STUDIES OF THE OXIDATION MECHANISM OF YTTRIUM IMPLANTED CHROMIUM USING XAFS AND GAXRD

The first stages of the oxidation of yttrium implanted chromium have b een examined using EXAFS at the yttrium and chromium K-edges. Initiall y a thin chromia layer forms on the surface, and the implanted yttrium rapidly oxidises to form nanocrystallites of yttria. Upon further oxi dation some yttrium is incorporated into the chromia scale, probably a t the grain boundaries. The local atomic structure around these yttriu m ions resembles that of YCrO4.