Zone-specific temperature distribution, densification trajectory and grain-growth kinetics of microwave-hybrid-sintered and conventionally sintered Al₂O₃ slip casts

Microwave hybrid and conventional sintering of Al2O3 and Al2O3/ZrO2 multilayers fabricated by aqueous tape casting

“…In another work, Khalid et al 17 . mentioned an estimated activation energy of 134.60 ± 1.4 kJ/mol for grain growth in conventionally sintered Al 2 O 3 slip cast, whereas an estimated activation energy of 106.15 ± 0.7 kJ/mol was calculated for grain growth in microwave‐hybrid‐sintered Al 2 O 3 slip cast.…”

“…In the presence of a susceptor material, such as SiC used in this work, the sample heats up from the surface by absorbing heat from the susceptor, relatively flattening the parabolic temperature‐distribution curve along the sample. Hence, the temperature difference between the surface and center is significantly reduced 17,48 . It is suggested that a low heating rate with 1 h holding at the sintering temperature helped in relatively homogenizing the microstructure and densification at the center and surface of the sample.…”

“…In another work, Khalid et al 17 mentioned an estimated activation energy of 134.60 ± 1.4 kJ/mol for grain growth in conventionally sintered Al 2 O 3 slip cast, whereas an estimated activation energy of 106.15 ± 0.7 kJ/mol was calculated for grain growth in microwave-hybrid-sintered Al 2 O 3 slip cast. Similarly, they calculated an estimated grain-growth rate of (18.75 ± 0.11) × 10 −21 m 3 /s for the conventionally sintered Al 2 O 3 slip cast, whereas the graingrowth rate increased to (49.77 ± 0.13) × 10 −21 m 3 /s when the sample was sintered with microwaves.…”

“…surface and center is significantly reduced. 17,48 It is suggested that a low heating rate with 1 h holding at the sintering temperature helped in relatively homogenizing the microstructure and densification at the center and surface of the sample. Additionally, it is suggested that hybrid heating reduced the temperature gradients, further homogenizing the microstructure throughout the sample.…”

“…Microwave hybrid sintering, another sintering method used to consolidate ceramic green bodies, has previously been seen as an alternative to the conventional sintering of Al 2 O 3 and Al 2 O 3 /ZrO 2 with lower energy and time consumption and temperature shifts toward lower readings. [17][18][19][20] However, no significant research has been conducted on the microwave hybrid sintering of green Al 2 O 3 and Al 2 O 3 /ZrO 2 tape casts. Therefore, it is necessary to investigate whether microwave hybrid sintering can enhance the mechanical properties of Al 2 O 3 and Al 2 O 3 /ZrO 2 laminated structures.…”