Chromium carbide, preparation from

Chromium carbide can be best prepared from pure chromic oxide [1308-38-9] (see Chromium compounds). Compacts containing 74 wt %... 

Chromium carbide is important in powder preparations designed for thermal spray apphcations of corrosion and wear-resistant coatings on tool and machine parts. Lower carbon carbides of chromium are important in hardfacing tods and electrodes for weld-apphed ovedays on machine wear surfaces. However, these carbides are usually formed in situ from Cr and C in the rod and not added as preformed carbides. The properties of Ci2C2 are hsted in Table 2. 

Chromium carbide can be best prepared from pure chromic oxide [1308-38-9], Cr203 (see Chromium compounds). Compacts containing 74 wt % Cr203 and 26 wt % carbon black can be heated in carbon-tube furnaces at 1600°C in the presence of hydrogen, giving a carbide containing 13—13.3 wt % total C and 0.1—0.3 wt % free C. 

The submitters employed an aqueous 1.64Jtf solution of chromium(II) perchlorate which was prepared by stirring a mixture of 5.7 g. of pure chromium metal pellets (United Mineral and Chemical Corporation, 129 Hudson St., New York, 10013) with 60 ml. of aqueous 20% perchloric acid under a nitrogen atmosphere at 30° for 12 hours.2,3 The rate of dissolution of the chromium metal is increased if the metal is washed successively with concentrated hydrochloric acid and with water just before it is added to the perchloric acid. The checkers employed aqueous 0.519J/ chromium(II) perchlorate solution which was prepared in a comparable manner with chromium metal obtained from the Mining and Metals Division, Union Carbide Corporation. The deep blue solution of chro-mium(ll) perchlorate is transferred to a storage vessel with a... 

Thomberg, T., Kurig, H., Janes, A., and Lust, E. Mesoporous carbide-derived carbons prepared from different chromium carbides. Microporous and Mesoporous Materials, 141, 88-93, 2011. 

Alloys of chromium and silicon are readily obtained by heating chromium sesquioxide with excess of silicon at 11 white heat, or with silicon carbide, or silicon carbide and carbon, in the electric furnace or by strongly heating chromium sesquioxide, silica, and aluminium. From these alloys several definite silicides have been isolated, which are usually grey in colour, hard and brittle, and very resistant to acids, except hydrofluoric acid, which readily, decomposes them. The silicides, CrjSi, CrjSi, CrgSia, and CrSij, have been obtained in a state of comparative purity by special methods of preparation. ... 

Moissan, Henri. (1852-1907). A Native of Paris, Moissan was a professor at the School of Pharmacy from 1886 to 1900 and at the Sorbonne from 1900 to 1907. At the former institution, he first isolated and liquefied fluorine in 1886 by the electrolysis of potassium acid fluoride in anhydrous hydrogen fluoride. His work with fluorine undoubtedly shortened his life as it did that of many other early experimenters in the field of fluorine chemistry. He won great fame by his development of the electric furnace and pioneered its use in the production of calcium carbide, making acetylene production and use commercially feasible in the preparation of pure metals, such as magnesium, chromium, uranium, tungsten etc. and in the production of many new compounds, e.g., silicides, carbides, and refrac-... 

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