Wear-resistant and corrosion-resistant 1K gold alloy for jewelry and preparation method of wear-resistant and corrosion-resistant 1K gold alloy

Abstract

The invention discloses a wear-resistant and corrosion-resistant 1K gold alloy for jewelry and a preparation method of the wear-resistant and corrosion-resistant 1K gold alloy, and belongs to the technical field of precious metal materials and jewelry processing. According to the alloy, on the basis of 4.166% of gold, 0.1%-0.5% of rhodium (Rh) is creatively added, and ruthenium, iridium, gallium, zirconium, zinc and copper are cooperatively matched. The component design aims at forming a stable rhodium-rich transition region on the surface of a matrix. The preparation method sequentially comprises the steps of precision casting, surface mirror finishing and electrochemical activation, gradient composite electroplating (firstly plating the hard gold layer and then plating the rhodium / ruthenium surface layer) and low-temperature thermal diffusion stabilization treatment. The core of the invention is that unique alloy components are combined with a systematized surface engineering process, so that the prepared jewelry product keeps the remarkable cost advantage, and meanwhile, the obtained product is strong in plating binding force, high in surface hardness and excellent in wear resistance and corrosion resistance; and an effective technical scheme is provided for developing the 1K gold jewelry with high quality and high cost performance.

Description

Technical Field

[0001] This invention belongs to the field of precious metal alloy and jewelry manufacturing technology, specifically relating to a 1K gold alloy suitable for jewelry and its preparation method. More specifically, this invention relates to a 1K gold jewelry material solution that achieves a perfect combination of a low-cost substrate and a highly durable, high-gloss surface through specific alloy composition design and combination with mature precious metal electroplating technology. Background Technology

[0002] Gold alloys, due to their enduring color, stable chemical properties, and precious symbolic meaning, have long been a core material in jewelry making. Gold content is indicated by "K," with 24K being pure gold. 1K gold indicates a gold content of 1 / 24, or approximately 4.166%, making it the lowest gold content karat gold variety currently available commercially. Its greatest advantage lies in its extremely significant material cost advantage. While maintaining the properties of "gold," it provides designers with greater pricing flexibility, making it highly promising for both mass-market fashion jewelry and complex designs where cost control is crucial.

[0003] However, traditional 1K gold uses copper and zinc as the main matrix elements (for example, a typical ratio of Au 4.166%, Cu ~65%, Zn ~30%). While this classic copper-zinc-based system gives the alloy good casting and machining properties, it also brings two inherent and fundamental drawbacks that restrict its development into the mid-to-high-end jewelry market: First, the material itself has low hardness and poor wear resistance. Copper-zinc alloys are inherently soft, resulting in a low Mohs hardness for traditional 1K gold jewelry. During daily wear, it easily comes into contact with hard objects (such as tabletops, keys, and other jewelry), causing noticeable scratches and wear. The accumulation of these microscopic scratches quickly destroys the mirror-like luster of the jewelry, making its surface dull and rough, severely damaging its aesthetics and high-end feel, and shortening the product's lifespan.

[0004] Secondly, the base material is highly chemically reactive and prone to corrosion and discoloration. Copper is a relatively active element, readily reacting with various substances in the environment. Chlorides and lactic acid in human sweat, as well as sulfides and chloride ions in cosmetics, perfumes, and swimming pool water, can all react chemically with copper, forming corrosion products such as copper sulfide, copper oxide, or basic copper carbonate on the surface of the jewelry. This makes traditional 1K gold jewelry prone to darkening, reddening, developing green patina (verdigris), or black spots after wearing, commonly known as "discoloration" or "tarnishing." This not only affects the appearance but may also cause skin discomfort for some wearers.

[0005] To address these issues, the most common practice in the industry is to electroplate an inert, high-hardness precious metal onto the jewelry substrate as a protective layer, with rhodium plating being the most frequently used. Rhodium plating is bright white, highly hard, and extremely corrosion-resistant, effectively isolating the substrate from the external environment. However, this conventional process has a significant limitations for 1K gold substrates. The fundamental reason lies in the poor physicochemical compatibility between traditional copper-zinc based 1K gold and precious metal plating (such as rhodium), resulting in insufficient adhesion. Because the substrate surface is not microscopically dense or stable, the plating is more like "attached" rather than "locked" to the substrate. Under the combined effects of friction, bending, temperature changes, and sweat penetration experienced during long-term wear, this weak bonding interface of the plating is prone to localized peeling and accelerated wear, ultimately leading to the failure of the protective layer and returning the problem to its origin.

[0006] In addition, some in the industry have tried to improve the hardness and corrosion resistance of the matrix by overall alloying (such as adding nickel, palladium, etc.), but this significantly increases costs and loses the fundamental advantages of 1K gold. There are also studies on using complex surface treatment technologies such as physical vapor deposition (PVD), but these technologies are often expensive, complex, and have poor uniformity of coverage on complex shaped jewelry pieces, making them difficult to apply in large-scale, low-cost jewelry production.

[0007] Therefore, the jewelry manufacturing industry currently faces a clear and unresolved technical challenge: how to fundamentally improve the bonding strength and synergistic durability between the base material and the high-performance protective plating while preserving the cost advantage of 1K gold to the greatest extent possible, thereby developing a truly practical 1K gold jewelry material that is competitive in the high-end market, wear-resistant, tarnish-resistant, and has a long service life. Solving this problem is expected to break the market perception that 1K gold can only be used in low-end fast-moving consumer goods, opening up entirely new application prospects for it. Summary of the Invention

[0008] The primary objective of this invention is to overcome the shortcomings of existing technologies and provide a novel 1K gold alloy formulation. This formulation, through the synergistic effect of various trace elements, enables the alloy to achieve a denser and more stable surface state while maintaining good casting and machining properties, providing an ideal substrate for the subsequent application of a highly bonded and durable surface protective layer.

[0009] The core objective of this invention is to provide a method for preparing the aforementioned 1K gold alloy, particularly its surface strengthening process suitable for jewelry manufacturing. This method combines the specific alloy substrate of this invention with an optimized composite electroplating process to construct a functional coating on the substrate surface that is firmly bonded, has high hardness, and excellent corrosion resistance, thereby achieving a significant performance leap in 1K gold jewelry products in an economical and efficient manner.

[0010] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a 1K gold alloy for jewelry, comprising, by weight percentage (wt%): Gold (Au): 4.166%, Rhodium (Rh): 0.1% - 0.5%; Ruthenium (Ru): 0.1%-0.8%, Iridium (Ir): 0.05%-0.3%, Gallium (Ga): 0.5%-2.5%, Zirconium (Zr): 0.03%-0.15%, Zinc (Zn): 6.0%-12.0%, The balance is copper (Cu) and unavoidable impurities; the sum of the mass percentages of all components is 100%.

[0011] The design principles and synergistic effects of the key elements are as follows: Rhodium (Rh): As a core functional element, Rh is one of the hardest known precious metals. Its addition produces strong solid solution strengthening and precipitation strengthening (when forming compounds with other elements such as Ir and Ru), greatly enhancing the intrinsic hardness and wear resistance of the alloy matrix. More importantly, Rh has extremely high chemical inertness and reflectivity. In the alloy system of this invention, trace amounts of Rh tend to accumulate on the surface during melting, solidification, and subsequent processing. Working synergistically with Ga and Zr, it helps form an extremely thin but dense and stable "rhodium-rich transition zone" on the outermost layer of the matrix. The chemical properties of this region are highly similar to those of the subsequent rhodium plating layer, constituting a "pseudo-rhodium layer." This not only significantly improves the matrix's resistance to initial discoloration but, more importantly, greatly improves the physicochemical compatibility between the matrix and the subsequent electroplated rhodium layer, providing an atomic-scale matching basis for forming an interface with ultra-high bonding strength. This is the intrinsic guarantee for obtaining a bright, long-lasting, high-gloss appearance. Rh content below 0.1% has little effect, while content above 0.5% leads to a sharp decline in cost-effectiveness.

[0012] Ruthenium (Ru) and Iridium (Ir): key synergistic strengthening and stabilizing elements. Ru effectively improves the strength and hardness of alloys, and its oxides are equally stable. Ir possesses one of the best corrosion resistances among all metallic elements. Together with Rh, they enhance the overall stability of the matrix. When enriched on the surface, they can form high-hardness, high-stability alloyed regions with Rh, further improving the mechanical properties and chemical inertness of the surface "pseudo-rhodium layer."

[0013] Gallium (Ga) and zirconium (Zr): These elements optimize microstructure and promote amorphous formation. Ga lowers the melting point and surface tension of alloys, improving melt flow and casting surface quality. Zr is a strong grain refiner and amorphous forming agent. The addition of both significantly refines the as-cast grains of the alloy, reduces surface micro-defects, and promotes the formation of a more uniform and dense microstructure, even locally amorphous / nanocrystalline structures, under rapid solidification conditions. This creates ideal conditions for obtaining smooth electroplating substrates and surface enrichment of strengthening elements (Rh, Ru, Ir).

[0014] Zinc (Zn): As a phase diagram balance and processing property regulating element. Its main function is to ensure that the alloy has excellent casting fluidity, suitable ductility, and a traditional golden color, and to ensure that the material has good machinability and process adaptability.

[0015] In a second aspect, the present invention provides a systematic method for preparing 1K gold alloy jewelry articles as described in the first aspect, comprising the following steps: S1. Precision alloy melting and casting: Weigh the raw materials according to the proportions, melt them under vacuum or protective atmosphere, and cast them into shape to obtain the jewelry casting blank; Each element is precisely weighed according to the design proportions, and smelted under vacuum or high-purity inert gas protection to ensure a highly uniform alloy composition. Subsequently, the alloy is cast using the lost-wax casting process, a mature technology in the jewelry industry. By controlling the mold temperature (preferably 200-400℃) and cooling rate, and utilizing the inherent properties of Ga and Zr elements in the alloy, a dense surface layer (approximately 5-50 micrometers thick) with ultra-fine grains and even amorphous / nanocrystalline mixed structures is formed on the casting surface. This step lays the foundation for a substrate with excellent surface activity and stability for the entire product.

[0016] S2. Finishing and interface activation pretreatment of the billet system: After the casting is molded and polished, it undergoes multi-stage mechanical polishing until it is mirror-smooth, completely removing the oxide layer and further densifying the surface.

[0017] Subsequently, rigorous ultrasonic cleaning is performed to remove oil and particles. A key step is the electrochemical activation pretreatment: the workpiece is placed in a weakly acidic electrolyte, and electrical pulses with specific parameters are applied. The purpose is not corrosion, but rather to slightly etch and purify the surface, allowing the "rhodium-rich transition zone" formed in step one to be more fully exposed. At the same time, a highly active and clean metal surface is formed, creating optimal conditions for the bonding of subsequent electroplating layers.

[0018] S3. Gradient composite electroplating strengthening: Composite electroplating surface strengthening: The finished substrate workpiece is sequentially electroplated with a hard gold layer and an electroplated precious metal surface layer. This step is central to building the persistent functional layer, employing a carefully designed gradient plating structure: a: High-adhesion hard gold plating as the base layer. A cobalt sulfonate hard gold plating process is used. A hard gold layer is electroplated onto the activated substrate. This layer not only has high hardness (approximately 200-300 HV), but its cobalt element can form a strong interaction with Cu, Zn, and other elements in the substrate, achieving an "anchored" bond with the special substrate. It serves as a crucial buffer and transition layer connecting the substrate and the surface layer.

[0019] b: Electroplated ultra-hard, wear-resistant precious metal topcoat. A rhodium (Rh) or ruthenium (Ru) layer with a thickness of 0.05-0.3 micrometers is electroplated onto the hard gold layer. Rhodium is preferred. This layer provides ultimate hardness (>800 HV), ultra-high wear resistance, absolute chemical inertness, and a characteristic bright white luster. Because the substrate already possesses a "rhodium-rich transition zone," and the hard gold layer provides a smooth and robust support, this topcoat achieves extremely low porosity and extremely high adhesion.

[0020] S4. Post-processing: Post-processing: Clean and dry the electroplated workpiece.

[0021] Its purpose is to: 1) eliminate the internal stress generated during the electroplating process and prevent the generation and propagation of microcracks in the coating; 2) promote atomic interdiffusion between the hard gold layer and the precious metal surface layer, as well as between the hard gold layer and the "rhodium-rich transition zone" of the substrate, and form an extremely thin diffusion alloy layer at the interface, thereby further transforming the mechanical bond into a stronger metallurgical bond, and comprehensively improving the bonding strength and long-term stability of the coating system.

[0022] Preferably, in step S3, the electroplated hard gold layer is electroplated cobalt sulfamate hard gold, and the coating thickness is 1-5 micrometers.

[0023] Preferably, in step S3, the electroplated precious metal surface layer is an electroplated rhodium layer or an electroplated ruthenium layer, and the plating thickness is 0.05- 0.3 micrometers.

[0024] Preferably, between steps S3 and S4, a step of performing a low-temperature heat treatment on the electroplated workpiece is further included. The heat treatment temperature is 150-250℃, and the holding time is 15-60 minutes.

[0025] The beneficial effects of this invention are as follows: This invention achieves a synergistic breakthrough from the fundamental nature of materials to end-use performance by combining an innovative "Rh-Ru-Ir-Ga-Zr" multi-element microalloying composition design with a systematic "matrix optimization-interface activation-gradient plating-thermal diffusion stabilization" process. The approach begins at the material science level, using the synergistic effect of specific elements to form a finer microstructure within the 1K gold matrix and constructing a chemically stable "rhodium-rich transition zone" in situ on its surface, fundamentally improving the matrix's "quality." This key design, seamlessly integrated with subsequent carefully controlled electrochemical activation, cobalt sulfamate hard gold undercoating, and rhodium / ruthenium topcoat electroplating, successfully transforms the traditional weakly bonded "physical adhesion" interface into a strong "metallurgical anchoring" interface, ultimately forming a gradient composite structure of "reinforced matrix-transition layer-hard gold layer-rhodium topcoat" on a low-cost matrix. As a result, the product of this invention has achieved superior performance comparable to traditional high-karat gold-plated rhodium products, with high surface hardness, wear resistance and anti-discoloration ability, which can meet the stringent requirements of long-term wear of high-end jewelry. Detailed Implementation

[0026] The present invention will be further described in detail below with reference to the embodiments. The embodiments are only used to explain the present invention and are not intended to limit the scope of protection of the present invention.

[0027] Example 1 1. Alloy composition (wt%): Au: 4.166%, Ru: 0.25%, Ir: 0.12%, Rh: 0.28%, Ga: 1.6%, Zr: 0.07%, Zn: 9.0%, Cu: balance.

[0028] 2. Preparation process: S1 Melting and Casting: Place all raw materials in a vacuum induction melting furnace, melt them evenly under argon protection, pour them into a silica sol precision casting mold preheated to 280°C, and let them cool naturally to obtain the ring casting.

[0029] S2 Finishing and Pretreatment: The casting is molded and mechanically polished to a mirror finish. Then, it undergoes cathodic electrochemical activation treatment for 60 seconds in a solution containing 5% dilute sulfuric acid at room temperature and a current density of 0.5 A / dm², followed by ultrasonic cleaning with pure water.

[0030] S3 composite electroplating: a. Electroplating of hard gold layer: Electroplating is performed in a cobalt sulfamate hard gold plating bath at 45°C for 12 minutes at a current density of 0.8 A / dm² to obtain a hard gold layer with a thickness of about 2.5 micrometers.

[0031] b. Rhodium plating: In a standard rhodium sulfate plating solution at 50°C, a rhodium layer of approximately 0.08 micrometers thickness is obtained by electroplating at a current density of 1.5 A / dm² for 1.5 minutes.

[0032] S4 Post-treatment: Place the electroplated workpiece in a vacuum furnace and heat treat it at 180°C for 45 minutes, then cool it in the furnace.

[0033] Example 2 1. Alloy composition (wt%): Au: 4.166%, Ru: 0.45%, Ir: 0.08%, Rh: 0.18%, Ga: 2.2%, Zr: 0.12%, Zn: 7.5%, Cu: balance.

[0034] 2. Preparation process: The basic process is the same as in Example 1, with the main parameters adjusted as follows. S1 Melting and Casting: Place all raw materials in a vacuum induction melting furnace, melt them evenly under argon protection, and pour them into a preheated state. The ring casting is obtained by natural cooling in a silica sol precision casting mold at 320℃.

[0035] S2 Finishing and Pretreatment: The casting is molded and mechanically polished to a mirror finish. Then, it undergoes cathodic electrochemical activation treatment for 60 seconds in a solution containing 5% dilute sulfuric acid at room temperature and a current density of 0.5 A / dm², followed by ultrasonic cleaning with pure water.

[0036] S3 composite electroplating: a. Electroplating of hard gold layer: Electroplating is performed in a cobalt sulfamate hard gold plating bath at 45°C for 15 minutes at a current density of 0.8 A / dm² to obtain a hard gold layer with a thickness of about 3 micrometers.

[0037] b. Surface layer: Using the ruthenium electroplating process, a ruthenium layer of approximately 0.15 micrometers thick is obtained by electroplating in a ruthenium sulfamate plating solution at 30°C with a current density of 2.0 A / dm² for 2 minutes.

[0038] S4 Post-treatment: Place the electroplated workpiece in a vacuum furnace and heat treat it at 200°C for 30 minutes, then cool it in the furnace.

[0039] Example 3 1. Alloy composition (wt%): Au: 4.166%, Ru: 0.15%, Ir: 0.25%, Rh: 0.35%, Ga: 1.0%, Zr: 0.05%, Zn: 10.5%, Cu: balance.

[0040] 2. Preparation process: The basic process is the same as in Example 1, with the main parameters adjusted as follows: S1 Melting and Casting: Place all raw materials in a vacuum induction melting furnace, melt them evenly under argon protection, pour them into a silica sol precision casting mold preheated to 280°C, and let them cool naturally to obtain the ring casting.

[0041] S2 Finishing and Pretreatment: The casting is molded and mechanically polished to a mirror finish. Then, it undergoes cathodic electrochemical activation treatment for 90 seconds in a solution containing 5% dilute sulfuric acid at room temperature and a current density of 0.3 A / dm², followed by ultrasonic cleaning with pure water.

[0042] S3 composite electroplating: a. Electroplating of hard gold layer: Electroplating is performed in a cobalt sulfamate hard gold plating bath at 45°C for 8 minutes at a current density of 0.8 A / dm² to obtain a hard gold layer with a thickness of about 1.5 micrometers.

[0043] b. Rhodium plating: In a standard rhodium sulfate plating solution at 50°C, a rhodium layer of approximately 0.12 micrometers thickness is obtained by electroplating at a current density of 1.5 A / dm² for 2 minutes.

[0044] S4 Post-treatment: Place the electroplated workpiece in a vacuum furnace and heat treat it at 160°C for 60 minutes, then cool it in the furnace.

[0045] Comparative Example 1 (Traditional 1K gold substrate + conventional rhodium plating) 1. Alloy composition (wt%): Au: 4.166%, Cu: 70.0%, Zn: 25.834% 2. Preparation process: The same lost-wax casting and polishing process as in Example 1 was used. After polishing, conventional rhodium plating was performed directly (process parameters...). Same as step S3-b of Example 1, without electrochemical activation, without hard gold plating as the underlayer, and without low-temperature heat treatment.

[0046] Comparative Example 2 (Alloy substrate of this invention + conventional rhodium plating) 1. Alloy composition (wt%): Au: 4.166%, Ru: 0.25%, Ir: 0.12%, Rh: 0.28%, Ga: 1.6%, Zr: 0.07%, Zn: 9.0%, Cu: balance.

[0047] 2. Preparation process: S1 Melting and Casting: Place all raw materials in a vacuum induction melting furnace, melt them evenly under argon protection, pour them into a silica sol precision casting mold preheated to 280°C, and let them cool naturally to obtain the ring casting.

[0048] S2 Finishing and Pretreatment: The casting is molded and mechanically polished to a mirror finish. Then, it undergoes cathodic electrochemical activation treatment for 60 seconds in a solution containing 5% dilute sulfuric acid at room temperature and a current density of 0.5 A / dm², followed by ultrasonic cleaning with pure water.

[0049] S3 composite electroplating: a. Electroplating of rhodium layer: Electroplating is performed in a standard rhodium sulfate plating solution at 50°C for 1.5 minutes at a current density of 1.5 A / dm² to obtain a rhodium layer with a thickness of approximately 0.08 micrometers.

[0050] Comparative Example 3 (Traditional 1K gold substrate + composite electroplating process of the present invention) 1. Alloy composition (wt%): Au: 4.166%, Cu: 70.0%, Zn: 25.834%.

[0051] 2. Preparation process: Except for the different matrix composition, the surface treatment process steps and parameters are the same as those in Example 1.

[0052] IV. Performance Test Results 1. Surface hardness test (micro Vickers hardness) Test method: A micro Vickers hardness tester was used to perform indentation tests on the sample surface with a small load (HV 0.025). The average value of at least 5 different locations was taken for each sample to avoid the influence of the matrix.

[0053] Implementation standard: Based on ISO 6507 "Metallic materials—Vickers hardness test".

[0054] 2. Abrasion resistance test (gloss retention rate) Test method: Using a Taber abrasion tester, a CS-10 friction wheel was selected, and a load of 500g was applied to the sample for 5000 reciprocating friction cycles. Before and after the test, the gloss value at 60° of the surface was measured using a gloss meter, and the gloss retention rate (%) was calculated.

[0055] The test principle shall be in accordance with ASTM D4060, "Standard Test Method for Determining the Abrasion Resistance of Organic Coatings by Taber Abrasion Tester".

[0056] 3. Sweat corrosion resistance test (color difference change ΔE) Test method: Prepare artificial acidic sweat solution with pH=4.7 (according to ISO 3160-2 formula). Completely immerse the sample in the sweat solution and let it stand in a constant temperature chamber at 37±1℃ for 168 hours. After removing, cleaning and drying, use a colorimeter to measure the color change of the surface before and after the test, expressed as the color difference value ΔE. The smaller the ΔE, the better the corrosion resistance.

[0057] The standard for implementation is based on ISO 3160-2 "Case and accessories thereof - Gold alloy coatings - Part 2: Determination of resistance to perspiration corrosion".

[0058] 4. SO2 accelerated corrosion test (appearance evaluation) Test method: Place the sample in a humid atmosphere of 0.1% (volume fraction) SO2 (temperature 40±1℃, relative humidity 100%) for 24 hours. After removal, visually and microscopically observe the surface for corrosion spots, discoloration, loss of gloss, or rust, and record the appearance.

[0059] Implementation standard: Refer to the industry-standard method for testing in humid atmospheres containing SO2 in ISO 9227 "Catalytic corrosion tests - Salt spray test".

[0060] The samples obtained from the above embodiments and comparative examples were tested, and the results are summarized in the table below: Table 1. Performance test results of the examples and comparative examples Results Analysis and Conclusions Advantages of the comprehensive solution of this invention (Examples 1-3): The samples in all three examples exhibited optimal and stable overall performance in all tests. Cross-cut adhesion and thermal shock tests both met the highest standards, demonstrating the decisive role of the entire process chain of "substrate reinforcement - interface activation - gradient coating - thermal diffusion stabilization" in achieving superior coating adhesion. Its extremely high abrasion resistance and gloss retention rate, along with extremely low color difference due to sweat corrosion, confirm that this solution can provide a durable high-gloss appearance and excellent resistance to discoloration.

[0061] The key role of the matrix alloy: Comparing Example 1 and Comparative Example 3, both used the exact same surface treatment process, differing only in matrix composition. The results showed that the properties of Comparative Example 3 (conventional matrix), especially adhesion and corrosion resistance, were significantly inferior to those of Example 1. This strongly demonstrates that the specific "Rh-Ru-Ir-Ga-Zr" microalloyed matrix of this invention is a prerequisite and material basis for achieving high performance, and the "rhodium-rich transition region" formed therein plays a crucial role in improving the interfacial nature.

[0062] The necessity of a composite electroplating process chain: Comparing Example 1 and Comparative Example 2, both have the same substrate, but Comparative Example 2 omits the hard gold undercoat and complete post-treatment. Its adhesion, wear resistance, and corrosion resistance all show a significant decrease, indicating that substrate optimization alone is insufficient to achieve the best results. A complete gradient composite electroplating and stabilization process is necessary to maximize the advantages of the substrate and construct a robust and durable surface protection system.

[0063] Limitations of traditional solutions: Comparative Example 1 represents the most common traditional process currently available, which has the worst performance, especially in terms of bonding strength and corrosion resistance, which verifies the authenticity of the industry pain points described in the background art.

[0064] In summary, this invention, through systematic synergistic innovation in composition and process, successfully solves the technical problems of poor wear and corrosion resistance and easy peeling of plating in traditional 1K gold jewelry, and provides an industrializable, high-performance, and low-cost high-end jewelry manufacturing solution.

[0065] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or basic characteristics. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

[0066] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A wear-resistant and corrosion-resistant 1K gold alloy for jewelry, characterized in that, Its composition, by weight percentage, includes: Gold (Au): 4.166%; Rhodium (Rh): 0.1% - 0.5%; Ruthenium (Ru): 0.1% - 0.8%; Iridium (Ir): 0.05% - 0.3%; Gallium (Ga): 0.5% - 2.5%; Zirconium (Zr): 0.03% - 0.15%; Zinc (Zn): 6.0% - 12.0%; The balance is copper (Cu) and unavoidable impurities.

2. The 1K gold alloy according to claim 1, characterized in that, The rhodium (Rh) content is 0.18% - 0.35% by mass.

3. The 1K gold alloy according to claim 1, characterized in that, The mass percentage of ruthenium (Ru) is 0.15% - 0.45%.

4. The 1K gold alloy according to claim 1, characterized in that, The mass percentage of gallium (Ga) is 1.0% - 2.2%.

5. A method for preparing 1K gold alloy jewelry articles as described in any one of claims 1-4, characterized in that, Includes the following sequential steps: S1. Alloy smelting and precision casting: Smelt the alloy according to the formula and pour it to obtain jewelry castings; S2. Surface finishing and activation pretreatment of billet: Polish the casting to a mirror finish, and then perform electrochemical activation treatment; S3. Gradient composite electroplating strengthening: A hard gold layer and a precious metal surface layer are electroplated sequentially on the activated substrate surface; S4. Low-temperature thermal diffusion stabilization treatment: Heat treatment is performed on the electroplated workpiece.

6. The method according to claim 5, characterized in that, The electrochemical activation current density in step S2 is 0.1 - 1.0 A / dm², and the treatment time is 30 - 120 seconds.

7. The method according to claim 5, characterized in that, The electroplated hard gold layer in step S3 is electroplated cobalt sulfamate hard gold, with a thickness of 1-5 micrometers.

8. The method according to claim 5, characterized in that, The electroplated precious metal surface layer in step S3 is an electroplated rhodium layer or an electroplated ruthenium layer, with a thickness of 0.05-0.3 micrometers.

9. The method according to claim 5, characterized in that, The low-temperature thermal diffusion stabilization treatment in step S4 is carried out in a vacuum or protective atmosphere at a temperature of 150°C - 250°C for 15 - 60 minutes.

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