B. Lonnberg et T. Lundstrom, DETERMINATION OF GRAIN-SIZE AND LATTICE-DISTORTIONS IN-GROUND YBA2CU3O7, Journal of Materials Science, 29(11), 1994, pp. 2993-2997
Grain size and lattice distortions as a function of milling time have
been determined using X-ray peak broadening analysis and Brunauer-Emme
tt-Teller (BET) measurements. The grain size decreases from 0.22 mum i
n unmilled samples to 0.06 mum at 25 h milling time. Prolonged milling
produced no further decrease of the grain size. The unmilled powder c
ontained lattice distortions of 0.06%. During the first 25 h of millin
g only small changes of the lattice distortions occurred; longer milli
ng times resulted in a rapid increase of the lattice distortions. At 4
7 h of milling, the lattice distortions had increased to about 0.11%.
The results obtained by BET measurements agreed well with those obtain
ed by X-ray analysis. No anisotropic grain size decrease was indicated
during milling.