Effect of Pluronic F-127 debinding temperature on the sintering and densification of alumina by direct ink writing

Hydrogel-based alumina (Al₂O₃) inks were prepared using Pluronic F-127 with 65 wt% of solid loading (Al₂O₃). The Al₂O₃ inks were deposited, and the freestanding samples were studied using TGA/DTA. Significant weight loss was observed between 180 and 360°C. A two-stage hydrogel debinding process of Al₂O₃ samples was carried out at 180 and 360°C with holding times of 30, 60, 90, 120, and 150 min. The Al₂O₃ samples were then sintered at 1600°C. X-ray diffraction was used for the phase analysis of the alumina inks, and a scanning electron microscope was used microstructural analysis. Based on the TGA/DTA analysis, a two-stage debinding process was adopted. Significant effect of hydrogel debinding temperature was observed on the sintering and densification behavior of alumina. It was observed that the porosities in the alumina samples were increasing when the debinding time was increased from 30 to 150 min, with the debinding temperature at 180 and 360°C. Moreover, the nature of the porosities was changing from closed porosities to interconnected porosities.