Three-dimensional printing of flash-setting calcium aluminate cement

Three-dimensional indirect printing of flash-setting calcium aluminate cement (CAC) was investigated. Upon water injection into a biphasic mixture of tricalcium aluminate (3CaO center dot Al(2)O(3)) and dodecacalcium heptaaluminate (12CaO center dot 7Al(2)O(3)) (phase ratio 0.56/0.44) initially a gel formed acting as a bonding phase which stabilizes the printed object geometry. Post-exposure in water finally resulted in the formation of 2CaO center dot Al(2)O(3)center dot 8H(2)O and 4CaO center dot Al(2)O(3)center dot 19H(2)O reaction phases as confirmed by SEM, X-ray diffraction, and FTIR analyses. Reduction of porosity by volume expansion upon hydrolysis reaction from 50% after printing to 20% after post-treatment gave rise for an increase of compressive strength from 5 to 20 MPa, respectively. A bone regenerating scaffold for a micro-vascular loop model was fabricated by 3D printing and hydraulic reaction bonding to demonstrate the potential of using flash-setting calcium aluminate cement powder for biomedical ceramic applications.