Processing of thermoplastic suspensions for additive manufacturing of ceramic- and metal-ceramic-composites by thermoplastic 3D-printing (T3DP)
Our new approach in the field of Additive Manufacturing (AM) - thermoplastic 3D printing (T3DP) - is presented. High-filled ceramic and metal feedstocks, based on thermoplastic binder systems, were used for AM of dense ceramic components and metal-ceramic-composites. Compared to other AM methods, the developed T3DP method has outstanding advantages. Two benefits can be highlighted. The first one concerns the portfolio of applicable materials, which is not limited. The second one refers to the process, which works nearly independent from the physical properties of the dispersed powder material. The application of T3DP in principle was demonstrated by samples, made of alumina and zirconia as well as stainless steel-zirconia composites. Different feedstocks with high powder contents up to 67 vol.-% were prepared. For the sintered samples a density of about 99% and higher was obtained. FESEM studies of the samples' cross-section presented a homogenous microstructure. With regard to steel-zirconia composites, the adjustment of the sintering shrinkage behavior was the main challenge. The sinterability of the metal powder could be increased by high energy milling and an adjustment of the powder content. The adapted AM method of T3DP offers new prospects for fabrication of multi-material components. This AM method will be applicable not only for steel-zirconia composites, but also for any other combination of materials which can be processed to a paraffin based thermoplastic feedstock and which can be co-sintered.