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CN-119593025-B - Trivalent chromium rapid chromium plating solution of sulfate and chloride mixed system and preparation and application thereof

CN119593025BCN 119593025 BCN119593025 BCN 119593025BCN-119593025-B

Abstract

The invention discloses a preparation and electroplating method of trivalent chromium quick chromium plating solution of a sulfate and chloride mixed system. The plating solution comprises chromium salt, complexing agent, conductive salt, buffering agent, stabilizer and wetting agent. The preparation method comprises the steps of heating 50% volume of water to 50-60 ℃, adding conductive salt and buffer, stirring until the solution is completely dissolved, sequentially adding chromium salt, complexing agent and stabilizer, finally adding wetting agent, adjusting pH to 2.0-3.0 by sulfuric acid or sodium hydroxide, and keeping the temperature between 50-60 ℃ for 4 hours to obtain the electroplating solution. The plating solution of the invention has simple preparation, the average deposition speed of chromium is 0.48 mu m/min, the thickness of the plating layer is 29 mu m, and the hardness is more than or equal to 1000HV.

Inventors

  • CHEN YAODONG
  • XU JINLAI
  • LIU NINGHUA
  • TIAN ZHIBIN
  • DENG ZHENGPING

Assignees

  • 广州三孚新材料科技股份有限公司

Dates

Publication Date
20260505
Application Date
20241122

Claims (6)

  1. 1. A trivalent chromium quick chromium plating solution of a sulfate and chloride mixed system is characterized by comprising 50g/L of chromium sulfate, 5g/L of chromium chloride, 10g/L of formic acid, 5g/L of sodium acetate, 120g/L of sodium sulfate, 50g/L of potassium sulfate, 4ml/L of methanol, 70g/L of boric acid, 2ml/L of 10% by weight of dodecyl sodium sulfate solution, a pH regulator and water, wherein the pH regulator is used for regulating the pH to 2.0-3.0 and fixing the volume by water, and the pH regulator is one or two of sulfuric acid and sodium hydroxide.
  2. 2. A method for preparing a trivalent chromium rapid chromium plating bath according to claim 1, characterized by comprising the steps of: A. heating part of water, adding sodium sulfate, potassium sulfate and boric acid, and stirring to obtain a first premix; B. Sequentially adding chromium salt chromium sulfate, chromium chloride, formic acid, sodium acetate, methanol and sodium dodecyl sulfate solution into the first premix, adjusting the pH to be acidic, and adding the balance of water to obtain a second premix; C. And (3) preserving the heat of the second premix, and then cooling to obtain the trivalent chromium rapid chromium plating solution of the sulfate and chloride mixed system.
  3. 3. The preparation method of claim 2, wherein in the step A, the heating temperature is 50-60 ℃, in the step B, the pH is adjusted to 2.0-3.0, in the step C, the heat preservation temperature is 50-60 ℃, the heat preservation time is 4 hours, the cooling temperature is 30-40 ℃, and the volume ratio of the added water in the step A to the added water in the step B is 1:1.
  4. 4. Use of a trivalent chromium quick chromium plating bath according to claim 1 for electroplating.
  5. 5. The use according to claim 4, comprising the steps of: s1, degreasing; s2, washing with water; S3, activating; s4, washing with water; s5, chromium plating: S5-1, filling trivalent chromium rapid chromium plating solution of the sulfate and chloride mixed system in a plating solution tank; s5-2, setting a working temperature; s5-3, regulating the circulation flow rate and speed of the plating solution; s5-4, immersing the workpiece into the plating solution tank; s5-5, setting the distance between the cathode and the anode; s5-6, setting current density and starting chromium plating; s6, washing the workpiece with water to obtain the electroplated workpiece.
  6. 6. The method according to claim 5, wherein in the step S5-2, the working temperature is 30-40 ℃, in the step S5-3, the circulation flow rate of the plating solution comprises circulation of the plating solution in the tank twice per hour, in the step S5-5, the distance between the cathode and the anode is 4-6 cm, the area ratio of the cathode to the anode is 1:1.2, and in the step S5-6, the current density is 8-13A/dm 2.

Description

Trivalent chromium rapid chromium plating solution of sulfate and chloride mixed system and preparation and application thereof Technical Field The invention belongs to the technical field of metal surface treatment, and particularly relates to trivalent chromium rapid chromium plating solution of a sulfate and chloride mixed system, and preparation and application thereof. Background The chromium coating has the performance advantages of white and bright appearance, high hardness, corrosion resistance and low friction coefficient, and is a coating with very wide application, including fields of automobiles, aviation, electronics, medical appliances, furniture, bathroom, decoration and the like. Hexavalent chromium is a known human carcinogen, and is difficult and high in cost to treat the chromium plating wastewater, and is difficult to completely remove by the traditional treatment method, so that secondary pollution is easily caused. Under the background, the environment-friendly trivalent chromium electroplating process is widely researched, the toxicity of trivalent chromium is only 1% of that of hexavalent chromium, the trivalent chromium electroplating process is relatively environment-friendly, chromium fog cannot be generated in the electroplating process, the harm to the operation environment is reduced, the wastewater treatment is relatively easy, and the treatment cost is reduced. For example, patent CN 108456898A of full sulfate system discloses a low-concentration sulfate trivalent chromium rapid chromium plating solution and a preparation method thereof, wherein the main salt is 15-35 g/L, the main complexing agent and the auxiliary complexing agent are 7.5-18 g/L, the mol ratio of the main salt to the total complexing agent is 1:0.95-2.6, the electric conduction is 80-120 g/L, the buffer is 60-100 g/L, the surfactant is 10-500 mg/L, the brightening agent is 60-750 mg/L, the hardness of a plating layer obtained by the plating solution is 780-830 HV, the chromium deposition speed is 0.25 mu m/min, and the deposition speed is difficult to improve. As another example, CN 103014784A of a full chloride system discloses a normal-temperature environment-friendly trivalent chromium plating solution and a plating method thereof, wherein 150-200g/L of chromium trichloride, 80-90g/L of potassium thiosulfate, 65-75g/L of potassium chloride, 30-50g/L of boric acid, 10-15g/L of ammonium oxalate, 5-10g/L of ammonium bromide, 0.2-0.5g/L of coumarin, 0.02-0.04g/L of sodium dodecyl sulfate and 0.02-0.2g/L of dioctyl sodium sulfosuccinate are used, the plating solution can be plated for 20-30min to obtain 10-15 mu m, the hardness is 600-800HV, the plating solution contains a large amount of chloride, more chlorine is generated during plating, and certain environmental hazard is caused. Therefore, trivalent chromium electroplating can not completely replace hexavalent chromium, has the problems of color and luster, low deposition speed, difficult thickening and low hardness at present, and is mainly applied to decorative trivalent chromium electroplating with lower film thickness requirement. Disclosure of Invention The invention aims to provide a preparation and electroplating method of trivalent chromium rapid chromium plating solution of a sulfate and chloride mixed system, wherein the deposition speed of a chromium layer is 0.5-1 mu m/min, the thickness of the electroplated layer can reach 29 mu m for 1 hour, the plating layer is bright, and the hardness is more than or equal to 1000HV. Solves the problems of slow deposition speed and difficult thickening of trivalent chromium electroplating, and the invention has less chloride content. In order to solve the technical problems, the invention adopts the following technical scheme: A trivalent chromium liquid for quickly plating chromium in the mixed system of sulfate and chloride is prepared from trivalent chromium salt, complexing agent, conducting salt, stabilizer, buffering agent, wetting agent and water. Preferably, the trivalent chromium salt comprises 50-75 g/L of trivalent chromium salt, 15-30 g/L of complexing agent, 150-200 g/L of conductive salt, 3-5 ml/L of stabilizer, 60-80 g/L of buffer agent, 1-3 ml/L of wetting agent and water for constant volume. Preferably, the method further comprises a pH regulator, wherein the pH of the trivalent chromium rapid chromium plating solution of the sulfate and chloride mixed system comprises 2.0-3.0. Preferably, the trivalent chromium salt comprises one or more of chromium sulfate and chromium chloride, the complexing agent comprises one or more of formic acid, acetic acid, glycine, tartaric acid, malic acid, citric acid and salts thereof, the conductive salt comprises one or more of potassium sulfate and sodium sulfate, the buffering agent comprises one or more of aluminum sulfate and boric acid, the stabilizer comprises one or more of methanol and sodium sulfite, the wetting agent comprises one or more of sod