The 3D-Printed building and performance of Al2O3 ceramic filters with gradient hole density structures

Ceramic filters with gradient hole density structures will be an attractive candidate for high-temperature alloy melt filtration because it combines good mechanical properties with filtration requirements. This paper focuses on the structural design, mechanical properties and printed forming mechanism of the new pattern Al2O3 filters with gradient hole density structures (Al2O3-GHDS). Al2O3-GHDS filters were designed based on a topologically optimized lattice and then fabricated by stereolithography (SLA) printing technology using our developed Al2O3 paste system. It was found that GHDS filters exhibited the resultant performances combining wide hole sizes and excellent structural stability, and their compressive strength, energy absorption value and bending strength were 4.7 MPa, 77.7 kJ/m3 and 6.7 MPa, respectively, which far exceeded the mechanical properties of the traditional ceramic foam filters. The thermal shock resistance of GHDS filters can reach 2.2 MPa, which was nearly five times the traditional ceramic foam filters. The GHDS ceramic filter finally can exhibit the hole diameter largely ranging from 0.76 mm to 5.35 mm, which covered the hole sizes from 10ppi to 40ppi uniform hole density structure (UHDS). Furthermore, the inner holes of our built GHDS ceramic filters also had the good connectivity without plugging phenomena.