High‐performance Al ₂ O ₃ ceramics prepared by DCC‐HVCI via microwave heating

Abstract A novel and rapid fabrication method for Al ₂ O ₃ ceramics by the DCC‐HVCI method via microwave heating was proposed. Effects of microwave heating temperature on coagulation time, micromorphology, as well as performance of the green body and ceramic sample were studied. As the microwave heating temperature rises, the coagulation time gradually reduced and compressive strength of green sample decreased while relative density and flexural strength of ceramics rose at the beginning and then dropped. The 50 vol.% Al ₂ O ₃ suspension was coagulated and demolded after treating at 60°C for 800 s by microwave heating. The compressive strength of green samples reached 1.12 ± 0.13 MPa. The relative density of Al ₂ O ₃ ceramic samples reached 99.39%. And the flexural strength of Al ₂ O ₃ ceramics reached 334.55 ± 26.41 MPa. The Weibull modulus of Al ₂ O ₃ ceramics reached 19. In contrast with the ceramic samples heated through water bath, the ceramic samples treated through microwave possessed uniform microstructures. Microwave heating could reduce the coagulation time by 77%. Meanwhile, it could significantly raise the compressive strength of green bodies by 65%. Additionally, it could increase the flexural strength of ceramics by 30%.