Abstract
A graphite capsule method was applied to the determination of oxygen in ferro-boron powder by the vacurn fusion method in order to eliminate incomplete fusion and/or extraction of oxygen from samples.
Neither tin foil nor iron capsule gave good results from flashing-out of sample when the sample was dropped into the crucible. Good results were obtained when a high purity grade graphite capsule (20 mm × 10 mmφ) loaded 18 mg of sample powder and 1 g of platinum as bath metal was dropped at 1850°C. An isotope dilution method using aluminum oxide containing 70.9 atom% 18O was applied to the same procedure and gave good agreement with the results obtained by the vacuum fusion analysis.
