Abstract
The paper reports on both the characteristics of ultrafine silicon nitride powder produced by plasma synthesis and the microstructure and properties of the relative sintered material. The powder, already containing yttria and alumina as sintering aids, has a bimodal particle size distribution and it is partly amorphous. The chemical composition and morphology of the particles are shown. Yttria and alumina were not found in separate particles but the elements constituting them (i.e., Y, Al, O) are either in solid solutions in the crystalline particles or dispersed within the amorphous portion of the powder. Dense materials were obtained by pressureless sintering at 1750 °C. Microstructure and composition of silicon nitride grains and of grain boundary phases are analyzed and discussed. When compared to a micro-sized Si3N4, nanoindentation tests clearly revealed the inverse Hall Petch relation. The nanosize Si3N4 shows a Young’s modulus which is almost independent on the peak load.
Sign-in/Register to access full text options 
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.
