This work demonstrates the suitability of using Direct Ink Writing (DIW) in combination with pressureless Spark Plasma Sintering (SPS) for the fabrication of complex parts of ultra-high temperature ceramic materials with applications in aerospace and energy generation industries. First, a colloidal suspension was prepared from a homogeneous mixture of commercial ZrB2 and MoSi2 powders in distilled water. The resulting ink was optimized (i.e., deflocculant content and solid load) to have rheological properties suitable for DIW extrusion.
Printing parameters for these inks were optimized and complex parts with internal channels were produced by DIW to demonstrate the capabilities of this fabrication technique. Such channeled parts might find applications as heat exchangers or thermal shields in aerospace and energy-related applications.
Debinding and sintering treatments were optimized to avoid the appearance of cracks and pores. A fast energy-efficient sintering processes like pressureless spark plasma sintering (SPS) was selected for densifying the samples avoiding the application of deleterious loads on the sample.
The density of the resulting materials was evaluated as a function of the selected sintering temperature and a thorough microstructural and mechanical characterization of the fabricated elements was performed. The results obtained demonstrate the suitability of the selected combination of manufacturing techniques for obtaining complex parts from ultra-high temperature ceramics which might find novel applications within the aerospace and energy generation industries.