The next-generation concentrated solar power (CSP) applications consider the use of heat exchangers characterised by outstanding corrosion and oxidation resistances. These chemical and physical features are essential when using molten salts and supercritical CO2 as heat transfer fluids into a Brayton power cycle. To improve the heat exchange, the contact surface in between the working fluids have to be enhanced, implying the utilization of a more complex geometry. Due to common production technology limits, the Additive Manufacturing (AM) via Direct Ink Writing (DIW) has been considered as an alternative. In this context the control of rheological properties of the produced inks represents a crucial step for the printing.