THE STUDYING OF ABSORPTION NATURE OF MECHANICAL ACTIVATED OXIDES IN OPTICAL-SPECTRA

This work is concerned with elucidating the causes of the increased ge neral background of oxides absorption in optical spectra. It has been shown that the mechanical activation of oxides (MoO3, WO3, SiO2, alpha -Al2O3) results in compression and stretching of metall-oxygen bonds. This phenomenon has been observed in optical spectra where absorption bands are displaced and the general background of absorption is increa sed, wich is associated with charge transfer transitions in the 400-25 00 nm region from the compressed Me-O bonds. Using optical methods and ESR it has been established that the: rupture of Me-O bonds can occur e as a result of stretching of them. And in this case the formation of cations with lower oxidation degrees takes place (for MoO3, WO3, It h as also shown that in the case of alpha-Al2O3 the Al-O bond is more st rong that the Me-O bond in the MoO3, WO3, SiO2 oxides and under the sa me mechanical acts the rupture of it does not occure. In the 200-2500 nm region of alpha-Al2O3 optical spectrum only compressed bonds are ob served.