Trivalent chromium electroplating solution and electroplating method

A trivalent chromium solution technology, applied in the field of electroplating, can solve the problem that the trivalent chromium coating cannot be thickened, and achieve the effects of reduced harm, good bonding force, and smooth surface

Inactive Publication Date: 2016-06-22
INST OF METAL RESEARCH - CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] The purpose of the present invention is to provide a trivalent chromium electroplating solution and an...

Method used

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Embodiment 1

[0037] In this embodiment, the composition of the electroplating solution: chromium chloride 0.8mol / L, formic acid 0.2mol / L, acetic acid 0.4mol / L, urea 2.0mol / L, boric acid 0.2mol / L, sodium chloride 0.5mol / L, chlorine Ammonium chloride 0.5mol / L, butynediol 6g / L, and the rest is water. Mix the above substances evenly and stir for 24 hours to prepare an electroplating solution with a pH value of 1.2. Cathode current density 30A / dm 2 , bath temperature 30 ℃, electroplating time 60min, coating thickness 70μm. This embodiment adopts chloride plating solution system and high-density graphite anode (fixed carbon content ≥ 99.99wt%, density 1.85g / cm 3 ), the coating is dense and bright.

Embodiment 2

[0039] In this embodiment, the components of the electroplating solution: chromium chloride 0.8mol / L, formic acid 0.2mol / L, acetic acid 0.4mol / L, urea 2.0mol / L, sodium chloride 0.5mol / L, ammonium chloride 0.5mol / L , boric acid 0.2mol / L, butynediol 6g / L, and the rest is water. Mix the above substances evenly and stir for 24 hours to prepare an electroplating solution with a pH value of 1.2. Cathode current density 45A / dm 2 , bath temperature 40 ℃, plating time 30min, coating thickness 45μm. This embodiment adopts chloride plating solution system and high-density graphite anode (fixed carbon content ≥ 99.99wt%, density 1.75g / cm 3 ), the quality of the middle part of the coating is better, and the end part is slightly blackened.

Embodiment 3

[0041] In this embodiment, the electroplating solution composition: chromium chloride 0.8mol / L, formic acid 0.4mol / L, glycolic acid 0.6mol / L, ammonium chloride 0.5mol / L, boric acid 0.3mol / L, sodium citrate 0.2mol / L L, polyethylene glycol 5g / L, the rest is water. Mix the above substances evenly and stir for 24 hours to prepare an electroplating solution with a pH value of 0.9. Cathode current density 40A / dm 2 , bath temperature 45 ℃, electroplating time 60min, coating thickness 50μm. This embodiment adopts chloride plating solution system and high-density graphite anode (fixed carbon content ≥ 99.99wt%, density 1.75g / cm 3 ), the coating is dense and has good bonding force.

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Abstract

The invention relates to the field of electroplating, in particular to a trivalent chromium electroplating solution capable of being used for electroplating thick chromium through trivalent chromium and an electroplating method. The trivalent chromium electroplating solution and the electroplating method effectively solve the problem that trivalent chromium coatings cannot be thickened. The trivalent chromium electroplating solution is composed of 0.4-1.2 mol/L of chromic chloride, 0.5-3.0 mol/L of coordination agents, 0.1-0.8 mol/L of buffering agents, 0.5-2.0 mol/L of conducting salt, 3-35 g/L of organic additives and the balance water. By adopting a chloride plating solution system and a high-density graphite anode, trivalent chromium coatings with the smooth surface, compact crystals and the thickness higher than 60 micrometers can be prepared at the current density of 25-45 A/dm<2>, the binding force between the trivalent chromium coatings and base bodies is high, and the hardness of the coatings can be higher than HV800.

Description

technical field [0001] The invention relates to the field of electroplating, in particular to an electroplating solution and an electroplating method capable of electroplating thick chromium with trivalent chromium. Background technique [0002] The electroplated chromium layer has high hardness, good wear resistance and corrosion resistance, and has excellent decorative properties. It is often used as a decorative coating for electronic and electrical equipment, hardware tools, etc., and as a functional coating for pistons, molds, shafts, etc. Coatings are widely used. At present, most of the electroplated chromium layers in the world use the hexavalent chromium electroplating process, which is simple, easy to maintain, and has good coating performance. However, hexavalent chromium ions are very toxic. Excessive intake can cause skin ulcers, damage liver and kidney functions, and have a strong carcinogenic effect. The U.S. Environmental Protection Agency has identified he...

Claims

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Application Information

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IPC IPC(8): C25D3/06
Inventor 赵焕张博刘伟华管勇刘建国严川伟
Owner INST OF METAL RESEARCH - CHINESE ACAD OF SCI
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