Abstract
An oxide-direct current excitation method using a sifter type electrode and ammonium bifluoride buffer has been applied successfully to the spectrographic determination of B, Fe, Mg, Mn, P, Pb, and Sn in yttrium metals and oxides.
Series of standards covering 0.1 to 100 and 1 to 1, 000 ppm of the above impurity elements each in four steps (e. g. 0.1, 0.3, 0.7, and 1.0 ppm) are prepared by diluting measured quantities of base materials with weighed quantities (1 to 5 g) of spectroscopically pure yttrium oxides. Every base material was prepared by adding dropwise each standard solution (1 mg/ml) containing the impurity element on spectroscopically pure yttrium oxide in a platinum crucible. It was dried on a hot plate, ignited in a muffle furnace at 800°C for 3 hours and ground in an agate mortar. The samples are treated in exactly the same manner as the base materials.
The spectrographic conditions are as follows: amounts of the oxide 50 mg, Shimadzu Littrow type spectrograph, excitation voltage D. C. 200 V, arc current 10 amp., slit width 15 μ and duration of exposure 40 sec.
Variation coefficients for 0.1 to 1, 000 ppm of impurities in yttrium are within 20%.
