Spark plasma sintering of MoO for production of Tc by neutron irradiation

Suematsu, Hisayuki*; Sato, Soma*; Nanko, Makoto*; Tsuchiya, Kunihiko ; Nishikata, Kaori  ; Suzuki, Tsuneo*; Nakayama, Tadachika*; Niihara, Koichi*

Spark plasma sintering of MoO was carried out for production of Tc from Mo by the (n,) method in a nuclear reactor. Powder of MoO with an average grain size of 0.8m and a purity of 99.99% was pressed in a graphite die with a diameter of 20 mm. Then, the green compact was heated in a spark plasma sintering apparatus with heating rates of 100 200C/min to 500 600C in vacuum. After holding the temperature for 5 min, the sample was quenched. The sintered samples were characterized by powder X-ray diffraction for phase identifications, electron energy loss spectroscopy for compositional analyses and scanning electron microscopy for grain size measurements. After sintering at 550C, a sintered bulk of MoO with a relative density of 98% was obtained. These properties are good enough for separation of Tc and recycle of Mo.