Non-aqueous gelcasting of AlN ceramics using a low-toxicity monomer (DMAA) as gelling agent

In this study, high-performance aluminum nitride (AlN) samples were prepared by gelcasting based on a low-toxicity monomer and organic solvents. We prepared a 50 vol% solid content AlN suspension with a solvent ratio of 3:1, 6 wt% N,N-dimethylacrylamide (DMAA) and 0.15 wt% Polyethyleneimine (PEI); after degassing, low viscosity and high stability were observed. It was proven that the AlN green bodies exhibited a bending strength of 18.68 MPa, which met the requirements for machining. An optimum debinding process was developed and the TG-DSC curves showed that the AlN green bodies were heated at 1 °C/min from 450 to 800 °C. The relative density, apparent porosity, bending strength, and thermal conductivity of the AlN sintered bodies prepared by non-aqueous gelcasting were 98.5%, 0.22%, 310 MPa, and 159 W m⁻¹ K⁻¹ respectively, representing optimum conditions. The uniform miscrostructure of the sintered bodies was observed by SEM images.