Direct ink writing of boron carbide monoliths

Robocasting of advanced ceramics: ink optimization and protocol to predict the printing parameters - A review

“…Recently, Lakhdar et al. presented a detailed study on the influence of ceramic solid loading and Pluronic F-127 binder concentration on the rheological properties and printing resolution in the fabrication process of B 4 C monoliths using robocasting and pressure-less sintering to produce fully-dense parts [ 56 ]. The inks were charged with B 4 C ranging from 46 to 50 vol%.…”

“…However, the achievement of high densities (90–97% TD) is generally pursued to produce geometrically complex structures for industrial applications (abrasive tools, sandblasting nozzles) (see Figure 3 a-d). These products are obtained by increasing the solid loading up to 50 vol% along with the use of SPS or SPSP sintering in argon or vacuum for 5 min [ 31 , 55 , 56 ]. Controlled blending and mixing of powders are usually done in optimised multistep mixing processes using a planetary centrifugal mixer.…”

“… De-binding: 500 °C in argon. Sintering: high-temperature vacuum furnace under argon gas up to 2275 °C for 1 h. [ 56 , 67 ] CEZ-12 Ceria-stabilized zirconia powder - Pluronic F127 - DARVAN - DI water 36 Planetary centrifugal mixer: 1800 rpm. Porosity: 85 vol%.…”

“…As mentioned earlier, maximizing the ceramic solid content of aqueous pastes for robocasting is crucial to obtain 3D-printed ceramics with high density and minimal drying/sintering shrinkage to prevent crack formation. However, higher solid contents result in increased viscosity, yield stress σ y and storage modulus G′, which could prevent paste extrusion and yield poor strut merging in the case of monolithic parts [ 56 ]. In the case of lattices and scaffolds, high solid loading leads to increased strut stiffness which is important for shape retention of free-standing and suspended struts [ 66 ].…”

“…Furthermore, changing the powder-to-solvent ratio may result in different drying kinetics which leads to the formation of printing defects and drying cracks. Higher solid loadings also tend to complicate extrudability by increasing the chance of nozzle clogging, which can result in having to increase the printing orifice diameter to prevent clogging; this in turn affects resolution, density and mechanical properties [ 56 , 94 ].…”