Additionally, chromic acid is used in chromate conversion coating, which produces a distinctive yellow finish on metal surfaces that may be used for corrosion inhibition or as a primer for further coatings. Chromium can be applied to metal surfaces via electroplating, and such surface treatments can provide wear resistance and, because chromium can be polished to an appealing silvery sheen, decoration. Additionally, nickel-based superalloys derive increased strength from the inclusion of chromium these alloys are frequently found in devices such as jet engines that require materials to be stable and strong at very high temperatures. High-speed tool steels include small percentages of chromium for added strength, while higher percentages of chromium produce stainless steel. Chromium strengthens and imparts corrosion resistance to alloys. The vast majority of chromium is used in metalworking, either as a component of alloys or in various types of surface treatments. Chromium (IV) oxide is magnetic, and is used to manufacture the magnetic tape used in audio cassettes. Both chromite and chromium(III) oxide can withstand high temperatures, and are frequently used as refractory materials such as brick molds and foundry sands. The first laser was built using a synthetic ruby. Chromium salts are used in wood preservatives, and chromium provides color to synthetic rubies and emeralds. A number of chemical processes use chromium-containing catalysts including the production of polyethylene, the most common form of plastic. Other chromium(III) compounds have been used in tanning since the early 19th century, as a reaction between chromium and the collagen fibers stabilizes leather.Ĭhromium compounds continue to find applications in industry. Viridian, a green pigment produced from chromium(III) oxide, is not toxic and is still used widely in ceramics and glassware. Use of actual lead chromate has declined significantly due to toxicity concerns, but the color is still used, replicated using less toxic alternatives.
Lead chromate, the main compound in crocoite, was used to produce a pigment called “chrome yellow”, a color well known due to its widespread use for school buses in the United States and postal vehicles in some European countries. The earliest uses of chromium exploited its compounds. Vauquelin went on to detect traces of chromium in precious gems such as rubies and emeralds, and to hypothesize correctly that chromium gave these gems their brilliant colors. The process he used to isolate pure chromium metal had produced a variety of vibrantly colored solutions and compounds, and it was due to this that Vauquelin’s colleagues had suggested the element be named from chroma, Greek for “color”. Vauquelin resolved the debate when he was able to isolate a new metallic element, chromium, from the sample, a discovery he reported in the scientific literature the following year.
When French chemist Louis Nicolas Vauquelin first received a sample of Siberian red lead in 1797, the mineral-known today as crocoite-had been in use as a pigment for over three decades, but its chemical composition had remained a subject of dispute. American Elements: The Materials Science Company™ | Certified bulk & lab quantity manufacturer of metals, chemicals, nanoparticles & other advanced materials
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