Water vapor corrosion behavior of lutetium silicates at high temperature

The corrosion behavior of hot-pressed lutetium disilicate (Lu2Si2O7) bulk sample in static state water vapor environment was examined at 1300 degrees C. The apparent corrosion rate was estimated as 1.427 x 10(-6) g/cm(2) h. The X-ray diffraction pattern showed a trace of Lu2O3 phase on the sample surface after corrosion test. SEM observation on the surface of the sample after corrosion test revealed that the surface morphology was not homogeneous but showing three different types of features. During high-temperature water vapor corrosion, lutetia-rich component first melted, and then removed from the grain surface by water vapor attack. Later, the excess boundary silica phase was removed by water vapor corrosion. These underlying corrosion mechanisms of bulk lutetium disilicate sample in static state water vapor environment were discussed in detail. (C) 2005 Elsevier Ltd and Techna Group S.r.l. All rights reserved.