Influence of Sintering Process on Microstructure and Properties of Al Doped Aluminum Nitride Ceramic Substrate

Y₂O₃-Al was chosen as the sintering additive, AlN ceramics were prepared through the tape casting method.The impacts of the debinding and sintering process on the phase composition, density, microstructure characteristics and thermal and mechanical properties of AlN ceramics were studied.The results show that the mitigation of Al oxidation during the debinding process is accomplished through a vacuum-air two-step debinding program. In the prepared AlN ceramics, the secondary phase is found to be isolated and distributed at the triangular grain boundaries. A measurable enhancement of thermal conductivity and bending strength, by 2.5% and 14.8% respectively, is seen to exceed that achieved with a one-step debinding process.When the sintering temperature is increased, a transition of the secondary phase from YAG to YAP with a higher Y₂O₃/Al₂O₃ ratio is revealed, the oxygen content in lattice decreases. After being sintered at 1800 ℃, the thermal conductivity and bending strength of the AlN ceramics are measured to be 171.23 W·m^-1·K^-1 and (456.77±19.34) MPa, respectively.