1498. HOUDREMONT, E., KLINGER, P., AND BLASCHCZYK, G. [New Electrolytic Isolation Procedure for Determining Iron Carbide.] Tech. Mitt. Krupp, Forschungsber., vol. 4, 1941, pp. 311-328; Arch. Eisenhüttenw., vol. 15, 1941, pp. 257-270; Chem. Zentralb., 1942, I, p. 2167; Chem. Abs., vol. 37, 1943, p. 3017.

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Literature Abstracts

In the electrolytic apparatus the anode compartment is separated from the cathode compartment by a diaphragm, which consists of a clay plate impregnated with agar agar. The sample of steel is made the anode in a neutral anolyte of such chemical composition that no precipitation of ferrous salt results from hydrolysis. The used anolyte contains ferrous salt from the anode and is therefore heavier than the original solution, so that it falls to the bottom of the anode chamber from whence it can be withdrawn and fresh anolyte introduced through a filtering arrangement. The anolyte consists of a 15% Na citrate solution containing about 1.2% KBr and 0.1% KI. The solution is diluted with boiled water and freed from O₂ before it is driven by N₂ or H₂ gas pressure into the anode compartment. The cathode is formed from Cu gauze dipping in 10% CuBr₂ solution. An ampere-hour counter, an ammeter, and a voltmeter are introduced into the electrical circuit as parts of the apparatus. To control the anode potential, which is important for the isolation of carbides, a measuring cell is introduced, which consists of a calomel cell with siphon and a Pehavi measuring instrument. For the isolation of the carbide, the apparatus is provided with a contrivance whereby the carbide can be removed while under a neutral gas atmosphere. In the experiments made with this apparatus, Fe₃C was the only carbide that could be isolated from either hypoeutectoidal or hypereutectoidal steel, produced under all conditions of heat-treatment. The literature often contains contrary statements, which doubtless are caused by decomposition of the very reactive lamella of carbide.