Oxyden in tantalum powders

Methods of X-ray diffraction, electron spectral and neutron activation analyses are used to investigate oxygen position and to determine oxygen amounts in initial tantalum powder and in powders after various heat treatments. It is shown that in initial tantalum powders oxygen enters into particles of nonequilibrium solid solution, its concentration does not depend on powder grade. On tantalum powders sintering at the temperature above 1300 deg C practically complete dissolution of surface oxygen in particle volume takes place. Oxygen can be present in nonequilibrium solid solution in amounts up to 0.2 mass% for tantalum powders sintered above 1300 deg C and cooled in vacuum furnaces