Optimization of a nanoparticle suspension for freeze casting

Autores: Lu, K.|Kessler, C.S.|Davis, R.M.
Fuente: J. Am. Ceram. Soc.
89 (8), 2459-2465
2006

Poly(acrylic acid) (PAA) dispersant concentration, suspension pH, and Al2O3 solids loading effects on PAA adsorption onto Al2O3 nanoparticles were studied; the stability and rheology of the Al2O3 nanoparticle suspensions were examined. The most desirable suspension conditions were 7.5-9.5 for pH and 2.00-2.25 wt% of Al2O3 for the PAA concentration. Electrical double-layer thickness and PAA adsorption layer thickness comparison showed that electrosteric stabilization was dominant. 45.0 vol% Al2O3 solids loading can be achieved for freeze casting. The maximum solids loading was predicted to be 50.7 vol%. The freeze-cast sample showed that pre-rest before freezing was critical for achieving desirable microstructures.