IMPROVED STRUCTURAL SILICON NITRIDE MATERIALS CONTAINING RARE EARTH OXIDES

摘要

A ceramic composition suitable for use as a high-temperature structural material in apparatus exposed to oxidizing atmospheres at temperatures of 400 to 1600 exp 0 C is described. It is found within the triangular area ABCA of the Si sub 3 N sub 4 -SiO sub 2 -M sub 2 O sub 3 ternary diagram. M is selected from the group of Yb, Dy, Er, Sc, and alloys having Yb, Y, Er, or Dy as one component and Sc, Al, Cr, Ti, (Mg + Zr) or (Ni + Zr) as a second component. The alloy has an effective ionic radius less than 0.89 A. (ERA citation 05:024433)