LnBa(2)Cu(3)O(7-x) and LnBa(2)Cu(4)O(8) high-T-c materials were synthesized
from fine powders obtained by mechanochemical activation of the starting m
ixtures. The heat-treatment conditions were shown to have a crucial effect
on the structural perfection and chemical composition of the resultant high
-T-c ceramics. According to thermogravimetric measurements, these materials
are stable up to 830 degrees C.