Strength of additively manufactured alumina with different debinding and sintering heat treatments

Lithography-based ceramic manufacturing (LCM) utilizes slurries with low solids loading, which makes pressureless sintering to full density especially difficult. A further compounding issue in sintering to full density and establishing structure-property-processing relationships for LCM alumina is the fact that the current literature lacks consensus on heat treatments to achieve full densities. Treatment specifics that are recorded are frequently ambiguous and insufficiently detailed. In this work, temperatures and times for debinding and sintering schedules were varied to characterize the influence of heat treatment parameters on density, microstructure, and flexural strength of high-purity, LCM-formed alumina. Removing the bisque-fire from debinding and fine-tuning sintering parameters produced parts with full densities, high flexural strengths, and Weibull moduli that match or exceed the values documented in a round robin study of traditionally processed alumina.

Automated summary

Lithography-based ceramic manufacturing (LCM) faces challenges in achieving full density due to the use of slurries with low solids loading. In addition, the current literature lacks consensus on heat treatments for reaching full densities. This study investigated the influence of varying debinding and sintering parameters on the density, microstructure, and flexural strength of LCM-formed alumina. The results showed that removing bisque-fire and fine-tuning sintering parameters can produce LCM alumina parts with full densities and high flexural strengths comparable to traditionally processed alumina.