Broadening the debinding temperature window by PEG addition to reduce defects and improve the mechanical properties of vat photopolymerized alumina ceramics

PEG400 broadens the debinding temperature window by ∼100 °C, enabling stepwise resin decomposition in VPP alumina. • Early PEG decomposition constructs 3D pores for efficient gas escape, suppressing delamination and cracks. • 10 vol% PEG optimizes defect control, achieving 234 MPa flexural strength (30% improvement) and 97.1% relative density. • Debinding window engineering is a generalizable strategy for defect regulation in light-cured 3D-printed ceramics. To address the critical challenges of narrow debinding window and defect formation in vat photopolymerization (VPP) 3D-printed alumina ceramics with high resin content (as high as 50 vol%), this study introduces polyethylene glycol (PEG400) as an auxiliary organic phase. The concentrated thermal decomposition of the single-resin system, typically occurring within a sharp temperature range of 300–500 °C, was transformed into a stepwise process spanning 200–500 °C by PEG pre-decomposition. This window broadening of ∼100 °C facilitated early gas release through interconnected pore channels formed at low temperatures, thereby alleviating internal pressure and stress accumulation during main resin decomposition. Quantitative X-ray computed tomography analysis confirmed significant defect suppression, with the 10 vol% PEG group (P1) achieving the lowest average defect volume and delamination fraction. Consequently, sintered samples exhibited 30% improvement in flexural strength (234 MPa) and 97.1% relative density. These results demonstrate that broadening the debinding temperature window is an effective strategy for defect control and mechanical property enhancement in VPP ceramics. Download: Download high-res image (227KB) Download: Download full-size image In this study, a PEG-mediated debinding strategy is proposed to address the critical challenges of narrow debinding window and crack formation in conventional single-resin systems. In the traditional system, rapid gas release leads to internal pressure accumulation and defect generation, resulting in a mechanical strength of only 185 MPa. In contrast, PEG decomposition constructs a connected pore network, achieving efficient debinding in a broadened temperature window of 200–500 °C, significantly reducing defects, and ultimately increasing the mechanical strength to 234 MPa, providing a new efficient debinding pathway for high-performance ceramic 3D printing.