Multicolor metal and preparation method thereof
By performing porous treatment on the metal surface and complexing reaction of dye solution, combined with high-temperature oxidation treatment, the problem of difficult multi-color effect in traditional metal coloring processes is solved, and the preparation and uniform coloring effect of multi-color metals are achieved.
Patent Information
- Application Number
- CN202510529465.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-25
- Publication Date
- 2025-07-11
AI Technical Summary
It is difficult to achieve multi-color effects in the existing metal tinting process, and traditional methods have problems such as uneven coloring effects and insufficient quality reproducibility.
By porous treatment on the metal surface, groups such as 4,4'-(9H-fluorene-9,9-diyl)bisphenol, 2,5-dihydroxy-1,4-benzyldicarboxyle, N'-hydroxy-2-phenylacetamide in the dye solution undergo complexation reaction with the metal surface, and combined with the catalytic action of the inorganic salts sodium dichromate, sodium silicate, and phosphoric acid, followed by oxidation treatment at high temperature to form a multicolor metal.
The preparation of multicolor metals is achieved, with a wide range of coloring, low cost, high quality control, uniform coloring effect, and good wear resistance of the coloring layer.
Smart Images
Figure CN120291071A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of metal processing, and more specifically discloses a multi-color metal and a preparation method thereof. Background Art
[0002] The applications of metals and their products in modern life involve many aspects of society and are important indispensable materials in modern society. People's clothing, food, shelter, and transportation all rely on metal materials. Metal materials play an important role in the process of historical civilization and are important material manifestations at different stages of the development of human social productive forces.
[0003] The metal surface coloring process can serve the purposes of preventing metal corrosion and decoration. With the development of social productive forces, people's demand for the appearance color of products is getting higher and higher. Metals form a compound with a certain color and certain corrosion resistance on the metal surface through processes such as chemical impregnation, electrochemistry, and heat treatment. These compounds have certain colors. At the same time, due to the different thicknesses of the compounds, different crystal forms or crystal sizes, they have effects such as reflection and interference on light and thus present different colors. Pigments can also be directly sprayed on the metal surface to change the metal surface color. For metals treated by the electrolytic coloring method, when the metal surface is smooth, the metallic luster is strong and relatively stable, and can be maintained for a long time. It has relatively high decorative value and use value and is a very commonly used metal coloring method. Electrolytic coloring requires professional equipment and complex electrolytes, and the process parameters have a significant impact on the coloring effect, and there are certain deficiencies in the quality reproducibility. The chemical coloring method has certain requirements for experimental conditions, temperature, reagent dosage, and metal surface treatment. Slight deviations will result in completely different effects. The dye coloring method directly coats a layer of pigment on the metal surface. Since the metal surface is generally smooth, the adhesion of the pigment on the metal surface is not strong. Conditions such as friction and oxidation during use will cause the pigment to fall off, and the situation is worse when the pigment layer is thicker, and the thickness difference of the coating layer is relatively large.
[0004] The above coloring technologies are often specific processes developed for specific colors. It is very difficult to obtain metal appearances of different colors with the same coloring process or parameters. Even if the color difference can be achieved by changing the technical parameters, the electrolyte composition needs to be completely replaced, or complex coloring reagents need to be replaced. Summary of the Invention
[0005] Object of the Invention: An object of the present invention is to provide a multi-color metal and a preparation method thereof; to solve the problem of uneven coloring effect of the current coloring process.
[0006] Technical Solution: A preparation method of a multi-color metal, comprising the following steps: S1: Rinse the metal material with clean water, then place it in a metal decontaminant to perform degreasing treatment until the water layer on the surface of the metal plate is complete and it is confirmed that there is no oil stain on the surface, thereby obtaining a metal material 1, wherein the metal material is made of iron, aluminum or an alloy containing iron and aluminum; S2: immersing the metal material 1 prepared in step S1 into an acid etching tank filled with an acid solution, while sealing the acid etching tank, controlling the solution temperature at 15-35°C to react for 1-3 hours, opening the venting valve of the acid etching tank, and after venting, taking out the metal material, rinsing it with clean water until the pH of the aqueous phase is 5-7, to obtain metal material 2; S3: dissolving 4,4'-(9H-fluorene-9,9-diyl)bisphenol, 2,5-dihydroxy-1,4-benzenedicarboxylic aldehyde, and N'-hydroxy-2-phenylacetamidoamide in methanol to prepare an organic phase solution, then adding sodium dichromate, sodium silicate, and phosphoric acid into purified water to prepare an aqueous phase solution, and fully mixing the aqueous phase solution and the organic phase solution to prepare a dye solution, wherein the mass ratio of the aqueous phase solution to the organic phase solution is 1:2; S4: adding the metal material 2 prepared in step S2 to the colorant solution prepared in step S3 and soaking for 2-5 hours at a soaking temperature of 16-55° C. After the colorant is adsorbed, removing moisture from the surface of the metal material, and lightly grinding the metal material with gauze to obtain metal material 3; S5: placing the metal material 3 prepared in step S4 in an inert gas at 70-120° C. for 10-12 hours to obtain a metal material 4; S6: The metal material 4 prepared in step S5 is colored into a multi-color metal by high-temperature baking coloring, oxidant solution immersion coloring, etc.
[0007] Preferably, in step S1, the metal decontaminant is an acidic chemical decontaminant.
[0008] Preferably, in step S2, the acidic solution is one of hydrochloric acid and sulfuric acid solution, and the molar concentration is 4-8 mol / L.
[0009] Preferably, in step S3, the mass concentration of 4,4'-(9H-fluorene-9,9-diyl)bisphenol in the dye is 1.0-1.2%, the mass concentration of 2,5-dihydroxy-1,4-benzenedicarboxylic acid aldehyde is 1.5-2.0%, the mass concentration of N'-hydroxy-2-phenylacetamidoamide is 0.8-1.1%, the mass concentration of sodium dichromate is 0.2-0.3%, the mass concentration of sodium silicate is 0.2-0.4%, and the mass concentration of phosphoric acid is 0.6-2.2%.
[0010] Preferably, in step S5, the inert gas is one of carbon dioxide, nitrogen and argon.
[0011] Preferably, in the step S6, the high-temperature baking coloring temperature is not lower than 150 °C.
[0012] Preferably, in the step S6, the oxidant component in the oxidant solution can be selected from one or a combination of potassium permanganate, sodium hypochlorite, pyridinium dichromate, and m-chloroperoxybenzoic acid.
[0013] A multicolored metal prepared by the above preparation method.
[0014] Beneficial effects: The technical solution of the present invention performs a porous treatment on the metal surface and then immerses it in a dye solution. The 4,4'-(9H-fluorene-9,9-diyl)bisphenol, 2,5-dihydroxy-1,4-benzenedicarboxaldehyde, and N'-hydroxy-2-phenylacetamidoamide in the dye solution contain a large number of hydroxyl, amino, and aldehyde groups. These groups can form complexes or intermolecular forces with the metal surface ions and firmly adsorb on the metal surface. These groups undergo chemical reactions under the action of oxidants, high temperatures, and electrophilic reagents to produce products of different colors, thereby achieving the coloring purpose. At the same time, by pre-adsorbing sodium dichromate, sodium silicate, and phosphoric acid, which are inorganic salts, in the pores of the metal surface, they act as oxidants, catalysts, and reaction reagents during the subsequent coloring process, further enhancing the coloring ability. The pre-adsorbed metal material has a single structure. Subsequently, through high-temperature coloring or chemical coloring with an oxidant solution, a rich multicolored metal can be obtained through one coloring process. The difference between it and the traditional metal coloring method is that in the coloring technical solution provided by this scheme, the coloring substance exists in the pretreated metal itself, rather than in the electrolyte or chemical solvent in the traditional coloring process. This method for preparing multicolored metals is simple, low in cost, has higher quality control, and a wider coloring range. Description of the Drawings
[0015] Appendix Figure 1 SEM image of the surface of the metal block containing the colorant prepared in Example 1 Appendix Figure 2 SEM image of the surface of the metal block containing the colorant prepared in Example 2 Detailed Embodiments
[0016] The present invention will be described in detail below with reference to the drawings and in combination with embodiments. It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. Example 1
[0017] Cut an iron metal into a square metal block with a length × width × thickness of 10 cm × 10 cm × 1 cm. Rinse the metal with clean water until there is no impurity residue on the surface, and then place it in an acidic metal detergent (HX360) for degreasing treatment until the water-hanging layer on the metal plate surface is complete and there is no oil stain on the surface; Immerse the degreased metal material in an acid etching tank containing 8 mol / L hydrochloric acid solution. At the same time, seal the acid etching tank, control the solution temperature at 15 - 35 °C and react for 1 h. Open the gas release valve of the acid etching tank. After the gas release is complete, take out the metal material and rinse it with clean water until the pH of the aqueous phase is 6; Dissolve 1.2 g of 4,4'-(9H-fluorene-9,9-diyl)bisphenol, 2.0 g of 2,5-dihydroxy-1,4-benzenedicarboxaldehyde, and 1.1 g of N'-hydroxy-2-phenylacetamidoamide in 62.3 g of methanol to prepare an organic phase solution. Then add 0.3 g of sodium dichromate, 0.4 g of sodium silicate, and 2.2 g of phosphoric acid to 30.4 g of purified water to prepare an aqueous phase solution. Mix the aqueous phase solution and the organic phase solution evenly to obtain a dye solution; Add the acid-etched metal block into the above dye solution and soak for 4 h at a soaking temperature of 40 °C. After the dye is adsorbed completely, remove the moisture on the surface of the metal material with a gauze, and gently grind the metal material in the same direction with the gauze. The SEM image of the surface of the prepared metal block containing the dye is shown in the appendix Figure 1 ; Place the above metal block adsorbed with the dye substance in a nitrogen atmosphere at 90 °C and keep it warm and activated for 11 h; Bake the above activated metal blocks at high temperatures of 150 °C, 250 °C, 450 °C, and 1000 °C for coloring for 15 min. The results are shown in Summary Table 1. Example 2
[0018] Cut the aluminum metal into square metal blocks with a length × width × thickness of 10 cm × 10 cm × 1 cm. Rinse the metal with clean water until there is no impurity residue on the surface, and then place it in an acidic metal degreaser (DFF019) for degreasing treatment until the water hanging layer on the surface of the metal plate is complete and there is no oil stain on the surface; Immerse the degreased metal material in an acid etching tank containing 4 mol / L hydrochloric acid solution. At the same time, seal the acid etching tank, control the solution temperature at 15 - 35 °C and react for 3 h. Open the gas release valve of the acid etching tank. After the gas release is complete, take out the metal material and rinse it with clean water until the pH of the aqueous phase is 7; Dissolve 1.2 g of 4,4'-(9H-fluorene-9,9-diyl)bisphenol, 2.0 g of 2,5-dihydroxy-1,4-benzenedicarboxaldehyde, and 1.1 g of N'-hydroxy-2-phenylacetamidoamide in 62.3 g of methanol to prepare an organic phase solution. Then add 0.3 g of sodium dichromate, 0.4 g of sodium silicate, and 2.2 g of phosphoric acid to 30.4 g of purified water to prepare an aqueous phase solution. Mix the aqueous phase solution and the organic phase solution evenly to obtain a dye solution; The acid-etched metal block was added to the above coloring agent solution and soaked for 4 h at a soaking temperature of 40 °C. After the coloring agent was adsorbed completely, the moisture on the surface of the metal material was removed with a gauze, and the metal material was gently ground in the same direction with the gauze. The SEM image of the surface of the metal block containing the coloring agent is shown in the appendix Figure 2 ; The metal block adsorbed with the coloring agent substance was placed in a nitrogen atmosphere at 90 °C and kept warm and activated for 11 h; The above-activated metal blocks were baked at high temperatures of 150 °C, 250 °C, 450 °C, and 1000 °C for coloring for 15 min respectively. The results are shown in Summary Table 1. Example 3
[0019] The iron metal was cut into square metal blocks with a length × width × thickness of 10 cm × 10 cm × 1 cm. The metal was rinsed with clean water until there was no impurity residue on the surface, and then placed in an acidic metal decontaminant (DFF019) for degreasing treatment until the water hanging layer on the surface of the metal plate was complete and there was no oil stain on the surface; The above decontaminated and degreased metal material was immersed in an acid etching tank containing 5 mol / L sulfuric acid solution. At the same time, the acid etching tank was sealed, and the reaction was carried out at a solution temperature of 15 - 35 °C for 2 h. The air release valve of the acid etching tank was opened. After the air release was completed, the metal material was taken out and rinsed with clean water until the pH of the water phase was 5; 1.0 g of 4,4'-(9H-fluorene-9,9-diyl)bisphenol, 1.5 g of 2,5-dihydroxy-1,4-benzenedicarboxaldehyde, and 0.8 g of N'-hydroxy-2-phenylacetamidoamide were dissolved in 63.3 g of methanol to prepare an organic phase solution. Then, 0.2 g of sodium dichromate, 0.2 g of sodium silicate, and 0.6 g of phosphoric acid were added to 32.3 g of purified water to prepare an aqueous phase solution. The aqueous phase solution and the organic phase solution were mixed evenly to obtain a staining agent solution; The acid-etched metal block was added to the above coloring agent solution and soaked for 5 h at a soaking temperature of 16 °C. After the coloring agent was adsorbed completely, the moisture on the surface of the metal material was removed with a gauze, and the metal material was gently ground in the same direction with the gauze; The metal block adsorbed with the coloring agent substance was placed in a carbon dioxide atmosphere at 70 °C and kept warm and activated for 10 h; The above-activated metal blocks were colored in 10% potassium permanganate solution with a pH of 2 for 5 h, in sodium hypochlorite solution with an available chlorine content of 11% for 5 h, in 15% pyridinium dichromate solution for 5 h, and in 17% m-chloroperbenzoic acid solution for 2 h respectively. The results are shown in Summary Table 1. Example 4
[0020] Cut the aluminum metal into square metal blocks with a length×width×thickness of 10 cm×10 cm×1 cm. Rinse the metal with clean water until there is no impurity residue on the surface, and then place it in an acidic metal detergent (HX360) for degreasing treatment until the water-hanging layer on the surface of the metal plate is complete and there is no oil stain on the surface; Immerse the above degreased metal material in an acid etching tank containing 4 mol / L sulfuric acid solution. At the same time, seal the acid etching tank, control the solution temperature at 15 - 35 °C and react for 2 h. Open the gas release valve of the acid etching tank. After the gas release is completed, take out the metal material and rinse it with clean water until the pH of the aqueous phase is 6; Dissolve 1.0 g of 4,4'-(9H-fluorene-9,9-diyl)bisphenol, 1.5 g of 2,5-dihydroxy-1,4-benzenedicarboxaldehyde, and 0.8 g of N'-hydroxy-2-phenylacetamidoamide in 63.3 g of methanol to prepare an organic phase solution. Then add 0.2 g of sodium dichromate, 0.2 g of sodium silicate, and 0.6 g of phosphoric acid to 32.3 g of purified water to prepare an aqueous phase solution. Mix the aqueous phase solution and the organic phase solution evenly to obtain a dyeing agent solution; Add the acid-etched metal blocks to the above dyeing agent solution and soak for 2 h at a soaking temperature of 55 °C. After the dyeing agent is adsorbed completely, remove the moisture on the surface of the metal material with a gauze, and gently grind the metal material in the same direction with the gauze; Place the above metal blocks adsorbed with the dyeing agent substance in an argon atmosphere at 120 °C and keep warm and activate for 10 h; Immerse the above activated metal blocks in a 10% potassium permanganate solution with a pH of 2 for 5 h, a sodium hypochlorite solution with an available chlorine content of 11% for 5 h, a 15% pyridinium dichromate solution for 5 h, and a 17% m-chloroperbenzoic acid solution for 2 h. The results are shown in Summary Table 1.
[0021] Comparative Example 1 Cut the iron metal into square metal blocks with a length×width×thickness of 10 cm×10 cm×1 cm. Rinse the metal with clean water until there is no impurity residue on the surface, and then place it in an acidic metal detergent (HX360) for degreasing treatment until the water-hanging layer on the surface of the metal plate is complete and there is no oil stain on the surface; Immerse the above degreased metal material in an acid etching tank containing 8 mol / L hydrochloric acid solution. At the same time, seal the acid etching tank, control the solution temperature at 15 - 35 °C and react for 1 h. Open the gas release valve of the acid etching tank. After the gas release is completed, take out the metal material and rinse it with clean water until the pH of the aqueous phase is 6; Remove the moisture on the surface of the metal material with a gauze, and gently grind the metal material in the same direction with the gauze; Place the above metal blocks in a nitrogen atmosphere at 90 °C and keep warm and activate for 11 h; The above-activated metal blocks were respectively baked at 150 °C, 250 °C, 450 °C, and 1000 °C for coloring for 15 min, and the results are shown in Summary Table 1.
[0022] Comparative Example 2 The aluminum metal was cut into square metal blocks with a length × width × thickness of 10 cm × 10 cm × 1 cm. The metal was rinsed with clean water until no impurities remained on the surface, and then placed in an acidic metal detergent (HX360) for degreasing treatment until the water-hanging layer on the metal plate surface was complete and there was no oil stain on the surface. The above degreased and decontaminated metal material was immersed in an acid etching tank containing a 4 mol / L sulfuric acid solution. At the same time, the acid etching tank was sealed, and the solution temperature was controlled at 15 - 35 °C for reaction for 2 h. The air release valve of the acid etching tank was opened. After the air release was completed, the metal material was taken out and rinsed with clean water until the pH of the aqueous phase was 6. The water on the surface of the acid-etched metal block was removed with a gauze, and the metal material was gently ground in the same direction with the gauze. The above-activated metal blocks were respectively colored in a 10% potassium permanganate solution with a pH of 2 for 5 h, a sodium hypochlorite solution with an available chlorine content of 11% for 5 h, a 15% pyridinium dichromate solution for 5 h, and a 17% m-chloroperbenzoic acid solution for 2 h. The results are shown in Summary Table 1.
[0023] Comparative Example 3 The iron metal was cut into square metal blocks with a length × width × thickness of 10 cm × 10 cm × 1 cm. The metal was rinsed with clean water until no impurities remained on the surface, and then placed in an acidic metal detergent (HX360) for degreasing treatment until the water-hanging layer on the metal plate surface was complete and there was no oil stain on the surface. The above degreased and decontaminated metal material was immersed in an acid etching tank containing a 5 mol / L hydrochloric acid solution. At the same time, the acid etching tank was sealed, and the solution temperature was controlled at 15 - 35 °C for reaction for 2 h. The air release valve of the acid etching tank was opened. After the air release was completed, the metal material was taken out and rinsed with clean water until the pH of the aqueous phase was 6. 2.0 g of 2,5-dihydroxy-1,4-benzenedicarboxaldehyde was dissolved in 64.6 g of methanol to prepare an organic phase solution. Then, 0.3 g of sodium dichromate, 0.4 g of sodium silicate, and 2.2 g of phosphoric acid were added to 30.4 g of purified water to prepare an aqueous phase solution. The aqueous phase solution and the organic phase solution were mixed evenly to obtain a dyeing agent solution. The acid-etched metal block was added to the above dyeing agent solution and soaked for 4 h at a soaking temperature of 40 °C. After the dyeing agent was adsorbed completely, the water on the surface of the metal material was removed with a gauze, and the metal material was gently ground in the same direction with the gauze. The above metal block adsorbed with the dyeing agent substance was placed in a nitrogen atmosphere at 90 °C and kept warm and activated for 11 h. The above-activated metal blocks were respectively colored in 10% potassium permanganate solution with a pH of 2 for 5 hours, in sodium hypochlorite solution with an available chlorine content of 11% for 5 hours, in 15% pyridinium dichromate solution for 5 hours, and in 17% m-chloroperbenzoic acid solution for 2 hours. The results are shown in Summary Table 1.
[0024] Table 1 Comparison Table of Coloring Results From the above results, it can be seen that the metal prepared by the solution of the present invention can exhibit rich appearance colors under high-temperature coloring or immersion in oxidizing agents, which are significantly different from the color of the metal material itself. The test results show that after the metal surface is subjected to porous treatment and then immersed in the staining solution, a large number of hydroxyl groups, amino groups, and aldehyde groups contained in the 4,4'-(9H-fluorene-9,9-diyl)bisphenol, 2,5-dihydroxy-1,4-benzenedicarboxaldehyde, and N'-hydroxy-2-phenylacetamidoamide structures in the staining solution undergo chemical reactions under the catalysis of inorganic salts sodium dichromate, sodium silicate, and phosphoric acid and under the action of oxidants, high temperature, electrophilic reagents, etc., to produce products of different colors, achieving the purpose of coloring. Without adding a colorant, after the coloring process, it basically presents the color of the metal itself. When only a single component of the colorant is added, the color after coloring is single, all belonging to the red series. After the staining solution added in this solution is subjected to the coloring process treatment, color changes can occur. After the compound is used in combination, the color after coloring is richer.
[0025] Abrasion resistance test: The surfaces of the metal blocks of the 150°C high-temperature coloring samples, 250°C high-temperature coloring samples, 450°C high-temperature coloring samples, 1000°C high-temperature coloring samples prepared in Example 1, the potassium permanganate coloring samples, sodium hypochlorite coloring samples, pyridinium dichromate coloring samples, and m-chloroperbenzoic acid coloring samples prepared in Example 3 were wiped with a woolen cloth 1000 times, and the color change of the sample surface was observed. The results are shown in Table 2.
[0026] Table 2 Abrasion Resistance Results The above abrasion resistance test results show that after 1000 times of friction, the multicolored metals prepared by this solution have no color change, and the abrasion resistance of the surface coloring layer is good. The hydroxyl groups, amino groups, and aldehyde groups in the 4,4'-(9H-fluorene-9,9-diyl)bisphenol, 2,5-dihydroxy-1,4-benzenedicarboxaldehyde, and N'-hydroxy-2-phenylacetamidoamide structures in the staining solution can produce complexation or intermolecular forces with the surface ions of the acid-etched metal material, and are firmly adsorbed on the metal surface, and are not easily shed after coloring.
[0027] Certainly, the above description is not a limitation to the present invention, nor is the present invention limited to the above examples. Any changes, modifications, additions or substitutions made by those of ordinary skill in the art within the scope of the essence of the present invention also fall within the protection scope of the present invention.
Claims
1. A method for preparing a multi-colored metal, characterized in that, The following steps are involved: S1: Rinse the metal material with clean water, then place it in a metal decontaminant to perform degreasing treatment until the water layer on the surface of the metal plate is complete and it is confirmed that there is no oil stain on the surface, thereby obtaining a metal material 1, wherein the metal material is made of iron, aluminum or an alloy containing iron and aluminum; S2: immersing the metal material 1 prepared in step S1 into an acid etching tank filled with an acid solution, while sealing the acid etching tank, controlling the solution temperature at 15-35°C to react for 1-3 hours, opening the venting valve of the acid etching tank, and after venting, taking out the metal material, rinsing it with clean water until the pH of the aqueous phase is 5-7, to obtain metal material 2; S3: dissolving 4,4'-(9H-fluorene-9,9-diyl)bisphenol, 2,5-dihydroxy-1,4-benzenedicarboxylic aldehyde, and N'-hydroxy-2-phenylacetamidoamide in methanol to prepare an organic phase solution, then adding sodium dichromate, sodium silicate, and phosphoric acid into purified water to prepare an aqueous phase solution, and fully mixing the aqueous phase solution and the organic phase solution to prepare a dye solution, wherein the mass ratio of the aqueous phase solution to the organic phase solution is 1:2; S4: adding the metal material 2 prepared in step S2 to the colorant solution prepared in step S3 and soaking for 2-5 hours at a soaking temperature of 16-55° C. After the colorant is adsorbed, removing moisture from the surface of the metal material, and lightly grinding the metal material with gauze to obtain metal material 3; S5: placing the metal material 3 prepared in step S4 in an inert gas at 70-120° C. for 10-12 hours to obtain a metal material 4; S6: The metal material 4 prepared in step S5 is colored into a multi-color metal by high-temperature baking or immersion in an oxidant solution.
2. The method for preparing a multicolor metal according to claim 1, wherein: The metal decontaminant in step S1 is an acidic chemical decontaminant.
3. The preparation method of the multicolor metal according to claim 1, characterized in that: The acidic solution in step S2 is one of hydrochloric acid and sulfuric acid solution, and the molar concentration is 4-8 mol / L.
4. The method for preparing a multicolor metal according to claim 1, wherein: In the dye in step S3, the mass concentration of 4,4'-(9H-fluorene-9,9-diyl)bisphenol is 1.0-1.2%, the mass concentration of 2,5-dihydroxy-1,4-benzenedicarboxylic acid aldehyde is 1.5-2.0%, the mass concentration of N'-hydroxy-2-phenylacetamidoamide is 0.8-1.1%, the mass concentration of sodium dichromate is 0.2-0.3%, the mass concentration of sodium silicate is 0.2-0.4%, and the mass concentration of phosphoric acid is 0.6-2.2%.
5. The method for preparing a multi-color metal according to claim 1, wherein: The inert gas in step S5 is one of carbon dioxide, nitrogen and argon.
6. The method for preparing a multicolor metal according to claim 1, characterized in that: The high temperature baking and coloring temperature in step S6 is not less than 150°C.
7. The preparation method of the multicolor metal according to claim 1, characterized in that: The oxidant component in the oxidant solution in step S6 is one of potassium permanganate, sodium hypochlorite, pyridinium dichromate, and m-chloroperbenzoic acid.
8. A multi-color metal prepared by the method according to any one of claims 1 to 7.