Control of the YSZ biaxial alignment on polycrystalline Ni[sbnd]Cr substrates by ion beam selective resputtering

Abstract

(001)-oriented and in-plane aligned yttria-stabilized zirconia (YSZ) films were synthesized on polycrystalline NiCr substrates by ion beam assisted deposition (IBAD). The YSZ biaxial alignment were found to be controlled by the assisted argon ion beam bombardment. The incident angle and energy of the assisted bombarding ion beam strongly influence the alignment. The optimal alignment was obtained with the assisted ion beam bombarding at 55° incident angle and 250–500 energy. The Monte Carlo method was used to simulate the alignment formation with argon ions bombarding the zirconia crystals. Results indicated that when the energy of the bombarding ions is less than 50 eV, there is no obvious difference in the sputtering yields and the radiation damage of zirconia between different incident angles. However with the ion energy increasing, the variation increases rapidly. When the ion energy reaches 250 eV, the sputtering yields and the radiation damage of zirconia induced by Ar★ bombarding along [111] direction (54.7° from the [001]) of the zirconia are much lower than those produced by Ar★ bombarding along other directions. It can be concluded that the (001)-oriented grains are resputtered less than other grains when the assisted ions bombarding at 55° incident angle, which causes YSZ grains with (001) orientation to prevail over initial random oriented grains and form the biaxial alignment.