CN116892051A

CN116892051A - Environment-friendly electroless plating process and reagent formula

Info

Publication number: CN116892051A
Application number: CN202310843993.8A
Authority: CN
Inventors: 商祖恩; 商祖国
Original assignee: Shenzhen Seven Gold Jewelry Co ltd
Current assignee: Shenzhen Seven Gold Jewelry Co ltd
Priority date: 2023-07-11
Filing date: 2023-07-11
Publication date: 2023-10-17

Abstract

The application has passed an environmental protection electroless plating process, the step includes fixing the work piece and placing the work piece in the positive pole of the electrolytic apparatus, the trough plate of the electrolytic apparatus is the negative pole, the said work piece is immersed in the first solvent completely after the circular telegram, last the operation for more than 60 seconds; removing the workpiece after power off, immersing the workpiece into the second solution, carrying out ultrasonic vibration cleaning, and removing the attached electrolyte and impurities on the surface layer; placing the cleaned workpiece in a third solvent for passivation; polishing the passivated workpiece by using a fourth solvent; and (3) removing wax from the polished workpiece, cleaning, immersing the workpiece in a third solvent for more than 60s, and the like. Compared with the prior art, the technical scheme can improve the hardness of the workpiece by more than 5HV, the purity by more than 0.1 percent, the specular glossiness by more than 10G, the requirements on production operation conditions are simple, the pollution to the environment is reduced, the performances of the silver product such as the glossiness, the hardness, the toughness, the purity and the corrosion resistance are effectively improved, and the practicability and the durability of the workpiece are enhanced.

Description

Environment-friendly electroless plating process and reagent formula

Technical Field

The application relates to the field of surface treatment of metallic silver products, in particular to an environment-friendly electroless plating process and a reagent formula.

Background

Silver is a silvery white metal, has attractive metallic luster and collection ornamental value, and is deeply favored by people. Is widely used as jewelry, ornaments, silverware, tableware, gifts and the like in life. Because the characteristics of silver have the characteristics of softness, easy deformation, difficult polishing, flatness, corrosion resistance and the like, after the silver is placed for a period of time in an atmospheric environment, the surface of the silver loses white luster and turns yellow and black, and the ornamental wearing effect of silver products, particularly jewelry, is seriously affected.

In order to improve the oxidation resistance and color change characteristics of silver, many researches have been carried out at home and abroad for many years. Surface coating and electroplating processes are known according to the known approaches. The surface coating film has poor weather resistance, short service life and higher recovery cost, and can prevent the silver from directly contacting with human bodies. The highly toxic potassium chloride is used in the electroplating process, belongs to the high pollution industry, and not only can harm the health of a manufacturer in the silver product production process, but also high cost and site treatment are required for pollution of waste liquid to the environment, and the increasingly serious environmental protection pressure is faced.

More patent information can also be found in the following documents:

chinese patent application publication No. CN104593795A discloses a silver ware brightness maintaining agent which is prepared by compounding, by weight, 5-10 parts of sodium hypophosphite or sodium phosphite, 1-5 parts of coconut oil fatty acid diethanol amine and 1-3 parts of deionized water; 1-2 parts of Tween, 1-3 parts of monopotassium phosphate, 1-3 parts of sodium dihydrogen phosphate, 35 parts of sodium carbonate, 1-3 parts of methylpropanotriazasibirica, 1-3 parts of 2-mercaptobenzo claim di-swooshing, 1-2 parts of sodium dodecyl sulfate and 0.5-1 part of sodium stearate. The brightening agent is convenient to operate, can effectively prevent the surface color change phenomenon of silver pieces within a certain time range, and has a certain protection performance. However, the protective layer formed by the brightening agent gradually fails under the combined action of illumination, water vapor and air, and loses the protective effect.

The Chinese patent document with the publication number of CN110158064B discloses an antioxidation material, in particular to an antioxidation silver and a preparation method thereof, wherein the surface of the silver is covered with an antioxidation film, and the antioxidation film comprises the following components in parts by weight, 45-60 parts of silicon dioxide, 5-10 parts of boron oxide, 5-15 parts of zinc oxide and 20-30 parts of potassium oxide. The film is nano-scale, compact, transparent, uniform and continuous, does not influence the appearance and the hand feeling of pure silver, and has oxidation resistance, high temperature resistance and good weather resistance.

In the process of implementing the present application, the inventor finds that the following problems exist in the prior art:

1. the environmental pollution is large, and health potential safety hazards exist in the processing and using processes;

2. the electroplated surface treated workpiece is not an integral body, has insufficient strength and aesthetic degree, and has large material consumption and is not durable.

Therefore, a new scientific, environment-friendly and quality excellent processing mode suitable for sustainable development is imperative.

Disclosure of Invention

In order to solve the problem of large environmental pollution in the prior art, in a first aspect, the application provides an environment-friendly electroless plating process comprising the following steps:

and fixing the workpiece and placing the workpiece in an anode of an electrolysis device, wherein a groove plate of the electrolysis device is a cathode, and the workpiece is completely immersed in the first solvent after being electrified for 3-5 seconds, and the operation is continued for 60-120 seconds.

And (5) cutting off the power, taking out the workpiece, immersing the workpiece into the second solution, carrying out ultrasonic vibration cleaning, and removing the attached electrolyte and impurities on the surface layer.

Placing the cleaned workpiece in a third solvent for passivation;

polishing the passivated workpiece by using a fourth solvent;

removing wax from the polished workpiece, cleaning, immersing in a third solvent for 60-90s again, and washing for multiple times by pure water to remove residual solution on the workpiece;

and (3) placing the workpiece into an oven, and drying the workpiece at 100-120 ℃ for 20 minutes.

The workpiece here may be not only a silver workpiece but also other metal workpieces. The working time can be adjusted according to the requirements of different metal materials. Hereinafter, a silver workpiece will be exemplified.

When the silver workpiece is immersed in the electrolyte, the workpiece forms cavitation effect on the surface of the anode under the action of the direct current electric field. The steam in the cavitation bubbles is gasified by the electrolyte, so that the cavitation bubbles are rich in electrolyte ions. Such as sulfate ion, citrate ion, etc. The voltage accelerates electrochemical reaction and other free radical reaction in the air cannon, thereby removing relatively active metal in the silver workpiece, improving purity and density, and the silver simple substance is not easy to be oxidized. Immersing in the electrolyte at high temperature and high pressure also has the effect of quenching, thereby improving the hardness.

The continuous operation time is controlled to be 60-120 seconds, and the arrangement is such that the metal workpiece and substances in the electrolyte can fully react to achieve a good impurity removal effect. Too long electrolysis times may cause damage to the workpiece.

And (5) cutting off the power, taking out the workpiece, immersing the workpiece into the second solution, carrying out ultrasonic vibration cleaning, and removing the attached electrolyte and impurities on the surface layer. And (3) placing the cleaned workpiece in a third solvent for passivation. Passivation refers to the process of oxidizing metal by a strong oxidant or an electrochemical method to change the surface into an inactive state, namely passivation, and is a method for converting the surface of the metal into a state not easy to oxidize so as to delay the corrosion speed of the metal.

Polishing the passivated workpiece by using a fourth solvent. And (5) removing wax from the polished workpiece, cleaning, and immersing the workpiece into a third solvent for 60-90s again. After the parts are worn greatly, the passivation effect is weakened, the required standard cannot be met, and the parts are immersed into the third solution again for 60-90s to be used as the supplementary time for subsequent passivation.

Further, the passivation time is 300s-350s. In this period, neither the passivation time is sufficient nor excessive passivation can produce acceptable products for stabilizing the passivation interval.

Further, when the workpiece is polished, the rotation speed of the cloth wheel is over 4000 revolutions. The rotation speed of the cloth wheel is more than 4000 turns to cause migration of the outermost electrons of the silver, and the surface of the workpiece is passivated in the polishing process by matching with the use of a fourth solvent, so that the outermost electrons of the silver workpiece reach a stable structure, are bright and smooth, and keep the silver workpiece durable, thereby having better capability of resisting external erosion.

Further, the voltage range is 300-450V. When the workpiece is in the voltage range, the generated high temperature and high pressure can achieve the best effect of removing copper, iron and other metal impurities in the silver workpiece under the condition that the integrity of the silver workpiece is not damaged, so that silver is more compact and a silver simple substance is formed, and the silver is more stable.

Further, heating water in the electrolysis equipment to 90-95 ℃, preparing into a first solvent, and then placing the first solvent into a workpiece. And the water in the electrolysis equipment is controlled to be in the temperature range of 90-95 ℃ as much as possible. This temperature range allows for higher solubility and a suitable environment for the electrolytic reaction to take place, allowing the solution to be optimally effective.

In a second aspect, the present application provides an environmentally friendly electroless plating reagent formulation comprising a first solvent, a second solvent, a third solvent and a fourth solvent as described in the first aspect;

the first solvent comprises conductive salt, reducing agent and slow release agent. The first solvent is used as electrolyte, and the conductive salt has the functions of increasing the conductivity of the electroplating solution and adjusting the pH value of the solution, so that the cell pressure of the electrolysis equipment can be reduced, and the dispersion capability of the electrolyte can be improved.

The second solvent comprises a surfactant, and is mainly used for removing greasy dirt and surface impurities remained on the surface of the metal through the active surface, so that the cleanness, glossiness and color fastness of the outer part of the object are maintained.

The third solvent includes a passivating agent.

The fourth solvent includes a surface brightening agent. The common silver ornament brightening agent can be sold in the market. The texture of the appearance is influenced by the grinding effect, so that the polishing efficiency is improved.

Further, the conductive salt comprises sodium sulfate, sodium citrate, ammonium citrate and ammonia water, wherein the concentration of the conductive salt is 60-120g/L, the concentration of the reducing agent is 1-3g/L, and the concentration of the slow release agent is 0.5-2g/L.

Further, the passivating agent comprises at least one of sodium carbonate 6-N and a thiol solution.

Further, the surface brightening agent includes at least one of sodium hydroxide, sucrose, and water.

Further, the reducing agent and the slow release agent are sodium sulfite. Sodium sulfite, an inorganic substance, of the chemical formula Na ₂ SO ₃ Sodium sulfite is mainly used as a stabilizer for artificial fibers, a fabric bleaching agent, a photographic developer, a bleaching deoxidizer, a perfume and dye reducing agent, a papermaking lignin remover and the like. The reducing agent is a substance that loses electrons or has electrons deviated in the oxidation-reduction reaction. The reducing agent itself has reducing property and is oxidized, and the product is called an oxidized product.

Unlike the prior art, the technical scheme has the following technical effects:

1. the hardness of the workpiece can be improved by more than 5HV, the purity is improved by more than 0.1 percent, the specular glossiness is improved by more than 10G degrees, the glossiness is in platinum color, the anti-discoloration reaction time of the normal-temperature potassium sulfide solution with the concentration of 2 percent is more than 300 seconds, the electric conductivity and the heat conductivity of silver are not affected in use, the surface layer is free of foreign matters, is not allergic, is not bulged, is not layered and is not light-lost, the placing time is more than 180 days, because the surface layer of the workpiece is free of foreign matters, the renovation efficiency is improved, no impurities are recovered, the production operation condition is required to be simple, the glossiness, the hardness, the toughness, the purity, the corrosion resistance and other performances of silver products are improved, and the practicability and the durability of the workpiece are enhanced.

2. Because the raw materials used in the processing process do not harm the human body, the method has no threat to the health of people who contact with the workpiece in the processing process, and the processed workpiece and the generated wastewater completely reach the environment-friendly requirement through detection, so that the method does not pollute the environment, and compared with the traditional electroplating process, the method effectively reduces the environmental pollution, and the hidden danger to the health of the human body in the processing and using processes.

3. Solves the problem of non-integrity of the electroplated surface treatment workpiece, reduces the link and consumption of material reuse and promotes the excellent development of industry.

The foregoing summary is merely an overview of the present application, and may be implemented according to the text and the accompanying drawings in order to make it clear to a person skilled in the art that the present application may be implemented, and in order to make the above-mentioned objects and other objects, features and advantages of the present application more easily understood, the following description will be given with reference to the specific embodiments and the accompanying drawings of the present application.

Drawings

The drawings are only for purposes of illustrating the principles, implementations, applications, features, and effects of the present application and are not to be construed as limiting the application.

In the drawings of the specification:

FIG. 1 shows the results of the inspection of the workpiece described in example 1.

Detailed Description

In order to describe the possible application scenarios, technical principles, practical embodiments, and the like of the present application in detail, the following description is made with reference to the specific embodiments and the accompanying drawings. The embodiments described herein are only for more clearly illustrating the technical aspects of the present application, and thus are only exemplary and not intended to limit the scope of the present application.

Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearances of the phrase "in various places in the specification are not necessarily all referring to the same embodiment, nor are they particularly limited to independence or relevance from other embodiments. In principle, in the present application, as long as there is no technical contradiction or conflict, the technical features mentioned in each embodiment may be combined in any manner to form a corresponding implementable technical solution.

Unless defined otherwise, technical terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application pertains; the use of related terms herein is for the purpose of describing particular embodiments only and is not intended to limit the application.

In the description of the present application, the term "and/or" is a representation for describing a logical relationship between objects, which means that three relationships may exist, for example a and/or B, representing: there are three cases, a, B, and both a and B. In addition, the character "/" herein generally indicates that the front-to-back associated object is an "or" logical relationship.

In the present application, terms such as "first" and "second" are used merely to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual number, order, or sequence of such entities or operations.

Without further limitation, the use of the terms "comprising," "including," "having," or other like terms in this specification is intended to cover a non-exclusive inclusion, such that a process, method, or article of manufacture that comprises a list of elements does not include additional elements but may include other elements not expressly listed or inherent to such process, method, or article of manufacture.

As in the understanding of "review guidelines," the expressions "greater than", "less than", "exceeding" and the like are understood to exclude this number in the present application; the expressions "above", "below", "within" and the like are understood to include this number. Furthermore, in the description of embodiments of the present application, the meaning of "a plurality of" is two or more (including two), and similarly, the expression "a plurality of" is also to be understood as such, for example, "a plurality of" and the like, unless specifically defined otherwise.

In the description of embodiments of the present application, spatially relative terms such as "center," "longitudinal," "transverse," "length," "width," "thickness," "up," "down," "front," "back," "left," "right," "vertical," "horizontal," "vertical," "top," "bottom," "inner," "outer," "clockwise," "counter-clockwise," "axial," "radial," "circumferential," etc., are used herein as a basis for the description of the embodiments or as a basis for the description of the embodiments, and are not intended to indicate or imply that the devices or components referred to must have a particular position, a particular orientation, or be configured or operated in a particular orientation and therefore should not be construed as limiting the embodiments of the present application.

Unless specifically stated or limited otherwise, the terms "mounted," "connected," "affixed," "disposed," and the like as used in the description of embodiments of the application should be construed broadly. For example, the "connection" may be a fixed connection, a detachable connection, or an integral arrangement; the device can be mechanically connected, electrically connected and communicated; it can be directly connected or indirectly connected through an intermediate medium; which may be a communication between two elements or an interaction between two elements. The specific meaning of the above terms in the embodiments of the present application can be understood by those skilled in the art to which the present application pertains according to circumstances.

The embodiment provides an environment-friendly electroless plating process, which comprises the following steps:

1) Heating water in the equipment to above 90-95 ℃ to prepare the first solvent.

Fixing and placing a silver product workpiece on an anode, taking a groove plate of equipment as a cathode, completely immersing the silver product workpiece in electrolyte after power-on, wherein the voltage range is 300-450V, and continuously operating for 60-120 s; the semi-finished product after electrolysis has certain brightness and oxidation resistance. But many impurities are attached to the surface of the semi-finished product, and the semi-finished product needs to be further processed to achieve a stronger effect.

2) And (3) taking out the silver workpiece after the operation is powered off, immersing the silver workpiece in the second solvent for 120s, and cleaning the silver workpiece by ultrasonic vibration to remove the first solvent and impurities on the surface layer.

3) Placing the cleaned silver workpiece in a third solvent for passivation for 300-350 s;

4) Polishing the passivated silver workpiece by using a fourth solvent, wherein the rotation speed of the cloth wheel is required to be more than 4000 revolutions.

5) And (3) cleaning the polished silver workpiece by removing wax, then immersing the polished silver workpiece into the solvent III again for 60-90s, and then flushing the polished silver workpiece for multiple times by using pure water.

Example 1

Material preparation: sodium sulfate, sodium citrate, ammonium citrate, ammonia water, sodium sulfite and slow release agent.

The water is heated to 90-95 ℃. Stirring water continuously, and adding the above raw materials into water according to the proportion of sodium sulfate, sodium citrate, ammonium citrate, ammonia water, sodium sulfite and slow release agent according to a specific sequence until the raw materials are completely dissolved. The first solvent is prepared.

Heating water to 60 ℃, adding sodium dodecyl sulfate according to the proportion, stirring uniformly, and heating to 80-90 ℃ to prepare the second solvent.

Heating purified water to 30-40 ℃, adding sodium carbonate, 6-N and mercaptan solution into water according to a specific sequence until the solution is completely dissolved, and preparing a third solvent.

The purchased brightening agent (any brand) is uniformly smeared on a polishing cloth wheel, the rotating speed of polishing equipment is adjusted to 4500 revolutions, and a workpiece is polished and ground. Immersing the polished workpiece into the third solvent again for 60-90s, and taking out. Repeatedly washing with pure water for several times. And (5) placing the workpiece into a drying box to be dried for a certain time at the temperature of 100-120 ℃ and drying the surface of the workpiece.

The testing method comprises the following steps:

silver workpieces produced in the same batch are respectively processed by the following processes: electroplated silver workpieces and silver workpieces processed by the method; the two processes are detected separately. The conventional electroplating process is used as a standard, and the standard electroplating process is compared with various data detected by the process.

Test results:

TABLE 1 sample detection information

TABLE 2 purity detection of electroplated product

Table 3 gloss comparison

Table 4 hardness comparison

Sample name	Test item	Test results	Test method
				The formula product	Vickers hardness HV0.1	110	GB/T4340.1
Silver electroplating decoration	Vickers hardness HV0.1	103.5	GB/T4340.1

The test results are shown in tables 1-4, the environment-friendly electroless plating process provided by the application improves the hardness of a workpiece by more than 5HV, improves the purity by more than 0.1%, improves the roughness by more than 3 levels, improves the specular glossiness by more than 10G degrees, and has a platinum color and a 2% concentration normal-temperature potassium sulfide solution with an anti-discoloration reaction time of more than 300 seconds, and does not influence the conductivity of silver in daily display and use.

The heat conducting performance, no foreign matters on the surface layer, no allergy, no bulge, no layering and no light loss, the placing time is more than 180 days, the refreshing efficiency is improved by more than ten times, no impurities are recovered, the workpiece can be directly subjected to the refreshing process, and the production operation condition requirement is simple.

The detection results of the content of harmful elements and the content of other elements are shown in figure 1.

Unlike the prior art, the technical scheme has the following technical effects:

Finally, it should be noted that, although the embodiments have been described in the text and the drawings, the scope of the application is not limited thereby. The technical scheme generated by replacing or modifying the equivalent structure or equivalent flow by utilizing the content recorded in the text and the drawings of the specification based on the essential idea of the application, and the technical scheme of the embodiment directly or indirectly implemented in other related technical fields are included in the patent protection scope of the application.

Claims

1. An environment-friendly electroless plating process, which is characterized by comprising the following steps:

fixing a workpiece and placing the workpiece in an anode of an electrolysis device, wherein a groove plate of the electrolysis device is used as a cathode, and the workpiece is completely immersed in a first solution after being electrified, and the operation is continued for 60-120 seconds;

removing the workpiece after power off, immersing the workpiece into the second solution, carrying out ultrasonic vibration cleaning, and removing the attached electrolyte and impurities on the surface layer;

placing the cleaned workpiece in a third solution for passivation;

polishing the passivated workpiece by using a fourth solution;

removing wax from the polished workpiece, cleaning, and immersing the workpiece into the third solution for 60-90s again; taking out, and then washing for multiple times by using pure water to remove residual solution on the workpiece;

and (3) placing the workpiece into an oven, and drying the workpiece at 100-120 ℃ for a certain time.

2. The environmentally friendly electroless plating process according to claim 1, wherein the passivation time is 300s to 350s.

3. The environmentally friendly electroless plating process of claim 1 wherein the wheel speed is 4000 revolutions or more when the workpiece is polished.

4. The environmentally friendly electroless plating process according to claim 1, wherein the energizing voltage is in the range of 300-450V.

5. The environmentally friendly electroless plating process according to claim 1, wherein the water in the electrolytic device is heated to 90-95 ℃ and maintained in this range, and the work piece is put after being prepared into the first solution.

6. An environmentally friendly electroless plating reagent formulation for use in an environmentally friendly electroless plating process according to any one of claims 1-5, comprising a first solvent, a second solvent, a third solvent, and a fourth solvent;

the first solvent comprises conductive salt, a reducing agent and a slow release agent;

the second solvent comprises a surfactant;

the third solvent comprises a passivating agent;

the fourth solvent includes a surface brightening agent.

7. The environment-friendly electroless plating reagent formula according to claim 6, wherein the conductive salt comprises sodium sulfate, sodium citrate, ammonium citrate and ammonia water, and the concentration of the conductive salt is 60-120g/L, the reducing agent is 1-3g/L, and the slow release agent is 0.5-2g/L.

8. The environmentally friendly electroless plating reagent formulation of claim 6 wherein said passivating agent comprises at least one of sodium carbonate 6-N and a thiol solution.

9. The environmentally friendly electroless plating reagent formulation of claim 6 wherein said surface brightening agent comprises at least one of sodium hydroxide, sucrose and water.

10. The environmentally friendly electroless plating reagent formulation of claim 6 wherein the reducing agent and the slow release agent is sodium sulfite.