Chrome electroplating

Solvent effects on the Cr—O bond lengths in [Cr(ox)3]3- have been studied by XAFS spectroscopy.628 The Cr111 oxalato complexes are used in Crm-based chrome-electroplating solutions, avoiding the use of toxic and carcinogenic CrVI.114,629... 

Chemicals for electroplating n. Most plastics plated today are finished with a copper/ nickel/chrome electroplate, but many other finishes are possible, such as bright brass antique brass, satin nickel, silver, black chrome, and gold. The actual composition of the electroplate is designed for the particular apphcation of the electroplate. 

Chromium, hard chrome (electroplate) A thick chromium layer designed to impart... 

Around 1800, the attack of chromite [53293-42-8] ore by lime and alkaU carbonate oxidation was developed as an economic process for the production of chromate compounds, which were primarily used for the manufacture of pigments (qv). Other commercially developed uses were the development of mordant dyeing using chromates in 1820, chrome tanning in 1828 (2), and chromium plating in 1926 (3) (see Dyes and dye intermediates Electroplating Leather). In 1824, the first chromyl compounds were synthesized followed by the discovery of chromous compounds 20 years later. Organochromium compounds were produced in 1919, and chromium carbonyl was made in 1927 (1,2). 

Another example of where ultrasound influences the discharge rate of chromium is in the chromium electroplating of steel plates. When cold-rolled steel plate is elecUo-lytically chromated from a silent aqueous solution containing chromates and dichromates, a chrome coating of 13 mg m is obtained after 1 s, whilst in the presence of ultrasound a coating of 45 mg m is obtained [25] in the same time. The product is also accompanied with an increase in the brightness of the metal. Similar results have been found by other workers [26]. 

In industry, it is used in rubber and plastic materials and in paints and sprays to neutralize unpleasant odours (Lake, 1999). In other fields, coumarin has a significant use in the electroplating industry, mostly in the automotive area, to provide high polished quality to chrome-plated steel, but this use is declining (Egan et al., 1990 Boisde Meuly, 1993). 

Point-of-Source Recovery - in certain circumstances, it is possible to utilize reverse osmosis to effect a "zero discharge" electroplating rinse water recovery system. The rinse water from the first rinse is pumped to a reverse osmosis system that concentrates the salts and directs them back to the plating bath. The purified rinse water (permeate) is directed to the last rinse, and neither solute nor solvent is lost. in the united States there are approximately 150 reverse osmosis systems operating in this manner on nickel baths and 12 on acid copper. There are also a few installations operating on copper cyanide, hexavalant chrome, and acid zinc. 

Bright P, Burge PS, O Hickey SP, et al. 1997. Occupational asthma due to chrome and nickel electroplating. Thorax 52 28-32. 

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