18K gold luster imitation gold alloy suitable for sculpture field and preparation method of 18K gold luster imitation gold alloy

Abstract

The invention discloses a 18K gold luster imitation gold alloy suitable for the sculpture field and a preparation method thereof, the 18K gold luster imitation gold alloy comprises the following basic components in percentage by weight: 20-22% of zinc, 10-20% of copper, 10-20% of zinc, 10-20% of copper, 10-20% of copper and 10-20% of zinc. 3%-4% of aluminum; 2%-3% of silicon; 0.9% to 1.9% of nickel; 0.1% of rare earth, and the balance copper and inevitable impurities. The method has the beneficial effects that one-time forming can be directly carried out through conventional copper art sculpture machining modes such as casting and forging, follow-up complicated procedures such as gilding and gilding are not needed, the sculpture production period is greatly shortened, the manual operation difficulty is reduced, and the 18K gold appearance is accurately matched.

Description

Technical Field

[0001] This invention relates to the field of gold-imitation alloy technology, and in particular to an 18K gold-luster gold-imitation alloy based on copper and zinc, which can directly replace the "copper-based + gold plating" process and is suitable for sculpture making, as well as its preparation method. Background Technology

[0002] 18K gold, with its warm and rich golden color, is widely used in sculpture (especially bronze sculptures, religious sculptures, and decorative sculptures). Traditionally, this is achieved by "gilding, plating, or gilding the bronze base sculpture after it has been formed." However, this process has significant drawbacks: First, it is complex, requiring multiple steps such as surface pretreatment, adhesive application, gilding, and polishing, resulting in a long production cycle and high labor costs. Second, the bonding stability between the gilded layer and the bronze base is limited, leading to problems such as peeling, flaking, and oxidation over long-term use, resulting in high maintenance costs. Third, the high price of gold raw materials keeps the overall cost of sculptures high, limiting the promotion of bronze sculptures in the low-to-mid-range market and the exploration of stylistic diversity.

[0003] Copper-zinc alloys have become an important direction for gold-imitation materials due to their low raw material cost and good casting and processing performance. However, existing copper-zinc gold-imitation alloys generally suffer from problems such as a light color (appearing as "white gold") or reddish color (appearing as "copper red"), poor luster persistence, and insufficient compatibility of added elements with the copper-zinc matrix leading to a decline in mechanical properties. They are difficult to accurately match the appearance and texture of 18K gold and cannot meet the core requirements of sculpture for material strength and formability. Therefore, developing a copper-zinc gold-imitation alloy that can be directly used in sculpture production, with a color and luster close to 18K gold and controllable cost, is of great practical significance for promoting simplified production, cost reduction and efficiency improvement, and stylistic diversification in the copper art sculpture industry.

[0004] For example, Chinese invention patent publication number CN118957354A discloses an imitation gold-colored bronze alloy for architectural decoration and its preparation method. The imitation gold-colored bronze alloy, calculated by weight percentage (100%), includes: 82-86% Cu, 0.4-0.8% Sn, 2.0-3.5% Mn, 0.8-1.4% Al, 0.6-0.8% Ni, and at least one element selected from La, In, Sc, and Ti. The remaining components of the copper alloy are Zn and unavoidable impurities. Although the patent provides a qualitative analysis of the color of the imitation gold alloy from the perspectives of brightness value, red-green value, and blue-yellow value, it does not provide a direct comparison photograph with 18K gold, and therefore cannot prove how close the color of the imitation gold-colored bronze alloy is to the color of gold.

[0005] For example, Chinese invention patent publication number CN117210715A discloses a novel imitation gold alloy and its preparation method. Based on 100% of the total weight of the novel imitation gold alloy, it includes the following components in the following weight percentages: Al: 0.5-2wt%, Zn: 35-43wt%, Ge: 0.01-0.5wt%, Dy: 0.01-0.5wt%, with the balance being Cu. This patent significantly increases the brightness of the alloy through trace amounts of germanium and dysprosium, and the combination with the basic components makes the alloy's color similar to gold. However, it also only qualitatively analyzes the color of the imitation gold alloy from the perspective of brightness value, red-green value, and blue-yellow value, without providing direct photographic comparisons to demonstrate the degree of similarity to the color of gold. Summary of the Invention

[0006] The technical problem to be solved by this invention is that the existing copper art sculpture "copper base + gold leaf" process is complicated and costly, and the appearance deviation of traditional copper-zinc imitation gold alloy is large. To this end, an 18K gold luster imitation gold alloy suitable for the field of sculpture and its preparation method are provided.

[0007] The technical solution of the present invention is: an 18K gold-luster imitation gold alloy suitable for the field of sculpture, comprising: copper and zinc as the basic components, and the contents of each component by weight percentage are as follows: zinc: 20% to 22%; aluminum: 3% to 4%; silicon: 2% to 3%; nickel: 0.9% to 1.9%; rare earth: 0.1%, with the balance being copper and unavoidable impurities.

[0008] A method for preparing an 18K gold-luster imitation gold alloy suitable for the field of sculpture includes the following steps: (1) Raw material pretreatment: Remove oil and impurities from copper, zinc, aluminum, silicon, nickel and rare earth raw materials and mix them in proportion; (2) Smelting: Place the above raw materials in a medium frequency induction furnace, introduce argon gas for protection, heat to 1150℃-1200℃, stir for 15min to make the composition uniform, and keep warm for 35min-40min to obtain a molten alloy; (3) Casting: Cast the molten alloy into a decorative sculpture silicone mold, and demold after natural cooling to room temperature.

[0009] The rare earth element mentioned in the above scheme is one or a mixture of two of lanthanum and cerium.

[0010] The improvement of the above scheme also includes step (4), post-processing: after sanding and polishing with cloth wheel, a decorative sculpture with full color and gloss consistent with 18K gold is obtained.

[0011] The beneficial effects of this invention are: 1. It replaces the traditional gilding process, simplifying the production process: It can be directly formed in one step through conventional copper art sculpture processing methods such as casting and forging, without the need for complicated subsequent gilding and plating processes, greatly shortening the sculpture production cycle and reducing the difficulty of manual operation; 2. It accurately matches the appearance of 18K gold, meeting the aesthetic needs of sculpture: Copper and zinc form the base color for imitation gold, aluminum can enhance the color saturation and suppress the reddish tendency of copper, and nickel can improve the surface metallic luster and oxidation resistance, ensuring that the finished sculpture has a full color and warm luster, with an appearance consistency of more than 95% with 18K gold sculptures; 3. It significantly reduces costs and expands application scenarios: The raw materials are mainly copper and zinc, and the overall cost is only 1 / 15 to 1 / 10 of that of 18K gold, and lower than the traditional "copper base + gilding" method. "40% of the process cost can promote the popularization of copper art sculptures to the low-end market such as civil decoration and small handicrafts; 4. Balancing the practicality and stability of sculptures: Silicon can improve the compatibility of copper-zinc matrix with other additives, and rare earths refine the grains, so that the alloy has both good casting fluidity (suitable for complex sculpture shapes) and mechanical strength (tensile strength ≥350MPa), and excellent surface oxidation resistance. After long-term exposure to air, there is no obvious discoloration or corrosion, reducing the later maintenance cost of sculptures; 5. Enriching the diversity of copper art sculptures: The combination of low cost and easy processing can support sculptors to be more daring in their design (such as complex hollow and thin-walled shapes). At the same time, different 18K gold texture effects such as matte and glossy can be achieved by adjusting the polishing process, expanding the stylistic diversity of copper art sculptures." Attached Figure Description

[0012] Figure 1 These are comparison photos of the gold-imitation alloy and 18K gold in Embodiment 1 of the present invention; Figure 2 These are comparison photos of the gold-imitation alloy and 18K gold in Embodiment 2 of the present invention; Figure 3 This is a partial photograph of the gold-plated alloy of Comparative Example 1 of the present invention. Detailed Implementation

[0013] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the examples. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments implemented by those skilled in the art without creative effort are within the protection scope of the present invention.

[0014] Example 1: A copper-zinc alloy suitable for small decorative sculptures, by weight percentage: Cu 71%, Zn 22%, Al 4%, Si 2%, Ni 0.9%, rare earth (lanthanum) 0.1%.

[0015] Preparation and Sculpting Process: 1. Raw Material Pretreatment: Remove oil and impurities from copper, zinc, aluminum, silicon, nickel, and rare earth raw materials and mix them in proportion; 2. Melting: Place in a medium-frequency induction furnace, introduce argon gas for protection, heat to 1150℃, stir for 15 minutes to ensure uniform composition, and hold at that temperature for 35 minutes; 3. Casting: Pour the molten alloy into a small decorative sculpture silicone mold, allow it to cool naturally to room temperature, and then demold; 4. Post-treatment: After sanding and polishing with a cloth wheel, a small decorative sculpture with a rich color and luster consistent with 18K gold is obtained, with no risk of gold leaf peeling off. Figure 1 As shown, the left side is a product photo of Example 1, and the right side is a photo of 18K gold. By comparison, it can be found that the color of the product of Example 1 is almost the same as the color of 18K gold.

[0016] Example 2: A copper-zinc alloy suitable for large outdoor bronze sculptures, by weight percentage: Cu 72%, Zn 20%, Al 3%, Si 3%, Ni 1.9%, rare earth (cerium) 0.1%.

[0017] Preparation and Sculpture Forming Process: 1. Raw Material Mixing: Weigh each component according to the proportion and mix them evenly using mechanical methods; 2. Melting: Melt at 1200℃ under nitrogen protection, stir for 20 minutes, and hold for 40 minutes; 3. Forging and Forming: Cast the molten alloy into thick slabs, process them into segmented parts of the large sculpture through forging, and then weld and assemble them; 4. Surface Treatment: After sandblasting and fine polishing, the finished large outdoor sculpture is obtained. After a 300-hour salt spray test, there was no obvious discoloration on the surface; after mechanical property testing, the tensile strength reached 380MPa, meeting the wind resistance and weather resistance requirements of outdoor sculptures. Figure 2 As shown, the left side is a product photo of 18K gold, and the right side is a photo of Example 1. By comparison, it can be found that the appearance of Example 2 is visually indistinguishable from that of the 18K gold outdoor sculpture.

[0018] Comparative Example 1: The difference from Example 1 is that Cu is 71.4% and Ni content is 2.5%, otherwise the same. The resulting product photo is shown below. Figure 3 As shown, the color turns bluish when the Ni content exceeds 2%.

Claims

1. An 18K gold-luster imitation gold alloy suitable for the field of sculpture, characterized by comprising: Based on copper and zinc as the base components, the content of each component by weight percentage is as follows: Zinc: 20%–22%; Aluminum: 3%–4%; Silicon: 2%–3%; Nickel: 0.9%–1.9%; rare earth elements: 0.1%, with the balance being copper and unavoidable impurities.

2. The method for preparing an 18K gold-luster imitation gold alloy suitable for the field of sculpture as described in claim 1, characterized in that: Includes the following steps: (1) Raw material pretreatment: Remove oil and impurities from copper, zinc, aluminum, silicon, nickel and rare earth raw materials and mix them in proportion; (2) Smelting: Place the above raw materials in a medium frequency induction furnace, introduce argon gas for protection, heat to 1150℃-1200℃, stir for 15min-20min to make the composition uniform, and keep warm for 35min-40min to obtain molten alloy; (3) Casting: Cast the molten alloy into a decorative sculpture silicone mold, and demold after natural cooling to room temperature.

3. The method for preparing an 18K gold-luster imitation gold alloy suitable for the field of sculpture as described in claim 2, characterized in that: The rare earth element is one or a mixture of two of lanthanum and cerium.

4. The method for preparing an 18K gold-luster imitation gold alloy suitable for the field of sculpture as described in claim 2, characterized in that: It also includes step (4) post-processing: after sanding and polishing with cloth wheel, a decorative sculpture with full color and luster consistent with 18K gold is obtained.

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