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Anti-tarnish silver alloy and method for manufacturing the same

A silver alloy and anti-tarnish technology, which is applied in the field of metal materials, can solve the problems of relatively harsh preparation process requirements, high cost of silver alloy, complex composition of silver alloy, etc., achieve good machinability, save electroplating costs, and have strong anti-tarnish ability Effect

Active Publication Date: 2013-03-20
深圳市瀛禾泰富珠宝首饰有限责任公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

To completely prevent sulfide formation, silver must be alloyed with at least 40% Pd, 70% Au, or 60% Pt, but this results in very expensive silver alloys
[0004] In recent years, people have developed a variety of anti-tarnish silver alloys, but most of these silver alloys have complex components. For example, there are as many as 10 silver alloy elements disclosed in patent CN01114354.1, and the requirements for the preparation process are more stringent.
In addition, these silver alloys often have some deficiencies in low temperature processability and surface gloss.

Method used

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  • Anti-tarnish silver alloy and method for manufacturing the same
  • Anti-tarnish silver alloy and method for manufacturing the same
  • Anti-tarnish silver alloy and method for manufacturing the same

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0037] The anti-tarnish silver alloy in this embodiment has the following weight percentages: 92.5% silver, 4.5% cobalt, 1.5% nickel, and 1.5% copper.

[0038] The raw materials are weighed and mixed according to the above ratio, then placed in a vacuum arc melting furnace for repeated melting 4 times, taken out and cooled to room temperature to form an ingot.

[0039] After testing, the microhardness (HV) of the prepared anti-tarnish silver alloy is 82, which is similar to the commonly used 925 silver alloy.

[0040] The anti-tarnish silver alloy sample prepared by the present embodiment is placed in 3.5% NaCl solution medium to carry out the discoloration test, and the common 925 silver alloy sample is used as a control test group, and the photomicrograph of the test result is as follows: Figure 1a and Figure 1b shown. At the same time, the anti-tarnish silver alloy sample prepared in this embodiment was placed in 0.2×10 -3 MNa 2 The discoloration test was carried out i...

Embodiment 2

[0043] The anti-tarnish silver alloy of this embodiment has the following weight percentages: 92.5% silver, 1.5% cobalt, 0.5% nickel, and 5.5% copper.

[0044] The production and processing method is as follows: weighing and mixing the raw materials according to the above ratio, then placing them in a vacuum induction melting furnace for melting, taking them out and cooling to room temperature to form an ingot, and the ingot can be repeatedly smelted for 1-10 times.

[0045] After testing, the microhardness (HV) of the prepared anti-tarnish silver alloy is 85, which is similar to the commonly used 925 silver alloy.

[0046] The anti-tarnish silver alloy sample prepared by the present embodiment is placed in 3.5% NaCl solution medium to carry out the discoloration test, and the common 925 silver alloy sample is used as a control test group, and the photomicrograph of the test result is as follows: image 3 a. At the same time, the anti-tarnish silver alloy sample prepared in t...

Embodiment 3

[0049] The anti-tarnish silver alloy of this embodiment has the following weight percentages: 82.5% silver, 1.8% cobalt, 0.7% nickel, and 15% copper.

[0050]The production and processing method is as follows: weighing and mixing the raw materials according to the above proportions, then placing them in a vacuum induction melting furnace to smelt, taking them out and cooling to room temperature to form an ingot, and the ingot can be repeatedly smelted for 1-10 times.

[0051] After testing, the microhardness (HV) of the prepared anti-discoloration silver alloy is 83, which is similar to the commonly used 925 silver alloy.

[0052] The anti-discoloration silver alloy sample prepared in this example was placed in a 3.5% NaCl solution medium to conduct a discoloration test, and an ordinary 925 silver alloy sample was used as a control test group; at the same time, the anti-discoloration silver alloy prepared in this example was The sample is placed in 0.2×10 -3 MNa 2 The discol...

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Abstract

Disclosed is a tarnish resistant silver alloy with the composition of (by wt%): silver 82.5-92.5%, cobalt 1.5-7.5%, nickel 0.5-2.5%, and copper 0.5-15%, wherein the weight ratio of cobalt and nickel is controlled within 2.5~3.5:1. The method for producing the silver alloy comprises the following steps: mixing raw materials according to the ratio, melting in a vacuum induction melting furnace, and then cooling to room-temperature to form cast ingot. The silver alloy comprises no noble metal and rare metal; has simple composition and low cost. The alloy can form a thin and dense intercalation oxide CoNiO on surface in atmosphere, has high tarnish resistance and can maintain the gloss of silver. The alloy has a hardness similar to that of sterling silver usually used at present and good machinability, and adapts to jewellry industry. The process of electric plating to the alloy is unnecessary.

Description

technical field [0001] The invention relates to the technical field of metal materials, in particular to an anti-tarnish silver alloy suitable for jewelry, decorations and the like and a preparation method thereof. Background technique [0002] Silver is located between gold and copper in the periodic table of elements, and its chemical properties are stable. It is not easy to oxidize even if it is heated in the air. However, silver alloys are prone to discoloration. This seriously affects the appearance of the jewelry. The discoloration of silver alloys is mainly due to the fact that silver easily reacts with sulfur to form black silver sulfide. In addition, sulfate, chloride, oxide, organic carbon and carbonate on the surface of silver jewelry. Both affect the apparent quality of silver alloys. In short, the discoloration of silver is a common phenomenon, and the exposure of corrosive media and water, sulfur and sulfide, oxygen, and light will cause and aggravate the ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22C5/06C22C5/08C22C1/02
CPCC22C1/02C22C5/06C22C5/08
Inventor 吴峰华
Owner 深圳市瀛禾泰富珠宝首饰有限责任公司
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