X-Ray tomography of additive-manufactured zirconia: processing defects – strength relations
M.Saâdaoui (1), F. Khaldoun (1), J. Adrien (2), H. Reveron (2), J. Chevalier (2)
Accepted in the Journal of the European Ceramic Society (5 April 2019 – Available on line)
X-ray Computed Tomography (XCT) analysis was applied to identify and quantify typical defects in dense 3Y-TZP zirconia processed by the Lithography-based Ceramic Manufacturing (LCM) technique. XCT derived strengths were anticipated from the XCT data and compared to experimental measurement. A good agreement between XCT data, bending strength measurement and fractographic analysis demonstrates the suitability of X-ray tomography for both defects detection and predictive mechanical strength estimation. It allows also to rank the different defects related to LCM in terms of their criticality versus mechanical resistance.
X-ray computed tomography, additive manufacturing, defects, strength, zirconia
Alkali-activated refractory wastes exposed to high temperatures: development and characterization
Bartolomeo Coppola, Caroline Tardivat, Stéphane Richaud, Jean-Marc Tulliania, Laura Montanaro, Paola Palmero
Accepted in the Journal of the European Ceramic Society (24 February 2020 – Available on line)
The feasibility to prepare alkali-activated materials starting from refractory wastes and their properties after exposure to high temperatures (800, 1000, 1200 and 1400 °C) were investigated. Two different aluminosilicate wastes were used: chamotte (CH, mainly composed of corundum, mullite and andalusite) and alumina-zirconia-silica (AZS, composed by baddeleyite, corundum and amorphous silica). Very high mechanical properties were achieved in both cases (28-days compressive strength of approx. 70 and 60 MPa for CH- and AZS-based pastes, respectively). Then, alkali-activated pastes were exposed to high temperatures. For both kinds of samples, a sharp increase of mechanical properties was obtained after exposure to 800 and 1000 °C thanks to the matrix densification. Above 1000 °C viscous sintering occurs leading to a further increase of mechanical properties. AZS-based materials were able to withstand high temperatures up to 1400 °C while CH-based pastes mechanical properties decrease at 1400 °C due to andalusite decomposition.
Chamotte; AZS; Alkali-activation; Refractory; High-temperature.