Bestimmung von Sauerstoff in Urancarbiden nach einer neuen badfreien Trägergasmethode

摘要

A report is given on the determination of oxygen in uranium carbide by a new method of hot extraction in a stream of nitrogen replacing the molten bath of the vacuum fusion method. The nitrogen is not only used as a carrier gas but also as a chemical reactant, which - by the formation of stable nitrides and carbonitrides - removes the oxygen impurities present as U0$_{2}$ and U(C,0) in the uranium carbide. The utility of the new method has been demonstrated by the results of several series of determinations which have been obtained under comparable conditions by vacuum fusion and by the use of argon as carrier gas. The results of thermodynamic calculations on the reaction mechanism of the removal of oxygen from UC-samples by hot extraction without fusion using a stream of nitrogen carrier gas as well as vacuum could be confirmed by chemical, X-ray diffraction, and metallographical analysis of outgassed samples. By avoiding the use of a molten-metal bath the nitrogen carrier gas method presents the following advantages over the other fusion methods: 1. The troublesome influence of graphite precipitations in the liquid metal bath on the process of dissolution and outgassing is avoided; 2. Losses of the gas by gettering on vapourised metal are avoided; 3. Both the possibility to use the graphite crucible several times and the saving of capsules and bath materials reduce the cost of series determinations. The applicability of this method is not limited to the determination of oxygen in uranium compounds. All elements the oxides of which react with carbon in a stream of nitrogen and form stable nitrides or carbonitrides and CO may be analysed by this method