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Microstructure and mechanical behavior of TiO 2 ‐MnO‐doped alumina/alumina laminates
Author(s) -
Daniel Barros Marcelo,
Jelitto Hans,
Hotza Dachamir,
Janssen Rolf
Publication year - 2021
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.17490
Subject(s) - materials science , microstructure , composite material , sintering , doping , dopant , tape casting , fracture toughness , porosity , flexural strength , optoelectronics
Tapes of TiO 2 ‐MnO‐doped alumina (d‐Al 2 O 3 ) and pure alumina (Al 2 O 3 ) were shaped via tape casting. Laminates with three different layer numbers and respective thicknesses were produced and sintered at 1200°C. The microstructure and mechanical behavior of laminates were investigated and compared to the respective monolithic references (d‐Al 2 O 3 and Al 2 O 3 ). The use of dopants in alumina decreased the initial sintering temperature, leading to higher densification at 1200°C (~98% theoretical density (TD)) when compared to Al 2 O 3 (~73% TD). The higher density was reflected in a higher Young's modulus and hardness for doped alumina. A region of diffusion of dopants in pure alumina layers was observed along the interface with doped layers. The mechanical strength of d‐Al 2 O 3 samples sintered at 1200°C was not statistically different from Al 2 O 3 samples sintered at 1350°C. The strength of laminates composed of doped layers with undoped, porous interlayers did not change. Nevertheless, as the thickness of these porous interlayers increases, a loss of strength was observed. Monolithic references showed constant values of fracture toughness (K IC ), ~2 MPa·m 1/2 , and linear crack path. On the other hand, K IC of laminates increases when the crack propagates from weak Al 2 O 3 layers to dense d‐Al 2 O 3 layers.