Direct Ink Writing 3D Printing of Graphene/Al₂O₃ Composite Ceramics with Gradient Mechanics

A new graphene (G)/Al₂O₃ composite ceramic with tunable mechanics is prepared by direct ink writing (DIW) 3D-printing technology. It is found that the bending strength, fracture toughness, and hardness all increase with increasing in content of G. The bending strength, fracture toughness, and hardness of G/Al₂O₃ composite ceramic (4.0 wt‰) are improved to be 45.0%, 40.6%, and 21.9% comparing to Al₂O₃ ceramic, respectively. The result is attributed to good reinforcement of G and inhibition of Al₂O₃ phase growth by G. Furthermore, the gear wheel with gradient mechanics is also designed and fabricated by the DIW 3D-printing technology from various G/Al₂O₃ composite gels. It exhibits excellent wear resistance and low generation of heat during rotational friction. Herein, a new method is provided to fabricate G-based ceramics with gradient structure and mechanics for various applications.