Corrosive degradation of a dense Si(3)N(4) in a burner rig
The demands for greater efficiency and reduced environmental pollution are two of the main factors behind intense research and development of new and improved materials for propulsion and power generation systems. On the grounds of density and retention of properties to high temperatures, ceramics are attractive alternatives to metallic materials. While much attention is focused on the problem of mechanical reliability, the question of corrosion resistance, and more importantly the synergism between corrosion and strength, are critical factors affecting the life of components. This investigation addresses the corrosion of a Si(3)N(4) material, hot-pressed with 3%Al(2)O(3) and 8%Y(2)O(3) in a combustion atmosphere, paying particular attention to corrosion. The results show that the dominant surface reaction in the atmosphere containing SO(2) and compounds of sodium was oxidation, giving a surface product of silica, but the kinetics were in some cases not parabolic as often reported. It was also shown that strength progressively decreased with increasing corrosion test temperature, probably due to the formation of subsurface defects.
Bibliographic Reference: Article: Journal of Materials Science (1997)
Record Number: 199711047 / Last updated on: 1997-09-16
Original language: en
Available languages: en