Studies on thermoplastic 3D printing of steel–zirconia composites

Additive manufacturing (AM) opens new possibilities for functionalization and miniaturization of components in many application fields. Different technologies are known to produce single- or multimaterial components from polymer ceramic or metal. Our new approach — thermoplastic 3D printing — makes it possible to produce metal–ceramic composites. High-filled metal and ceramic suspensions based on thermoplastic binder systems were used as they solidify by cooling. Hence, the portfolio of applicable materials is not limited. Paraffin-based thermoplastic feedstocks with stainless steel powder (17-4PH) and zirconia powder (TZ-3Y-E) were developed with an adapted powder content of 47 vol% steel and 45 vol% zirconia. As compared to other AM technologies, the suspensions were only applied at particular points and areas and not on the whole layer. The printed samples were conventionally debinded and sintered. FESEM studies of the cross-section of the sintered samples showed a homogenous, dense microstructure and a very good connection between the different materials and layers.