The more general methods for the separation of boron from associated elements, and for its estimation, are briefly considered.Work carried out in adapting Tschischewski's method to the estimation of boron in boronised iron, nickel, cobalt and copper is described, in which these metals are removed by mercury cathode electrolysis. In addition, a rapid method for the estimation of boron in boronised molybdenum is described in which the metal is separated as the sulphide. The boron after conversion to mannitoboric acid is finally determined by potentiometric titration with sodium hydroxide, which obviates the difficulties inherent in the use of colour-change indicators.The methods as described have an accuracy of about 1.4 per cent. of the amount of boron present over the range 0.27 to 4.30 per cent., which may be extended with slight modification.
A rapid method is described for the determination of lead in steel, alloy steel and cast iron. By this method the absorption due to the presence of colloidal lead sulphide in alkaline solution is measured with the Spekker absorptiometer, the interference of iron being prevented by complexing it as the ferrocyanide. The effect of individual constituents in alloy steel is considered briefly. The lead content of a steel can be determined in about 30 minutes on a 0-2-g sample, compared with the 1 to 2 days and 6 to 10-g sample required for the normal methods.
The equipment and techniques used for determining oxygen in vacuummelted steels, mol$bdenum and single-crystal silicon by vacuum fusion, at levels down to less than 1 p.p.m., are described.The oxygen content of steels at levels of 115 p.p.m. and 6 p.p.m. has been determined with coefficients of variation of 2.3 and 5.2 per cent., respectively. Results on sintered and arc-cast molybdenum with oxygen levels of 42 p.p.m. and 2 p.p.m. showed coefficients of variation of 2 and 8 per cent., respectively.Experiments with zone-refined molybdenum indicated that the oxygen content consisted of a residual surface contamination of 0-8 pg per sq. cm with an internal oxygen content of less than 0.2 p.p.m. With vacuum grown single-crystal silicon a coefficient of variation of 10 per cent. at a level of 17 p.p.m. was obtained on a limited sample weight of 0.5 g.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.