Abstract
The effects of postfabrication heat treatments in argon and air atmospheres at 1400°C on the microstructure of a hot-pressed silicon nitride are compared. Heating in argon leads to a disappearance of the intergranular glass phase (with the consequent formation of interconnected porosity) and a reduction in the content of silicon oxynitride, and results in a soft, easily abraded surface. On subsequent heating in air, an oxide scale, similar to that produced by oxidation, rich in impurity and additive cations, is formed on the surface. In addition, silicon oxynitride and silica are formed below the scale. On cooling, macroscopic cracking, attributed to the volume increase of SO2 on transformation to cristobalite, occurs. Material heated first in air and then in argon resembled that of material heated in argon alone.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
