KR20190131931A - Eco-friendly green gold alloy material - Google Patents

Abstract

The present invention relates to an environmentally friendly green gold alloy material. More specifically, the present invention relates to the environmentally friendly green gold alloy material which greatly improves a green color and brightness by mixing proportionally a predetermined amount of In into an Au-Ag-Cu ternary alloy system by replacing Cd which is a substance harmful to the human body, secures a lower melting point, increases hardness, and realizes a perfect bonding with other precious metals, thereby having excellent gloss. The present invention comprises: 58.5-75.0 wt% of gold (Au); 15.0-33.0 wt% of silver (Ag); 4.5-9.5 wt% of copper (Cu); and 4.0-6.0 wt% of indium (In).

Description

Eco-Friendly Green Gold Alloy Material {ECO-FRIENDLY GREEN GOLD ALLOY MATERIAL}

The present invention relates to an environmentally friendly green gold alloy material, and more specifically, by replacing a predetermined amount of In to the Au-Ag-Cu ternary alloy system in place of Cd, a substance harmful to a human body, greatly improving green color and brightness. The present invention relates to a green gold alloy material of environmentally friendly materials that can secure a lower melting point, increase hardness, realize perfect bonding with other precious metals, and give excellent gloss.

Jewelry, such as gold rings, is made of precious metals as an accessory, and many people want to wear it, but it is very expensive, and once purchased, it is often left in the drawer after the user gets tired or has passed the trend. On the other hand, when they want to sell it, they often do not receive the price and have to dispose of it at a low price. As a result, consumers are experiencing a significant burden on the purchase of precious metal accessories such as gold jewelry.

Accordingly, there have been attempts to create new value by applying a variety of luxurious colors to precious metal materials, such as used or trended precious metal accessories and silver, which are relatively inexpensive. For example, [C. Cretu, and EV Llngen, "Coloured gold alloys", Gold bulletin 32 (4): 115-126 (1999)] used 18K alloys containing cadmium (Cd) to add gold to existing precious metal materials. The introduction of color is disclosed.

However, the technology of introducing a green gold color to the precious metal of the processing technology of the precious metal material has not developed much yet.

On the other hand, in the case of the prior document has a big disadvantage to use cadmium (Cd), which is a harmful heavy metal to the human body, there is a problem that the environmental friendliness is poor, green color expression quality is not good.

C. Cretu, and E. V. Llngen, "Coloured gold alloys", Gold bulletin 32 (4): 115-126 (1999).

The present invention is to solve the problems of the prior art as described above, while eliminating the use of Cd, a substance harmful to the human body, greatly improves the green color and brightness, and is required such as low melting point, high hardness, adhesion and gloss It is a technical task to provide a new type of eco-friendly green gold alloy material that can harmonize the physical properties.

In order to achieve the above technical problem, the present invention is a gold (Au) 58.5 ~ 75.0 wt%; Silver (Ag) 15.0-33.0 wt%; 4.5 to 9.5 wt% copper (Cu); And indium (In) 4.0 ~ 6.0% by weight; and, characterized in that used as a solder material for realizing the green gold (Green gold), provides an environmentally friendly green gold alloy material. That is, by adding a predetermined amount of indium (In) instead of the existing cadmium (Cd) and by adjusting the content of other elements, it is possible to harmonize the physical properties required as a green gold alloy material. Specifically, the environmentally friendly green gold alloy material of the present invention can achieve an improved green color with high brightness by satisfying the conditions of L value 90 or more, a value negative, and b value 25 or less according to CIE Lab color coordinates with excellent optical properties. . In addition, the melting point of less than 1100 ℃ (for example, 800 ~ 1100 ℃) can reduce the energy required during the production through the actual casting process, Vickers hardness (Vickers hardness) of 40 or more excellent durability.

In a first preferred embodiment, the invention provides 75.0% by weight of gold (Au); Silver (Ag) 15.0 wt%; 5.0 weight percent copper (Cu); And indium (In) 5.0% by weight; consisting of, 18K solder material to implement a green gold (Green gold), it provides an environmentally friendly green gold alloy material. This green K alloy material for 18K solder material is L. 93.30, a value -2.79, b value 22.09, melting point 900.437 ° C, Vickers hardness 169 according to CIE Lab color coordinates, green for solder material The excellent characteristics required of the gold alloy material can be harmoniously implemented.

In a second preferred embodiment, the present invention comprises 58.5% by weight of Au; Silver (Ag) 30.0 wt%; 6.5 weight percent copper (Cu); And indium (In) 5.0% by weight; consisting of, 14K solder material to implement the green gold (Green gold), it provides an environmentally friendly green gold alloy material. This green K alloy material for 14K solder material has L value of 92.31, a value of -2.96, b value of 24.19, melting point of 854.271 ℃, Vickers hardness of 204.3, and average glossiness according to CIE Lab color coordinate. With 262.6Gu, excellent glossiness can be realized along with excellent characteristics required for the green gold alloy material for solder material.

According to another aspect of the present invention, there is provided a method for producing an environmentally friendly green gold alloy material, characterized in that the alloy material weighed in a predetermined ratio in the magnesia crucible, and dissolved using an LPG-oxygen torch. In this case, by coating the inside of the magnesia crucible with borax (Na ₂ B ₄ O ₇ · 10H ₂ O) to prevent the alloying element is absorbed into the fine pores (pores) in the magnesia crucible, to prevent the loss of the input alloy material There is an advantage in producing an environmentally friendly green gold alloy material exactly as initially determined.

The green gold alloy material of the present invention is an eco-friendly material excluding the use of Cd, which is a heavy metal element harmful to the human body, and an improved green gold color than the alloy material to which Cd is added and the simple Au-Ag-Cu ternary alloy system. High quality color) and high brightness.

In addition, it is possible to reduce the energy required by the manufacturing in the actual casting process by adding a significantly lower melting point compared to the case of the existing Cd and a simple Au-Ag-Cu ternary alloy system.

In addition, a Vickers hardness of 40 or more (up to 204.3) can be obtained, perfect bonding can be achieved when bonding with other heterogeneous precious metals, and a relatively high gloss can be achieved with respect to 100Gu, the reflectivity of glass.

In addition, it is possible to reduce manufacturing costs by reducing the relative usage of expensive Ag.

Figure 1 is a graph showing the melting point results of the green gold alloy material prepared in various compositions.
Figure 2 is an enlarged image of the outer diameter of the environment-friendly green gold / 925silver bonding ring according to the present invention.
Figure 3 is a photograph showing the EDS line scanning results of Ag in an environmentally friendly green gold alloy material according to the present invention.
Figure 4 is a photograph showing a sample for measuring the glossiness of the environmentally friendly green gold alloy material according to the present invention and the measurement.

Hereinafter, the present invention will be described in more detail with reference to Examples, Comparative Examples and Experimental Examples. However, these examples are only for the understanding of the present invention, and the scope of the present invention in any sense is not limited to these examples.

Examples and Comparative Examples

In order to develop an eco-friendly green gold alloy material, a solder material alloy was designed to exclude Cd, an element for manufacturing the existing green gold, and replace it with In. Table 1 shows the alloy design for producing the green gold 14K and 18K alloy material. 18K for # 1 to # 3 samples and 14K for # 4 to # 6 samples.

For # 1 samples, existing Cretu et al. [C. Cretu, and E. V. Llngen, "Coloured gold alloys", Gold bulletin 32 (4): 115-126 (1999), were the same compositions as the green gold alloy compositions reported.

In the case of the # 2 sample, the color comparison value according to the Au-Ag-Cu ternary state diagram was confirmed, and the inventors directly designed the composition using only three elements.

In the case of # 3 sample, a certain amount of In was added to replace Ag to improve color.

In the case of # 4 sample, 14K composition was used to confirm the green color on the ternary state diagram and the composition design was carried out using only Au-Ag-Cu element.

In the case of # 5 sample, the amount of Ag was increased by 1.0 wt% by replacing Cu to confirm the color change according to the difference of Ag and Cu composition in the ternary alloy.

In case of # 6 sample, 5.0 wt% of In was added in place of Ag to improve green color compared to basic green color ternary alloy material.

Sample preparation was carried out in a magnesia crucible using an LPG-oxygen torch, with the alloying materials weighed in each ratio and dissolved (and solidified if necessary). At this time, since gold or other alloying elements may be absorbed into the fine pores in the magnesia crucible, the content of the magnesia may be previously coated with borax.

[Table 1] Alloy Design for Development of Green Gold Alloy Materials (Unit: wt%)

Experimental Example

(1) Macro image of green gold alloy material

Table 2 shows a macro image of each green gold alloy material.

[Table 2] Macro image of each alloy

For sample # 1, existing references [C. Cretu, and EV Llngen, "Coloured gold alloys", Gold bulletin 32 (4): 115-126 (1999). It was confirmed that it appeared to be added as the interference color.

In the case of # 2 sample, it was manufactured with 18K composition, and the inventors made it to check the ternary state diagram and to realize the green color. It is confirmed that the amount of Ag is 5.0 wt% higher and 1.0 wt% lower than that of the existing literature. The brightness of the Ag is slightly higher due to the higher brightness compared to the # 1 sample, and thus, the green color can be seen more clearly.

In the case of the # 3 sample, 5.0 wt% of In was added to replace Ag, and the brightness and green color were improved over the # 1 sample.

In the case of the # 4 sample, the sample was manufactured in 14K, and the green color was produced after checking the state as in the # 2 sample. As the content of Ag increases with respect to 18K products, yellow color is reduced and white is raised, and thus green color can be clearly seen.

In the case of the # 5 sample, the amount of Ag was increased by 1.0 wt% for the purpose of improving the saturation of the green color by whitening, but no visual difference was observed with the # 4 sample.

In the case of the # 6 sample, 5.0 wt% of In was added to replace Ag and Cu, and no significant difference was observed with the # 4 and # 5 samples.

In the case of 18K, it was found that the yellow color was stronger as the content of gold was higher than that of 14K. In the case of 14K, as the body color was closer to white, the green color was more clearly seen. In addition, in the case of adding In instead of Ag, the sample was not significantly distinguished visually compared to the sample in which a large amount of Ag was actually added.

As a result, in the case of In-added samples (# 3, # 6) according to the present invention, the brightness was higher than that of the conventional # 1 sample to which Cd was added.

(2) Inspection of the produced sample (EDS analysis result of green gold alloy material)

EDS analysis was performed for each sample in order to determine whether the alloy was manufactured by the desired ratio. EDS mounted on normal SEM (normal scanning electron microscopy, Jeol's JSM-6010PLUS / LA model) was used to confirm the composition of samples # 1 to # 6. At this time, the final component was confirmed by mapping analysis by applying acceleration voltage of 20kV, T3 process time and dwell time of 0.5 msec.

Table 3 shows the results of EDS analysis of each green gold alloy material.

For sample # 1, existing references [C. Cretu, and EV Llngen, "Coloured gold alloys", Gold bulletin 32 (4): 115-126 (1999), prepared with the same composition as the 18K green gold alloy material. There is a feature to enter. In the case of Au-Ag-Cu, it can be confirmed that the alloy is properly within the error range of the EDS compared to the desired value. However, the Cd element shows a negative error of 1.12 wt%, which can be presumed to be due to heat oxidation and evaporation in the alloying process in addition to the measurement error of EDS. Therefore, it would be advantageous if the alloy of Cd was added in small increments to the target value or the alloy proceeded in a vacuum atmosphere.

For sample # 2, Au, Ag, and Cu were 75.57, 19.51, and 4.92 wt%, respectively, and were alloyed as desired within the measurement error of EDS.

In the case of # 3 sample, 5.0 wt% of In was added instead of Ag, and all alloying elements showed an appropriate alloy ratio within an error range.

In the case of # 4 ~ # 6 samples, as 14K green gold alloy material, it can be seen that the proper alloys were all progressed within some error ranges as in the previous sample.

On the other hand, when checking the error rate, all of Au shows positive error, and other Ag, Cu, In, Cd shows negative error range. Presumably due to evaporation potential. Unlike Au, other elements are relatively weak in oxidation, and in the process of alloying with LPG-oxygen torch, other elements may have been actually oxidized, but it is considered to be insignificant.

Therefore, in the present invention, it was confirmed that it was properly produced according to the desired alloy ratio.

[Table 3] EDS analysis result of green gold alloy material (unit: wt%)

(3) Lab Color Index (Green Color Implementation Characteristic) Analysis Result of Green Gold Alloy Material

Table 4 shows the Lab color index of the environmentally friendly green gold alloy of the composition specified in the existing literature and the composition proposed according to the present invention. In the Lab index, L represents the brightness of the sample in the range of 0 to 100, a represents the degree of green to red, and b represents the degree of blue to yellow. In the case of a, green becomes darker as it decreases to (-), and red color becomes larger as it increases to (+). In the case of b, the smaller the negative value, the darker the blue color. The larger the positive value, the more the yellow color becomes darker. Therefore, the L index is theoretically a gold alloy, so the high reflectivity, the L value should be high (more than 90), the a value should be negative and the b value should be 25 or less to have a green color.

In the case of sample # 1, the green gold material in which 4.0 wt% of Cd specified in the existing literature is added, has a green overtone color on a yellow gold base.

In the case of the # 2 sample, the alloy was alloyed with a composition capable of realizing the green color on the ternary diagram. Similarly, the a value was negative, but the green color was less than that of the Cd-injected sample.

In the case of # 3 sample, 5.0 wt% of In was substituted for Ag according to the present invention, and the value of a decreased to a negative value, and the value of a lower than Cd showed that the green color became darker.

In the case of the # 4 sample, the 14K sample was manufactured using the composition that can realize the green color in the ternary state diagram. As in the case of 18K, a showed a negative value and the green color was realized.

In the case of # 5 sample, the amount of Ag was increased by 1.0 wt% by substituting Cu, which may contribute to the red color development. As the value of a decreases to a negative value, the degree of green color increases.

In case of # 6 sample, 5.0 wt% of In was added to replace Ag. As the value of a is smaller than that of # 5 sample, it was confirmed to show better color performance than the simple Au-Ag-Cu tertiary alloy system. .

In addition, for each sample, the color difference of the green gold proposed in the existing literature including Cd was less than 5.0, and there was only a slight difference, confirming the possibility of replacing Cd harmful to the human body.

Therefore, in the case of In, it was confirmed that the excellent optical properties that can replace the Ag element associated with the green color implementation, and satisfies the target L> 90, a <0, b <25 value in the present invention .

[Table 4] Lab color index of green gold alloy

(4) Melting point analysis result of green gold alloy material

Figure 1 shows the melting point results of the environmentally friendly green gold alloy composition of the composition and the composition proposed in the present invention.

In the case of # 1 sample, the green gold alloy with 4.0 wt% of Cd specified in the existing literature shows a melting point of 920.860 ° C.

In the case of the # 2 sample, it is alloyed with a composition that can realize the green color on the ternary state diagram, and has a melting point of 980.667 ° C higher than that of the # 1 sample. In case of # 1 sample, melting point decreases as a large amount of Cd, a low melting point alloy material, is added.In the case of actual Cd element, about 10% is added to the noble metal solder material, and the melting point is lowered by -50 ° C or more compared to the existing base material. It is used as an element to make.

In the case of # 3 sample, 5.0 wt% of In was substituted for Ag according to the present invention, and the melting point was 900.437 ° C. It is determined that the melting point of about 80 ° C. is lower than that of the # 2 sample as 5.0 wt% of In, which is a low melting point alloy material, may play a role as Cd. On the other hand, the # 3 sample showed a lower melting point than the # 1 sample, which is about 980 ° C and In is 5.0 when Cd is added 5.0 wt% in relation to the state of Au-In and Au-Cd. When the wt% was added, it showed a melting point of about 940 ° C, and when the same amount of In was added, it was confirmed that the melting point was lower than that of Cd.

In the case of the # 4 sample, a 14K sample prepared using a composition capable of realizing a green color on a ternary diagram has a melting point of 931.697 ° C. This is believed to be low due to a decrease in the amount of gold compared to 18K and a large amount of other alloying elements.

In the case of the # 5 sample, the amount of Ag was increased by 1.0 wt% by substituting Cu, which may contribute to the red color expression, and was 924.91 ° C. similar to the # 4 sample. It was judged that the melting point decreased as the amount of Ag increased slightly, but there was no significant difference.

In case of # 6 sample, 5.0 wt% of In was added to replace Ag, and the melting point was 854.271 ° C. That is, as with the # 3 sample, it was confirmed that the melting point of the green gold ternary alloy material was greatly reduced by the addition of In.

Therefore, the melting point of quaternary alloy system containing # 1, # 3, # 6 samples Cd, or In is lower than that of the three-way alloy for green gold. It is believed that this can be reduced.

Overall, each alloy had a melting point of less than 1100 ° C., which was set as a quantitative target item so that it could be employed in jewelry casting infrastructure currently in use.

(5) Hardness analysis result of green gold alloy material

Table 5 shows the Vickers hardness results of each green gold alloy material.

The reference sample (# 1) containing Cd, which is harmful to the human body, has been averaged 180.7, and the hardness of green gold alloy material (# 2) consisting only of Au-Ag-Cu (10) was 107.3. . If Cd is included in addition to the simple ternary alloy, it is judged to be due to the solid solution strengthening according to the difference in atomic radius of each element.

On the other hand, in the case of the present invention environmentally friendly green gold alloy material (# 3) containing 5.0 wt% 169 was found to be higher than the sample # 2, which is determined by the solid solution strengthening like the green gold containing Cd It became.

Samples (# 4) made of 14K ternary alloy (# 4) and samples (# 5) with 1.0 wt% increase in Ag content showed hardness of 173.7 and 201.7, respectively. The reason for higher than 18K ternary alloy material is because the proportion of gold with relatively low hardness decreases and the content of silver and copper with high hardness increases.

In addition to the 14K ternary alloy, the sample added with 5.0 wt% of In to replace Cd (# 6) showed a hardness of 204.3, which was higher than that of 18K added to # 3. This is believed to be a result of increased copper and silver contents in addition to gold.

Overall, the hardness analysis showed a Vickers hardness of 40 or more targets in the present invention was confirmed to be a satisfactory level.

[Table 5] Vickers hardness results of green gold alloy

(6) Result of bonding rate analysis between eco-friendly green gold / 925silver

Figure 2 shows the optical magnified images of the ring surface portion bonded using an environmentally friendly green gold alloy material (# 3, # 6 samples) according to the present invention.

In order to quantitatively check the entire outer diameter of the ring, an optical image was obtained for the entire circumference by marking 5 mm units. As a result of the present inventors using a self-made flash bonding machine, the circumference of the different heterogeneous precious metal bonding samples was found to be 58.404 mm, and the pore length corresponding to the double bonding failure was found to be 0.000 mm. As a result of the calculation of the bonding ratio, it was confirmed that the bonding ratio was 100%.

Therefore, it was confirmed that the joint was successfully completed without joining dropouts or pores for the entire circumference of the outer diameter when joining different heterogeneous precious metals through a flash jointer.

(7) Diffusion distance analysis result between eco-friendly green gold / 925silver

Figure 3 shows the results of SEM and Ag elemental EDS line analysis for the green gold / 925silver bonded sample. The Ag content of the eco-friendly green gold alloy material was 30.0 wt% (# 6 sample), and the silver content of 925silver was 92.5 wt%.

In the case of simple magnification analysis through SEM, it was impossible to identify the interface part. This is considered to be the result of perfect bonding and polishing it with very low roughness. However, in the case of Ag, the distribution was clearly different. Ag was more distributed on the left side of the center. This is due to the difference between the alloy element of the environmentally friendly green gold alloy material and 925silver, it can be seen that the left side is 925silver.

In the case of the line scanning result, it can be seen that the intensity of the Ag element increases as the content of the left side is higher than the right side of the junction surface. The interdiffusion distance of the bonded sample was chosen as the point of change of both slopes around the two points of contact of which the slope of the line scanning spectrum is changed by the difference in content. Accordingly, it was confirmed that Ag exhibits a diffusion distance of 5.3 um.

This indicates that sufficient interdiffusion occurred between two green metals, which are environmentally friendly green gold and 925silver, and means that a healthy bonding was performed. In the present invention, it is confirmed that the diffusion distance of Ag is 2 nm or more.

(8) Glossiness analysis result of eco-friendly green gold alloy material

Glossiness measurement was carried out to determine whether the eco-friendly green gold alloy material proposed in accordance with the present invention has the same level of glossiness as the alloy material used as a conventional jewelry product. As shown in FIG. 4, a 14K eco-friendly green gold alloy material # 6 was fabricated into a disc having an actual 5 cm diameter and its glossiness was measured.

The measurement was performed three times, each showing a glossiness of 262.6, and finally an average glossiness of 262.6 Gu, which corresponds to an extremely high glossiness based on the reflectivity of glass 100Gu.

Claims (10)

Gold (Au) 58.5-75.0 wt%; Silver (Ag) 15.0-33.0 wt%; 4.5 to 9.5 wt% copper (Cu); And indium (In) 4.0 ~ 6.0 wt%;
Characterized in that it is used as a solder material for realizing the green gold (Green gold) color,
Eco-friendly green gold alloy material.
The method of claim 1,
75.0 wt% Gold (Au); Silver (Ag) 15.0 wt%; 5.0 weight percent copper (Cu); And indium (In) 5.0 wt%;
It is used as an 18K solder material to implement the green gold color,
Eco-friendly green gold alloy material.
The method of claim 1,
58.5 wt% Gold (Au); Silver (Ag) 30.0 wt%; 6.5 weight percent copper (Cu); And indium (In) 5.0 wt%;
It is used as a 14K solder material to implement the green gold color,
Eco-friendly green gold alloy material.
The method of claim 1,
The eco-friendly green gold alloy material is characterized in that L value of 90 or more, a value is negative, b value is 25 or less according to CIE Lab color coordinate,
Eco-friendly green gold alloy material.
The method of claim 4, wherein
The environmentally friendly green gold alloy has a melting point of 800 ~ 1100 ℃, Vickers hardness (Vickers hardness), characterized in that more than 40,
Eco-friendly green gold alloy material.
The method of claim 2,
The environmentally friendly green gold alloy material for 18K solder material is characterized in that L value of 93.30, a value of -2.79, b value of 22.09, melting point of 900.437 ° C, Vickers hardness of 169 according to CIE Lab color coordinates ,
Eco-friendly green gold alloy material.
The method of claim 3,
Eco-friendly green gold alloy material for 14K solder material is characterized in that L value of 92.31, a value of -2.96, b value of 24.19, melting point of 854.271 ℃, Vickers hardness of 204.3 according to CIE Lab color coordinates ,
Eco-friendly green gold alloy material.
The method of claim 7, wherein
Eco-friendly green gold alloy material for the 14K solder material, characterized in that the average glossiness is 262.6Gu,
Eco-friendly green gold alloy material.
As a method for producing an environmentally friendly green gold alloy material according to any one of claims 1 to 8,
Characterized in that the alloying materials weighed in a predetermined ratio into a magnesia crucible and dissolved using an LPG-oxygen torch,
Manufacturing method of eco-friendly green gold alloy material.
The method of claim 9,
By coating the inside of the magnesia crucible with borax (Na ₂ B ₄ O ₇ · 10H ₂ O), characterized in that the alloy element is prevented from being absorbed into the fine pores (pores) in the magnesia crucible,
Manufacturing method of eco-friendly green gold alloy material.

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