Effect of different silica particles on flowability of gypsum powder for 3D powder printing

摘要

3D powder printing (3DPP) attracts much attention in the field of construction and decoration. However, the strong hygroscopicity and high tendency to agglomerate of gypsum powder give rise to a poor flowability, which is crucial during large-size 3DPP procedure. This study aims to compare gliding effect of silica particles with different sizes, shapes and surface properties on poor-flow gypsum powder. Angle of repose (AOR), flow rate of the modified powders and surface morphology of the modified particles were evaluated. The results showed that silica particles of different hydrophobicity presented various extent of glidant effect. For hydrophobic nanosilica, an optimum content (1.0 wt% in this study) could best minimize AOR of the modified powder, leading to more smooth and voidless powder bed of gypsum powder than unmodified gypsum powder. The research found an optimum glidant which could improve the flowability of gypsum powder, resulting in good quality during 3DPP procedure. (C) 2019 Elsevier Ltd. All rights reserved.