Corrosion of Silicon Nitride Ceramics in Aqueous Hydrogen Chloride Solutions
- 1 December 1988
- journal article
- Published by Wiley in Journal of the American Ceramic Society
- Vol. 71 (12) , 1074-1079
- https://doi.org/10.1111/j.1151-2916.1988.tb05794.x
Abstract
The leaching behavior of pressureless sintered and hotpressed Si3N4 containing Y2O3, Al2O3, and AlN and hot isostatically pressed Si3N4 without additives was studied in 0.1M to 10M HCl aqueous solutions at 50° to 100°C. Y and Al ions contained in the grain‐boundary phase dissolved in HCl solutions, but dissolution of the Si ion from the matrix was negligible. The dissolution of Y and Al ions in HCl solutions was adequately described by a surface‐chemical‐reaction‐controlled, shrinking‐core model in 5M HCl solutions. The rates of dissolution of both Y and Al ions decreased as the degree of crystallinity of the grain‐boundary phase increased. The fracture strength of the corroded samples linearly decreased with increasing degree of dissolution of soluble Y and Al ions.Keywords
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