Effect of the Consolidation Technique on the Sintering Ability and Thermal Properties of AlN Processed from Aqueous Suspensions
In this work, two different consolidation techniques were used to obtain AlN samples: slip casting and dry pressing of granules obtained from aqueous suspensions by freeze granulation. The green samples were sintered at a temperature (1750°C) lower than those usually used (>1800°C), using CaF2 and YF3 as sintering aids. The microstructural features were analysed by scanning electron microscopy (SEM) and the crystalline phases formed were identified by X-ray (XRD). Full dense AlN-based ceramics were obtained from both consolidation techniques; however the thermal conductivity values were quite different. The presence of carbon in the samples derived from the freeze granulated powder containing organic processing additives de-waxed in an inert atmosphere revealed to be helpful in the cleaning of oxygen present at the grain boundaries and consequently, for enhancing the thermal conductivity.
Paula Maria Vilarinho
S. M.H. Olhero and J. M. F. Ferreira, "Effect of the Consolidation Technique on the Sintering Ability and Thermal Properties of AlN Processed from Aqueous Suspensions", Materials Science Forum, Vols. 514-516, pp. 1531-1535, 2006