Processing of Thermoplastic Suspensions for Additive Manufacturing of Ceramic‐and Metal‐Ceramic‐Composites by Thermoplastic 3D‐Printing (T3DP)

Abstract

In our study we investigated the additive manufacturing (AM) of ceramic-based 11 Functionally Graded Materials (FGM) by the direct AM technology Thermoplastic 3D-Printing 12 (T3DP). Zirconia components with a varying microstructure were additively manufactured by 13 using thermoplastic suspensions with different contents of pore forming agents (PFA) and were co-14 sintered defect-free. 15 Different materials were investigated concerning their suitability as PFA for the T3DP process. 16 Different zirconia-based suspensions were prepared and used for AM of single-and multi-material 17 test components. All samples were sintered defect-free and in the end we could realize a brick wall-18 like component consisting of dense (<1% porosity) and porous (approx. 5% porosity) zirconia areas 19 to combine different properties in one component. 20 The T3DP opens the door to AM of further ceramic-based 4D-components like multi-color or multi-21 material, especially multi-functional components. 22

Fused Filament Fabrication (FFF) of Metal-Ceramic Components

“…By using the mentioned materials and methods, it is possible to manufacture macroscopic defect-free parts by FFF for the first time. To the authors' knowledge, no other comparable AM method is known to manufacture such parts except for T3DP 19,20 . One application for metal ceramic components is shown in Figure 17, which is a heating element with an electrical conducting looped stainless steel in an isolating zirconia matrix.…”

“…Secondly during the high energy milling step (planetary ball milling, PBM), the brittle flakes will be broken into very fine-grained particles with an increased sintering ability. In this way, increased sintering activity of the metallic powder can be reached and the shrinking curve could be adjusted to the curve of zirconia, showing only small differences 19,20 . 1.…”

“…An additional benefit of FFF and T3DP compared to LCM is the use of thermoplastic binder systems instead of photo-curing polymers. The binder system enables the processing of powders independent of their optical properties such as absorption, emission and reflection of electromagnetic waves, e.g., dark and bright materials (in visible range), which is necessary for the production of metal-ceramic components 19,20 . Furthermore, low investment is required for the FFF equipment since a large variety of standard devices are available.…”

“…11 x 10 -6 /K) and can be sintered at the same conditions (reducing hydrogen atmosphere, sintering temperature: 1350 -1400 °C). However, for adjusting the shrinkage behavior, a special milling procedure for the metallic powder is required 19,20 .…”

Multi-material Ceramic-Based Components &#8211; Additive Manufacturing of Black-and-white Zirconia Components by Thermoplastic 3D-Printing (CerAM - T3DP)

“…The video component of this article can be found at https://www.jove.com/video/57538/ 14,15,16,17 . CerAM -T3DP is based on the selective deposition of single droplets of particle filled thermoplastic suspensions.…”