Jb. Veyret et al., INFLUENCE OF OXIDATION IN SO2-AIR MIXTURES ON THE ROOM-TEMPERATURE STRENGTH OF SILICON-NITRIDE, Journal of the European Ceramic Society, 13(4), 1994, pp. 313-321
The influence of oxidation in SO2-air mixtures on the mechanical prope
rties of two hot-pressed and one pressureless sintered Si3N4 ceramics
was investigated. Samples were corroded for 25 h in the range 800-1500
-degrees-C in 1 vol.% SO2 in dry air and the residual flexural strengt
h was measured at room temperature. In SO2, the dominant reaction proc
ess is oxidation, accompanied by reaction of sulphur oxides with the s
urface oxide layers, to yield sulphates where these are stable under t
he experimental conditions. This sulphate formation appears not to aff
ect the mechanical strength of silicon nitride.