The field dependence of electrical conductivity of powder compacts of the
mixtures ( ) X X KNO Cu 3 1− (0.2.≤.X ≤ 2.at.%) has been investigated. The currentvoltage
characteristics at fixed temperatures in the range (≈..30..≤..T..≤..160oC)
were found non-linear. The calculated characteristic length (L) possessed
values in the range ≈ 10−5.cm and proved significant dependence on the content
of copper and the conditions of sintering. The significant role of the applied
electric field was found to shorten the characteristic length.