Evaluating the suitability of fast sintering techniques for the consolidation of calcium phosphate scaffolds produced by DLP

Porous scaffolds were fabricated via Digital Light Processing (DLP) from beta-TCP powder and sintered by conventional sintering in air (CSA), rapid sintering in air (RSA) and pressure-less spark plasma sintering in vacuum (pl-SPS), at four different temperatures: 1200, 1300, 1400 and 1500 degrees C. Each sintering strategy resulted in scaffolds with different phase composition, microstructure and mechanical properties. Long dwell times or high temperatures were required to achieve a complete beta ->alpha transformation, and rapid cooling rates avoided the reverse transformation. The presence of graphite in the sintering chamber played a crucial role in stabilising the alpha-TCP phase, phase prevailing in SPS-treated scaffolds, hindered their densification and avoided the generation of transformation-induced cracks. All scaffolds exhibited compressive strengths within the range of cancellous bone, with the highest average value of 22 +/- 4 MPa achieved by the RSA scaffolds sintered at 1300 degrees C, thanks to their greater densification and fine microstructure.

Keywords

Scaffolds, Calcium phosphate, Mechanical properties, Digital Light Processing, Spark Plasma Sintering

Citation

JOURNAL OF THE EUROPEAN CERAMIC SOCIETY. 2023, vol. 43, issue 14, p. 6493-6503.
https://www.sciencedirect.com/science/article/pii/S0955221923004272?via%3Dihub

Document type

Peer-reviewed

Document version

Published version

Language of document

en

Document licence

Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International
http://creativecommons.org/licenses/by-nc-nd/4.0/