Determination of silicor in iron and steel by 14 MeV neutron activation and high resolution gamma-spectrometry

Silicon present as silica in iron and steel has been determined by non-destructive neutron-activation method. Samples are irradiated with 14 MeV neutrons and photopeaks of γ-rays are detected on Ge(Li) detector. It was found that the contribution of aluminium to the intensity of the 1.778 MeV γ-ray was less than 0.001%. The contribution of phosphorus was taken into account by estimating the 28Al activity produced from its known percentage and the measured calibration curve for phosphorus. A comparator is irradiated and counted simultaneously. Comparators are prepared with the following chemicals: MgO(4%), CaCO3(20%), Al2O3(3%), MnCO3(5%), Ca3(PO4)2(3%), Fe(COOH)3(2%), SiO2(0-45%), and CaF2(45-0). Silicon is determined in both steel and iron by this method and the results are compared with those obtained by chemical method. In neutron activation analysis the result of Si is higher than that of the chemical analysis. The discrepancy between the results indicates the unavoidable loss of silicon during the chemical analysis. (T.I.)