Lithography-based additive manufacturing of porosity graded alumina

Abstract

• In recent years, alumina ceramics exhibiting gradient in porosity, i.e., porosity graded alumina ceramics (PGACs), with a controlled amount of both open/closed or macro/micro pores is of high interest for several applications such as thick barrier coating, cores for precision casting, biocompatible implants, membranes/filters, and fabrication of functionally graded metals through infiltration. • Lithography-based Ceramic Manufacturing (LCM) offers high quality and near-net manufacturing of complex ceramic components with high resolution. • Two-vat system in the newly developed multi-material LCM printer setup enables not only assigning one material to any desired layer but also use of different materials in each layer by assigning the respective materials to selected pixels of the layer image. • This article introduces methodologies for the fabrication of porosity gradient alumina with continuous and discrete porosity transitions zones by combining sacrificial templating and LCM. With the developments in manufacturing technologies, interest on porosity graded alumina ceramics has increased for applications such as thick barrier coating, cores for precision casting and biocompatible implants. Lithography-based Ceramic Manufacturing (LCM) offers high quality and near-net manufacturing of complex ceramic components with high resolution. Multi-material LCM printing setup can overcome the main problems of conventional manufacturing techniques for fabrication of porosity graded alumina with desired microstructure and gradient architecture (i.e., gradient direction, fraction, type). Two-vat system in the newly developed multi-material LCM printer setup enables not only assigning one material to any desired layer but also use of different materials in each layer by assigning the respective materials to selected pixels of the layer image. This article introduces methodologies for the fabrication of porosity graded alumina ceramics (PGACs) with continuous and discrete porosity transitions zones by combining sacrificial templating and LCM. It is illustrated how the properties of the slurry and the desired gradient architecture play an important role for the selection of suitable method.