3D printing of high solid loading zirconia feedstock via screw-based material extrusion

Zirconia ceramic (3Y-TZP) feedstocks with solid loadings from 50 vol% to 68 vol%, in a 60:40 paraffin wax to LDPE ratio binder system, were prepared and printed using a screw-based material extrusion printer. A two-step debinding process involving solvent debinding (cyclohexane + ethanol) and thermal debinding (140 degrees C-600 degrees C at 0.2 degrees C/min) followed by sintering at 1500 degrees C for 2 h was employed. Tests performed include TGA, density test, Vickers hardness and fracture toughness, XRD, and SEM. The TGA result showed two significant drops in weight starting at 180 degrees C and 380 degrees C, which corresponds to the decomposition of paraffin wax and LDPE, respectively. A minimum of 40 wt% of soluble binder was removed from the green sample after solvent immersion for 3 h at 40 degrees C for solid loadings & GE;55 vol%. High solid loading feedstocks produced samples with comparable density, Vickers hardness and fracture toughness, which are 97.5%,-12.3 GPa, and-5.5 MPa m1/2, respectively; while XRD and SEM shows no adverse tetragonal to monoclinic phase transformation and grain growth, respectively. This study demonstrates that 3D printing of granular 3Y-TZP ceramic feedstock via screw-based material extrusion technique is feasible even with high solid loadings, which is usually difficult to fabricate into flexible filaments and print due to high viscosity.

Automated summary

In this study, 3Y-TZP ceramic feedstocks with different solid loadings were successfully prepared and printed using a screw-based 3D printing technique. The samples obtained after debinding and sintering showed desired density, hardness, and fracture toughness. The results demonstrated the feasibility of 3D printing granular 3Y-TZP ceramic feedstocks with high solid loadings.