Rheological characterization of pastes of alumina-toughened zirconia with additions of carbon nanofibers and evaluation of their printability via material extrusion

• Published in: Journal of manufacturing processes 2024-12, Vol.131, p.1784-1801
• Main Authors: dos Santos, Vivian Inês, Fredel, Márcio Celso, Costa de Matos, Rafael, Henriques, Bruno, Gremillard, Laurent
• Format: Article
• Language: English
• Subjects: Additive manufacturing; Alumina-toughened zirconia; Carbon nanofibers; Engineering Sciences; Material extrusion; Printability
• ISSN: 1526-6125; 1526-6125
• DOI: 10.1016/j.jmapro.2024.09.094

The field of rheology is vast and often overlooked, even in closely related areas such as additive manufacturing through the Material Extrusion technique of Direct Ink Writing (DIW or Robocasting). Hence, this study provides a comprehensive characterization of pastes consisting of alumina-toughened zirconia (ATZ) powder, a deflocculant, a binder, deionized water and, in some cases, carbon nanofibers (CNFs). The rheological behavior and fundamental properties of these pastes were determined and printability tests were conducted. The results were compared to established printability criteria/parameters outlined in existing literature (ф, K and FTI). These criteria were found to be suitable for assessing printability, although they presented some limitations in predicting some unprintable pastes. Furthermore, a new criterion based on the recovery rate was introduced, with the potential to predict printability with a single test. Overall, these findings shed light on the rheology field which is increasingly recognized as important by the research community and whose thorough understanding can unlock the potential to create more intricate pastes capable of constructing more elaborate structures. [Display omitted] •Comprehensive characterization of alumina-toughened zirconia (ATZ) pastes.•Discussion of the rheological effect of the addition of carbon nanofibers.•Comparison to established printability parameters in the literature (ф, K and FTI).•New printability parameter proposed based on the recovery rate of storage modulus.•Potential to predict printability with a single rheological test.