Matt precious metal preparation as well as preparation method and application thereof

Abstract

The invention discloses a matte precious metal preparation and a preparation method and application thereof, and belongs to the technical field of precious metal preparations. The matte precious metal preparation comprises the following components in percentage by weight: 88-99% of precious metal component, 0.5-6% of pearlescent pigment and 0.5-6% of glass frit, the glass frit is prepared from the following components in percentage by weight: 20 to 35 percent of SiO2, 10 to 20 percent of B2O3, 20 to 25 percent of K2O, 10 to 20 percent of Na2O and 10 to 15 percent of Al2O3. Applying the matt noble metal preparation to the ceramic substrate, and firing at 750-900 DEG C to obtain the ceramic decorated by the matt noble metal preparation. According to the matte precious metal preparation, the pearlescent pigment and the glass frit are added on the basis of conventional precious metal components, the matte precious metal preparation has a matte effect (low glossiness) when being used for ceramic decoration, and meanwhile, the matte precious metal preparation also has good surface flatness, hardness and adhesive force.

Description

Technical Field

[0001] This invention belongs to the field of precious metal formulation technology, specifically relating to a matte precious metal formulation, its preparation method, and its application. Background Technology

[0002] Precious metal preparations include bright precious metal preparations, matte precious metal preparations, and polished precious metal preparations.

[0003] Brightening precious metal formulations for decorative glass, ceramics, porcelain, bone china, or other silicate substrates typically consist of solutions of organoprecious metal compounds dissolved in materials that are primarily organic carriers, synthetic or natural resins, and fluxes to ensure adhesion to the respective substrates. The precious metals include gold, silver, ruthenium, rhodium, palladium, osmium, iridium, and platinum. Certain organometallic compounds are commonly used as fluxes, such as alkoxides, carboxylates, resin salts, or thioresinates, as well as compounds of elements like chromium, bismuth, vanadium, and silicon. During firing, the organic compounds decompose, and some metal forms, thereby improving the adhesion of the metal film to the substrate. Thioresinates are preferred among soluble organoprecious metal compounds. Other compounds suitable for brightening formulations include, for example, gold thiolates known in German Patents 1,284,808, 1,286,866, and 1,298,828. A brightening agent is applied to the object to be decorated and fired at a temperature of about 480°C to about 1230°C. Precious metal ornaments formed in this way have a high-gloss surface when they come out of the furnace.

[0004] Polished gold is a suspension of fine gold powder and / or sparingly soluble gold compounds in an organic carrier or bright gold solution, typically with a higher gold content than bright gold formulations. Because the gold layer surface exhibits a matte beige finish after firing, polishing is necessary. Most polished gold formulations, especially powdered gold, can form a pure gold decorative layer with a delicate matte appearance due to their high gold content. This method uses a large amount of precious metals, is costly, and requires polishing.

[0005] GB2099760A patent discloses a ceramic decal paper comprising an image layer with a bright precious metal composition, and a base layer between a backing paper and the precious metal layer. The base layer contains: lead silicate glass frit, a mixture of tin dioxide, zinc oxide, aluminum oxide, iron oxide, and chromium oxide, and an alkyd resin as a binder. This method allows for the formation of a precious metal decorative decal with a matte finish after firing.

[0006] The matte precious metal decorative layer can also be prepared according to the method described in patent DE3611273C1: the base layer consists of the following components before firing: 30 to 80% by weight of lead-free borosilicate frit, 20 to 70% by weight of titanium dioxide powder, and 20 to 70% by weight of a mixture of modified alkyd resin and aromatic hydrocarbons.

[0007] Patent EP0445537B1 discloses a similar system, but its underlying layer contains a metal oxide selected from the tin dioxide, cerium oxide, and / or zirconium oxide series as a matting agent. A matte surface can be obtained by applying a bright noble metal-based formulation, particularly a bright gold formulation, and then firing these two layers onto a silicate substrate.

[0008] International patent application WO95 / 09823A1 discloses another system for preparing a semi-matte precious metal decorative layer: to form a decorative layer with a matting effect, a matting layer needs to be applied below or above a glossy precious metal formulation layer. This matting layer may consist of a composition of: (A) a mixture of 40% to 80% by weight of glass frit and ceramic pigment, and (B) 20% to 60% by weight of an organic medium containing nitrocellulose resin.

[0009] All of the above methods involve firing multi-layered structures, and the preparation process is complicated.

[0010] In the preparation of a matte gold finish on ceramic tableware, pearlescent pigments (CA1180851A) are added to a precious metal formulation to achieve a unique matte effect. However, after firing this composition onto the ceramic body, several defects become apparent, including loss of luster after firing, decreased adhesion, unstable color, difficulty in application, low hardness, and reduced durability. These factors limit the practical performance and aesthetic reliability of this composition in commercial tableware applications. A single-layer firing method was also employed, but with unsatisfactory results.

[0011] Therefore, providing a matte noble metal formulation with a single-layer structure and good matte effect and surface properties has important application prospects. Summary of the Invention

[0012] To overcome the shortcomings of existing technologies, this invention provides a matte precious metal formulation, its preparation method, and its application; addressing the problems of existing matte precious metal formulations requiring large amounts of precious metal, multi-layer sintering, or surface defects. This invention adds pearlescent pigments and glass frit to the precious metal component, which, after sintering, gives the gold layer a matte effect with good hardness and adhesion.

[0013] The technical solution adopted by this invention to solve its technical problem is: This invention provides a matte precious metal formulation, comprising, by weight percentage, 88-99% precious metal components, 0.5-6% pearlescent pigments, and 0.5-6% glass frit; The glass frit comprises, by weight percentage, 20-35% SiO2, 10-20% B2O3, 20-25% K2O, 10-20% Na2O and 10-15% Al2O3.

[0014] When the matte precious metal preparation is applied to the surface of ceramic tableware and fired, it melts and bonds with the substrate surface to form a continuous, firmly adhered, and wear-resistant matte layer. This technical solution simultaneously enhances the aesthetic and practical performance of decorative ceramic products.

[0015] The glass frit described above in this invention is a lead-free borosilicate frit.

[0016] After firing, the matte noble metal formulation of the present invention forms a glass matrix with a controllable microstructure by the combination of oxides in the glass melt. Wherein: Silica, as the primary glass-forming material, provides structural integrity and chemical stability; Boron oxide acts as a flux, lowering the melting point of the mixture and promoting the formation of a homogeneous glass phase at the firing temperature; Potassium oxide and sodium oxide, as network modifiers, can break the silicon-oxygen network and promote the formation of microcrystals or phase-separated regions; Alumina can improve the chemical durability and hardness of the final glass layer.

[0017] The specific proportions of each oxide are selected to induce phase separation or microcrystallization within the glass layer during cooling. This microstructure scatters incident light, resulting in a matte, non-glossy surface effect. This matting effect is achieved through controlled roughness and inhomogeneity at the microscopic level; these structural features diffuse reflected light.

[0018] The introduction of alumina and silica ensures the coating possesses high mechanical strength and abrasion resistance. The resulting glass matrix adheres firmly to both the precious metal layer and the underlying ceramic substrate, providing a durable protective coating. This property effectively prevents premature wear of the precious metal decorative layer during handling and cleaning of tableware.

[0019] In some embodiments, the glass frit also contains small amounts of other oxides, such as ZnO and CaO, to adjust melting behavior or compatibility with the ceramic substrate.

[0020] In some embodiments, the d of the glass frit 50 The value ranges from 1 to 10 micrometers.

[0021] In some embodiments, the d of the glass frit50 The value ranges from 3 to 10 micrometers.

[0022] In some embodiments, the d of the glass frit 50 The value ranges from 7 to 8 micrometers.

[0023] In some embodiments, the complete melting temperature of the glass frit is lower than the firing temperature of the matte precious metal formulation.

[0024] In some embodiments, the complete melting temperature of the glass melt is less than or equal to 650°C.

[0025] In some embodiments, the pearlescent pigment is mica with a surface coated with titanium dioxide and a particle size of 5-25 micrometers. Specifically, it is a fine rutile green pigment, an interference pigment based on mica with a surface coated with rutile titanium dioxide.

[0026] In some embodiments, the matte precious metal formulation comprises, by weight percentage, 92-98% precious metal components, 1-4% pearlescent pigments, and 1-4% glass frit.

[0027] The precious metal components described above in this invention can be conventional bright precious metal formulations.

[0028] In some embodiments, the raw materials of the matte precious metal formulation include, by weight: 21-23% precious metal organometallic compound, 2.8-3.2% non-precious metal organometallic compound, 40.5-56.5% organic solvent, 15-25% binder, 1-3% elemental sulfur, 0.5-6% pearlescent pigment and 0.5-6% glass frit.

[0029] In some embodiments, the raw materials of the matte precious metal formulation include, by weight: 21-23% precious metal organometallic compound, 2.8-3.2% non-precious metal organometallic compound, 40.5-56.5% organic solvent, 15-25% binder, 1-3% elemental sulfur, 1-4% pearlescent pigment and 1-4% glass frit.

[0030] In some embodiments, the precious metal organometallic compound includes an organometallic compound of at least one selected from gold, palladium, silver, rhodium, and platinum.

[0031] In some embodiments, the noble metal organometallic compound includes at least one of noble metal resin salts, thio resin salts, sulfonate resin salts, carboxylates, thiols, and alkoxides.

[0032] In some embodiments, the precious metal organometallic compound includes at least one of gold sulfonate and rhodium sulfonate.

[0033] In some embodiments, the non-precious metal organometallic compound includes at least one organometallic compound selected from bismuth (Bi), chromium (Cr), vanadium (V), nickel (Ni), cobalt (Co), iron (Fe), tin (Sn), zirconium (Zr), copper (Cu), silicon (Si), and aluminum (Al).

[0034] In some embodiments, the non-precious metal organometallic compound includes at least one of non-precious metal resin salts, thioresin salts, carboxylates, and alkoxides.

[0035] In some embodiments, the organic solvent includes at least one of methyl ethyl ketone, cyclohexanone, ethyl acetate, amyl acetate, cellosol (ethylene glycol ether), butanol, nitrobenzene, toluene, xylene, petroleum ether, chloroform, carbon tetrachloride, terpenoids (pinene, etc.), dipentene, dipentene oxide, and essential oils (lavender oil, rosemary oil, fennel oil, turpentine oil, etc.).

[0036] In some embodiments, the adhesive includes at least one of hydrocarbon resins, pine oil, bitumen, rosin, balsam, synthetic resins, and rosin.

[0037] This invention provides a method for preparing the above-mentioned matte noble metal formulation, comprising the following steps: The components of the matte precious metal preparation are mixed and heated and stirred until homogeneous to obtain the matte precious metal preparation.

[0038] This invention provides a method for decorating ceramics, comprising the following steps: The above-mentioned matte precious metal preparation is applied to a ceramic substrate and fired at 750-900℃ to obtain ceramics decorated with matte precious metal preparation.

[0039] In some embodiments, the firing temperature is 780°C-820°C.

[0040] In some embodiments, the matte precious metal formulation is applied directly or indirectly to a ceramic substrate as a printable paste via screen printing.

[0041] In some embodiments, the ceramic substrate is porcelain, ceramic, or glass.

[0042] In some embodiments, the indirect screen printing is achieved using decal technology.

[0043] This invention provides a matte precious metal-decorated ceramic prepared by the above-described method.

[0044] In some embodiments, the ceramic decorated with the matte precious metal formulation has a gloss value of less than 35 GU when measured at a 60° angle.

[0045] The beneficial effects of this invention are: The matte precious metal formulation of the present invention is based on conventional precious metal components with the addition of pearlescent pigments and glass frits. When used for ceramic decoration, it has a matte effect (low gloss) and also has good surface smoothness, hardness and adhesion. Attached Figure Description

[0046] Figure 1 This is a 500x magnification microscopic observation of the cross-section of the matte precious metal preparation of Example 1 of the present invention after calcination.

[0047] Figure 2 This is a 1000x magnification microscopic observation of the cross-section of the matte precious metal preparation after calcination in Example 1 of the present invention.

[0048] Figure 3 This is a photograph of the matte precious metal formulation of Example 1 of the present invention after calcination.

[0049] Figure 4 This is a photograph of the precious metal formulation of Comparative Example 1 of the present invention after calcination.

[0050] Figure 5 This is a scratch photograph of the precious metal formulation of Comparative Example 2 of the present invention after calcination.

[0051] Figure 6 This is a photograph of the precious metal formulation of Comparative Example 3 of the present invention after calcination. Detailed Implementation

[0052] The present invention will be further described below with reference to embodiments.

[0053] The following will clearly and completely describe the concept, specific solutions, and technical effects of the present invention with reference to embodiments, so as to fully understand the purpose, features, and effects of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are all within the scope of protection of the present invention. The various technical features in the present invention can be combined interactively without contradicting each other.

[0054] The applicant conducted compatibility tests on various glass frit materials. The initial melting temperature of traditional glass frit is approximately 600℃, and its liquid-phase stable region is 600℃~1380℃. When introduced into this formulation, within the industry-standard firing temperature range of 720-800℃, these materials cannot achieve complete melting, resulting in microscopic roughness and unevenness on the surface of the final metal film, severely affecting the film's density and appearance quality.

[0055] In contrast, the specific glass frit selected in this invention has significantly lower melting temperature characteristics (initial melting temperature 450°C, full melting temperature 650°C), which can be fully melted in the above-mentioned general firing process to form a liquid phase with good fluidity, thereby achieving complete encapsulation and smooth coverage of the metal film layer, and thus significantly improving the smoothness and gloss of the film layer surface.

[0056] In addition, traditional glass frits usually function as sintering aids or high-temperature bonding carriers, while certain glass frits, in addition to having good low-temperature melting performance, also have multiple functional attributes such as enhanced hardness, weather resistance and covering power, which can effectively protect the metal film from scratches, oxidation and environmental corrosion, and extend the service life of the product.

[0057] Regarding chemical compatibility, traditional barium (Ba) glass frits, when co-fired with the precious metal formulations in this system, are prone to interfacial reactions and residues, forming black ash on the surface of the metal film, which severely affects the product's appearance and performance. This particular glass frit is a barium-free formulation and does not have the aforementioned compatibility issues. After firing, its surface is clean and residue-free, exhibiting superior compatibility and stability.

[0058] Table 1 shows the comparison of different glass frits.

[0059] Table 1:

[0060] This invention utilizes a specific low-melting-point glass powder. Based on its breakthrough low-temperature characteristics (initial melting at 450℃ / full melting at 650℃), it completely melts during firing at 720-800℃ to form a continuous liquid phase, achieving dense encapsulation of metal particles. Furthermore, its barium-free formulation (Al / Si / B / K / Na / O system) completely avoids ash formation, resulting in a pure metallic luster in the fired film. These dual advantages make this specific glass powder the only key material capable of simultaneously solving the problems of surface roughness and ash residue; the resulting technical effect cannot be achieved through optimization of traditional glass powders.

[0061] Table 2 compares the effects of traditional glass powder and specific glass powder combined with pearlescent pigments.

[0062] Table 2:

[0063] During the firing process of the matte precious metal formulation of the present invention, the molten phase of a specific glass powder (initial melting at 450°C and complete melting at 650°C) will undergo an in-situ interfacial reaction with the metal oxide (such as TiO2) on the surface of the pearlescent pigment to generate a novel aluminosilicate-metal oxide composite glass phase, as shown in Table 3 below.

[0064] This structure gives the metal film surface a matte texture and high wear resistance. Compared with a single pearlescent pigment film layer (which is easily scratched by a fingernail), the composite film layer has no visible scratches after being scratched by a fingernail. Compared with a single specific glass film layer (which has a mirror-like reflection), the composite film layer has no mirror-like spots under light. The bonding reaction only occurs when the pearlescent pigment and the specific glass powder coexist and the firing temperature is ≥650℃ (below this temperature, the two exist independently).

[0065] Table 3:

[0066] All percentages in the following examples and comparative examples are by mass percentages.

[0067] Example 1 A matte precious metal formulation (low melting point glass powder + pearlescent pigment) comprises the following components: Thio-resin gold (gold content 54%) 18.5% Rosemary oil 48.5% Low melting point glass powder (1.5%) + pearlescent pigment (1.5%) 3% Chromium chromate in resin (chromium content 3%) 1.0% Rhodium resin (5% rhodium content) 3.0% 2.0% pine resin silicate (silicon content 10%) 20% polyamide resin Sulfurized phenolic resin 2.0% Sulfur powder 2.0%.

[0068] The low-melting-point glass powder is graded NL-4 from Anmi Micro-Nano New Materials Co., Ltd. The pearlescent pigment is graded 1.03948 Iriodin®201 Rutile Fine Gold.

[0069] The preparation method of the above-mentioned matte precious metal preparation includes the following steps: Add all materials except "sulfur powder" to a beaker, stir at high speed and heat to 80°C, keep warm for 25-30 minutes until the paste is in a stringy state, cool down to 50°C and add sulfur powder, stir at high speed until uniform, and then disperse thoroughly using an internal mixer.

[0070] After standing overnight (12 hours) and solidifying, the viscosity was controlled at 800-1100 mPa·s using a precision three-roll mill (roll gap 5 micrometers, 3 times).

[0071] The method for using the above-mentioned matte precious metal preparation in ceramic decoration includes the following steps: The preparation is applied to transfer paper using a fully automatic / semi-automatic screen printing machine (a 350-mesh nylon screen is recommended). After drying for 40 minutes, it is soaked in water and transferred to the surface of the ceramic vessel. The water inside and outside is then scraped off with a rubber scraper. The vessel is then placed in a box-type sintering furnace and fired at 800 degrees Celsius for 3 hours, followed by a 25-minute holding at 800 degrees Celsius.

[0072] Performance testing: Hardness, adhesion and matteness were tested on the ceramics modified with matte precious metal formulations. The test methods are shown in Table 4.

[0073] Table 4:

[0074] The test data is shown in Table 5.

[0075] Table 5:

[0076] Microscopic observation of the cross-section after firing (≥200x) shows ( Figure 1 , Figure 2 ): Mica sheets are completely encapsulated by the glass phase, while the edges of mica sheets are exposed in unreacted samples.

[0077] When the matting powder is applied to the surface of the precious metal composition of ceramic tableware and fired at 800°C, it melts and bonds with the substrate surface to form a continuous, firmly adhered, and wear-resistant matting layer. This technical solution simultaneously improves the aesthetic and practical performance of decorative ceramic products. The final effect is shown in the image below. Figure 3 .

[0078] Comparative Example 1 A precious metal formulation (free of glass powder and pearlescent pigment) comprises the following components: Thio-resin gold (gold content 54%) 18.5% Rosemary oil 48.5% Chromium chromate in resin (chromium content 3%) 1.0% Rhodium resin (5% rhodium content) 3.0% 5.0% pine resin silicate (silicon content 10%) 20% polyamide resin Sulfurized phenolic resin 2.0% Sulfur powder 2.0%.

[0079] The preparation method, application method, and performance testing of the above-mentioned precious metal preparation are the same as in Example 1.

[0080] The test data is shown in Table 6, and the final result is shown in the figure. Figure 4 .

[0081] Table 6:

[0082] Comparative Example 2 A precious metal formulation (pearl pigment alone) comprises the following components: Thio-resin gold (gold content 54%) 18.5% Rosemary oil 48.5% Pearl pigment 3% Chromium chromate in resin (chromium content 3%) 1.0% Rhodium resin (5% rhodium content) 3.0% 2.0% pine resin silicate (silicon content 10%) 20% polyamide resin Sulfurized phenolic resin 2.0% Sulfur powder 2.0%.

[0083] The pearlescent pigment is the same as in Example 1.

[0084] The preparation method, application method, and performance testing of the above-mentioned precious metal preparation are the same as in Example 1.

[0085] The test data is shown in Table 7, and the final result is shown in the figure. Figure 5 .

[0086] Table 7:

[0087] Comparative Example 3 A precious metal formulation (low-melting-point glass powder alone) comprises the following components: Thio-resin gold (gold content 54%) 18.5% Rosemary oil 48.5% 3% low melting point glass powder Chromium chromate in resin (chromium content 3%) 1.0% Rhodium resin (5% rhodium content) 3.0% 2.0% pine resin silicate (silicon content 10%) 20% polyamide resin Sulfurized phenolic resin 2.0% Sulfur powder 2.0%.

[0088] The low-melting-point glass powder is the same as in Example 1.

[0089] The preparation method, application method, and performance testing of the above-mentioned precious metal preparation are the same as in Example 1.

[0090] The test data is shown in Table 8, and the final result is shown in the figure. Figure 6 .

[0091] Table 8:

[0092] Comparative Example 4 A precious metal formulation (high melting point glass powder alone) comprises the following components: Thio-resin gold (gold content 54%) 18.5% Rosemary oil 48.5% 3% high melting point glass powder Chromium chromate in resin (chromium content 3%) 1.0% Rhodium resin (5% rhodium content) 3.0% 2.0% pine resin silicate (silicon content 10%) 20% polyamide resin Sulfurized phenolic resin 2.0% Sulfur powder 2.0%.

[0093] Among them, the high melting point glass powder is grade D290 from Anmi Micro-Nano New Materials Co., Ltd.

[0094] The preparation method, application method, and performance testing of the above-mentioned precious metal preparation are the same as in Example 1.

[0095] The test data is shown in Table 9.

[0096] Table 9:

[0097] Comparative Example 5 A precious metal formulation (high melting point glass powder + pearlescent pigment) comprises the following components: Thio-resin gold (gold content 54%) 18.5% Rosemary oil 48.5% High melting point glass powder (1.5%) + pearlescent pigment (1.5%) 3% Chromium chromate in resin (chromium content 3%) 1.0% Rhodium resin (5% rhodium content) 3.0% 2.0% pine resin silicate (silicon content 10%) 20% polyamide resin Sulfurized phenolic resin 2.0% Sulfur powder 2.0%.

[0098] The high melting point glass powder was the same as in Comparative Example 4, and the pearlescent pigment was the same as in Example 1.

[0099] The preparation method, application method, and performance testing of the above-mentioned precious metal preparation are the same as in Example 1.

[0100] The test data is shown in Table 10.

[0101] Table 10:

[0102] Data Analysis: (1) As can be seen from Comparative Example 2, the effect of adding pearlescent pigment alone (without glass powder) on the fired metal film is: Mechanism of Influence: Pearl pigments (mica / TiO2-based) remain solid at the firing temperature, and their lamellar structure provides light scattering, reducing gloss. However, without glass powder, the pigment and metal particles are only physically bonded, resulting in a weak interface, and the pigment has low hardness (Mohs hardness of about 5-6), making it unable to resist scratches.

[0103] Chemical reaction analysis: TiO2 in pearlescent pigments is stable during sintering and shows no significant reaction with gold paste metal. The pigment particles exist as isolated phases, leading to interfacial stress and making them prone to microcracks.

[0104] Impact of quantization performance: Hardness: Slightly decreased due to the introduction of weak interfaces by the pigment, resulting in poor scratch resistance.

[0105] Adhesion: Decreased (cross-cut test grade drops to 0) due to weak pigment-metal interface bonding (extremely high risk of peeling).

[0106] Matte finish: Effectively enhances (gloss level drops to 40-50 GU) to achieve a matte effect, but at the cost of sacrificing mechanical properties.

[0107] Key difference: Adding pearlescent pigments alone can optimize optical performance, but it results in a looser film structure (porosity increases by about 10%) and deterioration of mechanical properties. The matte effect is not due to a chemical reaction, but rather to physical scattering.

[0108] (2) As can be seen from Comparative Example 3, the effect of adding low-melting-point glass powder alone (without pearlescent pigment) on the fired metal film is: Mechanism of Influence: Specific low-temperature glass powder (initial melting temperature 450°C) completely melts at the firing temperature, forming a flowing glass phase (mainly composed of Al / Si / B / K / Na / O), which wets the metal particles and fills the gaps. The molten glass solidifies upon cooling, forming a uniform and dense structure, thus increasing overall hardness. However, due to the lack of pearlescent pigments, the surface is smooth and lacks optical control.

[0109] Chemical reaction analysis: The glass powder itself undergoes a melt-solidification phase transition, and partially interdiffused with the gold paste metal particles (Au) (e.g., K). + Ions migrate to the metal interface, lowering the interface energy, and form Au-Si-O chemical bonds. However, the reaction is limited to the glass-metal binary system and has no external reinforcement.

[0110] Impact of quantization performance: Hardness: Significantly improved (HV increased by 25-30%), due to glass phase strengthening (density increased by about 20%). However, the upper limit of hardness improvement is limited by a single component.

[0111] Adhesion: Moderate improvement (cross-cut test level improved to level 4), due to enhanced interfacial bonding from the glass phase, but no synergistic optimization.

[0112] Matteness: Slight matte effect (gloss level approximately 80 GU, matteness slightly above the baseline) due to increased surface micro-refraction caused by the glass phase.

[0113] Key difference: At specific low temperatures, it acts as a single additive, effectively improving mechanical properties through melting, but its function is limited. Without pearlescent pigments, the optical properties of the film are not optimized, and the hardness improvement lacks a "reinforcing factor".

[0114] (3) As can be seen from Comparative Example 4, the effect of adding high-melting-point glass powder alone (without pearlescent pigment) on the sintered metal film is: Mechanism of Influence: High-melting-point glass powder cannot melt at the gold paste sintering temperature (720-800°C), remaining as solid particles. This causes the particles to exist as foreign matter in the metal film, failing to form an effective glassy phase to wet the metal particles. The interfacial bonding between the solid glass powder and the gold paste matrix (usually gold or alloy powder) is weak, and particle accumulation results in microscopic roughness of the surface.

[0115] Chemical reaction analysis: No significant chemical reaction occurred. The high-melting-point glass powder, in its unmelted state, only had physical contact with the gold paste metal particles (Au), with no element diffusion or new phase formation. The high interfacial energy resulted in weak bonding.

[0116] Impact of quantization performance: Hardness: Almost no improvement (HV increase ≤5%), because unmelted glass powder cannot strengthen the metal matrix. Increased surface roughness (Ra value increases by about 30%), which can easily lead to stress concentration and reduce scratch resistance.

[0117] Adhesion: Significantly reduced (cross-cut test grade dropped to level 3) due to unmelted particles causing internal pores and interface peeling of the film.

[0118] Matte finish: Surface roughness may slightly reduce gloss (gloss level drops to 76.5 GU, non-designed matte).

[0119] Key difference: High-melting-point glass powder cannot adapt to the sintering temperature of gold paste, resulting in defects in the film structure (an increase in porosity of approximately 15%), rather than functional improvement. The performance degradation stems from physical incompatibility, not chemical action.

[0120] (4) As can be seen from Comparative Example 5, the effects of adding high-melting-point glass powder and pearlescent pigment on the sintered metal film are: Mechanism of Influence: High-melting-point glass powder does not melt at the firing temperature and coexists with pearlescent pigments as rigid particles. Both remain solid and lack effective liquid wetting. Pearlescent pigments provide a matte finish, but the high-melting-point particles are incompatible with the pigment / metal interface, leading to multiple defects (such as particle aggregation and microcracks).

[0121] Chemical reaction analysis: No significant reaction was observed. High-melting-point glass powders (such as Ba / Si / O / Al / K / Na, etc.) and pearlescent pigments (TiO2 / mica) exhibit no interdiffusion of elements in the solid state, only physical mixing. High stress exists at the interface, making it prone to redox side reactions (such as TiO2 being reduced to Ti2O3 by metals, reducing stability).

[0122] Impact of quantization performance: Hardness: Slightly improved (HV increased by 2%), lower than the combined arithmetic sum (high melting point alone increased by 5% + pearlescent alone increased by 0% = 5%; actual value has no synergy).

[0123] Adhesion: Significantly deteriorated (cross-cut test grade dropped to level 3) due to multiple interfacial peeling (porosity increased by approximately 20%).

[0124] Matte finish: Effective (gloss level reduced to 40-45 GU), but surface is uneven (large local gloss deviation).

[0125] Key difference: The combination does not produce synergy because the high-melting-point glass powder does not melt and cannot activate the chemical reaction with the pearlescent pigment. Performance is similar to that of pearlescent pigments alone, but mechanical properties are worse.

[0126] (5) As can be seen from Example 1, the effects of adding low-melting-point glass powder (at a specific low temperature) and pearlescent pigment on the sintered metal film are as follows: Mechanism of Influence: After specific low-temperature glass powder melts (forming an Al-Si-BK-Na-O liquid phase), it wets and encapsulates pearlescent pigment particles, forming a "glass-pigment" composite phase through a chemical reaction. The TiO2 / mica of the pearlescent pigment provides reaction sites, reacting with B2O3 and SiO2 in the molten glass to generate reinforced borosilicates or titanium silicate compounds (such as TiB2 or Al2TiO5). This composite phase not only strengthens the pigment-glass interface but also facilitates elemental diffusion (such as K+). + Ions promote Au surface wetting, optimizing the bonding with the metal matrix. Simultaneously, the composite phase microstructure (homogenized by glass) provides uniform light scattering, enhancing the matte finish.

[0127] Chemical reaction analysis: During sintering at 720-800°C, the following key reactions occur: Main reaction: TiO2 + B2O3 → TiB2 + O2 (partially oxidized environment). TiB2 has high hardness (HV about 3000) and is dispersed as a reinforcing phase.

[0128] Auxiliary reaction: K2O + Al2O3 → KAlO2, which reduces interfacial energy and enhances adhesion.

[0129] Interface effect: The reaction products fill the pigment-metal gaps, reducing porosity and forming a continuous reinforcing network. Experiments show that the composite phase coverage is >90% (compared to only 70% for glass powder alone).

[0130] Impact of quantization performance: Hardness: The combined measured HV increased by 40-46%, significantly higher than the arithmetic sum of individual additions (26% increase at specific low temperatures + 0% increase in pearlescent material alone = 26%; the actual value is 21% higher, proving synergistic enhancement).

[0131] Adhesion: Cross-cut adhesion rating improved to level 5. Superior to specific low temperatures alone (level 4) and pearlescent finish alone (level 0), due to the reaction reducing interfacial stress (reduced interfacial energy).

[0132] Matte finish: Gloss is reduced to 30-35 GU, which is better than pearlescent alone (40-50 GU) due to the composite phase providing more uniform scattering (surface roughness Ra optimized to 0.2 μm).

[0133] Key difference: The combination not only achieves functional superposition (hardness + matte finish), but also generates a high-hardness phase (TiB2) and optimizes the interface through chemical reaction, making the mechanical properties surpass the arithmetic sum.

[0134] The above is a detailed description of the preferred embodiments of the present invention. However, the present invention is not limited to the embodiments described. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention. All such equivalent modifications or substitutions are included within the scope defined by the claims of the present invention.

Claims

1. A matte precious metal formulation, characterized in that, The matt precious metal preparation comprises by weight percentage 88-99% of precious metal component, 0.5-6% of pearlescent pigment and 0.5-6% of glass frit; The glass frit comprises by weight percentage 20-35% of SiO2, 10-20% of B2O3, 20-25% of K2O, 10-20% of Na2O and 10-15% of Al2O3.

2. The matte precious metal formulation of claim 1, wherein, The d50 of the glass frit ranges from 1 to 10 microns. 50 1 to 10 microns.

3. The matte precious metal formulation of claim 1, wherein, The complete melting temperature of the glass frit is lower than the firing temperature of the matt precious metal preparation.

4. The matte precious metal formulation of claim 1, wherein, The complete melting temperature of the glass frit is lower than 650℃.

5. The matte precious metal formulation of claim 1, wherein, The pearlescent pigment is mica coated with titanium dioxide, and the particle size is 5-25 microns.

6. The matte precious metal formulation of claim 1, wherein, The matt precious metal preparation comprises by weight percentage 92-98% of precious metal component, 1-4% of pearlescent pigment and 1-4% of glass frit.

7. The matte precious metal formulation of claim 1, wherein, The precious metal component is a conventional bright precious metal preparation. The raw materials of the matt precious metal preparation comprise by weight percentage 21-23% of precious metal organic metal compound, 2.8-3.2% of non-precious metal organic metal compound, 40.5-56.5% of organic solvent, 15-25% of adhesive, 1-3% of elemental sulfur, 0.5-6% of pearlescent pigment and 0.5-6% of glass frit.

8. Process for the production of a matt noble metal preparation according to any one of claims 1 to 7, characterized in that The method comprises the following steps: The components of the matt precious metal preparation are mixed and heated and stirred to obtain the matt precious metal preparation.

9. A method of decorating ceramics, characterized in that, The method comprises the following steps: The matt precious metal preparation of any one of claims 1-7 or prepared by the method of claim 8 is applied to a ceramic substrate and fired at 750-900℃ to obtain a ceramic decorated with the matt precious metal preparation.

10. The method of decorating ceramic according to claim 9, characterized in that, The firing temperature is 780-820℃; The matt precious metal preparation is applied to the ceramic substrate by direct or indirect screen printing; The ceramic substrate is porcelain, ceramic or glass; The indirect screen printing is realized by decal technology.

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