Silver enamel electroplating process based on precious metal deep processing

Abstract

The invention discloses a silver enamel electroplating process based on precious metal deep processing, and relates to the field of metal processing, and the silver enamel electroplating process comprises the following steps: step 1, casting a 925Ag silver blank by modules: slicing a three-dimensional figure structure into a head module, a trunk module, a clothes module and an accessory module according to a 3D model to manufacture a wax mold, and preparing the 925Ag silver blank by adopting an investment casting process, invisible welding interfaces are preset at the joints of the modules, and anti-oxidation electroplating is carried out; 2, glaze filling, wherein the pattern area on the surface of the silver body is accurately filled with glaze through a conical micropore injector, and the glaze comprises 55%-65% of SiO2, 10%-18% of K2O, 5%-10% of CuO and 3%-8% of CoO; the thermal stress is effectively relieved, the integrity of the enamel layer is ensured, the oxidation resistance and the wear resistance are remarkably improved, the cultural pattern visual effect of non-heritage products is protected, and the investment value of the non-heritage products serving as high-end cultural gifts is also increased.

Description

Technical Field

[0001] This invention relates to the field of metal processing technology, specifically to a silver enamel electroplating process for deep processing of precious metals. Background Technology

[0003] Intangible cultural heritage products involving silver objects and enamel craftsmanship, such as Tibetan, Miao, and Mongolian silver objects, often feature complex ethnic patterns and three-dimensional designs. Silver, as a precious metal, has high value as a store of value and investment. Its ductility and processing properties are suitable for making complex three-dimensional handicrafts. Enamel craftsmanship, as a traditional decorative technique, can endow silver products with rich colors and artistic expression. However, the process of combining enamel with silver base faces technical bottlenecks in high-temperature firing, material matching, and surface protection, which limits its widespread application in high-end cultural and creative products.

[0004] In existing technologies, the enamel layer of integrally cast silver bodies is prone to cracking or peeling during the enamel firing process due to differences in thermal expansion coefficients and uneven heating. This problem is particularly prominent in complex three-dimensional figurines, affecting the product's aesthetics and durability. Intangible cultural heritage silver products are easily oxidized and blackened on the surface due to long-term exposure to air, affecting the visual effect of cultural patterns and the product's value. Traditional anti-oxidation treatments often use simple varnish coatings, which have limited effectiveness and are prone to wear.

[0005] The ethnic patterns in intangible cultural heritage products are intricate and complex. Traditional hand-painting or carving is difficult to accurately reproduce on curved silver surfaces, which can easily lead to the distortion of cultural elements and weaken the cultural identity of the products. Summary of the Invention

[0006] (a) Technical problems to be solved

[0007] In view of the above-mentioned shortcomings of the existing technology, the present invention provides a silver enamel electroplating process for deep processing of precious metals, which can effectively solve the problems of the existing technology.

[0008] (II) Technical Solution

[0009] To achieve the above objectives, the present invention provides the following technical solution:

[0010] This invention discloses a silver enamel electroplating process for deep processing of precious metals, comprising the following steps:

[0011] Step 1, 925Ag silver base casting in modules: According to the 3D model, the three-dimensional character structure is divided into head, torso, clothing and accessories modules to make wax models. The 925Ag silver base is prepared by investment casting process. The connection points of each module are pre-set with invisible welding interfaces and subjected to anti-oxidation electroplating.

[0012] Step 2, glaze filling: The glaze is precisely filled into the patterned area on the surface of the silver body using a conical micro-injector. The glaze contains 55% to 65% SiO2, 10% to 18% K2O, 5% to 10% CuO, and 3% to 8% CoO.

[0013] Step 3, Gradient enamel firing: The silver body filled with enamel is fired at a stepped temperature. The clothing area is glazed at a low temperature of 680-720℃ and fired at a high temperature of 780-820℃.

[0014] Step 4, Laser Micro-etching: A laser etching machine is used to prepare micro-textures with a depth <0.2mm on the silver substrate surface. After firing, the surface undergoes ion cleaning with a current density of 1.0–1.5 A / dm². 2 A 0.3-0.5μm rhodium layer is plated using pulse electroplating with a duty cycle of 20%–40%.

[0015] Step 5, Pulse electroplating: Dip a fluorinated silane-containing nano-sealing agent onto the surface of the rhodium layer to form a hydrophobic protective film;

[0016] Step 6, Nano-sealing: Seamlessly weld and assemble each silver-plated module through invisible interfaces;

[0017] Step 7, Digital Adaptation: Based on the preset style database, generate pattern paths to adapt to the curved silver surface using a 3D topology algorithm.

[0018] Furthermore, in step 1, during the modular casting process, the invisible threaded groove interface is located on the inner side of the garment hem, with an interface depth of 0.5-1mm and a thread pitch of 0.3mm. Each silver-based module is treated with a 0.2μm thick gold-nickel alloy anti-oxidation pre-plating layer, and the surface of the threaded groove interface is pre-plated with a 0.1μm palladium layer, with a welding strength ≥50MPa.

[0019] Furthermore, in step 2, the glaze is reinforced with 0.5% nano-Ai2O3, which has a thermal expansion coefficient matching that of the silver body and a melting point range of 680-820℃, making it suitable for the zoned firing process.

[0020] Furthermore, in the gradient firing process of step 3, the glazing of the clothing area and the glazing of the metal accessories area are carried out in stages and fired separately. The firing process adopts a three-stage temperature control: heating up at 100℃ / min; holding at 30min; and slow cooling at 5℃ / min.

[0021] Furthermore, the laser micro-etching in step 4 uses a 1064nm fiber laser with an etching depth of <0.2mm, a positioning accuracy of ±0.05mm, a pattern line width of ≤0.15mm, and an aspect ratio of 1:1.2.

[0022] Furthermore, the pulse electroplating parameters in step 4 are: current density 1.2 A / dm³. 2The duty cycle is 30%; the rhodium plating layer thickness is 0.4±0.1μm; the plating solution contains 80g / L rhodium sulfate, the complexing agent is ammonium aminosulfonate, and the temperature is 40±2℃.

[0023] Furthermore, the nano-sealing agent in step 5 contains perfluorooctyltriethoxysilane, with 1% nano-SiO2 particles added, resulting in a film hardness of 3H, a contact angle ≥110° after film formation, and a film thickness of 80±20nm.

[0024] Furthermore, the 3D topology algorithm in step 7 achieves pattern recognition accuracy >99% and mapping distortion rate ≤3% by using curvature adaptive mapping and a convolutional neural network.

[0025] (III) Beneficial Effects

[0026] Compared with the known prior art, the technical solution provided by this invention has the following beneficial effects:

[0027] 1. By using split-structure casting and gradient firing technology, the complex three-dimensional shapes of intangible cultural heritage silver enamel products are prone to cracking. This technology enables zoned glazing and temperature control, effectively alleviating thermal stress and ensuring the integrity of the enamel layer. At the same time, the invisible threaded groove interface design takes into account both aesthetics and strength, significantly improving the product's durability and ability to reproduce cultural value, and providing a technological breakthrough for the modern application of intangible cultural heritage crafts.

[0028] 2. By introducing a pulsed electroplated rhodium layer and a nano-sealing agent to form a composite protective layer, the traditional intangible cultural heritage silver products are prone to oxidation and blackening. This significantly improves their anti-oxidation and wear resistance, extending the product's lifespan compared to traditional processes. It not only protects the visual effect of the cultural patterns on the intangible cultural heritage products but also enhances their investment value as high-end cultural gifts.

[0029] 3. By employing 3D topology algorithms and laser micro-etching technology, high-precision reproduction of intangible cultural heritage ethnic patterns on curved silver substrates is achieved, solving the problem of cultural element distortion in traditional handicrafts. This technology, combined with convolutional neural networks, standardizes the entire process from digital acquisition to adaptation and processing, ensuring the authenticity and consistency of cultural heritage transmission and facilitating the large-scale production of intangible cultural heritage products. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0031] Figure 1 This is a schematic diagram of the process of the present invention. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0033] like Figure 1 As shown, the present invention will be further described below with reference to embodiments.

[0034] Example 1

[0035] This embodiment describes a silver enamel electroplating process for precious metal deep processing, used to create a 15cm tall silver enamel figure statue, comprising:

[0036] Based on the pre-designed 3D model, the figure sculpture structure was divided into four modules: head, torso, clothing, and accessories. Each module was layered using slicing software to create wax models. A 925Ag silver base was then prepared using investment casting. Hidden threaded groove interfaces were pre-set at the connection points of each module, located inside the hem of the clothing, with an interface depth of 0.8mm and a thread spacing of 0.3mm. After casting, the silver base surface was polished, and each module surface underwent an anti-oxidation pre-plating treatment with a 0.2μm thick gold-nickel alloy layer. An additional 0.1μm palladium layer was pre-plated on the threaded groove interfaces to ensure a weld strength of 55MPa.

[0037] A conical micro-injector with a 0.1mm aperture was used to precisely fill the pre-designed pattern area on the silver substrate surface with glaze. The glaze composition was: 62% SiO2, 15% K2O, 8% CuO, 5% CoO, with 0.5% nano-Al2O3 added as a reinforcing phase. The coefficient of thermal expansion of the glaze was 19.5 × 10⁻⁶. -6 / ℃, compatible with silver-plated materials, with a melting point range of 680-820℃.

[0038] The silver body filled with glaze is placed in a firing furnace and fired using a zoned, stepped heating process. The glaze in the clothing area is fired at 700℃, and the glaze in the metal accessories area is fired at 800℃. The firing process is divided into three temperature control stages: the first stage involves heating to the target temperature at 100℃ / min; the second stage involves holding the temperature for 30 minutes; and the third stage involves slow cooling to room temperature at 5℃ / min.

[0039] A 1064nm fiber laser was used to fabricate microtextures on a silver substrate. The etching depth was 0.15mm, the positioning accuracy was ±0.05mm, the pattern linewidth was 0.12mm, and the aspect ratio was 1:1.2. After etching, ion cleaning was performed to remove surface impurities, followed by etching at a current density of 1.2A / dm³. 2 Pulse electroplating was performed under a duty cycle of 30%, with the plating solution containing 80 g / L rhodium sulfate and ammonium aminosulfonate as the complexing agent. The plating solution temperature was controlled at 40℃, ultimately forming a rhodium layer with a thickness of 0.4 μm.

[0040] A nano-sealing agent containing perfluorooctyltriethoxysilane was dipped onto the surface of a rhodium layer, and 1% nanoparticles were added. After film formation, the film thickness was 85 nm, the hardness reached 3H, and the contact angle was 112°, forming a hydrophobic protective film.

[0041] Each silver tire module is assembled by seamless welding using an invisible threaded groove interface, ensuring a welding strength of no less than 50MPa. After welding, the interface is polished.

[0042] Based on a preset pattern database, a 3D topology algorithm is used to generate pattern paths that are adapted to curved silver tires through curvature adaptive mapping and convolutional neural networks. The pattern recognition accuracy reaches 99.2%, and the mapping distortion rate is controlled below 2.5%.

[0043] This embodiment utilizes a silver enamel electroplating process based on precious metal deep processing to create a 15cm tall figure statue. Modular design and investment casting techniques, combined with concealed threaded groove interfaces and an anti-oxidation pre-plating layer, ensure seamless assembly and welding strength of each module within the silver base, enhancing the overall structural stability and aesthetics. Precise enamel filling and phased firing in designated areas match the thermal expansion coefficient of the enamel to that of the 925Ag silver base, resulting in a crack-free surface, uniform color, and a high-quality artistic effect after firing. Furthermore, laser micro-etching and pulsed rhodium plating further enhance the fineness and corrosion resistance of the surface patterns, while the application of a hydrophobic protective film effectively prevents water stains and fingerprint contamination, extending the statue's lifespan. The pattern paths generated by a 3D topology algorithm ensure precise adaptation to complex curved surfaces. Overall, the process enhances the artistic value and market competitiveness of the silver enamel product.

[0044] Example 2

[0045] This embodiment describes a silver enamel electroplating process for precious metal deep processing, used to create a 10cm × 8cm silver enamel decorative ornament, comprising:

[0046] Based on the 3D model, the decorative ornament is divided into three modules: the main body, the base, and the decorative patterns. A wax model is created, and a 925Ag silver base is prepared using investment casting. The module connections have pre-set invisible threaded groove interfaces with a depth of 0.6mm and a thread pitch of 0.3mm, located inside the base. After casting, the silver base surface is treated with a 0.2μm thick gold-nickel alloy anti-oxidation pre-plating layer, and the threaded groove interface surface is pre-plated with a 0.1μm palladium layer, achieving a welding strength of 52MPa.

[0047] Using a conical micro-injector with an aperture of 0.1 mm, the glaze was filled into the patterned areas of the silver substrate. The glaze composition was: 60% SiO2, 16% K2O, 9% CuO, 6% CoO, with 0.5% nano-Ai2O3 added as a reinforcing phase. The coefficient of thermal expansion was 19.5 × 10⁻⁶. -6 / ℃, melting point range 680-820℃.

[0048] The silver body filled with glaze was fired in sections. The glaze in the main decorative area was fired at 690℃, and the glaze in the metal base was fired at 810℃. The firing process adopted a three-stage temperature control: the first stage was to raise the temperature at 100℃ / min; the second stage was to hold the temperature for 30 minutes; and the third stage was to cool slowly at 5℃ / min.

[0049] A 1064nm fiber laser was used to etch microtextures to a depth of 0.18mm onto a silver substrate, with a positioning accuracy of ±0.05mm, a pattern linewidth of 0.14mm, and an aspect ratio of 1:1.2. After etching, ion cleaning was performed, followed by etching at a current density of 1.3A / dm³. 2 Pulse electroplating was performed under a duty cycle of 35%, with the plating solution containing 80 g / L rhodium sulfate, the complexing agent being ammonium aminosulfonate, and the temperature controlled at 41℃, to form a rhodium layer with a thickness of 0.45 μm.

[0050] A nano-sealing agent containing perfluorooctyltriethoxysilane was dip-coated onto the surface of a rhodium layer, and 1% nanoparticles were added to form a film with a thickness of 90 nm, a hardness of 3H, and a contact angle of 115°.

[0051] Each module is seamlessly welded using an invisible threaded groove interface, achieving a weld strength of 53 MPa. Post-weld polishing ensures a smooth interface.

[0052] Based on a preset pattern database, a 3D topology algorithm is used to generate pattern paths, with a pattern recognition accuracy of 99.5% and a mapping distortion rate controlled below 2.8%.

[0053] This embodiment utilizes a silver enamel electroplating process to create a 10cm x 8cm decorative ornament. Combined with an invisible threaded groove interface and an anti-oxidation pre-plating layer, it achieves high-strength welding and seamless assembly between modules, enhancing the overall aesthetics and structural stability of the ornament. Secondly, the enamel ratio is matched to the thermal expansion coefficient of the silver base. Combined with zoned firing and a three-stage temperature control process, this ensures strong enamel adhesion, a smooth and defect-free surface, and a rich sense of color gradation. Furthermore, laser micro-etching imparts exquisite surface patterns to the ornament, pulsed rhodium plating improves wear resistance and oxidation resistance, while a hydrophobic protective film effectively resists external moisture and pollution, maintaining a long-lasting luster. The pattern paths generated by the 3D topology algorithm achieve high-precision mapping of complex curved surface patterns, making the ornament both artistic and practical. Suitable for home decoration and the high-end gift market, it significantly enhances the product's added value and market acceptance.

[0054] Example 3

[0055] This embodiment describes a silver enamel electroplating process for precious metal deep processing, used to manufacture silver enamel jewelry pendants with a diameter of 3cm. The process includes: dividing the pendant into two modules—the main body and the hanging ring—based on a 3D model; creating a wax model and preparing a 925Ag silver base using investment casting. A concealed threaded groove interface is pre-set at the connection point, with an interface depth of 0.5mm and a thread spacing of 0.3mm, located inside the hanging ring. After casting, a 0.2μm thick gold-nickel alloy anti-oxidation pre-plating layer is applied to the surface of the silver base, and a 0.1μm palladium layer is pre-plated on the surface of the threaded groove interface, achieving a welding strength of 51MPa.

[0056] Using a conical micro-injector with an aperture of 0.1 mm, the glaze was filled into the patterned areas of the silver base surface. The glaze composition was: 58% SiO2, 17% K2O, 10% CuO, 7% CoO, with 0.5% nano-Ai2O3 added as a reinforcing phase. The coefficient of thermal expansion was 19.5 × 10⁻⁶. -6 / ℃, melting point range 680-820℃.

[0057] The silver body filled with glaze was fired in sections. The glaze in the main area was fired at 710℃, and the glaze in the metal area of ​​the hanging ring was fired at 790℃. The firing process adopted a three-stage temperature control: the first stage was to heat up at 100℃ / min; the second stage was to hold at that temperature for 30 minutes; and the third stage was to cool slowly at 5℃ / min.

[0058] A 1064nm fiber laser was used to etch microtextures to a depth of 0.1mm onto the surface of a silver substrate, with a positioning accuracy of ±0.05mm, a pattern linewidth of 0.1mm, and an aspect ratio of 1:1.2. After etching, ion cleaning was performed, followed by etching at a current density of 1.1A / dm³. 2Pulse electroplating was performed under a duty cycle of 25%, with the plating solution containing 80 g / L rhodium sulfate, the complexing agent being ammonium aminosulfonate, and the temperature controlled at 39℃, to form a rhodium layer with a thickness of 0.35 μm.

[0059] A nano-sealing agent containing perfluorooctyltriethoxysilane was dip-coated onto the surface of a rhodium layer, and 1% nanoparticles were added to form a film with a thickness of 75 nm, a hardness of 3H, and a contact angle of 110°.

[0060] The main body and lifting ring are seamlessly welded using an invisible threaded groove interface, with a welding strength of 50MPa, followed by polishing.

[0061] Based on a preset pattern database, a 3D topology algorithm is used to generate pattern paths, with a pattern recognition accuracy of 99.3% and a mapping distortion rate controlled below 2.7%.

[0062] This embodiment utilizes a silver enamel electroplating process to create a 3cm diameter jewelry pendant. The modular design, combined with an invisible threaded groove interface and an anti-oxidation pre-plating layer, ensures a seamless connection and strong weld between the main body and the pendant ring, enhancing the overall aesthetics and wearing safety. The enamel ratio is matched to the silver base, and the segmented firing process ensures uniform enamel adhesion and a delicate surface, presenting a refined visual effect befitting the high-end positioning of the jewelry. Furthermore, laser micro-etching adds delicate patterns to the pendant, and pulsed rhodium plating significantly improves corrosion resistance and wear resistance, meeting the needs of daily wear. The application of a hydrophobic protective film (110° contact angle, 75nm thickness) effectively prevents sweat and moisture corrosion, extending the pendant's lifespan. The pattern path generated by the 3D topology algorithm ensures the precise design of small curved surface patterns. The overall process enhances the refinement and personalization of the silver enamel jewelry, meeting consumers' demands for high-quality jewelry.

[0063] Performance testing

[0064]

[0065]

[0066] In summary, this invention effectively solves the problem of enamel cracking in complex three-dimensional shapes through a split structure design and gradient firing technology, ensuring the integrity and aesthetics of intangible cultural heritage silver products; by using pulse electroplating of a rhodium layer and nano-sealing agent to form a composite protective layer, the anti-oxidation performance of the silver base is greatly improved, the product life is extended, and its investment value as a high-end cultural gift is maintained.

[0067] By combining laser micro-etching with 3D topology algorithms, high-precision reproduction of ethnic patterns can be achieved, preserving the authenticity of intangible cultural heritage elements. At the same time, the application of modular casting, digital adaptation, and standardized glazing tools significantly improves production efficiency and product consistency, helping intangible cultural heritage handicrafts meet the mass production needs of the modern cultural and creative market.

[0068] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions will not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A silver enamel electroplating process for deep processing of precious metals, characterized in that, Includes the following steps: Step 1, 925Ag silver base casting in modules: According to the 3D model, the three-dimensional character structure is divided into head, torso, clothing and accessories modules to make wax models. The 925Ag silver base is prepared by investment casting process. The connection points of each module are pre-set with invisible welding interfaces and subjected to anti-oxidation electroplating. Step 2, glaze filling: The glaze is precisely filled into the patterned area on the surface of the silver body using a conical micro-injector. The glaze contains 55% to 65% SiO2, 10% to 18% K2O, 5% to 10% CuO, and 3% to 8% CoO. Step 3, Gradient enamel firing: The silver body filled with enamel is fired at a stepped temperature. The clothing area is glazed at a low temperature of 680-720℃ and fired at a high temperature of 780-820℃. Step 4, Laser Micro-etching: A laser etching machine is used to prepare micro-textures with a depth <0.2mm on the silver substrate surface. After firing, the surface undergoes ion cleaning with a current density of 1.0–1.5 A / dm². 2 A 0.3-0.5μm rhodium layer is plated using pulse electroplating with a duty cycle of 20%–40%. Step 5, Pulse electroplating: Dip a fluorinated silane-containing nano-sealing agent onto the surface of the rhodium layer to form a hydrophobic protective film; Step 6, Nano-sealing: Seamlessly weld and assemble each silver-plated module through invisible interfaces; Step 7, Digital Adaptation: Based on the preset style database, generate pattern paths to adapt to the curved silver surface using a 3D topology algorithm.

2. The silver enamel electroplating process for deep processing of precious metals according to claim 1, characterized in that, In step 1, during the modular casting process, the invisible threaded groove interface is located on the inner side of the garment hem, with an interface depth of 0.5-1mm and a thread spacing of 0.3mm. Each silver-based module is treated with a 0.2μm thick gold-nickel alloy anti-oxidation pre-plating layer, and the surface of the threaded groove interface is pre-plated with a 0.1μm palladium layer, with a welding strength ≥50MPa.

3. The silver enamel electroplating process for deep processing of precious metals according to claim 1, characterized in that, In step 2, the glaze is reinforced with 0.5% nano-Ai2O3, which has a thermal expansion coefficient that matches the silver body and a melting point range of 680-820℃, making it suitable for the zoned firing process.

4. The silver enamel electroplating process for deep processing of precious metals according to claim 1, characterized in that, In the gradient firing process of step 3, the glazing of the clothing area and the glazing of the metal accessories area are carried out in separate stages. The firing process adopts three-stage temperature control: heating up at 100℃ / min; holding at 30min; and slow cooling at 5℃ / min.

5. The silver enamel electroplating process for deep processing of precious metals according to claim 1, characterized in that, The laser micro-etching in step 4 uses a 1064nm fiber laser with an etching depth of <0.2mm, a positioning accuracy of ±0.05mm, a pattern line width of ≤0.15mm, and an aspect ratio of 1:1.

2.

6. The silver enamel electroplating process for deep processing of precious metals according to claim 1, characterized in that, The pulse electroplating parameters in step 4 are: current density 1.2 A / dm³. 2 The duty cycle is 30%; the rhodium plating layer thickness is 0.4±0.1μm; the plating solution contains 80g / L rhodium sulfate, the complexing agent is ammonium aminosulfonate, and the temperature is 40±2℃.

7. The silver enamel electroplating process for deep processing of precious metals according to claim 1, characterized in that, The nano-sealing agent in step 5 contains perfluorooctyltriethoxysilane and adds 1% nano-SiO2 particles, resulting in a film hardness of 3H, a contact angle ≥110° after film formation, and a film thickness of 80±20nm.

8. The silver enamel electroplating process for deep processing of precious metals according to claim 1, characterized in that, The 3D topology algorithm in step 7 achieves pattern recognition accuracy >99% and mapping distortion rate ≤3% through curvature adaptive mapping and convolutional neural network.

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