KR102066601B1 - Cd free solder material for 18 K red gold - Google Patents

Abstract

Cd free 18K red gold solder material is available.
The present invention is a solder material of 18K red gold master alloy composed of Au-Cu-Ag ternary system, Cu: 15 ~ 22wt%, In: 3 ~ 10wt%, and the balance for Cd free 18K red gold comprising a balance Au It is about material.

Description

Cd free solder material for 18K red gold}

The present invention relates to a Cd free 18K red gold soldering material, and more specifically, by adding In as an 18K red gold soldering material, the same color as the base material and the melting point of the base material is more than -30 ℃, wettability and hardness Relates to an excellent Cd free 18K red gold solder material.

In the jewelry market, yellow and white gold have traditionally formed the largest market, but recently, a red-pink-based gold alloy material containing a large amount of Cu was released according to various needs of consumers, and now has the largest market share. have. Such red gold mainly implements a red color because Cu is the main alloying element.

For the production of jewelry products, the soldering process is essential to join the elements and fill air bubbles on the surface. In this case, the solder material used is generally 1) the same content of the base material and gold, 2) difficult to distinguish color on the naked eye with the base material, 3) has a melting point of about 50 ℃ lower than the base material, 4 A) Wetting property is excellent, so that the melt of the solder material flows well into the gap of the base material, and 5) sufficient durability needs to be secured.

The conventional gold alloy material for jewelry is mainly Au-Ag-Cu ternary alloy, and at this time, the solder material is replaced by other alloy elements, such as Ag and Cu, except for Au by about 10wt% Cd to lower the melting point and improve the wettability An alloy material was used.

By the way, red gold jewelry is mainly used for 14K and 55.0 wt% of 18K alloys with 58.5wt% gold, but the solder material for 14K red gold products, which have relatively high copper alloy elements, has a Cd of about 10wt% to lower the melting point than the base metal. In this case, since the change in the copper content is not large, the color difference between the solder part and the base material is not large, and it was possible to use it without major problems except for human harmfulness. On the other hand, in the case of 18K red gold solder material, the copper content is relatively low to maintain the same gold content as the base metal, and the color becomes visible when 10.0 wt% or more of Cd is added to lower the melting point by about 50 ° C. There was a problem that the product is inferior in aesthetics.

As such, when the base material containing a large amount of existing Cd elements is 18K and the soldering material for red gold is also 18K, the color difference occurs largely due to the decrease in the content of Cu and is harmful to the human body. There is a problem that can be absorbed by the human body by elution by sweat or the like and may cause diseases.

Therefore, there is a demand for the development of a technology for the 18K red gold solder material which is excellent in physical properties and is harmless to the human body while meeting the conditions to be provided as the solder material.

 Therefore, the present invention is to solve the above-mentioned problems of the prior art, by adding In as an 18K red gold solder material, the same color as the base material and melting point than the base material -30 ℃ or more, excellent wettability and hardness Cd free The purpose is to provide a solder material for 18K red gold.

In addition, the technical problems to be achieved in the present invention are not limited to the above-mentioned technical problems, and other technical problems not mentioned above are clearly understood by those skilled in the art from the following description. Could be.

The present invention for achieving the above object,

As a solder material of 18K red gold master alloy composed of Au-Cu-Ag ternary system,

It relates to a Cd free 18K red gold solder material with improved physical properties including Cu: 15 ~ 22wt%, In: 3 ~ 10wt%, balance Au.

In the present invention, the 18K red gold solder material may be lower than the melting point of 30 ℃ or more compared to the reference base material does not contain In.

In addition, the 18K red gold solder material may have a color difference of 10 or less.

In addition, the 18K red gold solder material may have a gypsum / alloy wet angle of 85 ° or less.

According to the present invention of the above configuration, 1) the content of gold is sufficiently secured does not cause a decrease in the content of the final product, 2) the same color as the existing red gold base material, 3) has a melting point of about 30 ℃ or more lower than the base material 4) Excellent wettability, the melt of the solder material flows well into the gap of the base material, and 5) It is effective to provide the 18K red gold solder material that is harmless to the human body because Cd element is not used in the human body to ensure sufficient durability. Can be.

1 is a table showing a lab color analysis results and macro images of 18K red gold alloy material according to the In addition in the embodiment of the present invention.
Figure 2 is a graph showing the melting point change of 18K red gold alloy material according to the addition of In in the embodiment of the present invention.
Figure 3 is a graph showing the results of the wet angle analysis of 18K red gold alloy according to the addition of In in the embodiment of the present invention.
Figure 4 is a graph showing the Vickers hardness change of the 18K red gold alloy material with the addition of In in the embodiment of the present invention.

Hereinafter, the present invention will be described.

As described above, in the case of the solder material for 18K red gold products, since the copper content is relatively low to maintain the same gold content as the base material, when Cd is added 10.0wt% or more to lower the melting point by about 50 ° C. There was a problem in that the color is clearly distinguished by the naked eye, the product is less aesthetic. Accordingly, the present inventors have conducted research and experiments to solve the above problems, and as a result, 18K red gold solder material which does not use Cd is added with In corresponding to the lower content while lowering the Cu content, thereby reducing the color, melting point and It is to confirm that the brazing material can be obtained that the characteristics are excellent in terms of the wet angle, etc. and to present the present invention.

Cd free 18K red gold solder material of the present invention is a solder material of 18K red gold master alloy consisting of Au-Cu-Ag ternary system, including Cu: 15 ~ 22wt%, In: 3 ~ 10wt%, balance Au Is done.

The composition of the Cd free 18K red gold solder material of the present invention and the reason for limitation thereof will be described.

In the present invention, as a solder material for 18K red gold, it may be made of Cu: 15 ~ 22wt% and In: 3 ~ 10wt%.

In the present invention, while basically reducing the Cu content compared to the base material, the In content is added in the range of 3 to 10wt% by the decreasing amount thereof. If the In content is less than 3%, there is a problem in that the melting point difference is weak and loses the function as the solder material. If the In content is more than 10%, the brittleness becomes strong, and thus, the processing as the solder material may be difficult.

And the solder material of this invention contains Au as a residual component.

In the present invention, since it is used as the solder material of the 18K red gold mother alloy, it has approximately 75wt% Au relative to its own weight. However, it is apparent that 75 wt% of the content may have a slight margin of error in the art.

As described above, the 18K red gold solder material of the present invention may have a melting point of 30 ° C. or more compared to a reference base material not containing In.

In addition, the 18K red gold solder material may have a color difference of 10 or less.

In addition, the 18K red gold solder material may have a gypsum / alloy wet angle of 85 ° or less.

Hereinafter, the present invention will be described in detail through examples.

(Example)

Sample manufacturing

Commercially used members of 18k red gold are Au-Cu-Ag.

In this experiment, as shown in Table 1, No. containing a small amount of Ag. 1 A sample was assumed to be a 18K red gold base material, and 18K red gold solder material No. Ag, except for Ag, was changed to 1.0, 3.0, 5.0, and 10.0 wt% of Cu instead of Cu. 2-5 were prepared. Samples were prepared by injecting each of the prepared samples into a magnesia crucible with borax flux and dissolving them using an LPG-oxygen torch.

Sample number
Sample composition (wt%) Au Ag Cu In CD Sum One 75.0 1.3 23.7 0.0 - 100 2 75.0 - 24.0 1.0 - 100 3 75.0 - 22.0 3.0 - 100 4 75.0 - 20.0 5.0 - 100 5 75.0 - 15.0 10.0 - 100

Au content check

In order to quantitatively confirm the gold content of each prepared sample, a cupellation according to KS D ISO 11426 standard was performed. After taking 0.2g from each sample, place it on the top of the cupell crucible with 0.6g Ag and Pb foil, recover it through heat treatment at 1200 ℃, and finally obtain more than 99.9wt% of Au by nitric acid treatment. Was calculated to confirm that the net content of 18K is satisfied,

Table 2 below shows the gold content of each sample by the Cupel method. As shown in Table 2, each sample shows an Au content of 75.00 wt% or more, and shows some (+) content, which shows the oxidation of Cu, In, etc. during the manufacture of the alloy, and the sound alloy progressed even with the dissolution of general oxygen torch. have.

Sample No. One 2 3 4 5 Au content 75.44 45.04 75.26 75.18 75.06

Visual and Lab Color Check

 Each sample was plated for polishing for visual analysis, polished and photographed at 20 magnification with an optical microscope, and slit size 5, scan using UV-VIS-NIR (Shimadzu UV-3105PC model) for quantitative color analysis. Reflectance was measured using the reflectance mode in the visible region (380 ~ 780 nm) at the velocity medium.Then, the Lab index was obtained using the Color Analysis program and based on the 18K red gold base material (No. 1). Color difference is compared and the result is shown in FIG. Meanwhile, in FIG. 1, 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 within the Lab index.

As shown in FIG. 1, in the case of the base material sample (No. 1) to which In was not added, the Lab value was 81.82 / 11.64 / 23.5, indicating a red color, which is a normal red gold color, and a red color even when visually analyzed. It can be seen that it has a gold alloy color.

In the case of No. 2 to 3 samples containing 1.0 wt% and 3.0 wt% of In, Lab values of 81.14 / 11.17 / 21.02 and 84.17 / 8.34 / 22.65 were shown, respectively, so that the color difference was 2.61 and 4.14. It can be seen that. However, the minimum color difference that can be distinguished by the naked eye is 4.00, and since 6.00 is accepted as the same color, when In is included in an amount of 3.0 wt% or less, it was determined that the same color as a commercial red gold sample, and it was difficult to distinguish even when visual analysis.

On the other hand, in the case of the sample (No. 4-5) containing In and 5.0wt% and 10.0wt%, it was confirmed that the saturation of the red color slightly decreased when visual analysis. In the case of the color index, respectively, as the value of a decreased slightly, 7.67. The color difference was 7.50, which was the same as the result of visual analysis, but the base material and color difference occurred. Therefore, when the color difference is less than 10, it can be seen that consumers are more likely to judge the same color.

Therefore, the solder material sample No. 1 with In added up to 10.0wt%. 2-5 is the existing red gold sample No. It can be seen that the contrast difference of 1 shows excellent optical properties to the extent that it is difficult to distinguish clearly with the naked eye.

Melting Point Check

The melting point of each solder was checked through TGA-DTA (Shimadzu Corporation DTG-60 model) analysis. That is, about 14mg of each sample was taken for each condition and analyzed at a temperature increase rate of 20 ℃ / min in the temperature range of 20 ~ 1100 ℃, and in the nitrogen atmosphere to minimize the error range due to oxidation. Proceeded.

Figure 2 is a graph showing the melting point according to the TGA-DTA analysis of the red gold material and the solder material. The arrow on the graph Y-axis shows the melting point of the braze containing the commercially available Cd element.

As shown in FIG. 2, the melting point of 18K red gold, the reference base material sample (No. 1), was found to be 918.54 ° C., and then, the melting point of the solder alloy material to which 1.0 to 10.0 wt% of In was added for use as the solder material. It can be seen that the melting point decreases as the amount of In is increased to 911.2, 891.56, 859.64, and 760.22 ° C, respectively.

However, sample No. with 1.0wt% of In added. In the case of 2, the base material No. It can be seen that the melting point difference with 1 is not so large as 7.34 ° C. that it cannot be used as a solder material (solder material).

Meanwhile, in the case of samples (No. 3 to 5) to which 3.0 to 10.0 wt% of In was added, the base material No. 1 and 26.98, 58.9, and 158.32 ° C, respectively, and the melting point difference of 5.0 wt% and 10.0wt% of In was added (No. 4 to 5). It can be seen that the smooth soldering work can be performed by showing a large melting point difference of more than 50 ℃.

In addition, in the case of a commercial red gold solder containing 10.0wt% of Cd, it was confirmed that the melting point of 870.19 ℃, In has a higher melting point than the sample added 5.0wt%, In the case of putting In than the actual Cd It can be confirmed that it has advantageous melting point characteristics.

Therefore, if the proposed 5.0 wt%, 10.0wt% of the addition of the solder material is adopted, it will be advantageous in terms of the process energy required to lower the melting point by more than 100 ℃.

Wettability check

 In order to check the relative wettability according to the melting of each sample, 0.40 g of solder alloy material was placed in the upper part of the flat plaster mold, and then, at a temperature rising rate of 10 ° C./min using an air furnace (Model SK1700-B30, Thermotech Co., Ltd.), 1200 It was kept for 10 minutes at ℃, then cooled to obtain a hemispherical solid sample in contact with the gypsum. Afterwards, a dark field optical image was obtained using the backside illumination of the solid state sample, and the wetting angle was calculated using the Image J program.

 Figure 3 is a graph showing the wetting angle of the red gold solder, the figure in the graph is No. 1.0 wt% added. 2 Show the actual wet angle analysis image of the sample.

As shown in FIG. 3, in the case of the base material sample (No. 1) without In, the wetting angle was 50.7 °. In particular, considering the lower gypsum flask used in the analysis, the base material was well wetted during the lost wax casting process. It was expected to be advantageous.

In addition, in the case of the sample in which 1.0 wt% of In was added, the wetting angle increased slightly as In was added to 55.1 °, and then 73.5 °, 76.9 °, and 83.0 °, respectively, as the amount of In was increased to 3.0 to 10.0wt%. You can see that the increase.

In the case of the solder material (solder material) to which 10.0 wt% of Cd was added, it was found that In was higher than the sample to which In was added at the same ratio.

In general, casting materials must exhibit a contact angle of less than 70 ° to enable sound wetness. However, the solder material (solder material) containing Cd, which has already been used commercially, has a high contact angle of 92.4 °, because it is measured on the gypsum substrate rather than the contact angle with the 18K metal base material for the convenience of the experiment. However, in comparison with commercial red gold solder containing 10.0wt% Cd in 18K red gold solder containing indirectly up to 10.0wt%, solder containing relatively In 10.0wt% showed better wettability than Cd. Able to know.

Durability check

 Vickers hardness was measured using a Vickers hardness tester (Mitutoyo, MVK-H1 model) on a red gold sample that was plated with a post-alloy rolling mill. In general, the solder material is drawn and used with a diameter of 1mm, and after the cast sample is rolled to a thickness of 1mm, a load of 0.5kgf is applied to the sample for 15 seconds.Then, the hardness value is calculated by measuring three times per sample to reduce the error rate Decided.

4 is a graph showing the Vickers hardness of the 18K red gold solder according to the amount of In added.

As shown in FIG. 4, in the case of the red gold base material reference sample (No. 1), the average is 201.94. In case of 1.0 wt% and 3.0wt% of In, the Vickers hardness slightly increased to 205.66 and 242.19, and then the Vickers hardness increased to 389.15 and 465.33 respectively as the amount of In increased to 5.0wt% and 10.0 wt%. You can see that.

In the case of the jewelery alloy material, the Vickers hardness value is generally about 150. Since each sample is a rolled specimen considering wire processing rather than an as cast state, it is considered that the hardness of the alloy is higher than that due to the work hardening.

 In addition, the increase in the hardness of the addition of In is greater than the conventional solder with 10.0wt% Cd added due to the solid solution strengthening effect, because the difference in atomic radius between In and Au is larger than the difference between Cd and Au, the solid solution strengthening relatively This can be great.

Therefore, each of the solder samples added with more than 3.0wt% of In has a Vickers hardness value of 240 or more, which is much superior to that of commercial gold alloy materials, and can be confirmed as a solder material capable of linear processing.

As described above, in the detailed description of the present invention has been described with respect to the preferred embodiment of the present invention, those skilled in the art to which the present invention pertains various modifications without departing from the scope of the present invention Of course it is possible. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined by the equivalents as well as the claims to be described later.

Claims (4)

As a solder material of 18K red gold mother alloy consisting of Au-Cu-Ag ternary system,
Cu: 15 ~ 22wt%, In: 3 ~ 10wt%, and the remainder Au for Cd free 18K red gold solder material.
The solder material for Cd free 18K red gold according to claim 1, wherein the 18K red gold solder material has a melting point of 30 ° C. or more compared to a reference base material containing no In.
The solder material for Cd free 18K red gold according to claim 1, wherein the 18K red gold solder material has a color difference of 10 or less according to a Lab index.
The solder material for Cd free 18K red gold according to claim 1, wherein the 18K red gold solder material has a gypsum / alloy wet angle of 85 ° or less.

Images