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Chrome plating knowledge (I)

Release time:

2024-01-08

Source:

Hexavalent chromium has high toxicity and serious environmental pollution. Chromic anhydride is widely used in chromium plating solution, which is the main pollution source of chromium-containing wastewater in electroplating industry. This problem has aroused widespread concern, and countries have also strengthened legislative management. For example, the emission standard for hexavalent chromium in the United States has been reduced from 0.05mg/L to 0.01mg/L, and has been implemented since 1997. Low current efficiency and poor covering ability of the hexavalent chromium plating bath are also a problem. In order to fundamentally reduce pollution and improve current efficiency and coverage, trivalent chromium plating process is more and more popular.

Trivalent chromium plating has been more than 100 years since Bunsen published its first paper in 1854. Due to some technical problems, it is difficult to break through, so the progress is relatively slow. By the 1970 s, with the development of science and technology and the increase of chemical raw materials, as well as the further enhancement of people's awareness of environmental protection, the study of trivalent chromium plating has been mentioned on the agenda of electroplating workers. In 1974, the United Kingdom published a Alecra-3 trivalent chromium plating process, and in 1975 applied for a trivalent chromium plating patent using chromium trichloride as the main salt, namely Alecra-3000. In 1981, the United Kingdom developed the sulfate of environmentally friendly chromium (Envir0-chome) trivalent chromium plating process. The process uses a selective ion diaphragm to separate the cathode region from the anode region, thus avoiding the harm caused by the oxidation of hexavalent chromium on the anode plate to the trivalent chromium plating bath: almost at the same time, the United States Harsha0 Company also developed a Tri-chrome trivalent chromium plating process.

Key words:

Chrome plating knowledge (II)

Will chrome rust?

Chrome plating knowledge (II)

Will chrome rust?