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

• Main Authors: Lim I.Y., Ting C.H., Ng C.K., Tey J.Y., Yeo W.H., S R., Lee K.Y.S., Chuah Y.D., Teng W.D.
• Other Authors: 58203510000
• Format: Article
• Published: Elsevier Ltd 2024
• Subjects: Additive manufacturing; Debinding defects; Mechanical properties; ZrO₂ feedstock; 3D printing; Ductile fracture; Extrusion; Fracture toughness; Grain growth; Organic solvents; Paraffins; Screws; Sintering; Vickers hardness; X ray diffraction; Zirconia; 3-D printing; 3D-printing; Debinding; Debinding defect; High solid loading; Solid loading; Vicker hardness; XRD; Zirconia ceramic; ZrO2 feedstock; Feedstocks

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 �C�600 �C at 0.2 �C/min) followed by sintering at 1500 �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 �C and 380 �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 �C for solid loadings ?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