Preparation method and application of inorganic metal protective agent

Abstract

The invention discloses a preparation method and application of an inorganic metal protective agent, and belongs to the technical field of metal protection, the inorganic metal protective agent comprises the following raw materials by weight: 0.1-0.5% of a film-forming agent, 0.3-1.7% of a complexing agent 1, 2.5-3.5% of a complexing agent 2, 0.6-0.8% of a buffer agent, 15-17% of a conductive agent, 0.1-0.5% of cellulose nanocrystal powder, and the balance deionized water; the film-forming agent is one of indium sulfate, cerium chloride, beryllium sulfate and zirconium sulfate hydrate; the complexing agent 1 is one of EDTA (Ethylene Diamine Tetraacetic Acid), citric acid, potassium sodium tartrate and ammonium citrate; and the complexing agent 2 is one of HEDP, sodium hexametaphosphate, gluconic acid and glycolic acid. According to the mode, the complexing agent is firstly compounded with the cellulose nanocrystals, and then the second complex and the film-forming agent are added, so that the vulcanization resistance of the metal protective agent is improved, and the surface tension of the metal protective agent is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of metal protection, in particular to a preparation method of an inorganic metal protection agent and application thereof. BACKGROUND

[0002] With the rapid development of the automobile industry, new energy is gradually replacing traditional fuel vehicles, and metal surface electroplating process as a common key technology has been widely used in the field of new energy vehicles.

[0003] The high-voltage environment of new energy vehicles has given rise to high performance requirements for automobile connectors. Compared with traditional fuel vehicles, the core feature of new energy vehicles is the demand for high voltage and large current, which means that the safety, reliability and anti-interference of all electrical connection components inside the vehicle are extremely high. In order to meet these requirements, the core components (plastic parts molded by injection molding and metal parts stamped) of the connector need to be treated with silver electroplating. However, due to the characteristics of the silver electroplating layer, the silver electroplating layer is easily eroded and discolored in a high temperature and high humidity environment, so it is necessary to protect the silver electroplating layer to ensure its durability.

[0004] The common post-silver electroplating protection in the prior art is mostly water-based / oil-based organic coating (main film-forming substance is thiol substance), but this type of protection agent has significant technical defects in the use process of automobile connectors: a complete connector core component needs three steps to form, stamping first, electroplating last, and then secondary injection molding to realize the final insulation and sealing, so as to assemble a safe and reliable connector.

[0005] The secondary injection molding in this process requires complete tightness of the combination of plastic and metal. The traditional water-based / oil-based organic coating usually has a large surface tension, and it is difficult to ensure the tightness of the plastic attached to the metal surface after film formation and secondary injection molding, thereby affecting the sealing of the connector and causing the connector to be unreliable and unable to be used.

[0006] Therefore, the present application designs a preparation method of an inorganic metal protection agent and application thereof to solve the above problems. SUMMARY

[0007] In view of the above-mentioned shortcomings of the prior art, the present application provides a preparation method of an inorganic metal protection agent and application thereof.

[0008] To achieve the above purpose, the present application realizes the following technical scheme:

[0009] An inorganic metal protection agent is composed of the following raw materials by weight percentage:

[0010] 0.1-0.5% film forming agent, 0.3-1.7% complexing agent 1, 2.5-3.5% complexing agent 2, 0.6-0.8% buffering agent, 15-17% conductive agent, 0.1-0.5% cellulose nanocrystal powder, and the rest is deionized water;

[0011] The film forming agent is one of indium sulfate, cerium chloride, beryllium sulfate and hydrated zirconium sulfate;

[0012] The complexing agent 1 is one of EDTA, citric acid, potassium sodium tartrate and ammonium citrate;

[0013] The complexing agent 2 is one of HEDP, sodium hexametaphosphate, gluconic acid and glycolic acid;

[0014] The ratio of the complexing agent 1 to the complexing agent 2 is between 1:2 and 1:10;

[0015] The inorganic metal protection agent is prepared by first modifying the complexing agent 1 with the cellulose nanocrystal powder, then mixing the complexing agent 2, and then adding the film forming agent, the buffering agent and the conductive agent.

[0016] Further, the buffering agent is one of sodium hydroxide, borax, trifluoroacetic acid and sulfuric acid; and the conductive agent is one of potassium carbonate, sodium sulfate, sodium chloride and potassium chloride.

[0017] In order to better achieve the purpose of the present application, the present application further provides a preparation method of the inorganic metal protection agent, comprising the following steps:

[0018] (1) The raw materials are weighed according to the following weight percentages: 0.1-0.5% film forming agent, 0.3-1.7% complexing agent 1, 2.5-3.5% complexing agent 2, 0.6-0.8% buffering agent, 15-17% conductive agent, 0.1-0.5% cellulose nanocrystal powder, and the rest is deionized water;

[0019] (2) The complexing agent 1 and the cellulose nanocrystal powder are added to the deionized water, and ultrasonic treatment is carried out under the condition of ice water bath, and then the composite mother liquor is obtained, and the composite mother liquor is irradiated by high-energy electron beam, the absorption dose of the irradiation treatment is 20-40 kGy, the irradiation treatment time is 10-20 minutes, and then the mother liquor 1 is obtained;

[0020] (3) The deionized water is subjected to microwave heating, and then the mother liquor 1 and the complexing agent 2 are added and stirred after heating, and then the mixture 1 is obtained;

[0021] (4) adding film forming agent to mixture 1 and stirring to obtain mixture 2;

[0022] (5) adding buffer and conductive agent to mixture 2 in sequence and stirring to obtain mixture 3;

[0023] (6) adding deionized water to mixture 3 and treating by microwave and ultrasonic waves, microwave power is 300-600W, temperature is controlled at 40-50℃, ultrasonic power is 200-400W, ultrasonic frequency is 25-40kHz, and the treating time is 20-60 minutes, and an inorganic metal protection agent is obtained after the treating.

[0024] Further, the ultrasonic treating power in step (2) is 500-800W, and the treating time is 15-30 minutes.

[0025] Further, the microwave treating power in step (3) is 500-800W, and the microwave is heated to 40-50℃.

[0026] Further, the stirring speed in step (3) is 300-600rpm, the stirring speed in step (4) is 400-700rpm, and the stirring speed in step (5) is 450-650rpm.

[0027] In order to better realize the purpose of the present application, the present application further provides an application of the inorganic metal protection agent in metal protection, and the use method of the inorganic metal protection agent is as follows:

[0028] The prepared inorganic metal protection agent is diluted with water to obtain a working solution with a concentration of 30-60%, and heated to 30-60℃; the metal-plated workpiece is cleaned with 5% sulfuric acid for 5-10s, and then immersed in the diluted working solution for 20-60s, and then washed with water for 5-10s, and finally dried at 70-90℃.

[0029] Further, in the use method of the inorganic metal protection agent, the voltage of the power supply is 6-9V, the anode is platinum-titanium mesh or graphite, the cathode is the workpiece, and the area ratio of the anode to the cathode is greater than 3.

[0030] Compared with the prior art, the inorganic metal protective agent prepared by the application has the following beneficial effects: 1. The film forming agent of the inorganic metal protective agent prepared by the application is a chloride / sulfide of a rare metal. In the preparation process, the film forming agent is first subjected to a complexation reaction with a related complex, and then is reduced on the surface of the metal workpiece to be protected by being electrified in the subsequent use process, so as to form a dense metal / metal oxide protective layer. The protective layer is nearly silver-white, almost does not affect the appearance and wire performance of the workpiece, and most importantly, the protective layer can ensure that the surface tension and cleanliness of the workpiece surface do not affect the subsequent injection molding process, and realizes short-time protection of the metal workpiece to be protected from discoloration in the subsequent processing process.

[0031] 2. The application improves the anti-sulfuration capacity of the metal protective agent and reduces the surface tension of the metal protective agent by first compounding cellulose nanocrystals with a complexing agent, and then adding a second complex and a film forming agent.

[0032] 3. The inorganic metal protective agent prepared by the application uses inorganic / organic materials with good water solubility as raw materials, and is a substance with high safety and no toxicity and pollution in various properties. In addition, the inorganic metal protective agent can be mixed with water at any ratio at room temperature and above, and is easy to be mixed with water to form an aqueous solution with any concentration, and is easy to operate. The inorganic metal protective agent can be used for the protection of electroplated workpieces of various specifications and shapes. The inorganic metal protective agent is not only easy to use, but also has a wide range of applications. BRIEF DESCRIPTION OF DRAWINGS

[0033] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are only some embodiments of the application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.

[0034] Figure 1 SEM micrograph of the Ag-820 water-soluble gold and silver protective agent in the comparative example 3 of the application after film formation on the surface of a silver-plated workpiece;

[0035] Figure 2 SEM micrograph of the inorganic metal protective agent prepared in the embodiment 1 of the application after film formation on the surface of a silver-plated workpiece. DETAILED DESCRIPTION

[0036] In order to make the purposes, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0037] Embodiment 1: Preparation of an inorganic metal protection agent, comprising the following steps:

[0038] (1) Weighing raw materials

[0039] Weigh the raw materials according to the following weight percentages:

[0040] 0.3% indium sulfate, 0.8% potassium sodium tartrate, 2.9% HEDP, 0.6% sodium hydroxide, 17% potassium carbonate, 0.1% cellulose nanocrystal powder, and the rest is deionized water.

[0041] (2) Complexing agent 1 and cellulose nanocrystal compound treatment

[0042] Take 20% of the total amount of deionized water, add potassium sodium tartrate and cellulose nanocrystal powder, use a probe ultrasonic cell disruptor, and perform ultrasonic treatment under ice water bath conditions at a power of 500W. Pulse mode (2 seconds on and 1 second off) is adopted during ultrasonic treatment, the total treatment time is 30 minutes, and a uniform and stable compound mother liquor is obtained after treatment. The compound mother liquor is irradiated by high-energy electron beam, the absorption dose of irradiation treatment is 20kGy, the irradiation treatment time is 20 minutes, and the mother liquor 1 is obtained after irradiation treatment.

[0043] (3) Preparation of mixture 1

[0044] Take 30% of the total amount of deionized water, microwave heat to 40℃, microwave power is 800W, add mother liquor 1 and HEDP, adopt mechanical stirring, stirring speed is 300rpm, and stirring uniformly obtains mixture 1.

[0045] (4) Preparation of mixture 2

[0046] Add indium sulfate in three times, and the addition time is controlled within 1.5 hours. After stirring uniformly in mixture 1, mixture 2 is obtained, and the stirring speed is 400rpm.

[0047] (5) Preparation of mixture 3

[0048] Add sodium hydroxide and potassium carbonate in mixture 2 in sequence, further stir uniformly to obtain mixture 3, and the stirring speed is 450rpm.

[0049] (6) Preparation of inorganic metal protective agents

[0050] The remaining deionized water was added to mixture 3, and the mixture was subjected to a combination of microwave and ultrasonic treatment. The microwave power was 300W, the temperature was controlled at 50℃, the ultrasonic power was 200W, the ultrasonic frequency was 40kHz, and the treatment time was 20 minutes, resulting in an inorganic metal protectant.

[0051] The inorganic metal protectant prepared according to this invention patent was diluted with water to prepare a 50% working solution and heated to 60°C. The electroplated metal workpiece (silver plating in this case) was first cleaned with 5% sulfuric acid for 10 seconds, and then immersed in the diluted working solution with a constant voltage of 7V, with the workpiece as the cathode, for 30 seconds. After being taken out, it was rinsed with water for 5 seconds and then dried at 90°C. The surface tension was tested using an A.Shine dyne pen from the United States, and the dyne value reached 32. The workpiece was baked in a baking test chamber at 260°C, and white spots appeared on the surface of the workpiece after 16 minutes (silver oxide was generated).

[0052] Example 2: Preparation of an inorganic metal protective agent, comprising the following steps:

[0053] (1) Weigh the raw materials

[0054] Weigh the raw materials according to the following weight percentages:

[0055] 0.5% cerium chloride, 1.4% citric acid, 2.8% sodium hexametaphosphate, 0.7% borax, 15.6% sodium chloride, 0.5% cellulose nanocrystal powder, balance deionized water.

[0056] (2) Complexing agent 1 and cellulose nanocrystals

[0057] Take 20% of the total amount of deionized water, add citric acid and cellulose nanocrystal powder, and use a probe ultrasonic cell disruptor to perform ultrasonic treatment at a power of 800W under ice-water bath conditions. During the ultrasonic treatment, a pulse mode (on for 2 seconds and off for 1 second) is used. The total treatment time is 15 minutes. After the treatment, a homogeneous and stable composite mother liquor is obtained. The composite mother liquor is then irradiated with a high-energy electron beam. The absorbed dose of the irradiation treatment is 40 kGy, and the irradiation time is 10 minutes. After the irradiation treatment, mother liquor 1 is obtained.

[0058] (3) Preparation of mixture 1

[0059] Take 30% of the total amount of deionized water, microwave it to 50°C with a microwave power of 500W, add the mother liquor 1 and sodium hexametaphosphate, and stir mechanically at a speed of 600rpm until the mixture is homogeneous to obtain mixture 1.

[0060] (4) Preparation of mixture 2

[0061] Cerium chloride was added in three portions, with the addition time controlled within 1.5 hours. The mixture was then added to mixture 1 and stirred until homogeneous to form mixture 2. The stirring speed was 700 rpm.

[0062] (5) Preparation of mixture 3

[0063] Add borax and sodium chloride to mixture 2 in sequence, and stir further to obtain mixture 3. The stirring speed is 650 rpm.

[0064] (6) Preparation of inorganic metal protective agents

[0065] The remaining deionized water was added to mixture 3, and the mixture was subjected to microwave and ultrasonic co-treatment. The microwave power was 600W, the temperature was controlled at 40℃, the ultrasonic power was 400W, the ultrasonic frequency was 25kHz, and the co-treatment time was 60 minutes, resulting in an inorganic metal protectant.

[0066] The inorganic metal protectant prepared according to this invention patent was mixed with water to prepare a 50% concentration working solution and heated to 60°C. The electroplated metal workpiece (silver plating in this case) was first cleaned with 5% sulfuric acid for 5 seconds, and then immersed in the diluted working solution with a constant voltage of 7V, with the workpiece as the cathode, for 30 seconds. After removal, it was rinsed with water for 10 seconds and then dried at 70°C. The surface tension was tested using an A.Shine dyne pen from the United States, and the dyne value reached 30. The workpiece was baked in a baking test chamber at 260°C, and white spots appeared on the surface of the workpiece after 16 minutes (silver oxide was generated).

[0067] Example 3: Preparation of an inorganic metal protective agent, comprising the following steps:

[0068] (1) Weigh the raw materials

[0069] Weigh the raw materials according to the following weight percentages:

[0070] 0.2% beryllium sulfate, 1.3% EDTA, 3.5% gluconic acid, 0.7% sulfuric acid, 15% sodium sulfate, 0.2% cellulose nanocrystal powder, balance deionized water.

[0071] (2) Complexing agent 1 and cellulose nanocrystals

[0072] Take 20% of the total amount of deionized water, add EDTA and cellulose nanocrystal powder, use a probe ultrasonic cell disruptor, under ice water bath conditions, with a power of 600W, ultrasonic treatment, pulse mode is adopted during ultrasonic treatment (2 seconds on and 1 second off), the total treatment time is 20 minutes, a uniform and stable composite mother liquor is obtained after treatment, the composite mother liquor is irradiated by high-energy electron beam, the absorption dose of irradiation treatment is 25kGy, the irradiation treatment time is 25 minutes, and the mother liquor 1 is obtained after irradiation treatment is completed.

[0073] (3) Preparation of mixture 1

[0074] Take 30% of the total amount of deionized water, microwave heating to 45℃, microwave power is 550W, add mother liquor 1 and gluconic acid, adopt mechanical stirring, the stirring speed is 400rpm, and mixture 1 is obtained after stirring uniformly.

[0075] (4) Preparation of mixture 2

[0076] The beryllium sulfate is added in three times, the addition time is controlled within 1.5 hours, and the mixture 1 is stirred uniformly to obtain mixture 2, and the stirring speed is 500rpm.

[0077] (5) Preparation of mixture 3

[0078] Sulfuric acid and sodium sulfate are added in mixture 2 in sequence, and mixture 3 is obtained after further stirring uniformly, and the stirring speed is 500rpm.

[0079] (6) Preparation of inorganic metal preservative

[0080] The remaining deionized water is added in mixture 3, microwave ultrasonic is used for joint treatment, the microwave power is 400W, the temperature is controlled at 55℃, the ultrasonic power is 250W, the ultrasonic frequency is 30kHz, the joint treatment time is 35 minutes, and an inorganic metal preservative is obtained.

[0081] The inorganic metal preservative prepared by the patent is diluted into a working solution with a concentration of 50% and heated to 60℃, the metal-plated workpiece (silver-plated here) after electroplating is first cleaned with 5% sulfuric acid for 6s, then immersed in the diluted working solution (constant voltage 7V, workpiece as cathode) for 30s, then washed with water for 7s, and finally dried at 80℃; the surface tension is tested by using a U.S. A.Shine dyno pen, and the dyno value can reach 34; the workpiece is baked in a baking test box at 260℃, and white spots (silver oxide is generated) appear on the surface of the workpiece after 16 minutes.

[0082] Example 4: Preparation of an inorganic metal preservative, comprising the following steps:

[0083] (1) Weigh the raw materials

[0084] The raw materials are weighed according to the following weight percentages:

[0085] 0.1% zirconium sulfate hydrate, 0.3% ammonium citrate, 3.0% glycolic acid, 0.8% trifluoroacetic acid, 16.2% potassium chloride, 0.4% cellulose nanocrystal powder, and the rest is deionized water.

[0086] (2) Complex treatment of complexing agent 1 and cellulose nanocrystals

[0087] Take 20% of the total amount of deionized water, add ammonium citrate and cellulose nanocrystal powder, use a probe ultrasonic cell disruptor, under ice water bath conditions, with a power of 700W, ultrasonic treatment, pulse mode is used during ultrasonic treatment (on for 2 seconds and off for 1 second), the total treatment time is 25 minutes, after treatment, a uniform and stable composite mother liquor is obtained, the composite mother liquor is irradiated by high-energy electron beam, the absorbed dose of irradiation treatment is 35kGy, the irradiation treatment time is 15 minutes, after irradiation treatment, mother liquor 1 is obtained.

[0088] (3) Preparation of mixture 1

[0089] Take 30% of the total amount of deionized water, microwave heating to 58°C, microwave power is 650W, add mother liquor 1 and glycolic acid, use mechanical stirring, stirring speed is 500rpm, stirring uniformly to obtain mixture 1.

[0090] (4) Preparation of mixture 2

[0091] Zirconium sulfate hydrate is added in three times, the addition time is controlled within 1.5 hours, and the stirring speed is 600rpm after stirring uniformly in mixture 1 to obtain mixture 2.

[0092] (5) Preparation of mixture 3

[0093] Trifluoroacetic acid and potassium chloride are added in mixture 2 in turn, and further stirring uniformly to obtain mixture 3, the stirring speed is 550rpm.

[0094] (6) Preparation of inorganic metal preservative

[0095] The remaining deionized water is added to mixture 3, microwave and ultrasonic are used for co-treatment, microwave power is 450W, temperature is controlled at 47°C, ultrasonic power is 350W, ultrasonic frequency is 35kHz, co-treatment time is 45 minutes, and an inorganic metal preservative is obtained.

[0096] The inorganic metal protection agent prepared by the present application is diluted with water to a 50% concentration and heated to 60°C. The metal-plated workpiece (silver-plated in this case) after plating is first cleaned with 5% sulfuric acid for 8s, then immersed in the diluted working solution (the workpiece is the cathode at a constant voltage of 7V) for 30s, and then washed with water for 7s before being dried at 85°C. The surface tension is tested using an A.Shine daoyin pen, and the dyne value can reach 30. The workpiece is baked at 260°C for 16min, and white spots appear on the surface (silver oxide is generated).

[0097] Comparative Example 1: Compared with Example 3, no cellulose nanocrystal powder is added, and the cellulose nanocrystal is not compounded with complexing agent 1.

[0098] The inorganic metal protection agent prepared by the present application is diluted with water to a 50% concentration and heated to 60°C. The metal-plated workpiece (silver-plated in this case) after plating is first cleaned with 5% sulfuric acid for 8s, then immersed in the diluted working solution (the workpiece is the cathode at a constant voltage of 7V) for 30s, and then washed with water for 7s before being dried at 85°C. The surface tension is tested using an A.Shine daoyin pen, and the dyne value can reach 30. The workpiece is baked at 260°C for 16min, and white spots appear on the surface (silver oxide is generated).

[0099] Comparative Example 2: The ratio of complexing agent 1 and complexing agent 2 is changed, so that the weight percentage of complexing agent 1 (EDTA) is 1.7%, and the weight percentage of complexing agent 2 (gluconic acid) is 2.0%.

[0100] The inorganic metal protection agent prepared by the present application is diluted with water to a 50% concentration and heated to 60°C. The metal-plated workpiece (silver-plated in this case) after plating is first cleaned with 5% sulfuric acid for 8s, then immersed in the diluted working solution (the workpiece is the cathode at a constant voltage of 7V) for 30s, and then washed with water for 7s before being dried at 85°C. The surface tension is tested using an A.Shine daoyin pen, and the dyne value can reach 30. The workpiece is baked at 260°C for 16min, and white spots appear on the surface (silver oxide is generated).

[0101] Comparative Example 3: The commercially available silver protection agent Ag-820 water-soluble gold and silver protection agent (thiol-based protection agent, Dongguan Cuyu New Material Co., Ltd., referred to as Ag-820 hereinafter) currently used by the company is subjected to the above-mentioned sulfidation test in a 2% potassium sulfide solution, surface tension test, and baking test at 260°C using a baking test box. The experimental results are shown in Experimental Example.

[0102] Experimental Example:

[0103] The prepared inorganic metal protective agent (stock solution) has the following basic properties: transparent or translucent liquid at room temperature (25-28℃), pH=13-14, density of about 1 g / ml (close to water), no irritating odor, and can be mixed with water in any proportion to form a colorless to translucent stable solution.

[0104] (1) The EDS component analysis results of the film formed on the surface of the silver-plated workpiece using the method described in Example 1 of the present application are shown in Table 1.

[0105] Table 1 Component analysis results

[0106] Element Line type wt % Wt % Sigma At % C K line system 6.45 0.57 32.23 N K line system 1.78 1.19 7.61 O K line system 2.49 0.58 9.34 Fe K line system 1.30 0.34 1.39 Co K line system 0.00 0.38 0.00 Ni K line system 1.72 0.49 1.76 Cu L line system 1.89 0.72 1.79 Ag L line system 53.81 1.13 29.92 Ln L line system 30.56 0.83 15.96

[0107] (2) The protection effect test of the silver-plated pieces tested in Examples 1-3 and Comparative Examples 1-3 was tested, i.e. the partial preferred results of the sulfidation test in a 2% potassium sulfide solution (at room temperature 25-28℃), the surface tension test using a U.S. A.Shine dyna pen, and the baking test at 260℃ using a baking test chamber, and the results are shown in Table 2.

[0108] Table 2 Test results

[0109] Group Sulfidation / s Dyne value (dyn / cm) Bake / min Example 1 250 32 16 Example 2 330 30 18 Example 3 400 34 24 Example 4 310 30 17 Comparative Example 1 160 42 13 Comparative Example 2 120 40 12 Comparative Example 3 560 28 10

[0110] As can be seen from Example 3 and Comparative Example 1, if the cellulose nanocrystal powder is not added and the cellulose nanocrystal is not compounded with complexing agent 1, the prepared metal protective agent has reduced sulfidation resistance, increased surface tension, and reduced high temperature resistance.

[0111] As can be seen from Example 3 and Comparative Example 2, if the ratio of complexing agent 1 and complexing agent 2 is changed so that the ratio of complexing agent 1 to complexing agent 2 is not within the range of 1:2-1:10, the prepared metal protective agent has reduced sulfidation resistance, increased surface tension, and reduced high temperature resistance.

[0112] As can be seen from Example 3 and Comparative Example 3, the sulfidation resistance of the metal protective agent prepared in Example 3 is slightly worse than that of the commercially available silver protective agent Ag-820, but it has relative sulfidation resistance compared to the unprotected pure silver-plated workpiece (which cannot resist sulfidation), indicating that it can be used for short-term protection. In addition, the dyna value test and baking test results are better than the commercially available silver protective agent Ag-820 currently used by the company, indicating that it is more suitable for subsequent injection molding process than the commercially available silver protective agent Ag-820 currently used by the company, and can achieve short-term protection of silver-plated metal workpieces during subsequent processing procedures without discoloration.

[0113] From Figure 1 and Figure 2It can be known that the inorganic metal protection agent prepared in the embodiment 1 of the present application has a more uniform and smooth surface after film forming on the surface of the silver-plated workpiece than the surface after film forming of the commercially available Ag-820 water-soluble silver protection agent, the smooth surface reduces the risk of friction damage and enhances the wear resistance, thereby the film layer can better maintain the original metal luster and texture of the silver layer and the appearance is more bright, and for the precision electronic components, it also helps to ensure the stability of the electrical contact performance.

[0114] The above embodiments are only used to illustrate the technical solutions of the present application, but not limit the present application; although the present application is described in detail with reference to the foregoing embodiments, those skilled in the art should understand that the technical solutions recorded in the foregoing embodiments can be modified or some technical features can be replaced by the equivalent ones; and these modifications or replacements will not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. An inorganic metal protective agent, characterized in that, It consists of the following raw materials by weight percentage: 0.1-0.5% film-forming agent, 0.3-1.7% complexing agent 1, 2.5-3.5% complexing agent 2, 0.6-0.8% buffer, 15-17% conductive agent, 0.1-0.5% cellulose nanocrystal powder, balance deionized water; The film-forming agent is one of indium sulfate, cerium chloride, beryllium sulfate, and hydrated zirconium sulfate; The complexing agent 1 is one of EDTA, citric acid, potassium sodium tartrate, and ammonium citrate; The complexing agent 2 is one of HEDP, sodium hexametaphosphate, gluconic acid, and glycolic acid; The ratio of complexing agent 1 to complexing agent 2 is between 1:2 and 1:10; The inorganic metal protectant is first modified by using cellulose nanocrystal powder to treat complexing agent 1, then complexing agent 2 is added and mixed. After mixing, a film-forming agent is added. During the preparation process, the film-forming agent will first undergo a complexation reaction with the modified complex 1 and complex 2. Finally, a buffer and a conductive agent are added to obtain the inorganic metal protectant.

2. The inorganic metal protective agent according to claim 1, characterized in that, The buffer is one of sodium hydroxide, borax, trifluoroacetic acid, and sulfuric acid; the conductive agent is one of potassium carbonate, sodium sulfate, sodium chloride, and potassium chloride.

3. A method for preparing an inorganic metal protective agent according to any one of claims 1-2, characterized in that, Includes the following steps: (1) Weigh the raw materials according to the following weight percentages: 0.1-0.5% film-forming agent, 0.3-1.7% complexing agent 1, 2.5-3.5% complexing agent 2, 0.6-0.8% buffer, 15-17% conductive agent, 0.1-0.5% cellulose nanocrystal powder, and the balance is deionized water; (2) Add complexing agent 1 and cellulose nanocrystal powder to deionized water and sonicate under ice-water bath conditions. After treatment, a composite mother liquor is obtained. The composite mother liquor is then irradiated with a high-energy electron beam. The absorbed dose of the irradiation treatment is 20-40 kGy and the irradiation time is 10-20 minutes. After the irradiation treatment, mother liquor 1 is obtained. (3) Take deionized water and microwave it. After heating, add mother liquor 1 and complexing agent 2 and stir. After stirring, mixture 1 is obtained. (4) Add film-forming agent to mixture 1 and stir to obtain mixture 2; (5) Add buffer solution and conductive agent to mixture 2 in sequence, stir to obtain mixture 3; (6) Add deionized water to mixture 3 and co-treat it with microwave and ultrasound. The microwave power is 300-600W, the temperature is 40-50℃, the ultrasound power is 200-400W, the ultrasound frequency is 25-40kHz, and the co-treatment time is 20-60 minutes. After the treatment, an inorganic metal protectant is obtained.

4. The method for preparing the inorganic metal protective agent according to claim 3, characterized in that, In step (2), the ultrasonic treatment power is 500-800W and the treatment time is 15-30 minutes.

5. The method for preparing the inorganic metal protective agent according to claim 3, characterized in that, In step (3), the power of microwave processing is 500-800W, and microwave heating is performed to 40-50℃.

6. The method for preparing the inorganic metal protective agent according to claim 3, characterized in that, The stirring speed in step (3) is 300-600 rpm, the stirring speed in step (4) is 400-700 rpm, and the stirring speed in step (5) is 450-650 rpm.

7. The application of an inorganic metal protectant according to any one of claims 1-2 in metal protection, characterized in that, The method of using the inorganic metal protective agent is as follows: Prepare an inorganic metal protectant by adding water to form a working solution with a concentration of 30-60% and heat it to 30-60℃. After electroplating, clean the metal-plated workpiece with 5% sulfuric acid for 5-10 seconds, then immerse it in the diluted working solution for 20-60 seconds. Remove it, rinse it with water for 5-10 seconds, and then dry it at 70-90℃.

8. The application of the inorganic metal protectant according to claim 7 in metal protection, characterized in that, In the method of using the inorganic metal protective agent, the voltage of the energizer is 6-9V, the anode is a platinum titanium mesh or graphite, the cathode is the workpiece, and the area ratio of the anode to the cathode is greater than 3.

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