2025
S. Candela; J. Ottelin; J. Hongisto; H. Lehtonen; A. De Marzi; A. Campagnolo; C. Scian; R. Dima
W-Ta alloys processed by laser-based powder bed fusion: How microstructure and properties change with ta concentration Journal Article
In: International Journal of Refractory Metals and Hard Materials, pp. 107324, 2025.
Abstract | Links | BibTeX | Tags: Additive Manufacturing
@article{nokey,
title = {W-Ta alloys processed by laser-based powder bed fusion: How microstructure and properties change with ta concentration},
author = {S. Candela and J. Ottelin and J. Hongisto and H. Lehtonen and A. De Marzi and A. Campagnolo and C. Scian and R. Dima},
doi = {10.1016/j.ijrmhm.2025.107324},
year = {2025},
date = {2025-07-10},
urldate = {2025-07-10},
journal = {International Journal of Refractory Metals and Hard Materials},
pages = {107324},
abstract = {In this paper, a study of 4 tungsten‑tantalum binary alloys processed by Laser-Based Powder Bed Fusion (PBF-LB) is presented. The evolution of the microstructure and the properties of the material in dependence on the tenor of tantalum inside the alloy was investigated, selecting 0 wt%, 2.5 wt%, 7.5 wt%, and 15 wt% as the Ta concentrations. The optimal process window for each examined alloy was investigated. The introduction of tantalum in the alloy was effective in mitigating the cracks in the tungsten matrix. However, the energy provided to the material in the additive manufacturing process was also determinant for achieving an almost crack-free and low-porosity material. Moreover, the range of concentrations of Ta considered in this work allowed the authors to see that the properties of the binary alloys examined don't lead to a continuous improvement with the addition of Ta, but start decreasing for Ta contents higher than 7.5 wt%. The minimum porosity volume fraction achieved in this study was 0.7 % for the W-7.5 wt%Ta blend. The same alloy showed the highest hardness among the other materials investigated, reaching hardness values above 480 HV0.5, approximately 30 % higher than what was obtained for pure tungsten, and with a 50 % increase in the ultimate compressive strength compared to the unalloyed material. XRD analyses confirmed that the tantalum particles solubilize completely inside the tungsten matrix, assuring a good homogeneity of the composition and the absence of segregations and secondary phases inside the additively manufactured parts.},
keywords = {Additive Manufacturing},
pubstate = {published},
tppubtype = {article}
}
In this paper, a study of 4 tungsten‑tantalum binary alloys processed by Laser-Based Powder Bed Fusion (PBF-LB) is presented. The evolution of the microstructure and the properties of the material in dependence on the tenor of tantalum inside the alloy was investigated, selecting 0 wt%, 2.5 wt%, 7.5 wt%, and 15 wt% as the Ta concentrations. The optimal process window for each examined alloy was investigated. The introduction of tantalum in the alloy was effective in mitigating the cracks in the tungsten matrix. However, the energy provided to the material in the additive manufacturing process was also determinant for achieving an almost crack-free and low-porosity material. Moreover, the range of concentrations of Ta considered in this work allowed the authors to see that the properties of the binary alloys examined don't lead to a continuous improvement with the addition of Ta, but start decreasing for Ta contents higher than 7.5 wt%. The minimum porosity volume fraction achieved in this study was 0.7 % for the W-7.5 wt%Ta blend. The same alloy showed the highest hardness among the other materials investigated, reaching hardness values above 480 HV0.5, approximately 30 % higher than what was obtained for pure tungsten, and with a 50 % increase in the ultimate compressive strength compared to the unalloyed material. XRD analyses confirmed that the tantalum particles solubilize completely inside the tungsten matrix, assuring a good homogeneity of the composition and the absence of segregations and secondary phases inside the additively manufactured parts.
A. Zanini; G. Bombardelli; G. Giometti; A. De Marzi; J. Erler; D. Nissen; G. Franchin; P. Colombo
Additive Manufacturing of Multicomponent Glasses with Enhanced Optical Properties via Sol-Gel Journal Article
In: Additive Manufacturing, 2025, ISSN: 2214-8604.
Links | BibTeX | Tags: Additive Manufacturing
@article{Zanini2025,
title = {Additive Manufacturing of Multicomponent Glasses with Enhanced Optical Properties via Sol-Gel},
author = {A. Zanini and G. Bombardelli and G. Giometti and A. De Marzi and J. Erler and D. Nissen and G. Franchin and P. Colombo},
doi = {10.1016/j.addma.2025.104864},
issn = {2214-8604},
year = {2025},
date = {2025-06-00},
urldate = {2025-06-00},
journal = {Additive Manufacturing},
publisher = {Elsevier BV},
keywords = {Additive Manufacturing},
pubstate = {published},
tppubtype = {article}
}
A. De Marzi; F. Da Rin Betta; G. Franchin; R. M. Seabright; C. J. Footer; P. Colombo
Fabrication of continuous fiber reinforced ceramic matrix mini‐composites via direct ink writing Journal Article
In: J Am Ceram Soc., 2025, ISSN: 1551-2916.
Abstract | Links | BibTeX | Tags: Additive Manufacturing
@article{DeMarzi2025,
title = {Fabrication of continuous fiber reinforced ceramic matrix mini‐composites via direct ink writing},
author = {A. De Marzi and F. Da Rin Betta and G. Franchin and R. M. Seabright and C. J. Footer and P. Colombo},
doi = {10.1111/jace.20696},
issn = {1551-2916},
year = {2025},
date = {2025-05-26},
urldate = {2025-05-26},
journal = {J Am Ceram Soc.},
publisher = {Wiley},
abstract = {<jats:title>Abstract</jats:title><jats:p>Ceramic materials are valued for their exceptional heat and corrosion resistance, yet their inherent brittleness limits their use in applications requiring high strength‐to‐weight ratios, fatigue resistance, and durability under harsh conditions, such as those in the aerospace and automotive industries. The development of ceramic matrix composites (CMCs), incorporating continuous reinforcements, has enhanced the mechanical performance of ceramics, offering superior toughness compared to randomly oriented composites. Traditional fabrication methods for composites, such as polymer infiltration and pyrolysis (PIP) and chemical vapor infiltration (CVI), are effective but constrained by shaping complexities. Direct ink writing (DIW) has emerged as a fabrication approach for CMCs fabrication, enabling custom geometries and tailored reinforcement architectures. Extrusion‐based processes naturally align fibers, optimizing their orientation and enhancing composite properties. This study focuses on the fabrication of silicon oxycarbide matrix reinforced with continuous carbon fibers using two DIW approaches. Comparative analysis highlighted the benefits and limitations of each method, with post‐processing via PIP addressing crack formation and improving densification. Mechanical properties were evaluated at different fabrication stages, revealing key relationships between processing techniques and final composite performance.</jats:p>},
keywords = {Additive Manufacturing},
pubstate = {published},
tppubtype = {article}
}
<jats:title>Abstract</jats:title><jats:p>Ceramic materials are valued for their exceptional heat and corrosion resistance, yet their inherent brittleness limits their use in applications requiring high strength‐to‐weight ratios, fatigue resistance, and durability under harsh conditions, such as those in the aerospace and automotive industries. The development of ceramic matrix composites (CMCs), incorporating continuous reinforcements, has enhanced the mechanical performance of ceramics, offering superior toughness compared to randomly oriented composites. Traditional fabrication methods for composites, such as polymer infiltration and pyrolysis (PIP) and chemical vapor infiltration (CVI), are effective but constrained by shaping complexities. Direct ink writing (DIW) has emerged as a fabrication approach for CMCs fabrication, enabling custom geometries and tailored reinforcement architectures. Extrusion‐based processes naturally align fibers, optimizing their orientation and enhancing composite properties. This study focuses on the fabrication of silicon oxycarbide matrix reinforced with continuous carbon fibers using two DIW approaches. Comparative analysis highlighted the benefits and limitations of each method, with post‐processing via PIP addressing crack formation and improving densification. Mechanical properties were evaluated at different fabrication stages, revealing key relationships between processing techniques and final composite performance.</jats:p>
C. Gravino; N. Gargiulo; A. Peluso; P. Aprea; M. D'Agostini; G. Franchin; P. Colombo; D. Caputo
Equilibrium adsorption behaviour of a 3D-printed zeolite–geopolymer composite with high faujasitic content Journal Article
In: Mater. Adv., vol. 6, no. 8, pp. 2579–2587, 2025, ISSN: 2633-5409.
Abstract | Links | BibTeX | Tags: Additive Manufacturing, Materials for the environment
@article{Gravino2025,
title = {Equilibrium adsorption behaviour of a 3D-printed zeolite–geopolymer composite with high faujasitic content},
author = {C. Gravino and N. Gargiulo and A. Peluso and P. Aprea and M. D'Agostini and G. Franchin and P. Colombo and D. Caputo},
doi = {10.1039/d4ma01074d},
issn = {2633-5409},
year = {2025},
date = {2025-04-14},
urldate = {2025-04-14},
journal = {Mater. Adv.},
volume = {6},
number = {8},
pages = {2579--2587},
publisher = {Royal Society of Chemistry (RSC)},
abstract = {<jats:p>A potential CO<jats:sub>2</jats:sub> and water vapour adsorbent made of a NaX zeolite/Na-activated geopolymer composite material was fabricated as 3D-printed monoliths by means of Direct Ink Writing.</jats:p>},
keywords = {Additive Manufacturing, Materials for the environment},
pubstate = {published},
tppubtype = {article}
}
<jats:p>A potential CO<jats:sub>2</jats:sub> and water vapour adsorbent made of a NaX zeolite/Na-activated geopolymer composite material was fabricated as 3D-printed monoliths by means of Direct Ink Writing.</jats:p>
Luca Pezzato; Lorena Kostelac; Lavinia Tonelli; H. Elsayed; Daniel Kajánek; E. Bernardo; Carla Martini; Manuele Dabalà; Katya Brunelli
Effect of Different Types of Glass Powders on the Corrosion and Wear Resistance of Peo Coatings Produced on 6061 Aluminum Alloy Journal Article
In: vol. 31, no. 3, pp. 636 – 653, 2025.
@article{Pezzato2025636,
title = {Effect of Different Types of Glass Powders on the Corrosion and Wear Resistance of Peo Coatings Produced on 6061 Aluminum Alloy},
author = {Luca Pezzato and Lorena Kostelac and Lavinia Tonelli and H. Elsayed and Daniel Kajánek and E. Bernardo and Carla Martini and Manuele Dabalà and Katya Brunelli},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85201818433&doi=10.1007%2fs12540-024-01786-7&partnerID=40&md5=0e6283bb5a04c16030f006fa037f4077},
doi = {10.1007/s12540-024-01786-7},
year = {2025},
date = {2025-01-01},
urldate = {2025-01-01},
volume = {31},
number = {3},
pages = {636 – 653},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Mokhtar Mahmoud; H. Elsayed; Jozef Kraxner; Martin Michálek; Beáta Pecušová; Montaha Anjass; Nikhil Arya; E. Bernardo; Dušan Galusek
In: vol. 45, no. 16, 2025.
@article{Mahmoud2025,
title = {Additive manufacturing of scaffolds from porous glass microspheres via masked stereolithography: Printing challenges and sustainable applications},
author = {Mokhtar Mahmoud and H. Elsayed and Jozef Kraxner and Martin Michálek and Beáta Pecušová and Montaha Anjass and Nikhil Arya and E. Bernardo and Dušan Galusek},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-105010023419&doi=10.1016%2fj.jeurceramsoc.2025.117651&partnerID=40&md5=9934fef58c5c274a4a22473e66ef4df9},
doi = {10.1016/j.jeurceramsoc.2025.117651},
year = {2025},
date = {2025-01-01},
urldate = {2025-01-01},
volume = {45},
number = {16},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Abel W. Ourgessa; Ahmed Gamal Abd-Elsatar; Mokhtar Mahmoud; H. Elsayed; Jozef Kraxner; Dusan Galusek; E. Bernardo
Direct ink writing of lightweight 3D structures from alkali-activated waste fiberglass and glass microsphere fillers Journal Article
In: vol. 23, 2025.
@article{Ourgessa2025,
title = {Direct ink writing of lightweight 3D structures from alkali-activated waste fiberglass and glass microsphere fillers},
author = {Abel W. Ourgessa and Ahmed Gamal Abd-Elsatar and Mokhtar Mahmoud and H. Elsayed and Jozef Kraxner and Dusan Galusek and E. Bernardo},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-105010890163&doi=10.1016%2fj.oceram.2025.100825&partnerID=40&md5=c7833a1d037a62c175dfbb7b97279d69},
doi = {10.1016/j.oceram.2025.100825},
year = {2025},
date = {2025-01-01},
urldate = {2025-01-01},
volume = {23},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Ahmed Gamal Abd-Elsatar; H. Elsayed; Onat Basak; Kamalan Mosas; Aleksandra Nowicka; Hana Kaňková; Akansha Mehta; Jozef Rahel; Jozef Kraxner; Dušan Galusek; E. Bernardo
Greener, safer, and stronger: plasma ion-exchanged pharmaceutical glass vials for precision drug delivery dosing Journal Article
In: vol. 27, 2025.
@article{GamalAbd-Elsatar2025,
title = {Greener, safer, and stronger: plasma ion-exchanged pharmaceutical glass vials for precision drug delivery dosing},
author = {Ahmed Gamal Abd-Elsatar and H. Elsayed and Onat Basak and Kamalan Mosas and Aleksandra Nowicka and Hana Kaňková and Akansha Mehta and Jozef Rahel and Jozef Kraxner and Dušan Galusek and E. Bernardo},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-105004014563&doi=10.1016%2fj.apsadv.2025.100760&partnerID=40&md5=1eb1fbc387609004ea78a5ad04f3ca88},
doi = {10.1016/j.apsadv.2025.100760},
year = {2025},
date = {2025-01-01},
urldate = {2025-01-01},
volume = {27},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Elena Colusso; H. Elsayed; Paulina Ożóg; Jozef Kraxner; Dusan Galusek; E. Bernardo
Functionalization of LCD glass for the manufacturing of advanced 3D-printed translucent photocatalytic scaffolds Journal Article
In: vol. 21, 2025.
@article{Colusso2025,
title = {Functionalization of LCD glass for the manufacturing of advanced 3D-printed translucent photocatalytic scaffolds},
author = {Elena Colusso and H. Elsayed and Paulina Ożóg and Jozef Kraxner and Dusan Galusek and E. Bernardo},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85212863800&doi=10.1016%2fj.oceram.2024.100731&partnerID=40&md5=8494fac4ad1a24c0f2dcf33448a09c19},
doi = {10.1016/j.oceram.2024.100731},
year = {2025},
date = {2025-01-01},
urldate = {2025-01-01},
volume = {21},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
J. Adrien; H. Elsayed; F. Gobbin; A. Italiano; E. Maire; P. Colombo
X-ray computed tomography investigation on the geopolymer matrix formation during the binder jetting additive manufacturing process Journal Article
In: vol. 109, 2025.
@article{Adrien2025,
title = {X-ray computed tomography investigation on the geopolymer matrix formation during the binder jetting additive manufacturing process},
author = {J. Adrien and H. Elsayed and F. Gobbin and A. Italiano and E. Maire and P. Colombo},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-105008533693&doi=10.1016%2fj.addma.2025.104852&partnerID=40&md5=707058ce0d1533ed2df797a473a11567},
doi = {10.1016/j.addma.2025.104852},
year = {2025},
date = {2025-01-01},
volume = {109},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
H. Elsayed; Sara Micheli; Franco Matias Stabile; Altan Alpay Altun; Martin Schwentenwein; Elisa Cimetta; E. Bernardo
Advanced vat photopolymerization of polymer-derived 70S30C glass-carbon nano-composites: Topological control and biological validation Journal Article
In: vol. 45, no. 11, 2025.
@article{Elsayed2025,
title = {Advanced vat photopolymerization of polymer-derived 70S30C glass-carbon nano-composites: Topological control and biological validation},
author = {H. Elsayed and Sara Micheli and Franco Matias Stabile and Altan Alpay Altun and Martin Schwentenwein and Elisa Cimetta and E. Bernardo},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-105000651134&doi=10.1016%2fj.jeurceramsoc.2025.117384&partnerID=40&md5=845e9a3bf4b6a9903efb368d0b535e00},
doi = {10.1016/j.jeurceramsoc.2025.117384},
year = {2025},
date = {2025-01-01},
urldate = {2025-01-01},
volume = {45},
number = {11},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
V. Diamanti; H. Elsayed; Tobias Fey; E. Bernardo
Effect of MgO and Al2O3 precursors on 3D-printed cordierite lattice structures by a novel emulsion-based PDC route Journal Article
In: vol. 108, no. 12, 2025.
@article{Diamanti2025,
title = {Effect of MgO and Al2O3 precursors on 3D-printed cordierite lattice structures by a novel emulsion-based PDC route},
author = {V. Diamanti and H. Elsayed and Tobias Fey and E. Bernardo},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-105008684839&doi=10.1111%2fjace.70037&partnerID=40&md5=1e4af458f86010cf642911b4066088d6},
doi = {10.1111/jace.70037},
year = {2025},
date = {2025-01-01},
urldate = {2025-01-01},
volume = {108},
number = {12},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Mattia Maltauro; Luca Grigolato; H. Elsayed; Pierandrea Dal Fabbro; Roberto Meneghello; Gianmaria Concheri; Gianpaolo Savio
A Methodological Approach for the Evaluation of Deformations in Additively Manufactured Lattice Structures Journal Article
In: pp. 225 – 234, 2025.
@article{Maltauro2025225,
title = {A Methodological Approach for the Evaluation of Deformations in Additively Manufactured Lattice Structures},
author = {Mattia Maltauro and Luca Grigolato and H. Elsayed and Pierandrea Dal Fabbro and Roberto Meneghello and Gianmaria Concheri and Gianpaolo Savio},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85219211106&doi=10.1007%2f978-3-031-76594-0_26&partnerID=40&md5=9d7c7ace321f4ba807c73b990fcd90f3},
doi = {10.1007/978-3-031-76594-0_26},
year = {2025},
date = {2025-01-01},
urldate = {2025-01-01},
pages = {225 – 234},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
W. Wang; X. Gao; X. Chen; A. De Marzi; K. Huang; R. He; P. Colombo
Zhaozhou Bridge inspired embedded material extrusion 3D printing of Csf/SiC ceramic matrix composites Journal Article
In: Journal of the American Ceramic Society, 2025.
Abstract | Links | BibTeX | Tags: Additive Manufacturing
@article{Wang2025,
title = {Zhaozhou Bridge inspired embedded material extrusion 3D printing of Csf/SiC ceramic matrix composites},
author = {W. Wang and X. Gao and X. Chen and A. De Marzi and K. Huang and R. He and P. Colombo},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-105004352294&doi=10.1111%2fjace.20644&partnerID=40&md5=1118badf05310dcb65bf4ad0c3f26423},
doi = {10.1111/jace.20644},
year = {2025},
date = {2025-01-01},
urldate = {2025-01-01},
journal = {Journal of the American Ceramic Society},
abstract = {Material extrusion (MEX) 3D printing, while effective for many applications, faces challenges in fabricating arch shapes and suspended structures. This study advances MEX technology by drawing inspiration from ancient bridge construction techniques like the Zhaozhou Bridge, using an innovative embedded material extrusion (EMEX) method that eliminates the need for additional support structures in fabricating complex short carbon fiber reinforced SiC ceramic matrix composites (Csf/SiC CMCs). Utilizing solid powders as a supporting medium, EMEX enables the creation of intricate arch shapes and suspension structures, overcoming limitations associated with conventional MEX. The impact of supporting media (SiC powders and sugar) on the microstructure and mechanical properties of the composites was demonstrated. Residual SiC powders caused uneven material distribution, while residual sugar led to cracking. The presence of residual powders also influenced the shrinkage behavior and bending strength of the Csf/SiC CMCs, with a notable decrease observed when transitioning from air to SiC powders and then to sugar as the printing environment. The successful fabrication of Csf/SiC CMCs with complex geometries using EMEX indicates its potential as a promising supportless strategy for producing sophisticated CMC structures.},
keywords = {Additive Manufacturing},
pubstate = {published},
tppubtype = {article}
}
Material extrusion (MEX) 3D printing, while effective for many applications, faces challenges in fabricating arch shapes and suspended structures. This study advances MEX technology by drawing inspiration from ancient bridge construction techniques like the Zhaozhou Bridge, using an innovative embedded material extrusion (EMEX) method that eliminates the need for additional support structures in fabricating complex short carbon fiber reinforced SiC ceramic matrix composites (Csf/SiC CMCs). Utilizing solid powders as a supporting medium, EMEX enables the creation of intricate arch shapes and suspension structures, overcoming limitations associated with conventional MEX. The impact of supporting media (SiC powders and sugar) on the microstructure and mechanical properties of the composites was demonstrated. Residual SiC powders caused uneven material distribution, while residual sugar led to cracking. The presence of residual powders also influenced the shrinkage behavior and bending strength of the Csf/SiC CMCs, with a notable decrease observed when transitioning from air to SiC powders and then to sugar as the printing environment. The successful fabrication of Csf/SiC CMCs with complex geometries using EMEX indicates its potential as a promising supportless strategy for producing sophisticated CMC structures.
G. Tameni; D. Lago; H. Kaňková; L. Buňová; J. Kraxner; D. Galusek; D. M. Dawson; S. E. Ashbrook; E. Bernardo
Alkaline attack of boro-alumino-silicate glass: New insights of the molecular mechanism of cold consolidation and new applications Journal Article
In: Open Ceramics, vol. 21, 2025, (Cited by: 0; All Open Access, Gold Open Access).
Links | BibTeX | Tags: Materials for the environment
@article{Tameni2025,
title = {Alkaline attack of boro-alumino-silicate glass: New insights of the molecular mechanism of cold consolidation and new applications},
author = {G. Tameni and D. Lago and H. Kaňková and L. Buňová and J. Kraxner and D. Galusek and D. M. Dawson and S. E. Ashbrook and E. Bernardo},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85213004207&doi=10.1016%2fj.oceram.2024.100726&partnerID=40&md5=00a43152438bfcaacfcd8003f6f709c4},
doi = {10.1016/j.oceram.2024.100726},
year = {2025},
date = {2025-01-01},
urldate = {2025-01-01},
journal = {Open Ceramics},
volume = {21},
note = {Cited by: 0; All Open Access, Gold Open Access},
keywords = {Materials for the environment},
pubstate = {published},
tppubtype = {article}
}
V. Diamanti; H. Elsayed; E. Bernardo
3D-printed porous mullite lattice structures by hybrid direct ink writing of silicone suspension-emulsions Journal Article
In: Journal of the American Ceramic Society, vol. 108, no. 4, pp. e20290, 2025.
Abstract | Links | BibTeX | Tags: Additive Manufacturing
@article{https://doi.org/10.1111/jace.20290,
title = {3D-printed porous mullite lattice structures by hybrid direct ink writing of silicone suspension-emulsions},
author = {V. Diamanti and H. Elsayed and E. Bernardo},
url = {https://ceramics.onlinelibrary.wiley.com/doi/abs/10.1111/jace.20290},
doi = {https://doi.org/10.1111/jace.20290},
year = {2025},
date = {2025-01-01},
urldate = {2025-01-01},
journal = {Journal of the American Ceramic Society},
volume = {108},
number = {4},
pages = {e20290},
abstract = {Abstract Silicones added with nano-sized alumina particles are already known as starting materials for phase pure mullite ceramics, synthesized at quite low temperatures. The present paper deals with a fundamental upgrade, based on a novel suspension-emulsion concept, for the easy fabrication of highly porous lattice structures. An aqueous suspension of γ-Al2O3 nanoparticles in water was first distributed as emulsion within an “oily phase,” consisting of a silicone/acrylates blend, with the help of a surfactant. The mixture was later employed to fabricate highly porous structures (∼80% open porosity), by direct ink writing, that is, an extrusion-based 3D printing technology requiring specific rheological behavior of the feedstock ink. Finally, the structures were rapidly stabilized through a photo-polymerization step (configuring a form of “hybrid” direct ink writing). The presence of water also allowed the application of a freeze-curing procedure, for a second series of samples. The abundant water vapor release from the starting mixtures, upon firing (up to 1300°C), led to structures with enhanced pore interconnectivity. The freeze-curing protocol proved beneficial to the homogeneity of pore distribution and to the achievement of high strength-to-density ratios.},
keywords = {Additive Manufacturing},
pubstate = {published},
tppubtype = {article}
}
Abstract Silicones added with nano-sized alumina particles are already known as starting materials for phase pure mullite ceramics, synthesized at quite low temperatures. The present paper deals with a fundamental upgrade, based on a novel suspension-emulsion concept, for the easy fabrication of highly porous lattice structures. An aqueous suspension of γ-Al2O3 nanoparticles in water was first distributed as emulsion within an “oily phase,” consisting of a silicone/acrylates blend, with the help of a surfactant. The mixture was later employed to fabricate highly porous structures (∼80% open porosity), by direct ink writing, that is, an extrusion-based 3D printing technology requiring specific rheological behavior of the feedstock ink. Finally, the structures were rapidly stabilized through a photo-polymerization step (configuring a form of “hybrid” direct ink writing). The presence of water also allowed the application of a freeze-curing procedure, for a second series of samples. The abundant water vapor release from the starting mixtures, upon firing (up to 1300°C), led to structures with enhanced pore interconnectivity. The freeze-curing protocol proved beneficial to the homogeneity of pore distribution and to the achievement of high strength-to-density ratios.
L. Lattanzi; A. Conte; A. Sin; J. M. Garcia; C. A. Randall; P. Colombo
Cold sintering of geopolymer powders Journal Article
In: Journal of the American Ceramic Society, vol. 108, no. 4, pp. e20331, 2025.
Abstract | Links | BibTeX | Tags: Materials for the environment
@article{https://doi.org/10.1111/jace.20331,
title = {Cold sintering of geopolymer powders},
author = {L. Lattanzi and A. Conte and A. Sin and J. M. Garcia and C. A. Randall and P. Colombo},
url = {https://ceramics.onlinelibrary.wiley.com/doi/abs/10.1111/jace.20331},
doi = {https://doi.org/10.1111/jace.20331},
year = {2025},
date = {2025-01-01},
urldate = {2025-01-01},
journal = {Journal of the American Ceramic Society},
volume = {108},
number = {4},
pages = {e20331},
abstract = {Abstract Geopolymers (GP) represent a promising class of inorganic materials with diverse applications due to their properties, including high temperature resistance and strong interfacial bonding ability. They are produced through alkali activation of aluminosilicate sources, such as metakaolin or fly ashes. Despite their attractive characteristics, conventional casting methods for GP production often result in prolonged curing times and inferior mechanical properties to OPC or other benchmark materials. In this study, we investigated the feasibility of rapidly densifying GP matrices using cold sintering technology (CSP), a novel approach previously employed in ceramic systems. Through CSP, it was possible to obtain a dense body starting from GP sodium-based powder with optimal moisture content (10% wt.) under mild isostatic pressure (70 MPa) and moderate temperature (150°C) conditions, with a short duration process (10 min). The resulting products exhibited chemical stability (high resistance to boiling test), high density (> 90% theoretical density) and good mechanical properties (flexural strength equal to 30 MPa and compressive strength over 200 MPa) without requiring additional thermal treatments. SEM, EDS and NMR studies indicated that the predominant densification mechanism was likely to be homogeneous dissolutions and precipitation of the material, consistent with pressure solution creep. Dilatometric tests were performed to track the densification process in real-time and to determine the activation energy, which revealed an exceptionally low value for the system (21.7 kJ/mol). Our results demonstrate the potential of CSP as a rapid and efficient method for producing high-quality GP-based components, paving the way for their broader application in various fields.},
keywords = {Materials for the environment},
pubstate = {published},
tppubtype = {article}
}
Abstract Geopolymers (GP) represent a promising class of inorganic materials with diverse applications due to their properties, including high temperature resistance and strong interfacial bonding ability. They are produced through alkali activation of aluminosilicate sources, such as metakaolin or fly ashes. Despite their attractive characteristics, conventional casting methods for GP production often result in prolonged curing times and inferior mechanical properties to OPC or other benchmark materials. In this study, we investigated the feasibility of rapidly densifying GP matrices using cold sintering technology (CSP), a novel approach previously employed in ceramic systems. Through CSP, it was possible to obtain a dense body starting from GP sodium-based powder with optimal moisture content (10% wt.) under mild isostatic pressure (70 MPa) and moderate temperature (150°C) conditions, with a short duration process (10 min). The resulting products exhibited chemical stability (high resistance to boiling test), high density (> 90% theoretical density) and good mechanical properties (flexural strength equal to 30 MPa and compressive strength over 200 MPa) without requiring additional thermal treatments. SEM, EDS and NMR studies indicated that the predominant densification mechanism was likely to be homogeneous dissolutions and precipitation of the material, consistent with pressure solution creep. Dilatometric tests were performed to track the densification process in real-time and to determine the activation energy, which revealed an exceptionally low value for the system (21.7 kJ/mol). Our results demonstrate the potential of CSP as a rapid and efficient method for producing high-quality GP-based components, paving the way for their broader application in various fields.
S. Bhandari; T. Heim; E. De Bona; V. M. Sglavo; W. Rheinheimer; M. Biesuz; G. Franchin
Rapid processing of Al2O3 ceramics by fused filament fabrication and ultrafast high-temperature debinding and sintering Journal Article
In: Journal of Alloys and Compounds, pp. 178812, 2025, ISSN: 0925-8388.
Abstract | Links | BibTeX | Tags: Additive Manufacturing
@article{BHANDARI2025178812,
title = {Rapid processing of Al2O3 ceramics by fused filament fabrication and ultrafast high-temperature debinding and sintering},
author = {S. Bhandari and T. Heim and E. De Bona and V. M. Sglavo and W. Rheinheimer and M. Biesuz and G. Franchin},
url = {https://www.sciencedirect.com/science/article/pii/S0925838825003706},
doi = {https://doi.org/10.1016/j.jallcom.2025.178812},
issn = {0925-8388},
year = {2025},
date = {2025-01-01},
urldate = {2025-01-01},
journal = {Journal of Alloys and Compounds},
pages = {178812},
abstract = {Fused filament fabrication (FFF) is widely used for ceramic prototyping due to its compatibility with low-cost, custom-made printers designed for polymers. However, the bottleneck of the whole process lies in the slow thermal debinding and sintering that are usually employed to obtain dense and defect-free ceramics. In this study, a filament with ~79wt.% alumina powder in a thermoplastic binder was used to print gyroid structures with nozzle diameters of 0.4, 0.6, and 0.8mm. The components were at first partially solvent-debinded (acetone) and thereafter thermally debinded and consolidated in a single step (60s) by ultra-fast high-temperature sintering. Samples printed with a 0.4mm nozzle diameter resisted the ultra-rapid heating (UHS) and cooling rates (~103K/min), whereas some defects appear when considering larger nozzle size. On the other hand, all samples either cracked or shattered into pieces when fast-fired in air, highlighting the relevance of the thermal debinding atmosphere. Moreover, the densification upon UHS was largely improved compared to conventional sintering while retaining a finer grain size. This work provides a guideline for the rapid debinding and firing of fused filament fabricated ceramics and could be easily extended to other ceramic systems.},
keywords = {Additive Manufacturing},
pubstate = {published},
tppubtype = {article}
}
Fused filament fabrication (FFF) is widely used for ceramic prototyping due to its compatibility with low-cost, custom-made printers designed for polymers. However, the bottleneck of the whole process lies in the slow thermal debinding and sintering that are usually employed to obtain dense and defect-free ceramics. In this study, a filament with ~79wt.% alumina powder in a thermoplastic binder was used to print gyroid structures with nozzle diameters of 0.4, 0.6, and 0.8mm. The components were at first partially solvent-debinded (acetone) and thereafter thermally debinded and consolidated in a single step (60s) by ultra-fast high-temperature sintering. Samples printed with a 0.4mm nozzle diameter resisted the ultra-rapid heating (UHS) and cooling rates (~103K/min), whereas some defects appear when considering larger nozzle size. On the other hand, all samples either cracked or shattered into pieces when fast-fired in air, highlighting the relevance of the thermal debinding atmosphere. Moreover, the densification upon UHS was largely improved compared to conventional sintering while retaining a finer grain size. This work provides a guideline for the rapid debinding and firing of fused filament fabricated ceramics and could be easily extended to other ceramic systems.
S. Bhandari; O. Hanzel; M. Kermani; V. M. Sglavo; M. Biesuz; G. Franchin
Rapid debinding and sintering of alumina ceramics fabricated by direct ink writing Journal Article
In: Journal of the European Ceramic Society, vol. 45, no. 5, pp. 117144, 2025, ISSN: 0955-2219.
Abstract | Links | BibTeX | Tags: Additive Manufacturing
@article{BHANDARI2025117144,
title = {Rapid debinding and sintering of alumina ceramics fabricated by direct ink writing},
author = {S. Bhandari and O. Hanzel and M. Kermani and V. M. Sglavo and M. Biesuz and G. Franchin},
url = {https://www.sciencedirect.com/science/article/pii/S0955221924010173},
doi = {https://doi.org/10.1016/j.jeurceramsoc.2024.117144},
issn = {0955-2219},
year = {2025},
date = {2025-01-01},
urldate = {2025-01-01},
journal = {Journal of the European Ceramic Society},
volume = {45},
number = {5},
pages = {117144},
abstract = {Direct ink writing (DIW) is a widely used additive manufacturing technique to fabricate complex-shaped ceramics. Unlike vat photopolymerization or fused filament fabrication, the limited amount of binder in DIW facilitates rapid debinding. In this study, alumina inks with suitable rheology were prepared with two different ceramic loadings (42.8 vol% and 48.1 vol%). Subsequently, log-pile structures were printed using two different nozzle diameters (0.41 mm and 0.84 mm). The fabricated samples were dried at room temperature and subjected to different rapid sintering procedures: ultra-fast high temperature sintering (UHS), pressureless spark plasma sintering (PSPS) and fast-firing (FF). Both UHS and PSPS successfully densified the samples in Ar without any defects. Conversely, the fast-firing in air resulted in some cracks, with the intensity of failures increasing with the nozzle size. UHS and PSPS allowed for nearly fully dense materials with refined microstructure which are not achievable by conventional heating.},
keywords = {Additive Manufacturing},
pubstate = {published},
tppubtype = {article}
}
Direct ink writing (DIW) is a widely used additive manufacturing technique to fabricate complex-shaped ceramics. Unlike vat photopolymerization or fused filament fabrication, the limited amount of binder in DIW facilitates rapid debinding. In this study, alumina inks with suitable rheology were prepared with two different ceramic loadings (42.8 vol% and 48.1 vol%). Subsequently, log-pile structures were printed using two different nozzle diameters (0.41 mm and 0.84 mm). The fabricated samples were dried at room temperature and subjected to different rapid sintering procedures: ultra-fast high temperature sintering (UHS), pressureless spark plasma sintering (PSPS) and fast-firing (FF). Both UHS and PSPS successfully densified the samples in Ar without any defects. Conversely, the fast-firing in air resulted in some cracks, with the intensity of failures increasing with the nozzle size. UHS and PSPS allowed for nearly fully dense materials with refined microstructure which are not achievable by conventional heating.
S. Bhandari; G. Vajpayee; L. Lemos Silva; M. Hinterstein; G. Franchin; P. Colombo
A review on additive manufacturing of piezoelectric ceramics: From feedstock development to properties of sintered parts Journal Article
In: Materials Science and Engineering: R: Reports, vol. 162, pp. 100877, 2025, ISSN: 0927-796X.
Abstract | Links | BibTeX | Tags: Additive Manufacturing
@article{BHANDARI2025100877,
title = {A review on additive manufacturing of piezoelectric ceramics: From feedstock development to properties of sintered parts},
author = {S. Bhandari and G. Vajpayee and L. Lemos Silva and M. Hinterstein and G. Franchin and P. Colombo},
url = {https://www.sciencedirect.com/science/article/pii/S0927796X24001074},
doi = {https://doi.org/10.1016/j.mser.2024.100877},
issn = {0927-796X},
year = {2025},
date = {2025-01-01},
urldate = {2025-01-01},
journal = {Materials Science and Engineering: R: Reports},
volume = {162},
pages = {100877},
abstract = {Piezoelectric ceramics are extensively used in several engineering applications in the field of sensors, actuators, energy harvesting, biomedical, and many more. Traditional ways of manufacturing piezoelectric devices result in better piezoelectric/ferroelectric performance. However, they are restricted to only simple shapes. With the widespread influence of additive manufacturing (AM), it is now possible to fabricate complex structures which were not possible by conventional technologies. In order to fabricate such complex structures with precision, it is necessary to understand in detail the factors influencing the feedstock preparation and the challenges associated with different AM technologies. With an emphasis on the most commonly used AM techniques (direct ink writing, fused filament fabrication, vat photopolymerization, binder jetting, and selective laser sintering) for fabricating ceramic parts, this review paper intends to provide a deep insight into the factors affecting the feedstock preparation as well as post-processing conditions required to develop a high-performance piezoelectric device. The summarized tables detailing the various piezoelectric ceramic compositions and additives or ingredients used in formulating a printable feedstock, along with the optimum printing and post-processing conditions, will aid the readers in developing their own printable formulations and determining the best post-processing parameters to achieve the best performance out of the fabricated piezoelectric device. The advantages and disadvantages of the AM technologies are analyzed with specific reference to piezoceramic materials and the remaining challenges that require further research are emphasized. Furthermore, with the ongoing and continuous developments in additive manufacturing of piezoelectric materials, it is expected that such advancements will progressively transition towards commercialization, with the ultimate goal of widely incorporating additively manufactured devices into practical applications.},
keywords = {Additive Manufacturing},
pubstate = {published},
tppubtype = {article}
}
Piezoelectric ceramics are extensively used in several engineering applications in the field of sensors, actuators, energy harvesting, biomedical, and many more. Traditional ways of manufacturing piezoelectric devices result in better piezoelectric/ferroelectric performance. However, they are restricted to only simple shapes. With the widespread influence of additive manufacturing (AM), it is now possible to fabricate complex structures which were not possible by conventional technologies. In order to fabricate such complex structures with precision, it is necessary to understand in detail the factors influencing the feedstock preparation and the challenges associated with different AM technologies. With an emphasis on the most commonly used AM techniques (direct ink writing, fused filament fabrication, vat photopolymerization, binder jetting, and selective laser sintering) for fabricating ceramic parts, this review paper intends to provide a deep insight into the factors affecting the feedstock preparation as well as post-processing conditions required to develop a high-performance piezoelectric device. The summarized tables detailing the various piezoelectric ceramic compositions and additives or ingredients used in formulating a printable feedstock, along with the optimum printing and post-processing conditions, will aid the readers in developing their own printable formulations and determining the best post-processing parameters to achieve the best performance out of the fabricated piezoelectric device. The advantages and disadvantages of the AM technologies are analyzed with specific reference to piezoceramic materials and the remaining challenges that require further research are emphasized. Furthermore, with the ongoing and continuous developments in additive manufacturing of piezoelectric materials, it is expected that such advancements will progressively transition towards commercialization, with the ultimate goal of widely incorporating additively manufactured devices into practical applications.