The formation of thermal vacancies in Cu3Sn was investigated by using positron annihilation lifetime spectroscopy. Positron lifetime measurements were performed in situ between 293 and 673K. The positron lifetime below 433K was found to be about 140ps, which indicated that there were no detectable vacancies below 433K. A sharp increase in the mean positron lifetime, τm, which was due to thermal vacancy formation began at around 453K and the saturation trapping of positrons by thermal vacancies was observed above 633K. The Arrhenius plot of the positron trapping rate, which was proportional to the vacancy concentration, represented a linear behavior and the vacancy formation enthalpy was determined to be 0.63eV. This value was relatively low when compared with that expected from the melting temperature (950K).

Thermal Formation of Vacancies in Cu3Sn. I.Shishido, H.Yasueda, M.Mizuno, H.Araki, Y.Shirai: Physica Status Solidi C, 2007, 4[10], 3563-6