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Trivalent chromium hard chromium electroplating solution and application of trivalent chromium hard chromium electroplating solution in hard chromium electroplating

A technology of trivalent chromium and hard chromium, which is applied in the field of metal surface treatment, can solve the problems of sensitivity to impurity elements, difficulty in plating thickness, and plating of only a few microns, up to 20 to 30 microns, etc., to achieve good wear resistance , The appearance is smooth and white, and the effect of excellent stability

Active Publication Date: 2016-03-09
WUHAN DESYTEK ENVIRONMENTAL PROTECTION NEW MATERIAL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although trivalent chromium has high current efficiency, it is difficult to plate thickly. Some trivalent chromium plating solutions can only plate a few microns, at most 20 to 30 microns, so it cannot meet the needs of functional hard chromium plating. Chromium plating solution is very sensitive to impurity elements, as long as there are 10 ppm or even several ppm of impurities, it will not work normally
The normal plating life of many trivalent chromium solutions is very short, and it is often necessary to stop work to deal with impurities in the solution

Method used

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  • Trivalent chromium hard chromium electroplating solution and application of trivalent chromium hard chromium electroplating solution in hard chromium electroplating
  • Trivalent chromium hard chromium electroplating solution and application of trivalent chromium hard chromium electroplating solution in hard chromium electroplating
  • Trivalent chromium hard chromium electroplating solution and application of trivalent chromium hard chromium electroplating solution in hard chromium electroplating

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1-9

[0040] A kind of trivalent chromium hard chromium electroplating solution, its composition and content are listed in following table 1:

[0041] Table 1

[0042]

[0043]

[0044]

[0045] The pH value of above-mentioned each trivalent chromium hard chromium electroplating solution is listed in following table 2:

[0046] Table 2

[0047]

[0048]

[0049] The trivalent chromium hard chrome electroplating solution of above-mentioned embodiment 1-12 is all formulated according to the following method:

[0050] First, dissolve the complexing agent, buffer, catalyst and conductive salt in 50% measured deionized water, heat to 90°C, react for 2.5 hours, and let it stand for 12 hours. Then, add trivalent chromium main salt and stir thoroughly for 2 hours. The electroplating solution contains nano-materials, then add it at this time, then add the remaining 50% of the measured deionized water, stir evenly, use the iridium-tantalum-coated titanium plate with low oxyge...

Embodiment 12

[0054] Embodiment 12 Electroplating object: base material No. 45 steel shaft-shaped parts (diameter 30 × length 200mm)

[0055] Mechanical polishing - chemical degreasing 5min - hanger, install shielding - anode electrolytic degreasing 1min - water washing - activation until bubbles - water washing - pure water washing - hard chrome plating (start directly to the specified current Density) - washing - pure water washing - unloading

[0056] Hard chrome plating conditions: 40°C, 30A / dm 2 , plating time 20min.

[0057] Results: The coatings of the 12 experimental groups were all peeled and cracked.

Embodiment 13

[0058] Embodiment 13 Electroplating object: base material No. 45 steel shaft-shaped parts (diameter 30 × length 200mm)

[0059] Mechanical polishing - chemical degreasing 5min - hanger, install shielding - anode electrolytic degreasing 1min - water washing - activation to bubbles - water washing - pure water washing - hard chrome plating (soft start, cathode remains static , solution without stirring) - washing - pure water washing - unloading

[0060] Hard chrome plating condition: 40℃, 60A / dm 2 , Plating time 25min.

[0061] Results: The coating thickness of each experimental group was 55-65um, the current efficiency exceeded 36%, the hardness reached 950HV, and the bonding force passed the 300°C thermal shock test without peeling, peeling or cracking.

[0062] The corrosion resistance of the coatings in the five groups of Examples 8-12 all reached the neutral salt spray test for more than 150 hours.

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Abstract

The invention belongs to the technical field of metal surface treatment, and particularly relates to a trivalent chromium hard chromium electroplating solution and application of the trivalent chromium hard chromium electroplating solution in hard chromium electroplating. The electroplating solution is prepared from trivalent chromium main salt, a carboxylic acid or carboxylate complexing agent, a buffering agent, conducting salt and a catalyst. The deposition velocity reaches 2.5 micrometers / minute or above, the current efficiency reaches 36% or above, the thickness of an electroplating layer can reach 150 micrometers or above, each liter of the electroplating solution can be used for performing continuous electroplating for 900 ampere hours (an additive is supplemented during the process), high efficiency and high stability are maintained, the hardness of the electroplating layer reaches HV950 or above, and the electroplating layer has wear resistance the same as or similar to that of hexavalent chromium, has large binding force with steel, copper and copper alloy and is free of peeling or stripping or cracking in a 300 DEG C thermal shock test. As nanometer materials are added, corrosion resistance lasts for 150 h or longer in a neutral salt spray test. The trivalent chromium hard chromium electroplating solution has broad application prospects in the fields of rollers, hydraulic components, printing cylinders, shock absorbers, coal mine hydraulic supports and the like.

Description

technical field [0001] The invention relates to the technical field of metal surface treatment, in particular to a trivalent chromium hard chromium electroplating solution and its application in hard chromium electroplating. Background technique [0002] Hexavalent chromium electroplating hard chromium is a very widely used electroplating process. Because hard chromium has very high hardness, good wear resistance and other good mechanical properties, it is used in hydraulic supports, printing cylinders, automobile shock absorbers and rolled steel Rolls and many other aspects have been widely used. However, hexavalent chromium ions are toxic substances, strong oxidants, and strong corrosive chemicals that seriously pollute the environment, and are also strong carcinogens for humans. For this reason, since the 1980s, the international community has begun to restrict or even ban the use of hexavalent chromium electroplating, and the Chinese government has successively issued m...

Claims

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Application Information

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IPC IPC(8): C25D3/06
CPCC25D3/06
Inventor 陆飚
Owner WUHAN DESYTEK ENVIRONMENTAL PROTECTION NEW MATERIAL CO LTD
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