NANOPOROSITY OF AL2O3 COATINGS OBTAINED BY IMPULSE PLASMA DEPOSITION

Investigations of the size distribution of nanopores were carried out for alumina coatings deposited by the impulse plasma method. The singl e-phase (metastable and stable correspondingly) alumina coatings were deposited under different conditions of impulse plasma processes. The investigation of nanopore distribution was carried out using small-ang le X-ray scattering. Despite the different phase composition of the co atings obtained, the most probable value of nanopores for both alumina coating materials were practically the same and equal to 5 nm. It app ears that a coating porosity of the order of nanometres is characteris tic for all coatings deposited by the impulse plasma method, because p reviously similar dimensions of nanopores were found for diamond, TiN and BN. It seems that during the impulse plasma deposition the coating grows on the substrate surface by condensation of ultra-small particl es nucleated in the impulse plasma.