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Chrome plating knowledge (II)

Release time:

2024-01-08

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The main advantages of trivalent chromium plating bath are as follows:

(1) Low toxicity and easy wastewater treatment. It is reported that the toxicity of trivalent chromium is only 1/100 of that of hexavalent chromium, and hexavalent chromium acid mist is not generated during the electroplating process. The concentration of the plating solution is low, only about 1/7 of the hexavalent chromium plating solution, so the amount of the plating solution is small and the waste water treatment is easy.

(2) The current density range of the plating solution is wide, and the qualified coating can be obtained in the wide cathode current range of 0.5 ~ 100A/dm.

(3) The dispersion ability and covering ability of the plating solution are better than that of the hexavalent chromium plating solution.

(4) The current efficiency of the plating solution is high, up to about 25%.

(5) The plating solution can work at room temperature without heating, thus saving energy.

(6) the corrosion resistance of the coating is good, and the micro discontinuous chromium coating can be directly plated.

(7) During electroplating, the bonding force is not affected even if the current is interrupted.

However, the shortcomings of the early trivalent chromium coating are more prominent, mainly as follows.

(1) The color is not like the bluish white taken out of the hexavalent chromium plating solution, but with the yellow white of stainless steel, so it is difficult to accept the user.

(2) The thickness of the coating can only reach 3μm and cannot be thickened, so it is not suitable for hard chrome plating. (3) Poor stability of plating solution.

(4) the hardness of the coating is low.

Fortunately, through the unremitting efforts of electroplating workers, the above four problems have been basically broken through.

(1) It is now possible to plate a bluish white color close to the color of the hexavalent chromium plating solution.

(2) The thickness of the coating can reach tens of microns or even hundreds of microns.

(3) The stability of the plating solution is also greatly improved.

(4) Although the hardness of the coating is low (HV600 ~ 900), the hardness can reach HVl200 ~ 1800 after heat treatment at a certain temperature, and the wear resistance is also greatly enhanced. We know that this hardness value has greatly exceeded the hexavalent chromium chromium coating.

Key words:

Chrome plating solution

Chrome plating, a process that makes metal shiny!

Chrome plating knowledge (I)

Chrome plating, a process that makes metal shiny!

Chrome plating knowledge (I)