Method for trivalent chromium electroplating of non-micro-crack crystalline chromium and chromium alloy coating in ionic liquid

An ionic liquid and chromium alloy technology, applied in the field of ionic liquid electroplating of metal chromium and chromium alloy, can solve the problems of short service life, flammability, low hardness, etc., achieve high thermal stability and chemical stability, and wide liquid temperature range. , the effect of large heat capacity

Inactive Publication Date: 2014-08-20
HUNAN UNIV OF TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0003] In order to solve the defects of poor stability, flammability, short service life, high toxicity and high volatility of ordinary aqueous solution system plating solution, the added brightener and stabilizer are prone to failure, and the quality of trivalent chromium and chromium alloy coatings (micro Cracks, graying, dull, low hardness) and process defects (low current efficiency) and difficult to directly prepare crystalline chromium and chromium alloy coatings in the existing ionic liquid system, the present invention makes full use of the characteristics of the ionic liquid plating solution system, Provide a [BMIM]HSO 4 Method for direct electroplating non-microcrack crystalline chromium and chromium alloy coating in ionic liquid

Method used

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  • Method for trivalent chromium electroplating of non-micro-crack crystalline chromium and chromium alloy coating in ionic liquid

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Effect test

Embodiment 1

[0010] Anhydrous chromium trichloride was dried to constant weight, and the ionic liquid [BMIM]HSO 4 As a solvent, 1.0 mol·L -1 Anhydrous chromium trichloride dissolved in [BMIM]HSO 4 ionic liquid, and stirred at a temperature of 90° C. until fully dissolved, and left to stand for 36 hours to obtain a ready-to-use trivalent chromium ionic liquid plating solution. Copper samples with a size of 10 mm × 5 mm × 2 mm were pretreated by conventional electroplating. The pretreated copper sample was used as the cathode, and the insoluble graphite was used as the anode, which was directly placed in the ionic liquid plating solution system for rack plating, with a current density of 1.0 A dm -2 , the distance between the anode and the substrate was 40 cm, the electroplating time was 80 min, and the electroplating temperature was 90 °C. The substrate with the electroplated layer is taken out from the ionic liquid plating solution, rinsed with an organic solvent (such as ethanol) and ...

Embodiment 2

[0012] Anhydrous chromium sulfate was dried to constant weight, and ionic liquid [BMIM]HSO 4 As a solvent, 0.7 mol·L -1 Anhydrous chromium sulfate dissolved in [BMIM]HSO 4 ionic liquid, and stirred at a temperature of 95° C. until fully dissolved, and left to stand for 36 hours to obtain a ready-to-use trivalent chromium ionic liquid plating solution. The No. 40 carbon steel sample with a size of 10 mm × 5 mm × 2 mm was pretreated by conventional electroplating. The pretreated No. 40 carbon steel sample was used as the cathode, and the insoluble graphite was used as the anode, which were directly placed in the ionic liquid plating solution system for rack plating. The current density is 1.5 A dm -2 , the distance between the anode and the substrate was 25 cm, the electroplating time was 70 min, and the electroplating temperature was 90 °C. The substrate with the electroplated layer is taken out from the ionic liquid plating solution, washed with an organic solvent and tap...

Embodiment 3

[0014] Cr 2 (SO 4 ) 3 ·6H 2 O was dried to constant weight, and the ionic liquid [BMIM]HSO 4 As a solvent, 0.6 mol·L -1 Cr 2 (SO 4 ) 3 ·6H 2 O dissolved in [BMIM]HSO 4 ionic liquid, and stirred at a temperature of 90° C. until fully dissolved, and left to stand for 36 hours to obtain a ready-to-use trivalent chromium ionic liquid plating solution. The zinc sheet samples with a size of 10 mm × 5 mm × 2 mm were pretreated by conventional electroplating. The pretreated zinc sheet sample is used as the cathode, and the insoluble graphite is used as the anode, which are directly placed in the ionic liquid plating solution system for rack plating. The current density is 2.0 A·dm -2 , the distance between the anode and the substrate was 25 cm, the electroplating time was 70 min, and the electroplating temperature was 90 °C. The substrate with the electroplating layer is taken out from the ionic liquid plating solution, washed with an organic solvent and tap water in sequ...

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Abstract

The invention discloses a method for trivalent chromium electroplating of a non-micro-crack crystalline chromium and chromium alloy coating in a 1-butyl-3-methyl imidazole hydrosulfate ([BMIM]HSO4) ionic liquid system, relating to a surface engineering and surface treatment technology. The method comprises the configuration of a novel ionic liquid plating solution, an electroplating technological process and the like. The current efficiency of the electroplating chromium and chromium alloy coating of a plating solution system can reach more than 95%, and is 45% higher than that of a conventional aqueous solution system; moreover, the defects that the plating solution of a normal aqueous solution system is poor in stability, easy in combustion, short in service life and high in toxicity and volatility, and an additive brightening agent and a stabilizing agent are easy to be out of operation can be overcome by using the method. The prepared non-micro-crack crystalline chromium and chromium alloy coating disclosed by the invention is compact and smooth in surface, has a strong combining capacity with a substrate, is excellent in corrosion resistance and high in hardness, is suitable for the demands on corrosion prevention, decoration and the like of the surfaces of metals and alloys, is easy in operation, and has the characteristics of economic practicality and low toxicity.

Description

technical field [0001] The present invention relates to the method for ionic liquid electroplating metal chromium and chromium alloy, particularly 1-butyl-3-methylimidazolium bisulfate ([BMIM]HSO 4 ) A method for electroplating trivalent chromium in ionic liquid without microcracks in crystalline chromium and chromium alloy coatings. Background technique [0002] And chromium alloy coatings, especially crystalline chromium and chromium alloy coatings prepared by electroplating methods have excellent corrosion resistance, wear resistance, high temperature oxidation resistance, and good decoration. It has been widely used in magnetic materials and soft magnetic materials. There are two major problems in electroplating chromium and chromium alloy coating technology in ordinary aqueous solution system: first, organic additives are generally added to the plating solution, because these organic substances will also participate in the electroplating reaction and cause the coating ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C25D3/06C25D3/10
Inventor 何新快侯柏龙朱清云
Owner HUNAN UNIV OF TECH
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