not develop. Moreover, if it exceeds 20% by weight, the gold alloy becomes too hard and post-processing after casting becomes difficult. Furthermore, since titanium (Ti) develops a black color at a low content compared to each of the above elements, the content should be 1 to 10% by weight.
If it exceeds 10% by weight, it becomes extremely hard and brittle.

Furthermore, zinc (Zn) is a deoxidizing agent when melting gold alloys, and is added to prevent local blistering caused by gas (mainly oxygen) in the selective oxide film during blackening treatment of gold alloys. If it is less than 0.5% by weight, the above effects are not sufficient, and if it exceeds 5% by weight, there is no further effect.

Gold alloys composed of the various elements mentioned above are
It is obtained by melting each of the above-mentioned compositions in a vacuum or an inert gas atmosphere using an arc melting furnace or a high frequency melting furnace equipped with a water-cooled copper crucible.

Further, the amount of dissolution at one time is usually about 50 to 100 g.

The ingots of each alloy produced as described above are melted in vacuum or in an inert gas atmosphere, such as argon gas, and cast into a mold made of magnesia, zircon, alumina, mullite, silica, or the like. In this case, it is desirable to use pressurization with an inert gas or centrifugal force during casting to improve filling of the cavity in the mold.

The gold alloy product obtained by casting as described above is subjected to sanding, scraping, grindstone polishing, and buffing, and then is heated in the atmosphere or in an oxidizing atmosphere higher or lower than the oxygen partial pressure of the atmosphere. Usually 850-950
After heating at ℃ for about 20 to 30 minutes, cool in air, oil, or water.

The heating process for the gold alloy described above may be carried out in the atmosphere, and the heating temperature can be arbitrarily changed as long as it is below the melting point of each alloy, and the heating time can also be arbitrarily changed.

If the black gloss formed on the surface is insufficient after the above-mentioned blackening treatment is completed, lightly buff the surface again and then turn off the flame of a gas burner using city gas, propane gas, etc. Sufficient gloss can be generated by applying it to the surface of the product for a short time and polishing it by buffing.

By the way, the black coloring treatment by heating of the present invention varies depending on the size of the processed product, but it can be applied over a fairly wide range, and the heating temperature is about 800 to 1000°C in the air, and the heating time can be varied. The longer it is, the thicker the blackening layer becomes, so the degree of blackening increases, but for small items such as rings and brooches, it is 15 to 20
30 to 40 minutes seems to be enough for slightly larger fish.

<Example> Examples are shown below.

(A) One or more of Pt, Pd, Rh, Ir, Ru, and Os is added to gold (Au), and Cu,
For alloys containing one or more of Fe, Co, and Ti.

Example 1 Au alloy composition Pure Au 75g Pure Pd 10g Electrolytic Fe 15g The above composition was melted by arc melting in an argon gas atmosphere. Using a mold made of this alloy by the lost wax method under vacuum,
After finishing the surface by filing and polishing the cast product (ring) obtained by centrifugal casting, it is placed in the atmosphere.
After soaking at 900°C for 15 minutes for color development, the mixture was cooled with water. Thereafter, when the product was buffed again, a beautiful, shiny black product was obtained. The thickness of the blackening layer formed by the coloring treatment is 3 to 3.
The composition that forms the blackening layer is Au,
It was an oxide of Fe ₃ O ₄ containing Pd.

Example 2 Composition of Au alloy Pure Au 75g Pure Pd 10g Electrolytic Co 15g The cast product (ring) obtained by melting and casting in the same manner as Example 1 was soaked in the air at 850°C for 20 minutes. After that, the product was air cooled to blacken the entire surface layer of the product. The black layer had a thickness of about 2 to 3 μm, and most of the composition of the black layer was CoO containing Au and Pd.

Example 3 Composition of Au alloy Pure Au 75g Pure Pd 17g Pure Ti 8g The cast product (ring) obtained by melting and casting in the same manner as Example 1 was soaked in the air at 850°C for 20 minutes. After that, the product was air cooled to blacken the entire surface layer of the product. The black layer had a thickness of about 2 to 3 μm, and the composition of the black layer was a low-order oxide of TiO ₂ containing Au and Pd.

Example 4 Au alloy composition Pure Au 84g Pure Ru 6g Oxygen-free Cu 10g The cast product (ring) obtained by melting and casting in the same manner as Example 1 was equalized in the air at 800℃ for 20 minutes. After heating, the product was air cooled to blacken the entire surface layer of the product. The black layer had a thickness of about 3 to 4 μm, and the composition of the black layer was CuO containing Au and Pt.

Example 5 Composition of Au alloy Pure Au 75g Pure Rh 5g Electrolytic Fe 20g The cast product (ring) obtained by melting and casting in the same manner as Example 1 was soaked in the air at 850°C for 20 minutes. After that, the product was air cooled to blacken the entire surface layer of the product. The black layer had a thickness of about 3 to 4 μm, and most of the composition of the black layer was Fe ₃ O ₄ containing Au and Rh.

Example 6 Au alloy composition Pure Au 59g Pure Pd 26g Electrolytic Co 5g Electrolytic Fe 10g A cast product (ring) obtained by melting and casting in the same manner as in Example 1 was heated at 900°C in the air for 15 minutes. After soaking for a minute, the product was air cooled to blacken the entire surface layer of the product. The thickness of the black layer was about 3 to 4 μm, and the composition of the black layer was a composite oxide of Fe ₃ O ₄ containing Au and Pd.

Example 7 Au alloy composition Pure Au 75g Pure Pt 5g Electrolytic Co 15g Pure Ti 5g The cast product (ring) obtained by melting and casting in the same manner as Example 1 was heated at 900℃ in the air for 15 minutes. After soaking for a minute, the product was air cooled to blacken the entire surface layer of the product. The black layer had a thickness of about 2 to 3 μm, and the composition of the black layer was a composite oxide of CoC containing Au and Pt and a lower oxide of TiO ₂ .

Example 8 Au alloy composition Pure Au 42g Pure Pd 43g Electrolytic Co 10g Oxygen-free Cu 5g The cast product (ring) obtained by melting and casting in the same manner as in Example 1 was heated at 800°C in the atmosphere. After soaking for 20 minutes, the product was air cooled to blacken the entire surface layer of the product. The thickness of the black layer was about 3 to 4 μm, and the composition of the black layer was a composite oxide of CoO and CuO containing Au and Pd.

Example 9 Au alloy composition Pure Au 75g Pure Pt 5g Electrolytic Fe 10g Oxygen-free Cu 10g The cast product (ring) obtained by melting and casting in the same manner as in Example 1 was heated at 850°C in the atmosphere. After soaking for 20 minutes, the product was air cooled to blacken the entire surface layer of the product. The black layer had a thickness of about 3 to 4 μm, and the composition of the black layer was a composite oxide of Fe ₃ O ₄ and CuO containing Au and Pt.

Example 10 Au alloy composition Pure Au 75g Pure Pt 5g Pure Pd 10g Electrolytic Co 10g Au-Pt-Pd was made by the same melting method as Example 1.
-Co alloy was obtained. Thereafter, a cast product (ring) obtained by performing centrifugal casting using this alloy was heat-treated at 900°C for 15 minutes in the air to develop a black color, and then cooled with water. The thickness of the blackened layer was about 3 to 4 μm, and it was beautiful.

Example 11 Composition of Au alloy Pure Au 59g Pure Pd 24g Pure Rh 2g Electrolytic Co 5g Electrolytic Fe 10g The same coloring treatment as in Example 1 was performed by melting, casting, and heating. The thickness of the blackening layer is about 3 to 4μm, and the blackening layer contains Ag, Co, including Au, Pd, and Rh.
It was a composite oxide of Fe and Ti.

Example 12 Au alloy composition Pure Au 75g Pure Pd 10g Oxygen-free Cu 5g Electrolytic Co 10g The same coloring treatment as in Example 1 was performed by melting, casting, and heating, and the blackened layer was 3 to 4 μm thick and beautiful. It was hot.

Example 13 Composition of Au alloy Pure Au 75g Pure Pd 12.5g Pure Ir 2g Oxygen-free Cu 5g Electrolytic Fe 5.5g The same coloring treatment as in Example 1 was performed by melting, casting, and heating, and the blackening layer was 3~ It was 4 μm and beautiful.

Example 14 Composition of Au alloy Pure Au 84g Pure Ru 3g Pure Pd 8g Oxygen-free Cu 5g Coloring treatment was performed by melting, casting, and heating in the same manner as in Example 1. The blackened layer was 3 to 4 μm thick and beautiful. It was hot.

Example 15 Au alloy composition Pure Au 75g Pure Pd 10g Non-breathing Cu 5g Electrolytic Co 5g Electrolytic Fe 5g The same coloring treatment as in Example 1 was carried out by melting, casting, and heating, and the blackening layer was 3 to 4 μm thick. And it was beautiful.

Example 16 Au alloy composition Pure Au 75g Pure Pd 10g Oxygen-free Cu 5g Electrolytic Co 8g Pure Ti 2g Coloring treatment was performed by melting, casting, and heating in the same manner as in Example 1, and the blackening layer was 3 to 4 μm thick. Yes, it was beautiful and warm.

Example 17 Au alloy composition Pure Au 59g Pure Pt 19g Pure Pd 15g Oxygen-free Cu 5g Pure Ti 2g Coloring treatment was performed by melting, casting, and heating in the same manner as in Example 1, and the blackening layer was 3 to 4 μm thick. Yes, it was beautiful.

Example 18 Au alloy composition Pure Au 75g Pure Pd 5g Oxygen-free Cu 5g Electrolytic Co 10g Electrolytic Fe 5g The same coloring treatment as in Example 1 was carried out by melting, casting, and heating, and the blackening layer was 3 to 4 μm thick. Yes, it was beautiful and warm.

Example 19 Au alloy composition Pure Au 75g Pure Pt 1g Oxygen-free Cu 3g Electrolytic Co 20g Pure Ti 1g The same coloring treatment as in Example 1 was carried out by melting, casting, and heating, and the blackening layer was 3 to 4 μm thick. Yes, it was beautiful and warm.

Example 20 Au alloy composition Pure Au 75g Pure Pd 8g Oxygen-free Cu 2g Electrolytic Co 10g Electrolytic Fe 10g Pure Ti 1g The blackening layer was 3, which was subjected to coloring treatment by melting, casting, and heating as in Example 1. It was ~4 μm and beautiful.

Example 21 Au alloy composition Pure U 84g Pure Pd 2g Electrolytic Co 10g Oxygen-free Cu 3g Pure Zn 1g Coloring treatment was performed by melting, casting, and heating in the same manner as in Example 1, and the blackening layer was 3 to 4 μm thick. Yes, it was beautiful and warm.

(B) Gold (Au), one or two of Ag and Ni
Pt, Pd, Rh, Ir,
For alloys containing one or more of Ru and Os, and one or more of Cu, Fe, Co, and Ti.

Example 22 Au alloy composition Pure Au 75g Pure Ag 5g Pure Pd 5g Electrolytic Co 15g Coloring treatment was performed by melting, casting, and heating in the same manner as in Example 1, and the blackening layer was 3 to 4 μm and beautiful. It was hot.

Example 23 Au alloy composition Pure Au 75g Electrolytic Ni 8g Pure Pd 6g Electrolytic Fe 10g Pure Ti 1g The same coloring treatment as in Example 1 was carried out by melting, casting, and heating, and the blackening layer was 3 to 4 μm. , it was beautiful and warm.

Example 24 Au alloy composition Pure Au 59g Pure Ag 15g Electrolytic Ni 5g Pure Pd 16g Pure Ti 5g The same coloring treatment as in Example 1 was performed by melting, casting, and heating, and the blackening layer was 3 to 4 μm. , it was beautiful and warm.

Example 25 Composition of Au alloy Pure Au 75g Pure Ag 6g Pure Pt 1g Pure Pd 2g Electrolytic Co 6g Electrolytic Fe 10g The blackening layer was 3 to 3, which was subjected to coloring treatment by melting, casting, and heating in the same manner as in Example 1. It was 4 μm and beautiful.

Example 26 Composition of Au alloy Pure Au 84g Pure Ag 3g Pure Pt 2g Pure Pd 3g Electrolytic Ni 3g Electrolytic Co 5g The blackening layer was 3~ It was 4 μm and beautiful.

Example 27 Au alloy composition Pure Au 75g Pure Ag 5g Electrolytic Ni 3g Pure Pd 6g Electrolytic Fe 5g Electrolytic Co 5g Pure Ti 1g Blackened layer subjected to coloring treatment by melting, casting, and heating in the same manner as in Example 1 It was 3 to 4 μm and beautiful.

Example 28 Au alloy composition Pure Au 75g Pure Ag 5g Pure Pd 5g Electrolytic Co 10g Oxygen-free Cu 4g Pure Zn 1g The blackening layer was 3, which was subjected to coloring treatment by melting, casting, and heating in the same manner as in Example 1. It was ~4 μm and beautiful.

Example 29 Au alloy composition Pure Au 38g Electrolytic Ni 38g Pure Pd 13g Electrolytic Fe 10g Pure Ti 1g The same coloring treatment as in Example 1 was performed by melting, casting, and heating, and the blackening layer was 8 to 10 μm. , it was beautiful and warm.

Example 30 Au alloy composition Pure Au 38g Pure Ag 40g Pure Pt 12g Electrolytic Co 7g Oxygen-free Cu 3g The same coloring treatment as in Example 1 was performed by melting, casting, and heating, and the blackening layer was 8 to 10 μm thick. Yes, it was beautiful and warm.

Example 31 Au alloy composition Pure Au 38g Pure Ag 35g Pure Pd 15g Electrolytic Co 6g Oxygen-free Cu 5g Pure Zn 1g The blackening layer was 8, which was subjected to coloring treatment by melting, casting, and heating in the same manner as in Example 1. It was ~10 μm and beautiful.

Above, we have mainly described examples for 18K (karat) Au alloys, but we can also apply heating to noble metal products of Au alloys in which the added elements and amounts have been adjusted within the ranges shown in the configuration of the present invention. By applying the treatment, it is possible to obtain a blackened product.

<Effects of the Invention> As explained above, the gold alloy of the present invention adds black to the conventional Au alloy, which has five colors of red, yellow, yellow-green, white, and purple, and is suitable for precious metal ornaments. As well as allowing for more diverse designs,
This leads to higher added value for decorative items.

Furthermore, the method for producing a gold alloy that is colored bright black according to the present invention does not require special raw materials or processing equipment, and therefore has extremely high practicality.

Claims (1)

[Scope of Claims] 1 (A) Pure gold (Au) or having a gold content of 38% by weight or more, silver (Ag), nickel (Ni), platinum group elements (Pt, Pd, Rh, Ir, Ru , Os)
(B) Copper (Cu) in an amount of 3 to 20% by weight based on the total amount, iron (Fe) in an amount of 3 to 20% by weight based on the total amount, and 3 to 2% by weight based on the total amount. % cobalt (Co), 1 to 10% by weight of titanium (Ti), and the total amount of elements other than gold does not exceed 62% by weight. After heat treatment in the atmosphere or in an oxidizing atmosphere higher or lower than the oxygen partial pressure of the atmosphere at a temperature below the melting point, the alloy is cooled in air, water or oil, and then the entire or part of the surface layer of the processed alloy is heated. A gold alloy colored bright black, characterized by the formation of a black oxide layer. 2 (A) Pure gold (Au) or gold content of 38% by weight or more and one of silver (Ag), nickel (Ni), or platinum group elements (Pt, Pd, Rh, Ir, Ru, Os)
(B) Copper (Cu) in an amount of 3 to 20% by weight based on the total amount, iron (Fe) in an amount of 3 to 20% by weight based on the total amount, and 3 to 20% by weight based on the total amount % cobalt (Co), 1 to 10% by weight of titanium (Ti), and the total amount of elements other than gold does not exceed 62% by weight. After heat treatment in the atmosphere or in an oxidizing atmosphere higher or lower than the oxygen partial pressure of the atmosphere at a temperature below the melting point, the entire or part of the surface layer of the processed alloy is cooled by air, water or oil cooling. A method for coloring a gold alloy to a bright black color, characterized by forming a black oxide layer. 3 (A) Pure gold (Au) or gold content of 38% by weight or more and one of silver (Ag), nickel (Ni), or platinum group elements (Pt, Pd, Rh, Ir, Ru, Os)
(B) Copper (Cu) in an amount of 3 to 20% by weight based on the total amount, iron (Fe) in an amount of 3 to 20% by weight based on the total amount, and 3 to 20% by weight based on the total amount % of cobalt (Co), one or more of titanium (Ti) of 1 to 10% by weight based on the total amount, and (C) zinc (Zn) of 0.5 to 5% by weight based on the total amount, An alloy in which the total amount of elements other than gold does not exceed 62% by weight is heat-treated in the atmosphere or in an oxidizing atmosphere higher or lower than the oxygen partial pressure of the atmosphere at a temperature below the melting point of the alloy, and then air-cooled. A gold alloy colored in bright black, characterized by forming a black oxide layer on the whole or part of the surface layer of a processed alloy product by water cooling or oil cooling. 4 (A) Pure gold (Au) or gold content of 38% by weight or more and one of silver (Ag), nickel (Ni), or platinum group elements (Pt, Pd, Rh, Ir, Ru, Os)
(B) Copper (Cu) in an amount of 3 to 20% by weight based on the total amount, iron (Fe) in an amount of 3 to 20% by weight based on the total amount, and 3 to 20% by weight based on the total amount % of cobalt (Co), one or more of titanium (Ti) of 1 to 10% by weight based on the total amount, and (C) zinc (Zn) of 0.5 to 5% by weight based on the total amount, An alloy in which the total amount of elements other than gold does not exceed 62% by weight is heat-treated in the atmosphere or in an oxidizing atmosphere higher or lower than the oxygen partial pressure of the atmosphere at a temperature below the melting point of the alloy, and then air-cooled. A method for coloring a gold alloy to a bright black color, characterized by forming a black oxide layer on the whole or part of the surface layer of a processed alloy product by water cooling or oil cooling.