66 results about "Cathode current density" patented technology

The cyanide-free copper-zinc alloy plating solution comprises 18-24 g / L of polycuprous thiocyanate, 9-13 g / L of polyzinc thiocyanate, 130-170 g / L of polysodium thiocyanate and 8-12 mL / L of brightener, the pH value of the plating solution is 10-12, the temperature of a plating bath is 35-55 DEG C, the cathode current density is 0.5-1.5 A / dm < 2 >, the cathode movement speed is 3-5 m / min, a copper-zinc alloy plate with the copper mass fraction being 68% is used as an anode, and the anode movement speed is 3-5 m / min. The brightening agent is prepared from 60 to 100 parts of N, N '-di-n-propylethylenediamine, 10 to 20 parts of waterborne polyurethane resin, 80 to 120 parts of polyacrylamide of which the molecular weight is less than 8000 and 770 to 870 parts of deionized water. A steel matrix or zinc alloy matrix copper-zinc alloy and bright nickel plated sample piece is subjected to an acetate fog test for 72 h according to GB / T 10125-2021 Artificial Atmosphere Corrosion Test Salt Spray Test, the surface of the steel matrix or zinc alloy matrix copper-zinc alloy and bright nickel plated sample piece is free of rust, and according to GB / T 5270-2005 Metal Covering Layer Electro-Deposition and Chemical Deposition Layer Adhesive Strength Test Method, the coating binding force is tested by a thermal shock method. And the result meets the standard requirement.

The invention belongs to the technical field of grinding materials and grinding tools, and particularly relates to a diamond electroplated grinding wheel directionally arranged in a magnetic field and a preparation method and application thereof. Firstly, electroplating liquid is added into an electroplating bath, then 30%-40% of magnetic diamond abrasive materials are added into the electroplating liquid, directional magnetic sanding is carried out with the grinding wheel base body A as a cathode and a nickel plate as an anode, the magnetic field intensity is controlled to be 0.1-1 T, the cathode current density is controlled to be 0.4 A / dm < 2 >-0.6 A / dm < 2 >, the electroplating time is 10-20 min, and a grinding wheel base body B is obtained; removing floating sand from the grinding wheel base body B to obtain a grinding wheel base body C; and the grinding wheel base body C is thickened to obtain a grinding wheel base body D, and the grinding wheel base body D is modified to obtain the grinding wheel. The grinding rate of the manufactured grinding wheel is reduced by 10%-25%, the service life is prolonged by 30%-50%, the machined surface roughness (Ra) can reach 0.3 micrometer or below, and the machined surface precision is reduced by 10%-25%. The grinding wheel is applied to nanoscale grinding of optical glass, sapphire and silicon carbide wafers and forming machining of turbine blade mortises and ceramic matrix composites, and the precision and roughness of the grinding wheel can be effectively guaranteed.

The invention relates to a process for preparing 4N-grade pure iron by electrolysis by taking pig iron as an anode. The 4N-grade pure iron is prepared by adopting soluble pig iron as the anode, an inert titanium plate as a cathode, a mixed solution of ferrous chloride and hydrochloric acid and addition of a reagent for ensuring the stability of an electrolyte. The pH value of the electrolyte is 2-5, the temperature of the electrolyte is 60-95 DEG C, the cathode current density is 50-300 A / m < 2 >, the purity of the prepared pure iron is 99.95-99.995 wt%, and the thickness is 2-4 mm. The method has the advantages that pig iron serves as the anode material, the cost of the soluble anode material is reduced, and industrial production of 4N-grade high-purity iron is achieved.

The plating solution comprises the following components and process parameters: 25-35 g / L of cadmium chloride, 4-6 g / L of ferrous chloride tetrahydrate, 100-140 g / L of potassium chloride, 100-140 g / L of a coordination agent, 1.5-2.5 mL / L of a leveling agent, 1.5-2.5 mL / L of a brightening agent, 25-30 mL / L of an auxiliary agent and 25-35 g / L of a stabilizer, the pH value of the plating solution is 6-8, the temperature of a plating tank is 20-35 DEG C, the cathode current density is 0.5-1.5 A / dm < 2 >, and the cathode movement is 2-4 m / min. According to the prepared cadmium-plated iron alloy sample piece subjected to color passivation through hexavalent chromium, the surface of the sample piece is free of white rust in an acetate mist test for 520 h according to GB / T 10125-2021 Artificial Atmosphere Corrosion Test Salt Spray Test, and a plating layer has excellent corrosion resistance.

The invention relates to the field of inorganic chemistry, electrochemistry and powder metallurgy science, in particular to a preparation device and a preparation method of metal Ti. The preparation device of the metal Ti comprises the reactor, the anode device and at least one group of cathode devices, preferably, the number of the cathode devices is multiple, so that cathode reactions can be carried out at the same time to improve the yield, different cathodes can also be carried out in turn to carry out the cathode reactions, continuous production is realized, and the production efficiency is improved. According to the preparation method of the metal Ti, the yield and quality of titanium are improved by improving the electrochemical performance of an electrolyte and the mass transfer rate of titanium tetrachloride, molten salt MgCl2 is used as the electrolyte, and the depth of a metal cathode immersed in the molten salt MgCl2 is continuously changed in the reaction process, so that the metal Ti is uniformly deposited on the surface of the metal cathode; and meanwhile, the cathode current density is controlled to be 0.1-10A / cm < 2 >, and the feeding rate of TiCl4 is 130-200g / A.h, so that the yield and the quality of a metallic titanium product are improved.

The invention discloses a magnesium alloy and galvanized iron alloy combined process, bottom plating layer preparation and a plating layer structure. The process comprises the step of sequentially preparing a chemical zinc deposition layer, a cyanide-free copper plating layer, a cyanide-free copper-zinc alloy plating layer, a high-corrosion-resistance nickel-phosphorus alloy plating layer, a zinc-iron alloy plating layer, a chromium-free chemical conversion film, a silane chromium-free passivation layer and a graphene modified sealing layer on a magnesium alloy matrix. According to the potassium chloride zinc-iron alloy plating process, 50 g / L to 70 g / L of zinc chloride, 2 g / L to 12 g / L of ferrous chloride tetrahydrate, 180 g / L to 220 g / L of potassium chloride, 25 g / L to 35 g / L of boric acid, 8 g / L to 40 g / L of a coordination agent, 0.1 mL / L to 0.2 mL / L of a brightening agent and 20 mL / L to 30 mL / L of an auxiliary agent are adopted, the pH value of a plating solution is 4.5 to 5.6, the temperature of a plating tank is 15 DEG C to 30 DEG C, and the cathode current density is 1 A / The surface of a plated part is free of white rust after being subjected to a neutral salt spray test for 560 h according to the GB / T 10125-2021 standard. According to the scheme, the corrosion resistance, wear resistance and other performance of the magnesium alloy part protection layer are remarkably improved, and the good market application prospect is achieved.

The invention provides a gold and palladium electrolytic separation method which comprises the following steps: placing a solution containing gold and palladium in a cathode region of an electrolytic bath, and carrying out first-stage electrolysis under stirring to obtain elemental gold; the cathode is replaced for second-stage electrolysis, and elemental palladium is obtained; in order to guarantee the separation effect, in the first-stage electrolysis process, the ratio of the cathode current density to the gold concentration in the catholyte is smaller than or equal to 200 (A.m <-2 >) / (g.L <-1 >), and the mass concentration ratio of gold to palladium in the catholyte needs to be kept larger than or equal to 0.004 in the first-stage electrolysis process. According to the method, clean separation and recovery of gold and palladium can be achieved, and corresponding metal products are directly obtained. The whole process mainly consumes electric energy, does not consume a large amount of reagents, does not generate extra waste gas and waste water, and is clean and environment-friendly.

The invention discloses electrodeposition equipment, and relates to the technical field of metal electrodeposition, wastewater treatment and resource recycling, the electrodeposition equipment comprises an electrodeposition cell, an electrodeposition assembly and a vibrator, an electrodeposition cavity is formed in the electrodeposition cell, and the electrodeposition cavity comprises a reaction cavity and a collection cavity; the cavity wall of the collecting cavity is gradually shrunk; an anode piece and a cathode piece in the electrodeposition assembly are both located in the reaction cavity, and the proportion of conductive areas of the anode piece and the cathode piece is freely adjusted; the vibrator is used for vibrating the cathode piece. According to the technical scheme, after the vibrator vibrates the cathode piece, metal powder is vibrated to fall off from the cathode piece and sinks into the collecting cavity from the reaction cavity, and the metal powder is taken out from the discharging opening to be subjected to filter pressing and dewatering; in the whole electrodeposition collection process, the metal powder can be taken out without closing the electrodeposition cell and stopping the electrodeposition cell; and meanwhile, the electrodeposition device can obtain relatively high cathode current density under the condition of relatively low anode current density, so that the cathode can obtain an electrodeposition effect of adjusting the fineness of metal powder under the condition of protecting the service life of the anode.

The invention discloses an electrolyte for preparing refined antimony by electrolytically separating a lead-antimony alloy and application of the electrolyte, and belongs to the technical field of electrochemical metallurgy. According to the method, a mixed acid solution prepared from antimony sulfate, ammonium fluoride and oxalic acid is adopted as an electrolyte, a stainless steel plate, a copper plate or a pure antimony plate is adopted as a cathode, a lead-antimony alloy plate is adopted as an anode, electrolysis is conducted for 24-120 h under the conditions that the density of direct current and cathode current is 200-400 A / m < 2 >, the heteropolar distance is 40-100 mm, and the electrolysis temperature is room temperature (20-30 DEG C), and the cathode refined antimony is obtained. The electrolysis process can be one-stage electrolysis or multi-stage electrolysis. The electrolysis method has the advantages of being clean, environmentally friendly, low in energy consumption, low in cost, low in electrolytic bath voltage, high in current efficiency, low in direct current consumption and the like, and the cathode antimony product which is high in purity and compact and excellent in surface appearance can be rapidly prepared from the lead-antimony alloy through electrolysis.

The application discloses a potassium chloride zinc-iron alloy plating solution and a plating process, and the plating solution composition and process parameters are as follows: zinc chloride 50-70 g / L, ferrous chloride tetrahydrate 2-12 g / L, potassium chloride 180-220 g / L, boric acid 25-35 g / L, complexing agent 8-40 g / L, brightener 0.1-0.2 mL / L, auxiliary agent 20-30 mL / L, plating solution pH value 4.5-5.6, plating bath temperature 15-30 DEG C, cathode current density 1-3 A / dm 2 , and cathode moving speed 3-5 m / min. The zinc-iron alloy sample prepared by the application and sealed by trivalent chromium blue-white passivation and graphene modified sealing agent has no white rust on the surface after neutral salt spray test for 480 h according to GB / T 10125-2021 "Salt Spray Test for Artificial Atmosphere Corrosion Test", and the plating layer has excellent corrosion resistance.

The present invention belongs to the field of electrode material technology, and provides a titanium-based platinum-nickel electrode material, a preparation method thereof, and an application thereof. The method comprises the following steps: sequentially performing a first anodization and a second anodization on a titanium sheet in an ammonium fluoride solution to obtain an oxidized titanium sheet; calcining the oxidized titanium sheet to obtain a titanium sheet containing a titanium dioxide layer; and electro-depositing the titanium sheet containing the titanium dioxide layer in a platinum-based electrolyte to obtain a titanium-based platinum-nickel electrode material. The titanium-based platinum-nickel electrode material prepared by the present invention effectively reduces the usage of Pt-based precious metals, and can maintain high activity and stability to generate hydrogen peroxide online under neutral conditions; its cathode current density efficiency reaches 76.40%, its anode current density efficiency reaches 70.23%, and its dual capacitance value is 1.33mF·cm ‑2 It is 4.2 times the dual capacitance value of titanium-based platinum-nickel electrode materials obtained without anodic oxidation, and has good prospects for industrial application.

The application discloses a kind of based on the coupling of electrochemical parameter gap corrosion evaluation method and device, it is related to electrochemical corrosion evaluation technical field.Gap corrosion evaluation method includes the following steps: based on gap structure establishes oxygen concentration cell, determines anode, cathode and its surface area;In the oxygen-poor medium environment, the anodic polarization curve of target material is measured, the cathodic polarization curve of target material is measured in the oxygen-rich medium environment, obtains anode current density-potential relationship and cathode current density-potential relationship;According to the electrochemical balance formula that total cathode current is equal to total anode current, the coupling potential of oxygen concentration cell is calculated, and further the gap corrosion current density corresponding to coupling potential is obtained, and the gap corrosion rate is calculated according to gap corrosion current density.The gap corrosion evaluation method provided by the application is suitable for the rapid prediction of initial stage of gap corrosion, with the characteristics of convenient, high repeatability, the result is more accurate.

This invention discloses a process and coating structure for rare earth modified trivalent chromium pearl chromium plating on zinc alloys. The process includes sequentially preparing a cyanide-free copper plating layer, a cyanide-free copper-zinc alloy plating layer, a high-corrosion-resistant nickel-phosphorus alloy plating layer, a bright nickel-cobalt alloy plating layer, a pearl nickel plating layer, a rare earth modified trivalent chromium pearl chromium plating layer, and an anti-discoloration protective film on a zinc alloy substrate. The rare earth modified trivalent chromium pearl chromium plating process is as follows: chromium chloride hexahydrate 90-130 g / L, potassium chloride 90-160 g / L, ammonium chloride 90-160 g / L, ammonium bromide 18-28 g / L, ammonium formate 40-60 g / L, boric acid 45-65 g / L, rare earth additives 8-12 mL / L, leveling agent 2-4 mL / L, accelerator 1-3 mL / L, plating bath pH 2.5-3.2, plating bath temperature 25-35℃, and cathode current density 8-16 A / dm². The rare earth additives have a synergistic effect on improving the performance of trivalent chromium plating solution. No rust was observed on the surface of the plated parts after undergoing a neutral salt spray test for 132 hours according to GB / T 10125–2021 standard.

The invention relates to the technical field of copper electrolysis, in particular to a copper electrolytic refining method and application thereof. The copper electrolytic refining method comprises the following steps: placing an anode and a cathode in an electrolytic bath containing electrolyte for electrolysis; the distance between the electrodes is 85 to 95 mm; the electrolyte is prepared from the following components: 38 to 42 g / L of CuSO4, 185 to 205 g / L of H2SO4, 1 to 2 g / L of Fe, 6 to 8 g / L of As and 13 to 16 g / L of Ni; the electrolyte further comprises bone glue, thiourea and a polyethylene glycol-amino silane copolymer. According to the invention, by reducing the inter-electrode distance, the cathode current density is reduced, and the cell voltage and the power consumption are reduced; by optimizing an electrolyte system, the ion migration rate is increased, it can be ensured that copper ions rapidly and uniformly reach the surface of an electrode for a deposition reaction, and the electrolysis efficiency is remarkably improved; by adopting the ternary additive system, the crystal morphology of the cathode copper can be improved, and the purity of the cathode copper can be improved.

The device comprises an electrolyser, an anode basket (6) of said electrolyser being made of an insulator and the filling of said anode basket (6) being made of copper granulate (3) forming a directly soluble electrode of the electrolyser. The main active surface of each anode basket (6) is oriented vertically, is shaped according to the shape of the rotatable cathode roller (7) and is provided with an electrically conductive inert surface contact (9) on the rear side in the direction away from the cathode roller (7). The face (15) of the anode basket (6) is perforated and coated with a first filter layer (16) of non-woven fabric and an adjacent sedimentation pre-chamber (17), the face (19) of the pre-chamber (17) being perforated and coated with a second filter layer (18). An auxiliary inert anode (20) is provided at the bottom of the rotatable cathode roller (7). On the cathode roller (7), there is an auxiliary roller (12) for unwinding a strip (11) of copper foil through a rinsing tunnel (14) onto pulleys (13). The device comprises a galvanising current source (8) whose anode electric current has a cathode current density of 0.1 to 20 A / dm2 . The device may also have several anode baskets (6).

The invention discloses a magnesium alloy cyanide-free cadmium-iron alloy plating process. A chemical zinc deposition layer, a cyanide-free copper-zinc alloy plating layer, a high-corrosion-resistance nickel-phosphorus alloy plating layer, a cyanide-free cadmium-iron alloy plating layer and a passivation layer are sequentially prepared on a magnesium alloy matrix from inside to outside. According to the cyanide-free cadmium iron alloy electroplating process, 25-35 g / L of cadmium chloride, 4-6 g / L of ferrous chloride tetrahydrate, 100-140 g / L of potassium chloride, 100-140 g / L of a coordination agent, 1.5-2.5 mL / L of a leveling agent, 1.5-2.5 mL / L of a brightening agent, 25-30 mL / L of an auxiliary agent and 25-35 g / L of a stabilizer are adopted, the pH value of a plating solution is 6-8, the temperature of a plating tank is 20-35 DEG C, the cathode current density is 0.5-1.5 A / dm < 2 >, and the cathode movement is 2-4 m / min. The surface of the prepared magnesium alloy cadmium-plated iron alloy colored passivated sample piece is free of white rust after being subjected to an acetate fog test for 480 h according to the GB / T 10125-2021 standard, and a plating layer has excellent corrosion resistance.

A method for preparing nickel powder through electrolysis of nickel sulfate waste liquid in one step comprises the steps that the nickel sulfate waste liquid is diluted to a certain concentration by controlling the reduction degree of Ni < 2 + > under different cathode conditions, and different nickel electrolysis products are selectively prepared in the diluent; ti plated TaO2 / I rO2 alloy is used as an anode, a Ti sheet is used as a cathode, electrolysis is carried out under the conditions that the current density is 30-2000A / m < 2 >, the electrolyte temperature is 20-60 DEG C and the nickel ion concentration is 0.025-1.0 mo l / L, and nickel powder is obtained through electrodeposition on the cathode after electrolysis is finished; a circulating pump is used for recycling waste liquid; the electrolytic nickel powder prepared through the method is simple in required equipment, short in technological process, mild in condition, low in production cost, high in efficiency, environmentally friendly, suitable for one-step preparation of the nickel powder through the high-impurity nickel sulfate waste liquid and suitable for one-step preparation of the electrolytic nickel powder through the pure nickel sulfate solution. The method is especially suitable for environmental protection enterprises of nickel-containing waste liquid.

The invention discloses a process for plating high-strength structural steel with a low-hydrogen brittleness zinc-nickel alloy and a plating structure. The process comprises the steps that cobalt-titanium alloy plating, zinc-nickel alloy plating and hexavalent chromium passivation are sequentially carried out on a high-strength structural steel matrix. The cobalt-titanium alloy plating process comprises the following components and parameters: 160-200 g / L of cobalt sulfate heptahydrate, 8-12 g / L of potassium fluotitanate, 2-8 g / L of sodium fluoride, 80-120 g / L of sodium sulfate, 30-50 g / L of sodium hydrogen succinate, 8-12 mL / L of a walking agent and 1-3 mL / L of a wetting agent, the pH value of a plating solution is 3.8-4.4, the temperature of a plating tank is 20-35 DEG C, the cathode current density is 1-2 A / dm < 2 >, and the cathode movement is 4-6 m / min. The hydrogen brittleness test is carried out according to HB 5067.1-2005 Part 1 of Hydrogen brittleness Test of Plating Process: Mechanical Method, and the test result meets the standard requirement. According to the technical scheme, the problem that high-strength structural steel galvanized nickel alloy is prone to hydrogen brittleness is solved.

The present disclosure relates to the technical field of electrode materials and provides a titanium-based platinum-nickel electrode material, a preparation method, and an application thereof. The method includes: performing a first anodic oxidation and a second anodic oxidation sequentially on a titanium sheet in an ammonium fluoride solution to obtain an oxidized titanium sheet; performing calcination on the oxidized titanium sheet to obtain a titanium sheet containing a titanium dioxide layer; and performing electrodeposition on the titanium sheet containing the titanium dioxide layer in a platinum-based electrolyte to obtain the titanium-based platinum-nickel electrode material. The prepared titanium-based platinum-nickel electrode material effectively reduces the usage amount of Pt-based precious metals and can maintain high activity and stability to generate hydrogen peroxide on-line under the neutral condition; its cathode current density efficiency reaches 76.40%, the anode current density efficiency reaches 70.23%, and the bilayer capacitance value is 1.33 mF·cm−2, which is 4.2 times the bilayer capacitance value of the titanium-based platinum-nickel electrode material obtained without anodic oxidation, and has a very good industrial application prospect.

The invention discloses a technological method for micro-arc oxidation and zinc-iron alloy plating of a magnesium alloy workpiece. The technological method comprises the step that a micro-arc oxidation layer, a chemical nickel preplating layer, a chemical copper plating layer, a copper-zinc alloy plating layer, a zinc-iron alloy plating layer, a trivalent chromium passivation film and a graphene modified sealing layer are sequentially prepared on a magnesium alloy matrix from inside to outside. According to the zinc-iron alloy electroplating process, 50-70 g / L of zinc chloride, 2-12 g / L of ferrous chloride tetrahydrate, 180-220 g / L of potassium chloride, 25-32 g / L of boric acid, 8-40 g / L of a coordination agent, 0.1-0.2 mL / L of a brightening agent and 20-30 mL / L of an auxiliary agent are adopted, the pH value of a plating solution is 4.5-5.6, the temperature of a plating tank is 15-30 DEG C, the cathode current density is 1-3 A / dm < 2 >, and cathode movement is 3-5 m / min. The prepared magnesium alloy galvanized iron alloy sample piece is high in corrosion resistance and has a good market prospect.

The invention discloses a neodymium-iron-boron trivalent chromium plating method with a triple electrochemical protection effect and a plating layer structure. The method comprises the step of sequentially preparing a cyanide-free copper-zinc alloy plating layer, a cyanide-free copper plating layer, a nickel-copper alloy plating layer, a semi-bright nickel plating layer, a nickel-cobalt alloy plating layer, a trivalent chromium plating layer and a rare earth electrolysis protection film on a neodymium-iron-boron substrate. According to the process for preparing the cyanide-free copper plating layer, 18-24 g / L of polycuprous thiocyanate, 130-170 g / L of polysodium thiocyanate, 20-30 g / L of sodium hydroxyethylidene diphosphonate and 8-12 mL / L of a copper plating brightener are adopted, the pH value of a plating solution is 12-13, the temperature of a plating tank is 30-40 DEG C, the cathode current density is 0.5-1.5 A / dm < 2 >, the cathode movement speed is 3-5 m / min, oxygen-free electrolytic copper particles serve as an anode, and the anode movement speed is 3-5 m / min. The surface of the prepared trivalent chromium-plated sample piece is not rusted after being subjected to a neutral salt spray test for 142 hours according to the GB / T 10125-2021 standard.

The invention discloses a method for co-producing metal lead and manganese dioxide through same-tank solid-phase electrolysis, and relates to the technical field of solid-phase electrolysis. According to the method, the lead-containing solid waste serves as a solid-phase cathode, a manganese-containing precursor serves as a solid-phase anode, in the same electrolytic bath, a sodium sulfate aqueous solution with the initial pH being 6-8 and the concentration being 10-400 g / L serves as electrolyte, electrolysis is conducted at the temperature of 20-95 DEG C, the anode current density is controlled to be 10-1000 A / m < 2 >, and the cathode current density is two times that of the anode current density; after electrolysis, stripping a product to obtain metal lead meeting YS / T 71-2013 lead bullion Pb96.0 C standard requirements and a manganese dioxide energy storage material with high additional value, high specific capacitance and controllable morphology; adjusting the pH value of the electrolyte to 6-8, and then recycling to ensure continuous production. Compared with traditional hydrometallurgy, the total energy consumption of co-production of metal lead and manganese dioxide per ton is reduced by 70.3%, and the production efficiency is remarkably improved.

The invention discloses a magnesium alloy gold plating method with triple electrochemical protection effects and a plating layer structure. The process comprises the following steps: sequentially preparing a chemical zinc deposition layer, a cyanide-free copper-tin alloy plating layer, a cyanide-free copper-zinc alloy plating layer, a bright nickel-copper alloy plating layer, a nickel-phosphorus alloy plating layer, a gold plating layer and an anti-discoloration protective film on a magnesium alloy substrate. According to the cyanide-free copper-tin alloy plating process, 18-24 g / L of polycuprous thiocyanate, 0.2-0.6 g / L of stannous oxalate, 130-170 g / L of polysodium thiocyanate, 20-30 g / L of sodium 1-hydroxyethylidene-1, 1-diphosphonate and 8-12 mL / L of a copper-tin alloy plating brightener are adopted, the pH value of a plating solution is 12-13, the temperature of a plating tank is 30-40 DEG C, the cathode current density is 0.5-1.5 A / dm < 2 >, the cathode movement speed is 3-5 m / min, oxygen-free electrolytic copper particles serve as an anode, the copper particles are loaded into a titanium anode basket, the area ratio of the anode to the cathode is larger than 3: 1, and the anode movement speed is 3-5 m / min. And the surface of a plated part is not rusted after the plated part is subjected to an acetate mist test for 200 hours according to the GB / T 10125-2021 standard.

The invention discloses a rare earth electrolytic protection process for electroplating gun black tin-nickel alloy and a combined coating, including a bottom coating, a bright nickel coating, a gun black tin-nickel alloy coating, and a rare earth electrolytic protective film, which are prepared sequentially from the inside to the outside on a metal substrate. The rare earth electrolytic protective film is prepared by a rare earth electrolytic protection process: 1 to 8 g / L of rare earth salt, 5 to 50 g / L of HEDP complexing agent, 80 to 160 g / L of anhydrous potassium carbonate, a pH range of 11 to 13, an operating temperature of 15°C to 40°C, and a cathode current density of 0.5 to 1.2 A / dm 2 , using the plated part as the cathode and the titanium plate as the anode, electrolyzing for 30 to 100 seconds, wherein the rare earth salt includes one or two of lanthanum chloride, cerium chloride, and praseodymium chloride. The combined coating is subjected to a neutral salt spray test for 72 hours in accordance with GB / T 10125-2012 "Artificial Atmosphere Corrosion Test Salt Spray Test", and no white corrosion products are generated on the surface of the plated part. The rare earth electrolytic protection process of the present invention replaces the traditional potassium dichromate electrolytic protection process, thereby solving the problem of high pollution of hexavalent chromium.

The invention provides a method for removing iron impurities in coal ash lixivium. The removal method comprises the following steps: pretreating the coal ash leachate, adding iron powder, and carrying out reduction reaction to obtain aluminum chloride clear liquid; sequentially performing a first electrolytic reaction, a second electrolytic reaction and a third electrolytic reaction on the aluminum chloride clear liquid to obtain an aluminum chloride refined liquid; wherein the cathode current density in the first electrolytic reaction, the cathode current density in the second electrolytic reaction and the cathode current density in the third electrolytic reaction are p1, p2 and p3 respectively, and the size relation of the cathode current density in each electrolytic reaction is selected from any one of the following relations: p1 > p2 > p3, p1 = p2 > p3 or p1 > p2 = p3. By adjusting the multi-stage current density in the electrolysis process, the removal efficiency of iron impurities is effectively improved, the energy consumption is reduced, meanwhile, a large amount of waste generated in a traditional chemical precipitation method is avoided, the method is environmentally friendly, removal of the iron element can be accurately controlled, and the aluminum chloride refined solution with high purity is obtained.

The invention discloses a potassium chloride zinc-iron alloy plating process for a neodymium-iron-boron permanent magnet. A cyanide-free copper-zinc alloy plating layer, a zinc-iron alloy plating layer, a passive film and a graphene modified sealing layer are sequentially prepared on a neodymium-iron-boron substrate from inside to outside. According to the potassium chloride zinc-iron alloy plating process, 50-70 g / L of zinc chloride, 2-12 g / L of ferrous chloride tetrahydrate, 180-220 g / L of potassium chloride, 25-35 g / L of boric acid, 8-40 g / L of a coordination agent, 0.1-0.2 mL / L of a brightening agent and 20-30 mL / L of an auxiliary agent are adopted, the pH value of a plating solution is 4.5-5.6, the temperature of a plating bath is 15-30 DEG C, the cathode current density is 1-3 A / dm < 2 >, and the cathode movement is 3-5 m / min. A neodymium iron boron galvanized iron alloy sample piece passivated by trivalent chromium blue and white and sealed by the graphene modified sealing agent is free of white rust on the surface after being subjected to a neutral salt spray test for 400 h according to the GB / T 10125-2021 standard, and a plating layer has excellent corrosion resistance.

The plating solution comprises the following components and process parameters: 50-70 g / L of zinc chloride, 2-12 g / L of ferrous chloride tetrahydrate, 180-220 g / L of potassium chloride, 25-35 g / L of boric acid, 8-40 g / L of a coordination agent, 0.1-0.2 mL / L of a brightening agent and 20-30 mL / L of an auxiliary agent, the pH value of the plating solution is 4.5-5.6, the temperature of a plating tank is 15-30 DEG C, the cathode current density is 1-3 A / dm < 2 >, and the cathode movement is 3-5 m / min. According to a neutral salt spray test for 480h according to GB / T 10125-2021 Artificial Atmosphere Corrosion Test Salt Spray Test, a galvanized iron alloy sample piece passivated by trivalent chromium blue and white and sealed by the graphene modified sealing agent has no white rust on the surface, and a coating has excellent corrosion resistance.

The invention relates to the technical field of electrochemical surface treatment, and discloses a platinum electroplating process for corrosion prevention and scale inhibition of an inner cavity of a converter valve aluminum radiator, which comprises the following steps: degreasing and activating the surface of an aluminum alloy radiator with a runner, and constructing a microscopic rough surface; an auxiliary counter electrode wrapped with a polypropylene net sleeve is arranged in the center of the runner; injecting an electrolyte consisting of chloroplatinic acid, phosphate and an interfacial agent into the runner; and adjusting the pressure of a circulating pump, so that the flow velocity of the electrolyte is periodically switched between a high speed and a low speed, and the cathode current density is controlled to be synchronously adjusted and increased in a flow velocity rising edge interval. And a compact platinum layer with uniform thickness and stable adhesion is formed on the inner surface of the radiator.

The invention relates to non-ferrous metal industry and can be used for refining aluminium alloys from metallic impurities. The device comprises no less than one porous removable diaphragm, permeable to bath and impermeable to molten aluminium, filled with bath, wherein cathode is vertically mounted and immersed in molten aluminium with metallic impurities, placed in a vessel with an anode current lead. The method involves placing a melt of contaminated aluminium and a bath of salts of alkali or alkaline-earth metals and aluminium salt into an electrolytic refining device and performing electrolytic refining at a cathodic current density from 0.5 to 21 A / cm2 a temperature ranging from 780 °C to 920 °C. Technical effect: increased capacity, with the ability to adjust the bath composition.

The invention discloses a high-strength steel cobalt-titanium alloy plating solution, an electroplating process and a combined plating layer preparation method. The cobalt-titanium alloy plating solution and the electroplating process comprise the following components and parameters: 160-200 g / L of cobalt sulfate heptahydrate, 8-12 g / L of potassium fluotitanate, 2-8 g / L of sodium fluoride, 80-120 g / L of sodium sulfate, 30-50 g / L of sodium hydrogen succinate and 8-12 mL / L of a displacement agent, the pH value of the plating solution is 3.8-4.4, the temperature of a plating tank is 20-35 DEG C, the cathode current density is 1-2 A / dm < 2 >, and the cathode movement is 4-6 m / min. The preparation method of the coating comprises the step of sequentially preparing the cobalt-titanium alloy coating, the potassium chloride zinc-iron alloy layer, the trivalent chromium passivation layer and the graphene modified sealing layer on the high-strength steel substrate. The hydrogen brittleness test is carried out according to HB 5067.1-2005 Part 1 of Hydrogen brittleness Test of Plating Process: Mechanical Method, and the test result meets the standard requirement. The coating preparation process has a good market prospect.