The determination of oxygen in beryllium by the vacuum fusion method on a micro scale. With a note on the determination of oxygen in zirconium

Abstract

It is shown that the oxygen present as impurity in beryllium metal can be determined by means of the micro-scale vacuum fusion apparatus, by using samples of 2 to 10 mg containing as little as 0.2 per cent. of oxygen, provided that a rigorous experimental procedure is followed. This consists essentially of exact temperature control and the use of a molten-platinum bath in the graphite crucible.The factors determining the optimum conditions are discussed fully and the difficulties involved in working with beryllium are stressed. The results obtained for different types of beryllium and beryllium '' spiked " with beryllium oxide are given, and thus the degree of accuracy possible with such very small samples is shown.Hydrogen can also be determined by this method.

Method and Apparatus for Determination of Small Isotopic Oxygen Variations in Beryllium Oxide.

“…The reaction furnace shown in Figure 1 follows accepted vacuum fusion techniques (5). Samples were contained in a, series of loading galleys whose total capacity was 30 samples.…”

“…In 5 minutes the Pt flux reached 2200°C. and was held at that temperature for an additional 5 minutes. The Toepler pump was then isolated, the gaseous sample container removed, and the fusion apparatus opened to the vacuum pumps for outgassing until a pressure of 2 X 10-5 was reached.…”

“…Another instrument based on a design by Nier and Roberts (4, 10-12) has been described by Craig and Errock (5). Beynon (1) has pioneered the application of high resolution mass spectrometers to organic chemistry.…”

“…Of the established procedures such as volatilization, differential solubility, inert gas fusion, radio isotope formation, and isotopic dilution, vacuum fusion seemed most applicable to the present problem of liberating the oxygen in BeO for isotopic oxygen ratio determination. Gregory and Mapper (5), using BeO as a standard during the development of a micro method for the determination of total oxygen in beryllium metal, showed that the oxygen in BeO was quantitatively liberated as CO within 4 minutes when reacted with carbon dissolved in a platinum flux at 1900°C. Their recommendation of a maximum Be concentration in the platinum flux of one part in fifty was based on the determination of small amounts of oxygen in beryllium.…”

“…The choice of metals for the bath material is wide, but platinum seems most applicable to the work at hand. Development of the method was simplified because the weight of Be added to the system was quite small and thus did not lead to the gettering problems reported by Gregory and Mapper (5). Also, a reasonable assumption could be made that any isotope effect upon the reaction was small and could be neglected.…”