Platinum wires were quenched from 1700°C and the 4.2°K resistivity of the quenched-in vacancy defects was measured. Field ion microscope (FIM) specimens were then prepared from these same wires and the vacancy defects were imaged in a FIM as each specimen was dissected by pulse field evaporation. The image was recorded on ciné film after each pulse and every atomic site in a large number of consecutive layers was recorded, A total of 157 monovacancies and 9 divacancies were found in 593,800 sites in 3 as-quenched specimens and 76 monovacancies and 1 divacancy were found in 321,300 sites in 5 specimens which were partially annealed after quenching. To correct for the presence of surface artifact vacancy defects, 319,600 sites were scanned in well-annealed specimens under identical conditions and only 11 artifact monovacancies were found. These observations constitute direct evidence that the predominant equilibrium defect at elevated temperatures is the monovacancy. The value of the monovacancy concentration quenched-in from 1700°C is (2.64 ± 0.14) · 10-4 at.fr. which is less than the equilibrium value because of quenching losses. The combination of the measured concentrations and resistivity increments yielded a monovacancy resistivity of (5.75 ± 0.30) · 10-4 Ωcm (at.fr.)-1. An observed perferential loss of divacancies from the 5 partially annealed specimens provided direct evidence that the divacancy is more mobile than the monovacancy. The measured ratio of the divacancy concentration to the monovacancy concentration in the as-quenched specimens was (0.06 ± 0.02). The relationship of this value to the divacancy binding free energy is analyzed in Part II.
ASJC Scopus subject areas