Rheological Properties of Aqueous Si3N4 and MoSi2 Suspensions Tailor-Made for Direct Inkjet Printing
Abstract:The aim of this study was to reveal the feasibility of adjusting aqueous nonoxide ceramic inks for producing complex-shaped functional ceramic parts by direct inkjet printing using the example of silicon nitride (Si3N4) and molybdenum disilicide (MoSi2). In a first step, aqueous Si3N4 and MoSi2 suspensions with high solid contents were prepared by the addition of organic and inorganic additives to meet the requirements regarding rheological properties of the printing system. For this purpose, viscosity, zeta potential, and surface tension were adjusted. Because of the physical conditions of the printing head, the particle size distribution of the suspensions was optimized. The experiments were verified by calculating the Ohnesorge number of suspensions. The results show that the values fit well into the required range. Printing of 3D-components and Si3N4/MoSi2 multilayers was carried out. Optimal performance and control of the printing process resulted in fabrication of homogeneous green bodies without delaminations or other process-dependent defects.
Document Type: Research Article
Affiliations: Department of Ceramics and Refractory Materials, RWTH Aachen University, 52064 Aachen, Germany
Publication date: January 1, 2011