Abstract
Slip casting of commercial Si3N4 powder dispersed in de-ionized water with Y2O3 and Al2O3 as sintering aids was carried out using optimum slurry conditions arrived through zeta potential and viscosity measurements. The cast specimens were sintered in graphite furnace in the temperature range of 1600 °C to 1800 °C under 0.15 MPa static N2 pressure. The sintered Si3N4 show density variation from 59% to 82% of theoretical value in the sintering temperature range studied. The 3-point flexural strength varied between 80 MPa and 320 MPa and dielectric constant 3.9 to 5.7 as a function of decreasing porosity from 39% to 17%. The samples exhibit uniform distribution of micro porosity in the range 0.5 μm–2.0 μm and grain size of 0.5 μm–3.0 μm. The microstructure changed from equiaxed and platelet shaped α-Si3N4 grains to needle shaped β- Si3N4 with increase in sintering temperature from 1600 °C to 1800 °C. The dielectric and flexural strength properties found promising for high temperature radome applications.
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.
