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Chrome plating (less commonly chromium plating) is a technique of electroplating a thin layer of chromium onto a metal object. A chrome plated part is called chrome , or is said to have been chromed .
Electroplating of acid gold on underlying copper- or nickel-plated circuits reduces contact resistance as well as surface hardness. Copper-plated areas of mild steel act as a mask if case-hardening of such areas are not desired. Tin-plated steel is chromium-plated to prevent dulling of the surface due to oxidation of tin.
In particular, concerns about the exposure of workers to chromates and dichromates while handling the immersion bath and the wet parts, as well as the small residues of those anions that remain trapped in the coating, have motivated the development of alternative commercial bath formulations that do not contain hexavalent chromium; [17] for ...
Black nickel plating was developed around 1905, and between the two wars, black chrome plating (first German patent 1929.GP 607, 420), which saw wider use only from the mid-1950s. [14] After the First World War, the first procedures for anodic oxidation and coloring of anodically oxidized aluminium were developed (1923, 1924.DRP. 413876).
The Pourbaix diagram for chromium in pure water, perchloric acid, or sodium hydroxide [27] [28] Chromium is a member of group 6, of the transition metals. The +3 and +6 states occur most commonly within chromium compounds, followed by +2; charges of +1, +4 and +5 for chromium are rare, but do nevertheless occasionally exist. [29] [30]
Electroless deposition is an important process in the electronic industry for metallization of substrates. Other metallization of substrates also include physical vapor deposition (PVD), chemical vapor deposition (CVD), and electroplating which produce thin metal films but require high temperature, vacuum, and a power source respectively. [20]
Barium chromate has been found to be useful in many capacities. The compound is often used as a carrier for the chromium ions. One such case is the use of barium chromate as a sulfate scavenger in chromium electroplating baths. [5] Over time the chromium concentration of the bath will decrease until the bath is no longer functional.
Such zinc electroplating or zinc alloy electroplating maintains a dominant position among other electroplating process options, based upon electroplated tonnage per annum. According to the International Zinc Association, more than 5 million tons are used yearly for both hot-dip galvanization and electroplating. [ 1 ]