Non-toxic sodium cyanide or potassium cyanide imitation gold electroplating solution and preparation method therefor

Description

Non-poisonous sodium cyanide or potassium cyanide imitation gold plating solution and preparation method thereof TECHNICAL FIELD

[0001] The present application relates to a non-poisonous sodium cyanide or potassium cyanide imitation gold plating solution and preparation method thereof, and belongs to the technical field of plating solution and preparation thereof. BACKGROUND

[0002] Gold plating is widely used in decorative plating. However, pure gold plating is limited in application due to high price of gold, low hardness and poor wear resistance. The golden color of imitation gold plating can meet the requirements of decoration, and the hardness and wear resistance of the plating layer are greatly improved. The cost is low, and it is mainly used for decorative plating on jewelry, handicrafts, lamps, buttons, watches, lighters and other parts, which has obvious economic benefits and broad development prospects. Imitation gold plating mostly uses cyanide plating, and the plating layer has fine crystals, good plating solution dispersion and covering ability, and the color of the plating layer is similar to that of pure gold. However, the process uses highly toxic cyanide, which is harmful to the human body and the environment.

[0003] In recent years, people have developed various non-poisonous sodium cyanide or potassium cyanide imitation gold plating solutions, such as pyrophosphate system, tartrate system, HEDP system and citric acid system. These plating solutions have their own advantages, but also have their own limitations and cannot fundamentally replace cyanide imitation gold plating solution.

[0004] The inventors of the present application have previously developed a non-cyanide complexing agent. The imitation gold plating solution prepared from the complexing agent has stable quality, good dispersibility, a wide range of process current density that can be used, and a wide range of application of the plating solution. However, with higher requirements for the quality of the plating product, after meeting the higher complexing force, the deep plating capacity of the complexing agent also needs to be considered. The plating layer needs to be more compact, and the plating efficiency needs to be improved to achieve energy saving of the plating process. Based on the problems to be solved in the newly proposed non-cyanide plating, the inventors of the present application have developed a new non-poisonous sodium cyanide or potassium cyanide imitation gold plating solution and disclosed a preparation method thereof. SUMMARY

[0005] One of the purposes of the present application is to solve the defects of the prior art and provide a new non-poisonous sodium cyanide or potassium cyanide imitation gold plating solution. The plating solution has strong deep plating capacity, finer and more compact plating layer crystals, high plating efficiency and can achieve energy saving of the plating process.

[0006] The second purpose of the present application is to provide a new preparation method of non-poisonous sodium cyanide or potassium cyanide imitation gold plating solution. The method is easy to realize industrial production, and the quality of the produced plating solution product is stable.

[0007] The technical scheme adopted by the present application to solve the technical problems is:

[0008] A non-toxic sodium cyanide or potassium cyanide gold-like electroplating solution, comprising a complexing agent, a complexing agent copper salt, a tin salt and water, wherein the general formula of the complexing agent copper salt in the non-toxic sodium cyanide or potassium cyanide gold-like electroplating solution is Cu n [C 2n N 2n+1 S n O n H n+3 ] and the structural formula is as follows:

[0009] The general formula of the complexing agent zinc salt is Zn n [C 4n N 4n+2 S 2n O 2n H 2n+6 ] and the structural formula is as follows:

[0010] The tin salt is potassium stannate or sodium stannate, wherein n is 1, 2, 3, …, 50.

[0011] Preferably, the general formula of the complexing agent in the non-toxic sodium cyanide or potassium cyanide gold-like electroplating solution is R m [C 2m N 2m+1 S m O m H m+3 ] and the structural formula is as follows:

[0012] wherein R is K or Na, and m is 1, 2, 3, …, 50.

[0013] The foregoing technical solutions are explained below with several examples:

[0014] A: when R is K and m is 1, the general formula of the complexing agent is K[C2N3SOH4] and the structural formula is as follows:

[0015] The structural formula of the complexing agent copper salt obtained by processing this kind of complexing agent is Cu[C2N3SOH4], n = m, and the structural formula is as follows:

[0016] The structural formula of the complexing agent zinc salt obtained by processing this kind of complexing agent is (1 / 2)Cu[C2N3SOH4], n = m, that is, Zn[C4N6S2O2H8], and the structural formula is as follows:

[0017] B: when R is K and n is 20, the general formula of the complexing agent is K 20 [C 40 N 41 S 20 O20 H 23 ],its structure is as follows:

[0018] The structure of the complexing agent copper salt prepared by processing the complexing agent is as follows:

[0019] The structure of the complexing agent zinc salt prepared by processing the complexing agent is as follows:

[0020] C: when R is Na and n is 50, the general formula of the complexing agent is Na 50 [C 100 N 101 S 50 O 50 H 53 ],its structure is as follows:

[0021] The structure of the complexing agent copper salt prepared by processing the complexing agent is as follows:

[0022] The structure of the complexing agent zinc salt prepared by processing the complexing agent is as follows:

[0023] Preferably, R is K and n is 1, 2, or 3, and the structures are as follows, respectively:

[0024] Preferably, in the non-toxic sodium cyanide or potassium cyanide gold-like electroplating solution, the mass fraction of the complexing agent is 1-30%, the mass fraction of the complexing agent copper salt is 1-10%, the mass fraction of the complexing agent zinc salt is 1-10%, the mass fraction of the complexing agent tin salt is 1-10%, and the balance is water.

[0025] More preferably, in the non-toxic sodium cyanide or potassium cyanide gold-like electroplating solution, the mass fraction of the complexing agent is 20%, the mass fraction of the complexing agent copper salt is 10%, the mass fraction of the complexing agent zinc salt is 10%, the mass fraction of the complexing agent tin salt is 10%, and the balance is water.

[0026] In the non-toxic sodium cyanide or potassium cyanide gold-like electroplating solution of the present application, at least the complexing agent copper salt, the complexing agent zinc salt, and the complexing agent tin salt are prepared by reacting the complexing agent of the present application with soluble copper salt, zinc salt, and tin salt, respectively, and further mixing the complexing agent in the electroplating solution. The complexing agent can be selected from conventional complexing agents, the complexing agent of the present application, or preferably the complexing agent of the present application.

[0027] The n value in the complexing agent copper salt, zinc salt and tin salt can be the same or different, and can be the same as or different from the m value in the complexing agent. For example, the complexing agent in the aforementioned A is mixed with the complexing agent copper salt and complexing agent zinc salt in the aforementioned A, or is mixed with the complexing agent copper salt and complexing agent zinc salt in the aforementioned B, and all can be processed into the non-toxic sodium cyanide or potassium cyanide imitation gold plating solution of the present application.

[0028] Preferably, the complexing agent is prepared from the raw materials of ferric ferrocyanide, sodium or potassium thiosulfate (when R is K, potassium thiosulfate is used, and when R is Na, sodium thiosulfate is used) and urea, in an oxygen-containing atmosphere, using rhodium and / or platinum as catalyst, through solid-state polymerization of inorganic salt, dissolution in water, separation, concentration and drying of the separated liquid.

[0029] The reaction formula of the complexing agent preparation method of the present application is as follows: (n / 4)[K4Fe(CN)6]+nNa2S2O3+nCH4N2O+20 / nO2=K n [C 2n N 2n+1 S n O n H n+3 ]+(n / 12)Fe3C+(5n / 12)C+(n / 4)N2+nNa2SO3+(n-1)NH3,

[0030] or; (n / 4)[K4Fe(CN)6]+nK2S2O3+nCH4N2O+20 / nO2=K n [C 2n N 2n+1 S n O n H n+3 ]+(n / 12)Fe3C+(5n / 12)C+(n / 4)N2+nK2SO3+(n-1)NH3;

[0031] The present application also discloses a specific preparation method of a complexing agent, and the steps of the preparation method are as follows:

[0032] The ferric ferrocyanide, sodium or potassium thiosulfate and urea are placed in a rotary kiln, the catalyst rhodium and / or platinum is added, the reaction is carried out at 450-650°C for 5-7 hours, the polymerized inorganic salt is dissolved in water, the insoluble substances are removed, the separated liquid is obtained, and the separated liquid is dried to obtain the finished complexing agent.

[0033] Preferably, the separation is carried out by any one or several of suction filtration, plate and frame pressure filtration and centrifugal separation.

[0034] Preferably, the separation liquid is concentrated before drying, the separation liquid is concentrated to 30-40% of water content, and the concentrated material is dried to less than 5% of water content, and the concentration is performed by vacuum concentration.

[0035] Preferably, the drying is performed by spray drying, and the inlet air temperature of the spray drying is 100-200℃.

[0036] The preparation method of the copper salt of the complexing agent is as follows: water is added into a reactor, then a molar amount of the complexing agent and a water-soluble copper salt are added, and then a molar amount of sodium sulfite and sodium hydroxide is added, and the reaction is performed by stirring, and after the reaction is completed, the precipitate obtained by filtration is rinsed and dried to obtain the copper salt of the complexing agent.

[0037] The preparation method of the copper salt of the complexing agent and the zinc salt of the complexing agent is as follows: water is added into a reactor, then a molar amount of the complexing agent and a water-soluble zinc salt are added, and the reaction is performed by stirring, and after the reaction is completed, the precipitate obtained by filtration is rinsed and dried to obtain the zinc salt of the complexing agent.

[0038] The preparation method of the non-poisonous sodium cyanide or potassium cyanide gold-like electroplating solution of the present application is as follows: the copper salt of the complexing agent, the zinc salt of the complexing agent, a tin salt, the complexing agent and water are mixed according to the proportion, and then dissolved by stirring, and then the pH value is adjusted to 12.0-13.0 to obtain the non-poisonous sodium cyanide or potassium cyanide gold-like electroplating solution.

[0039] The present application has the following advantages:

[0040] The raw materials for preparing the complexing agent of the present application are widely available, and the preparation process, transportation, storage and use are simple, and the production cost is low; the complexing agent of the present application is applied to the production of electroplating solution, and the processing is convenient, and the electroplating solution prepared has strong complexing ability to metals, for example, the complexing constant of the complexing agent of the present application to copper ions can reach 10 26-27 (which is equivalent to the existing non-cyanide complexing agent), which is much better than the conventional complexing agent in the prior art (especially potassium pyrophosphate, citric acid and HEDP), the gold-like electroplating solution prepared from the complexing agent of the present application has stable quality, good dispersibility, a wide range of process current density, and a wide range of application (the listed performances are equivalent to the electroplating solution prepared from the existing non-cyanide complexing agent), in addition, the deep plating capacity is strong, the plated layer is finer and denser, the electroplating efficiency is high, and the energy saving of the gold-like electroplating process can be realized.

[0041] In summary, the gold-like layer obtained by the electroplating method of the present application has golden color, good brightness, good adhesion to the substrate of the plated part, good leveling ability and excellent covering ability, the method has a wide range of current density and good repeatability. DETAILED DESCRIPTION

[0042] The technical solutions of the present application are further described below with specific examples. The reagents, raw materials and devices and facilities used in the following examples are all commercially available conventional reagents, raw materials, devices and facilities.

[0043] Example 1

[0044] A complexing agent, the structural formula of which is as follows:

[0045] The polymineral salt reaction formula of the complexing agent is as follows:

[0046] (1 / 4) [K4Fe(CN)6] + K2S2O3 + CH4N2O + 20O2 = K[C2N3SOH4] + (1 / 12) Fe3C + (5 / 12) C + (1 / 4) N2 + K2SO3; the preparation method steps are as follows:

[0047] The yellow prussiate, sodium or potassium thiosulfate and urea are placed in a rotary reaction kiln, which is fixed with a catalyst rhodium and / or platinum, in an oxygen-containing atmosphere, at 450-460℃, for 7 hours; the polymerized polymineral salt is dissolved in water, separated, and the insoluble substances are removed to obtain a separation liquid, which is dried to obtain the finished complexing agent.

[0048] In Example 1, the separation uses suction filtration, and the separation liquid is concentrated before drying, and the separation liquid is concentrated to a water content of 30%, and the concentrated material is dried to a water content of less than 5%, the concentration uses vacuum concentration, and the drying uses spray drying, and the inlet air temperature of the spray drying is 100-110℃.

[0049] Example 2

[0050] A complexing agent, the structural formula of which is as follows:

[0051] The polymineral salt reaction formula of the complexing agent is as follows:

[0052] (1 / 2) [K4Fe(CN)6] + 2K2S2O3 + 2CH4N2O + 10O2 = K2[C4N5S2O2H5] + (1 / 6) Fe3C + (5 / 6) C + (1 / 2) N2 + 2K2SO3 + NH3; the preparation method steps are as follows:

[0053] The yellow prussiate, sodium or potassium thiosulfate and urea are placed in a rotary reaction kiln, which is fixed with a catalyst rhodium and / or platinum, in an oxygen-containing atmosphere, at 640-650℃, for 5 hours; the polymerized polymineral salt is dissolved in water, separated, and the insoluble substances are removed to obtain a separation liquid, which is dried to obtain the finished complexing agent.

[0054] In Example 1, the separation uses plate-frame filter pressing, the separation liquid is concentrated before drying, the separation liquid is concentrated to a water content of 40%, the concentrated material is dried to a water content of less than 5%, the concentration uses vacuum concentration, and the drying uses spray drying with an air inlet temperature of 190-200°C.

[0055] Example 3

[0056] A complexing agent, the structural formula of which is as follows:

[0057] The polymineral salt reaction formula of the complexing agent is as follows: (3 / 4) [K4Fe(CN)6] + 3K2S2O3 + 3CH4N2O + 20 / 3O2 = K3[C6N7S3O3H6] + (1 / 4) Fe3C + (5 / 4) C + (3 / 4) N2 + 3K2SO3 + 2NH3, and the preparation method steps are as follows:

[0058] The yellow prussiate, sodium or potassium thiosulfate and urea are placed in a rotary reaction kiln, the rotary reaction kiln is fixed with a catalyst rhodium and / or platinum, in an oxygen-containing atmosphere, at 590-600°C, and reacted for 6 hours; the polymeric polymineral salt is dissolved in water, insoluble substances are removed through separation, to obtain a separation liquid, and the separation liquid is dried to obtain a complexing agent finished product.

[0059] In Example 3, the separation uses centrifugal separation, the separation liquid is concentrated before drying, the separation liquid is concentrated to a water content of 35%, the concentrated material is dried to a water content of less than 5%, the concentration uses vacuum concentration, and the drying uses spray drying with an air inlet temperature of 160-170°C.

[0060] Example 4

[0061] A complexing agent, the structural formula and preparation method of which are the same as those in Example 3, except that n = 50.

[0062] Example 5

[0063] A complexing agent, the structural formula and preparation method of which are the same as those in Example 1, except that Na is used instead of K.

[0064] Example 6

[0065] A complexing agent, the structural formula and preparation method of which are the same as those in Example 2, except that Na is used instead of K.

[0066] Example 7

[0067] A complexing agent, the structural formula and preparation method of which are the same as those in Example 3, except that Na is used instead of K.

[0068] Example 8

[0069] A complexing agent, the structural formula of which is the same as that of Example 4, except that Na is used instead of K.

[0070] The complexing agent of Examples 1-8 of the present application is used for electroplating, and is exemplified by a gold-imitating electroplating solution. The amount of the complexing agent in the electroplating solution is 1-30%, preferably 20%. The application of the complexing agent of the present application is exemplified by the use of 20%.

[0071] The reaction formula for preparing a complexing agent copper salt from the complexing agent is as follows, with n=2 and R=K as an example:

[0072] 2CuSO4+K2[C4N5S2O2H5]+Na2SO3+2NaOH=K2SO4+2Na2SO4+H2O+Cu2[C4N5S2O2H5]. The reaction conditions are normal temperature and pressure.

[0073] The reaction formula for preparing a complexing agent zinc salt from the complexing agent is as follows, with n=1 as an example:

[0074] ZnSO4+2K[C2N3SOH4]=K2SO4+Zn[C2N3SOH4]2. The reaction conditions are normal temperature and pressure.

[0075] Example 9: The complexing agent of Example 1 is used in an electroplating solution for pre-plating copper and zinc

[0076] Water is added to a reaction kettle, the complexing agent of Example 1 is added in a molar ratio, and a molar amount of copper salt is added for reaction. After the reaction is completed, the precipitate is filtered, rinsed, and dried to obtain a complexing agent copper salt.

[0077] Water is added to a reaction kettle, the complexing agent of Example 1 is added in a molar ratio, and a molar amount of zinc salt is added for reaction. After the reaction is completed, the precipitate is filtered, rinsed, and dried to obtain a complexing agent zinc salt.

[0078] The electroplating solution is prepared as follows: the mass fraction of the complexing agent is 20%, the mass fraction of the complexing agent copper salt is 1.0%, the mass fraction of the complexing agent zinc salt is 1.0%, the mass fraction of sodium stannate is 5%, and the balance is water. The mixture is uniformly mixed, and sodium hydroxide is used to adjust the pH to 12.0.

[0079] Example 10: The complexing agent of Example 2 is used in an electroplating solution for pre-plating copper

[0080] Into a reaction kettle, water was added, and the complexing agent of Example 1 was added at a molar ratio, and a molar amount of copper salt was added to react. After the reaction was completed, the precipitate was filtered, and the precipitate was rinsed and dried to obtain a complexing agent copper salt.

[0081] Into a reaction kettle, water was added, and the complexing agent of Example 1 was added at a molar ratio, and a molar amount of zinc salt was added to react. After the reaction was completed, the precipitate was filtered, and the precipitate was rinsed and dried to obtain a complexing agent zinc salt.

[0082] The plating solution was prepared by mixing 20% of the complexing agent, 1.0% of the complexing agent copper salt, 1.0% of the complexing agent zinc salt, 5% of sodium stannate, and the rest of water, and adjusting the pH to 12.0 with sodium hydroxide.

[0083] Example 11: The complexing agent of Example 3 was used in a plating solution for pre-plating copper

[0084] Into a reaction kettle, the complexing agent of Example 3 was added at a molar ratio, and a molar amount of copper salt solution (copper sulfate solution) was added to react. After the reaction was completed, the precipitate was filtered, and the filtrate was dried to obtain a complexing agent copper salt.

[0085] Into a reaction kettle, water was added, and the complexing agent of Example 3 was added at a molar ratio, and a molar amount of zinc salt was added to react. After the reaction was completed, the precipitate was filtered, and the precipitate was rinsed and dried to obtain a complexing agent zinc salt.

[0086] The plating solution was prepared by mixing 20% of the complexing agent, 1.0% of the complexing agent copper salt, 1.0% of the complexing agent zinc salt, 5% of sodium stannate, and the rest of water, and adjusting the pH to 12.0 with sodium hydroxide.

[0087] Examples 12-16: The complexing agents of Examples 4-8 were used in plating solutions for gold-like plating, respectively

[0088] Into a reaction kettle, the complexing agents of Examples 4-8 were added at a molar ratio, respectively, and a molar amount of copper salt solution (copper sulfate solution) was added to react. After the reaction was completed, the precipitate was filtered, and the filtrate was dried to obtain a complexing agent copper salt.

[0089] Into a reaction kettle, water was added, and the complexing agents of Examples 4-8 were added at a molar ratio, and a molar amount of zinc salt was added to react. After the reaction was completed, the precipitate was filtered, and the precipitate was rinsed and dried to obtain a complexing agent zinc salt.

[0090] The configuration of the electroplating solution: the mass fraction of the complexing agent is 20%, the mass fraction of the complexing agent copper salt is 1.0%, the mass fraction of the complexing agent zinc salt is 1.0%, the mass fraction of sodium stannate is 5%, and the balance is water, which is mixed uniformly, and the pH is adjusted to 12.0 by sodium hydroxide.

[0091] Comparative Example 17: potassium pyrophosphate complexing agent

[0092] The configuration of the electroplating solution: the complexing agent 20%, copper pyrophosphate 1.0%, zinc pyrophosphate 1.0%, sodium stannate 5%, and the balance is water, which is mixed uniformly, and the pH is adjusted to 12.0 by sodium hydroxide.

[0093] Comparative Example 18: complexing agent of Patent No. 2014100151872

[0094] The configuration of the electroplating solution: the complexing agent 20%, the complexing agent copper salt 1.0%, the complexing agent copper salt 1.0%, the complexing agent tin 5%, and the balance is water, which is mixed uniformly, and the pH is adjusted to 12.0 by sodium hydroxide.

[0095] Performance test:

[0096] The above Examples 9-16, Comparative Examples 17-18 were tested for performance according to the following method.

[0097] The gold-like electroplating solutions prepared from Examples 9-16 and Comparative Examples 17-18 were subjected to the following studies:

[0098] 1. Hull cell test (267ml)

[0099] 1.1 Preliminary test: The gold-like electroplating solutions prepared from Examples 9-16 and Comparative Examples 17-18 were tested under the conditions of temperature 25℃, circuit 1A (constant current), air stirring, time 5min. During the plating process of Examples 9-16, it was observed that under the condition of constant current, the cell voltage was also relatively stable, and the plated pieces showed the characteristics of half-spot and fine crystals on a large area. Examples 9-16 were all superior to Comparative Example 18, and Comparative Example 18 was superior to Comparative Example 17.

[0100] 1.2 Hull cell test to determine the current density range:

[0101] The gold-like electroplating solutions prepared from Examples 9-16 and Comparative Examples 17-18 were tested at a temperature of 55℃, a current of 1A, and a time of 10min to determine the optimal current density range by Hull plating. The selected sheet material for plating was A3 steel sheet of 0.5*70*100, polished with 600# water sandpaper. The current density of each point of the test piece was calculated according to the empirical formula Jk=I(5.1-5.24LgL). Through plating and current density calculation, it was found that the current density range of the electroplating solution prepared from Examples 9-16 was 0.5A / dm 2 to 5A / dm2 between.

[0102] 2. Test of plating solution and plating performance

[0103] 2.1 Measurement of current efficiency: The average current efficiency of the plating solution prepared in Examples 9-16 was 95.3%, the current efficiency of the plating solution prepared in Example 17 was 87.8%, and the current efficiency of the plating solution prepared in Example 18 was 91.8%, as measured by a copper coulometer.

[0104] 2.2 Measurement of throwing power of plating solution

[0105] The throwing power of the plating solution was measured by the bending cathode method under the conditions of a current of 1 A, air agitation without oil, a temperature of 55°C, a time of 30 min, and a test material of a 0.5*70*100 A3 copper sheet polished with 600# water sandpaper.

[0106] The average throwing power of the plating solution of Examples 9-16 was 94.3%, the throwing power of the plating solution of Example 17 was 89.1%, and the throwing power of the plating solution of Example 18 was 90.3%.

[0107] 2.3 Measurement of covering power

[0108] The covering power of the plating solution was measured by the inner hole method under the conditions of a copper tube size of 10mm*100mm, a through hole and blind hole method, a plating solution temperature of 55°C, a cathode current density of 0.5A / dm 2 , and a time of 5 min. After the experiment, the iron tube was cut open and the plating layer inside the tube was observed.

[0109] The gold-like plating solutions prepared in Examples 9-16 and Comparative Examples 17-18 were used as experimental plating solutions, and after the experiment, it was found that the through holes and blind holes were all plated with a gold-like layer, indicating that the covering power of the plating solutions prepared in Examples 9-16 was excellent, better than that of Example 18, and much better than that of Example 17.

[0110] 2.4 Test of adhesion

[0111] 2.4.1 Bending experiment: A polished iron sheet (A3) having a thickness of 0.5mm was used, the temperature of the plating solution was 55°C, the cathode current density was 2A / dm 2 , and the time was 15 min.

[0112] The gold-like plating solutions prepared in Examples 9-16 and Comparative Examples 17-18 were used as experimental plating solutions, and after the experiment, the plated test pieces were repeatedly bent until they broke, and there was no peeling phenomenon at the crack, proving that the plating layer and the substrate were not separated.

[0113] 2.4.2 Thermal shock test: polished iron sheet (A3) with thickness of 0.5 mm was used, the temperature of plating solution was 55°C, cathode current density was 2 A / dm 2 , and time was 15 min.

[0114] The gold-like plating solutions prepared in Examples 9-16 and Comparative Examples 17-18 were used as experimental plating solutions, and after the experiments, the plated test pieces were baked in an oven to 200°C for 1 h, and then immediately immersed in water at 0°C. As a result, no blistering or peeling of the plated layers was observed.

[0115] 2.5 Test of plating layer flexibility: A3 steel sheet with thickness of 1 mm was passivated with chromic acid, washed, and then directly hung in the plating solutions of Examples 9-16 and Comparative Examples 17-18. After the thickness of the plated layer reached 20 μm, the plated layer was peeled off, bent to 180°, and pressed at the bent portion. The plated layer did not break, indicating that the plated layer was flexible. Among them, Examples 9-16 were superior to Example 18, and Example 18 was superior to Example 17.

[0116] 2.6 Test of plating layer porosity: polished iron sheet (A3) with thickness of 0.5 mm was used, the temperature of plating solution was 55°C, cathode current density was 1 A / dm 2 , and time was 20 min. The porosity test was performed using the filter paper test method with potassium ferricyanide solution.

[0117] Potassium ferricyanide 10 g / L; sodium chloride 20 g / L.

[0118] The experimental results showed that the porosities of the plated layers formed using the plating solutions of Examples 9-16 as experimental objects were all ≤0.53 pieces / dm 2 , which were superior to 0.9 pieces / dm 2 of Example 18, and 1.5 pieces / dm 2 of Example 17.

[0119] 2.7 Measurement of deposition rate: the current was set to 1 A, the temperature was set to 55°C, and the time was set to 30 min. The results showed that the deposition rate of the plating solution of Examples 9-16 was 0.78 μm / min, the deposition rate of the plating solution of Example 17 was 0.55 μm / min, and the deposition rate of the plating solution of Example 18 was 0.65 μm / min.

[0120] Further pilot experiments were performed on the plating solutions prepared in Examples 9-16. The pilot process parameters were as follows:

[0121] Process flow: steel workpiece → ultrasonic degreasing → water washing 1 → water washing 2 → anode electrolytic degreasing → water washing 1 → water washing 2 → acid degreasing → water washing 1 → water washing 2 → hydrochloric acid washing → water washing 1 → water washing 2 → terminal electrolytic degreasing → water washing 1 → water washing 2 → acid activation → water washing 1 → water washing 2 → plating solution of Examples 9-16 → recovery → water washing 1 → water washing 2 → acid activation → acid copper plating.

[0122] Ultrasonic degreasing: degreasing powder concentration 50±5 g / L, temperature 70±5℃, current density 1-5 A / dm 2 , time 5 minutes.

[0123] Cathode electrolytic degreasing: electrolytic degreasing powder concentration 50±5 g / L, temperature 70±5℃, current density 1-5 A / dm 2 , time 5-7 minutes.

[0124] Anode electrolytic degreasing: electrolytic degreasing powder concentration 50±5 g / L, temperature 70±5℃, current density 1-5 A / dm 2 , time 3-5 minutes.

[0125] Acid pickling: industrial hydrochloric acid concentration 15-20%, time 8-10 min, room temperature.

[0126] Activation: industrial hydrochloric acid concentration 5-10%, time 3-5 min, room temperature.

[0127] Plating solution of Examples 9-16: Baume degree 32-36, pH value 8.0, temperature 50-55℃, current density 0.5-5 A / dm 2 , time 5 min to several hours, and it has been proved that the plating to 100 μm is very good in flatness and brightness, better than Comparative Example 18, and much better than Comparative Example 17.

[0128] The plating solution prepared according to Examples 9-16 has been verified to have reliability and stable performance through continuous running of a 50 L pilot production line for 20 months and a 350 L pilot production line for 11 months. The consumption of the plating solution is 10-50 ml / KAH. On the basis of the above-mentioned pilot experiments, the process conditions for industrial production of the plating solution prepared according to Examples 9-16 are obtained.

[0129] 1. Steel workpiece:

[0130] Process flow: steel workpiece → ultrasonic degreasing → water washing 1 → water washing 2 → anode electrolytic degreasing → water washing 1 → water washing 2 → acid degreasing → water washing 1 → water washing 2 → hydrochloric acid washing → water washing 1 → water washing 2 → terminal electrolytic degreasing → water washing 1 → water washing 2 → acid activation → water washing 1 → water washing 2 → pre- immersion → plating solution of Examples 9-16 → recovery → water washing 1 → water washing 2 → acid activation → acid copper plating.

[0131] Process conditions:

[0132] Density of plating bath: 32-36 Baume

[0133] Temperature 45-60°C

[0134] pH: 12-13

[0135] Agitation: air agitation plus cathode movement

[0136] Anode: electrolytic copper or oxygen free electrolytic copper

[0137] Anode to cathode area ratio: 1:1.5-2.

[0138] Current: 0.5-5 A / dm 2

[0139] 2. Zinc alloy workpiece:

[0140] Process flow: zinc alloy workpiece → hot dip wax removal → ultrasonic wax removal → water wash 1 → water wash 2 → ultrasonic oil removal → water wash 1 → water wash 2 → anodic electrolytic oil removal → water wash 1 → water wash 2 → acid salt activation → water wash 1 → water wash 2 → ultrasonic pre-dip pre-dipping for 30 seconds → plating bath of Examples 9-16 (charged into bath at 25-35°C) → recovery → water wash 1 → water wash 2 → acid activation → acid copper.

[0141] Process conditions:

[0142] Density of plating bath: 32-38 Baume

[0143] Temperature 25-35°C

[0144] pH: 12-13

[0145] Agitation: air agitation plus cathode movement

[0146] Anode: electrolytic copper or oxygen free electrolytic copper

[0147] Anode to cathode area ratio: 1:1.5-2.

[0148] Current: 0.5-1.5 A / dm 2 .

[0149] The above-described examples are only a preferred scheme of the present application, and do not limit the present application in any form, and other variations and modifications are possible without departing from the technical scheme recited in the claims.

Claims

1. A non-poisonous sodium or potassium cyanide gold imitation plating solution, characterized in that: The cyanide-free alkaline copper electroplating solution comprises a complexing agent, a complexing agent copper salt, a complexing agent zinc salt, a tin salt, and water, and the general formula of the complexing agent copper salt in the cyanide-free alkaline copper electroplating solution is Cu n [C 2n N 2n+1 S n O n H n+3 ] and the structural formula is as follows: The general formula of the complexing agent zinc salt is Zn n [C 4n N 4n+2 S 2n O 2n H 2n+6 ] and its structural formula is as follows: The tin salt is potassium stannate or sodium stannate, wherein n is 1, 2, 3, 50.

2. The non-poisonous sodium or potassium cyanide gold strike plating solution according to claim 1, characterized in that: The general formula of the complexing agent in the non-poisonous sodium cyanide or potassium cyanide gold-like electroplating solution is R m [C 2m N 2m+1 S m O m H m+3 ] and the structural formula is as follows: The R is K or Na, and m is 1, 2, 3, 50.

3. The non-poisonous sodium or potassium cyanide gold strike plating solution according to claim 1 or 2, characterized in that: The mass fraction of the complexing agent in the non-toxic sodium cyanide or potassium cyanide gold-like electroplating solution is 15-25%, the mass fraction of the complexing agent copper salt is 0.8-1.5%, the mass fraction of the complexing agent zinc salt is 0.8-1.5%, the mass fraction of the tin salt is 4-6%, and the rest is water.

4. The non-poisonous sodium or potassium cyanide gold strike plating solution according to claim 3, wherein: The mass fraction of the complexing agent in the non-toxic sodium cyanide or potassium cyanide gold-like electroplating solution is 20%, the mass fraction of the complexing agent copper salt is 1.0%, the mass fraction of the complexing agent zinc salt is 1.0%, the mass fraction of the complexing agent tin salt is 5%, and the rest is water.

5. The non-poisonous sodium or potassium cyanide gold strike plating solution according to claim 1 or 2, characterized in that: The preparation method of the complexing agent copper salt is as follows: a reactor is added with water, then added with a molar amount of the complexing agent and a water-soluble copper salt, and then added with a molar amount of sodium sulfite and sodium hydroxide, and stirred to react, and after the reaction is completed, the precipitate is obtained by filtration, rinsing and drying to obtain the complexing agent copper salt. The preparation method of the complexing agent copper salt and the complexing agent zinc salt is as follows: a reactor is added with water, then added with a molar amount of the complexing agent and a water-soluble zinc salt, and stirred to react, and after the reaction is completed, the precipitate is obtained by filtration, rinsing and drying to obtain the complexing agent zinc salt.

6. The non-poisonous sodium or potassium cyanide gold strike plating solution according to claim 2, wherein The preparation method of the complexing agent is as follows: the yellow blood salt, sodium or potassium thiosulfate and urea are used as raw materials, rhodium and / or platinum is used as catalyst in an oxygen-containing atmosphere, and after the solid-state polymineral salt is reacted, it is dissolved in water, and then separated, concentrated and dried to obtain the complexing agent.

7. The non-poisonous sodium or potassium cyanide gold plating solution of claim 6, wherein: ###0002### The preparation method of the complexing agent is as follows: The yellow blood salt, sodium or potassium thiosulfate and urea are placed in a rotary kiln, the catalyst rhodium and / or platinum is added, and the reaction is carried out at 450-650℃ for 5-7 hours, the polymeric polymineral salt is dissolved in water, and then separated by removing the insoluble substances to obtain a separation liquid, and the separation liquid is dried to obtain the finished complexing agent.

8. The non-poisonous sodium or potassium cyanide gold imitation plating solution according to claim 6 or 7, characterized in that: The separation is any one or several of suction filtration, plate and frame pressure filtration and centrifugal separation.

9. The method for preparing non-poisonous sodium cyanide or potassium cyanide imitation gold plating solution according to claim 6 or 7, characterized in that: The separation liquid is concentrated before drying, the separation liquid is concentrated to a water content of 30-40%, and the concentrated material is dried to a water content of less than 5%, the concentration is vacuum concentration, and the drying is spray drying with an air inlet temperature of 100-200℃.

10. The method for preparing non-poisonous sodium cyanide or potassium cyanide imitation gold plating solution according to any one of claims 1 to 9, characterized in that: The complexing agent copper salt, the complexing agent zinc salt, the tin salt, the complexing agent and water are mixed according to the proportion, stirred and dissolved, and then the pH value is adjusted to 12.0-13.0 to obtain the non-toxic sodium cyanide or potassium cyanide gold-like electroplating solution.

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