The mechanical properties of silicon nitride ceramics are closely linked to the α-β phase transformation. Spark plasma sintering (SPS) technique has been used to density pure α-Si3N4 commercial powder, using Y2O3 and Al2O3 as additives; from 2.5 and 5.0 wt% and 1.5 and 3 wt%, respectively. Such powder admixtures were previously spray-dried at 160°C in such a way that powder was thoroughly homogenized. The sintering treatment included: 3 to 20 min holding time, 38 MPa axial load, sintering temperature of 1500°C and heating rate of 300°C/min. The maximum relative density developed on studied specimens is nearly 99% of theoretical value, which corresponds to 2M-series specimens and could only be attained once the β-phase nucleated from the α-silicon nitride matrix. X-ray diffraction (XRD) and scanning electron microscope (SEM) analyses confirmed the presence of two mains phases in the resultant microstructures: α- and β-Si3N4. Both the β-Si3N4 grain growth and the role that different amount of additives can play during SPS-sintering are analyzed.
|Original language||American English|
|Title of host publication||Grain growth of β-Si3N4 using Y 2O3 and Al2O3 as sintering aids|
|Number of pages||63|
|State||Published - 1 Jan 2012|
|Event||Ceramic Transactions - |
Duration: 1 Jan 2012 → …
|Period||1/01/12 → …|
Ceja-Cárdenas, L., Lemus-Ruiz, J., De La Torre, S. D., & Bedolla-Becerril, E. (2012). Grain growth of β-Si<inf>3</inf>N<inf>4</inf> using Y <inf>2</inf>O<inf>3</inf> and Al<inf>2</inf>O<inf>3</inf> as sintering aids. In Grain growth of β-Si3N4 using Y 2O3 and Al2O3 as sintering aids (pp. 71-77). (Ceramic Transactions; Vol. 232).