Additive manufacturing of zirconia parts via selective laser sintering combined with cold isostatic pressing

Abstract

Zirconia has great application prospect for its excellent properties in the industrial production. But due to high brittleness and hardness, complex shape zirconia parts are often difficult to form and machine. To obtain complex zirconia parts, nano-zirconia powder is coated by the binder nylon 12 by solvent precipitation method. Coated powder is then formed via selective laser sintering (SLS) combined with cold isostatic pressing (CIP). Through the experiment, when laser energy density is 0.415 J/mm2, SLS ceramics had the biggest density. The subsequent 200 MPa CIP process is carried out on SLS parts with different laser energy density. According to the thermal debinding mechanism and TG curve of the binder, the reasonable thermal debinding process is formulated respectively. After furnace sintering (FS), with the steps of subsequent processing increased, parts affected by the SLS forming process gradually weakened, the largest relative density and Vickers hardness of SLS/CIP/FS parts are respectively 97% and 1180 HV1, radial and axial shrinkage rate were 58.1% and 67.8% respectively, and fracture of specimens are analysed by scanning electron microscope (SEM). Although the final density and hardness of the ZrO2 are still to be improved, a potential technical method for manufacturing complex zirconia parts with high performance is provided.