• 2 mol% yttria-stabilized zirconia was printed by vat photomolymerization • Increased fracture toughness was observed for 2YSZ compared to 3YSZ • Bending strength of sintered 2YSZ specimens up to 1 GPa were observed • Transformation bands are visible in 2YSZ during and after mechanical loading • Complex shaped parts can be fabricated successfully from 2YSZ 2 mol% yttria-stabilized zirconia (2YSZ) has attracted increasing attention in recent years. Its key characteristic is the lower degree of stabilization compared to 3 mol% yttria-stabilized zirconia (3YSZ), which results in higher fracture toughness. In this study, 2YSZ and 3YSZ samples were fabricated using lithography-based ceramic manufacturing (LCM) and compared with respect to maximum printable wall thickness, microstructure, three-point bending strength (3PB), ball-on-three-balls biaxal strength (B3B), hardness, and fracture toughness. The 2YSZ samples exhibited higher bending strength in both 3PB and B3B tests, as well as higher fracture toughness (889 and 1004 MPa, and 7 MPa m 0.5 , respectively), compared with the 3YSZ material (754 and 969 MPa, and 4.2 MPa m 0.5 ). Microscopy and XRD analyses revealed that these enhanced properties are attributable to the higher phase transformability of 2YSZ. Overall, these results demonstrate that 2YSZ is a promising material for additive manufacturing, particularly for applications requiring high fracture resistance and complex geometries.

The impact of cyclic cold isostatic pressing (C-CIP) on the oxidation resistance and physical properties of a boron-free self-glazing Al2O3-C refractory for steel casting applications was investigated. Pulsations with amplitudes of 20, 40 and 65 MPa were thereby applied either at maximum isostatic pressure or at increasing pressure. The maximum isostatic pressures applied were 80, 100 and 150 MPa, respectively. Both cycling pressurizations improved the oxidation resistance and physical properties. Higher densities were obtained at higher cycling amplitudes, in particular when the pulsations were applied at maximum isostatic pressure. In addition, the evolution of a broader pore size distribution with peaks at pores larger than 4 μm was found. The pore size distributions of the samples pressed by C-CIP at increasing pressure were narrower, with higher peaks at smaller pore sizes in the area of 2.5 μm. It was shown that utilizing cycling pressurization enables tailoring of pore sizes in carbon-bonded refractories as well, providing a powerful tool for the material design of refractories.

This work aimed to assess how recycled fired clay brick affects the physical, microstructural and compressive strengths of volcanic ash based geopolymer materials made in an acidic environment. The volcanic ash was substituted with 0, 10, 20, 30 and 40 wt.% of recycled fired clay brick powder. A phosphoric acid solution with a molarity of 10 M is utilised as hardener. When the amount of recycled fired clay brick is increased from 0 to 40 wt.%, the compressive strengths of the geopolymer materials rise from 23.19 to 62.22 MPa, water absorption and porosity decrease from 7.73 to 5.96% and from 13.66 to 11.61%, respectively. The compact and dense microstructures can be observed on the micrographies of the acid-based geopolymer materials. It can be concluded that incorporation of recycled bricks into volcanic ash improves cohesion between the two aluminosilicate sources in the presence of phosphoric acid, resulting in higher compressive strength of acid-based geopolymers.

Laser-Induced Forward Transfer (LIFT) is a widely used laser-based technique intended to print materials without modifying their properties. One of the main advantages of this transfer technique is that, properly setting the laser parameters and the structure of the donor substrate, materials with different rheology and even physical state can be printed, ranging from low viscosity newtonian fluids to solid state materials. On the other hand, Blister-Assisted Laser-Induced Forward Transfer (BA-LIFT) is a variant of the standard LIFT, wherein a polyimide layer is interposed between the donor substrate and the material to be printed. This configuration eliminates direct laser-material interaction, thereby mitigating photothermal degradation and, in particular in the case of bioinks containing living cells, preserving cell viability. In addition, as nozzle free technologies both avoid clogging problems when ceramic particles are added in the formulation. In this study, we optimized key parameters for the fabrication of three-dimensional scaffolds composed of alginate and tri-calcium phosphate (ALG–TCP) composites using BA-LIFT. The aim was to engineer bone-mimetic constructs capable of acting as extracellular matrices that support cell adhesion and proliferation. The formulation and curing process were tailored and studied to enhance crosslinking efficiency, improving overall biocompatibility while preserving the mechanical stability in the final structure, and minimizing aggressive conditions during the curing process, allowing good cell viability in case of use the formulation to design an ink within embedded living cells. This study demonstrates that a 0.1 M CaCl₂ solution is sufficient to induced effective gelation. Furthermore, the inclusion of TCP particles (20% wt) enhanced the gelation efficiency (75–95%) via surface-mediated release of Ca 2+ ions.