Thermoresponsive Pluronic F‐127 Based Alumina–Graphite Inks for Direct Ink Writing

Alumina inks were prepared with graphite as additive and dispersed in Pluronic‐F127 hydrogel. The effect of 0.5, 1, 1.5, and 2 wt% graphite as an additive on the rheological characteristics of alumina inks was studied for direct ink writing (DIW) applications. Significant effect of graphite addition on the viscosity of alumina inks was observed. The viscosity of the all the inks with graphite as additive was observed to be less than that of alumina ink. The gelation temperature for alumina ink was observed to be at 8°C, whereas for alumina inks with graphite addition the temperature increased from 8°C to 15°C. The yield stress of the inks with graphite addition was observed to be less than that of alumina ink showing that the graphite addition decreases the yield stress of the inks. The hexagonal shells were printed by DIW process. Sintering of the printed components at 1350°C and 1600°C systematically reduced the percentage density from 83% to 69.3% and 92.8% to 85.9% with increasing graphite content, respectively. Graphite addition to alumina inks significantly influences the rheological properties and printability of the inks, along with the density and microstructure of the sintered samples.