CN105087997B - A kind of red billon and preparation method thereof for firing temperature resistant transparent enamel - Google Patents

Abstract

The invention discloses a red gold alloy for firing high-temperature transparent enamel and a preparation method thereof. A red gold alloy for firing high-temperature transparent enamel, which is composed of the following components: 75.0-75.5wt% gold, 22.5-23.2wt% copper, 0.9-1.2wt% silver, 0.5-0.8wt% zinc, 0.2 ‑0.4wt% palladium, 0.01‑0.03wt% silicon, 0.008‑0.02wt% scandium, 0.0005‑0.001wt% boron, and other unavoidable impurities. The method for preparing red gold alloy for firing high-temperature transparent enamel is characterized in that the steps are: 1) smelting the raw materials in a protective atmosphere; 2) after all the materials are melted, adjust the temperature of the molten metal, and cast to obtain a cast iron ingot. The red gold alloy of the invention has good high temperature oxidation resistance, can better withstand high temperature firing; the thermal expansion coefficient is close to the thermal expansion coefficient of common high temperature glazes for gold; it has excellent cold working performance, and no brittle fracture occurs during processing Phenomenon; the grains are fine and the structure is dense, which is conducive to obtaining a highly polished surface.

Description

A kind of red gold alloy for firing high temperature transparent enamel and preparation method thereof

technical field

The invention relates to a red gold alloy used for firing high-temperature transparent enamel and a preparation method thereof.

Background technique

In the K gold series, K red gold, compared with gorgeous gold and low-key white gold, has become a fashionable fashion in today's international jewelry industry, especially in eastern countries, because of its gorgeous and elegant color. According to its unique color, industry insiders give this material a romantic name called rose gold, which represents the eternal theme of human beings---love. The application of enamel technology to rose gold jewelry can significantly increase the artistic effect of the jewelry. However, when using rose gold, which is common on the market, as the base for firing high-temperature enamel, several prominent problems are often encountered: First, the alloy material is fired at high temperature. The surface oxidation after making is very serious, which affects the decorative effect of enamel, as shown in Figure 1; the second is that the metal base after firing enamel becomes brittle, and it is prone to fracture in the subsequent grinding, stone setting, polishing and other processes, and alloys are prone to fracture when the brittleness is serious. It is easy to fold like dry wood, as shown in Figure 2. It is completely different from precious metal alloys with excellent toughness and plasticity, which brings great trouble and difficulty to jewelry production; third, rose gold jewelry is used or placed for a period of time, and the surface is easy to dull and discolor. , there is no initial brightness and color; Fourth, when casting rose gold jewelry, the problem of surface shrinkage is often encountered, which seriously deteriorates the surface quality of the jewelry, as shown in Figure 3. Especially when shrinkage occurs on the glazed surface of the base, it will seriously affect the decorative effect of the enamel, causing the color of the enamel layer to be cloudy or burst. When there is a large-scale shrinkage problem in jewelry, such as welding or grinding and polishing, the workload is heavy, time-consuming, and the effect is poor. In many cases, only the jewelry is scrapped, which affects the production progress and cost of the enterprise.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a red gold alloy for firing high temperature transparent enamel and a preparation method thereof.

The technical scheme adopted by the present invention is:

A red gold alloy for firing high temperature transparent enamel, which is composed of the following components: 75.0-75.5wt% gold, 22.5-23.2wt% copper, 0.9-1.2wt% silver, 0.5-0.8wt% zinc, 0.2 -0.4wt% palladium, 0.01-0.03wt% silicon, 0.008-0.02wt% scandium, 0.0005-0.001wt% boron, and other unavoidable impurities.

It is made of the following raw materials by mass percentage: 1-2wt% copper-scandium alloy, 5-8wt% copper-palladium alloy, 0-11wt% silver-copper alloy, 0-1wt% silver-zinc alloy, 1-3wt% copper-silicon alloy , 0-1wt% pure silver, 4.5-11.5wt% copper-zinc alloy, 0.4-0.5wt% copper boron alloy, 2-7wt% pure copper, 75.0-75.5wt% pure gold.

In the silver-copper alloy, the content of silver is 5wt%.

In the copper-palladium alloy, the content of palladium is 5wt%.

In the copper-scandium alloy, the content of scandium is 1wt%.

In the copper-silicon alloy, the content of silicon is 1wt%; in the silver-zinc alloy, the content of zinc is 30wt%.

The preparation method of the red gold alloy for firing high temperature transparent enamel comprises the following steps:

1) Smelting the raw materials in a protective atmosphere;

2) After all the materials are melted, adjust the temperature of the molten metal and cast to obtain an ingot;

3) After rolling the ingot, annealing.

In step 1), the protective atmosphere is industrial pure argon.

In step 1), smelting is performed in an induction furnace, and the smelting temperature is 1020-1040°C.

In step 2), the temperature of the molten metal is adjusted to 1010-1030°C.

The beneficial effects of the present invention are:

(1) The red gold alloy of the present invention has good high-temperature oxidation resistance, can better withstand high-temperature firing, the fired transparent enamel layer has good transparency, and after repeated firing for several times, the crystal grains are not grow up.

(2) The thermal expansion coefficient of the red gold alloy of the present invention is close to the thermal expansion coefficient of the common high-temperature glaze for gold, which makes the fired enamel layer more stable and less prone to problems such as bursting and peeling.

(3) The red gold alloy of the present invention has excellent cold working properties, and no brittle fracture occurs during the processing.

(4) The red gold alloy of the present invention has fine grains and dense organization, which is beneficial to obtain a highly polished surface.

Description of drawings

Figure 1 is a physical picture of the serious oxidation of the commercially available 18K rose gold when firing enamel;

Figure 2 is the actual picture of the brittle fracture in the grinding process after the enamel is fired in commercially available 18K rose gold;

Figure 3 is a physical map of the surface shrinkage of commercially available 18K rose gold;

Figure 4 is the microstructure (300×) of the 18K red gold alloy of the present invention;

Figure 5 is the polarization curve of the 18K red gold alloy of the present invention in artificial sweat at 37°C;

Fig. 6 is the reflectance curve of the 18K red gold alloy of the present invention after being soaked in sodium sulfide solution for 1 hour;

Figure 7 is a comparison diagram of the oxide film of the 18K red gold alloy of the present invention and a commercially available 18K red gold alloy after heating at 750°C for 1.5 hours (200×);

Fig. 8 is the temperature thermal expansion curve of the 18K red gold alloy of the present invention;

FIG. 9 is the cold work hardening curve of the 18K red gold alloy of the present invention.

Detailed ways

A red gold alloy for firing high temperature transparent enamel, which is composed of the following components: 75.0-75.5wt% gold, 22.5-23.2wt% copper, 0.9-1.2wt% silver, 0.5-0.8wt% zinc, 0.2 -0.4wt% palladium, 0.01-0.03wt% silicon, 0.008-0.02wt% scandium, 0.0005-0.001wt% boron, and other unavoidable impurities.

It is made of the following raw materials by mass percentage: 1-2wt% copper-scandium alloy, 5-8wt% copper-palladium alloy, 0-11wt% silver-copper alloy, 0-1wt% silver-zinc alloy, 1-3wt% copper-silicon alloy , 0-1wt% pure silver, 4.5-11.5wt% copper-zinc alloy, 0.4-0.5wt% copper boron alloy, 2-7wt% pure copper, 75.0-75.5wt% pure gold.

Preferably, in the raw materials used in the present invention (including the embodiments): in the silver-copper alloy, the content of silver is 5wt%; in the copper-palladium alloy, the content of palladium is 5wt%; the copper-scandium In the alloy, the content of scandium is 1wt%; in the copper-silicon alloy, the content of silicon is 1wt%; in the silver-zinc alloy, the content of zinc is 30wt%.

The preparation method of the red gold alloy for firing high temperature transparent enamel comprises the following steps:

1) Smelting the raw materials in a protective atmosphere;

2) After all the materials are melted, adjust the temperature of the molten metal and cast to obtain an ingot;

3) After rolling the ingot, annealing.

Preferably, in step 1), the protective atmosphere is industrial pure argon.

Preferably, step 1) is: rolling pure gold into thin sheets, wrapping silver-scandium alloy, silver-palladium alloy, silver-copper alloy, copper-zinc alloy, copper-silicon alloy, pure silver with it, putting it into a graphite crucible, and placing it in a protective atmosphere The smelting temperature is 1020-1040 ℃ by induction heating;

Preferably, in step 2), the temperature of the molten metal is adjusted to 1010-1030°C.

Preferably, the annealing treatment is: annealing at 700-800° C. for 3-10 minutes.

Below in conjunction with specific embodiment, the present invention will be further described:

Example 1:

The red gold alloy used for firing high-temperature enamel in this embodiment is composed of the following components by mass percentage:

75.20wt% gold, 22.87wt% copper, 1.07wt% silver, 0.53wt% zinc, 0.30wt% palladium, 0.015wt% silicon, 0.013wt% scandium, 0.0008wt% boron, and other inevitable impurities.

The preparation method of this embodiment comprises the following steps:

Smelting in a vacuum induction furnace, the mass percentages of the raw materials are: 1.3wt% copper-scandium alloy, 6wt% copper-palladium alloy, 7.3wt% copper-silver alloy, 1.5wt% copper-silicon alloy, 0.7wt% pure silver, 7.6wt% copper-zinc alloy, 0.4wt% copper-boron alloy, 75.2wt% pure gold. Put the above materials into a graphite crucible in turn, fill it tightly and close the furnace cover, evacuate to 4.4Pa, and fill with industrial pure argon to 1.01atm. Start induction heating for smelting, and the smelting temperature is 1030-1040 ℃. After the charge is completely melted, the molten metal temperature is adjusted to 1020-1030°C, and the molten metal is poured into the ingot mold to obtain an ingot. After rolling the ingot, it was annealed at 750°C for 5 minutes.

The 18K red gold alloy prepared in this example has no obvious shrinkage defects, and the annealed microstructure is shown in Figure 4. The alloy structure is dense and fine equiaxed crystals, which is beneficial to the strength and polishing properties of the material.

The initial color coordinate values L*, a*, b* of the 18K red gold alloy prepared in this example are 85.93, 9.94 and 16.21, respectively, which are located in the red gold alloy area of the color zone diagram, showing a good red color. The polarization behavior of the alloy in artificial sweat at 37 °C is shown in Figure 5. The alloy has obvious passivation during the potential scanning process, resulting in a high passivation potential. The alloy suspension was immersed in a sodium sulfide solution with a concentration of 5% and a temperature of 30 ° C for corrosion test. After 1 hour of etching, it appeared reddish and yellowish relative to its initial color, the brightness decreased, and the reflectance did not change significantly, such as Figure 6 shows no color difference to the naked eye, indicating that the alloy has good corrosion resistance and discoloration resistance.

The comparison of the oxide film of the 18K red gold alloy prepared in this example and the commercially available 18K red gold alloy after heating at 750° C. for 1.5 hours is shown in Figure 7. The oxide film layer of the alloy of the present invention is very thin and dense in structure, which plays an effective role. It has a protective effect to prevent the internal metal from continuing to oxidize, and has better anti-oxidation performance at high temperature, and the oxide film layer of the commercially available alloy is obviously thicker than that of the alloy of the present invention.

The melting temperature range of the 18K red gold alloy of the present invention is 905-918 DEG C, which can better withstand the firing temperature of enamel. When the temperature is between 38-828°C, the temperature thermal expansion curve of the alloy is shown in Figure 8, which is close to the thermal expansion coefficient of common high-temperature glazes for gold, so it is conducive to the combination of the enamel surface and the substrate, and is not prone to bursting or peeling, etc. question.

The annealed hardness of the 18K red gold alloy prepared in this example is HV185, and the cold working curve is shown in Figure 9, showing good workability and no brittle fracture.

The transparent enamel inlaid jewelry made of the 18K red gold alloy of the invention as the base has high transparency of the enamel layer, clearly visible texture of the base, few bubbles, stable combination with the base, and firm inlaid gemstones.

Example 2:

The red gold alloy used for firing high-temperature enamel in this embodiment is composed of the following components by mass percentage:

75.0wt% gold, 1.13wt% silver, 23.06wt% copper, 0.51wt% zinc, 0.26wt% palladium, 0.028wt% silicon, 0.020wt% scandium, 0.0010wt% boron, and other inevitable impurities.

The preparation method of this embodiment comprises the following steps:

Smelting in a vacuum induction furnace, the mass percentages of the raw materials are: 2wt% copper-scandium alloy, 5.1wt% copper-palladium alloy, 6.5wt% copper-silver alloy, 2.8wt% copper-silicon alloy, 0.8wt% pure silver, 7.3wt% copper-zinc alloy, 0.5wt% copper-boron alloy, 75.0wt% pure gold. The above materials were put into the graphite crucible in turn, filled tightly and closed the furnace cover, vacuumed to 4.7Pa, and filled with industrial pure argon to 1.02atm. Start induction heating for smelting, and the smelting temperature is 1020-1030 °C. After the charge is completely melted, the molten metal temperature is adjusted to 1010-1020°C, and the molten metal is poured into the ingot mold to obtain an ingot. After rolling the ingot, it was annealed at 750°C for 5 minutes.

Example 3:

The red gold alloy used for firing high-temperature enamel in this embodiment is composed of the following components by mass percentage:

75.5wt% gold, 0.90wt% silver, 22.64wt% copper, 0.60wt% zinc, 0.30wt% palladium, 0.030wt% silicon, 0.016wt% scandium, 0.0010wt% boron, and other inevitable impurities.

The preparation method of this embodiment comprises the following steps:

Smelting in a vacuum induction furnace, the mass percentages of the raw materials are: 1.6wt% copper-scandium alloy, 6wt% copper-palladium alloy, 4wt% copper-silver alloy, 3wt% copper-silicon alloy, 0.7wt% pure silver, 8.7wt% % copper-zinc alloy, 0.5wt% copper-boron alloy, 75.5wt% pure gold. Put the above materials into a graphite crucible in turn, fill it tightly and close the furnace cover, evacuate to 4.8Pa, and fill with industrial pure argon to 1.0atm. Start induction heating for smelting, and the smelting temperature is 1030-1040 ℃. After the charge is completely melted, the molten metal temperature is adjusted to 1020-1030°C, and the molten metal is poured into the ingot mold to obtain an ingot. After rolling the ingot, it was annealed at 750°C for 5 minutes.

Example 4:

The red gold alloy used for firing high-temperature enamel in this embodiment is composed of the following components by mass percentage:

75.10wt% gold, 0.97wt% silver, 23.18wt% copper, 0.50wt% zinc, 0.20wt% palladium, 0.027wt% silicon, 0.015wt% scandium, 0.0008wt% boron, and other inevitable impurities.

The preparation method of this embodiment comprises the following steps:

Smelting in a vacuum induction furnace, the mass percentages of the raw materials are: 1.5wt% copper-scandium alloy, 4wt% copper-palladium alloy, 11wt% copper-silver alloy, 0.6wt% silver-zinc alloy, 2.7wt% copper-silicon alloy, 4.7wt% copper-zinc alloy, 0.4wt% copper-boron alloy, 75.1wt% pure gold. Put the above materials into a graphite crucible in turn, fill it tightly and close the furnace cover, evacuate to 4.6Pa, and fill with industrial pure argon to 0.99atm. Start induction heating for smelting, and the smelting temperature is 1020-1030 °C. After the charge is completely melted, the molten metal temperature is adjusted to 1010-1020°C, and the molten metal is poured into the ingot mold to obtain an ingot. After rolling the ingot, it was annealed at 750°C for 5 minutes.

Example 5:

The red gold alloy used for firing high-temperature enamel in this embodiment is composed of the following components by mass percentage:

75.40wt% gold, 0.90wt% silver, 22.51wt% copper, 0.78wt% zinc, 0.39wt% palladium, 0.010wt% silicon, 0.011wt% scandium, 0.0008wt% boron, and other inevitable impurities.

The preparation method of this embodiment comprises the following steps:

Smelting in a vacuum induction furnace, the mass percentages of the raw materials are: 1.1wt% copper-scandium alloy, 7.7wt% copper-palladium alloy, 1wt% copper-silicon alloy, 0.9wt% pure silver, 11.2wt% copper-zinc alloy, 0.4wt% copper boron alloy, 2.3wt% pure copper, 75.4wt% pure gold. The above materials were put into the graphite crucible in turn, filled tightly and closed the furnace cover, evacuated to 5.0Pa, and filled with industrial pure argon to 1.0atm. Start induction heating for smelting, and the smelting temperature is 1030-1040 ℃. After the charge is completely melted, the molten metal temperature is adjusted to 1020-1030°C, and the molten metal is poured into the ingot mold to obtain an ingot. After rolling the ingot, it was annealed at 750°C for 5 minutes.

Example 6:

The red gold alloy used for firing high-temperature enamel in this embodiment is composed of the following components by mass percentage:

75.30wt% gold, 0.95wt% silver, 22.92wt% copper, 0.55wt% zinc, 0.25wt% palladium, 0.014wt% silicon, 0.010wt% scandium, 0.0010wt% boron, and other inevitable impurities.

The preparation method of this embodiment comprises the following steps:

Smelting in a vacuum induction furnace, the mass percentages of the raw materials are: 1wt% copper-scandium alloy, 5wt% copper-palladium alloy, 1wt% copper-silver alloy, 1.4wt% copper-silicon alloy, 0.9wt% pure silver, 8wt% Copper-zinc alloy, 0.5wt% copper boron alloy, 6.9wt% pure copper, 75.3wt% pure gold. Put the above materials into a graphite crucible in turn, fill it tightly and close the furnace cover, evacuate to 4.8Pa, and fill with industrial pure argon to 1.0atm. Start induction heating for smelting, and the smelting temperature is 1020-1030 °C. After the charge is completely melted, the molten metal temperature is adjusted to 1010-1020°C, and the molten metal is poured into the ingot mold to obtain an ingot. After rolling the ingot, it was annealed at 750°C for 5 minutes.

Claims (10)

1. a red gold alloy for firing high-temperature transparent enamel, characterized in that: it is composed of the following components: 75.0-75.5wt% gold, 22.5-23.2wt% copper, 0.9-1.2wt% silver, 0.5- 0.8wt% zinc, 0.2-0.4wt% palladium, 0.01-0.03wt% silicon, 0.008-0.02wt% scandium, 0.0005-0.001wt% boron, and other inevitable impurities. 2. a kind of red gold alloy for firing high temperature transparent enamel according to claim 1, is characterized in that: it is made of the raw material of following mass percentage: 1-2wt% copper-scandium alloy, 5-8wt% Copper-palladium alloy, 0-11wt% silver-copper alloy, 0-1wt% silver-zinc alloy, 1-3wt% copper-silicon alloy, 0-1wt% pure silver, 4.5-11.5 wt% copper-zinc alloy, 0.4-0.5 wt% copper Boron alloy, 2-7 wt% pure copper, 75.0-75.5 wt% pure gold. 3 . The red gold alloy for firing high temperature transparent enamel according to claim 2 , wherein: in the silver-copper alloy, the content of silver is 5wt%. 4 . 4. A kind of red gold alloy for firing high temperature transparent enamel according to claim 2, is characterized in that: in described copper-palladium alloy, the content of palladium is 5wt%. 5. A red gold alloy for firing high temperature transparent enamel according to claim 2, characterized in that: in the copper-scandium alloy, the content of scandium is 1wt%. 6. A red gold alloy for firing high temperature transparent enamel according to claim 2, characterized in that: in the copper-silicon alloy, the content of silicon is 1wt%; in the silver-zinc alloy, the content of zinc is 30wt%. 7. the preparation method of the red gold alloy for firing high temperature transparent enamel described in any one of claim 1-6, is characterized in that: step is: 1) Smelting the raw materials in a protective atmosphere; 2) After all the materials are melted, adjust the temperature of the molten metal and cast to obtain an ingot; 3) After rolling the ingot, annealing. 8 . The method for preparing red gold alloy for firing high temperature transparent enamel according to claim 7 , wherein in step 1), the protective atmosphere is industrial pure argon. 9 . 9 . The preparation method of red gold alloy for firing high temperature transparent enamel according to claim 7 , wherein: in step 1), smelting is performed in an induction furnace, and the smelting temperature is 1020-1040° C. 10 . 10 . The method for preparing red gold alloy for firing high temperature transparent enamel according to claim 7 , wherein: in step 2), the temperature of the molten metal is adjusted to 1010-1030° C. 11 .