  The chemical stability of the powder DyBa2Cu3O6+{\delta} has been studied by
X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and thermal
analysis at ambient conditions. The powder was subjected to mechanical
processing in a ball mill-activator to accelerate chemical degradation. The
kinetic regularities of hydrolytic decomposition of DyBa2Cu3O6+{\delta} under
the influence of air moisture have been determined. The resistive properties of
DyBa2Cu3O6+{\delta} to water have been found to be better, but not much
different from analogous properties of YBa2Cu3O6+{\delta} which is unstable in
a wet environment. Chemical degradation of the material is triggered by crucial
concentrating of water particles near the free surface of the solid reactant
(due to their low diffusibility in the bulk) leading to rapid chemical
decomposition of the respective regions.
