Powder samples were tribophysically activated by grinding in air, and were investigated by using electron paramagnetic resonance methods to clarify the effect of the duration of tribophysical activation upon defect formation. Six electron paramagnetic resonance signals were detected and it was shown that these were caused by the formation of VZn-:Zni0, VZn-, (VZn-)2-, F+, SDC, and interaction products of mill-material with ZnO. The dependence of the formation of various centers upon grinding time suggested that the defect structures in polycrystalline samples during grinding evolved in the order: Zn2+lattice → VZn-:Zni+ → VZn-:Zni0 → VZn- + Zni-→ (VZn-)2-, and O2+lattice → VO+ + O-.

Electronic Paramagnetic Resonance Investigation of the Evolution of Defects in Zinc Oxide during Tribophysical Activation. Kakazey, N.G., Srećković, T.V., Ristić, M.M.: Journal of Materials Science, 1997, 32[5], 4619-22