On Properties of Point Defects in Platinum

Experimental results on properties of point defects in platinum which were obtained during the last forty-five years are discussed in the light of the modified two-interstitial model. After a low temperature irradiation correlated 〈100〉-split interstitial–vacancy pairs annihilate in recovery stages I and II with activation energies ranging from very small values up to the activation energy of migration of free 〈100〉-split interstitials of . Free 〈100〉-split interstitial recover in recovery stage III at about 300 K and vacancies in recovery stage IV at about 600 K. The recovery of vacancies after quenching is also observed in recovery stage IV and their activation energy of migration is . Di-vacancies obtained by quenching have an activation energy of migration of annihilating in a temperature range below that corresponding to the recovery stage IV range. Correlated 〈100〉-crowdion–vacancy pairs and 〈100〉 crowdions recover in the recovery sub-stages I and I , respectively. The activation energy of migration of 〈100〉-crowdions is The increase of the electrical resistivity of platinum during irradiation with 1.85 MeV electrons from a Van de Graaff generator was measured in situ for various irradiation temperatures at and below the temperature region corresponding to the recovery stage III temperature region. The increase was very small and almost not detectable, because the electrical resistivity of a Frenkel defect decreases from = 10 · 10 Ωcm at the temperature of liquid helium to very small values at ambient temperature. After large irradiation doses only vacancies were present which recovered during an anneal of 24 hours at 300 °C.