Title:
X-Ray tomography of additive-manufactured zirconia: processing defects – strength relations
Authors:
M.Saâdaoui (1), F. Khaldoun (1), J. Adrien (2), H. Reveron (2), J. Chevalier (2)
Journal:
Accepted in the Journal of the European Ceramic Society (5 April 2019 – Available on line)
Abstract:
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.
Keywords:
X-ray computed tomography, additive manufacturing, defects, strength, zirconia
Title:
Alkali-activated refractory wastes exposed to high temperatures: development and characterization
Authors:
Bartolomeo Coppola, Caroline Tardivat, Stéphane Richaud, Jean-Marc Tulliania, Laura Montanaro, Paola Palmero
Journal:
Accepted in the Journal of the European Ceramic Society (24 February 2020 – Available on line)
Abstract:
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.
Keywords:
Chamotte; AZS; Alkali-activation; Refractory; High-temperature.