Controlling the permeability of the particle-stabilized ceramic foams with polymethyl methacrylate microsphere as pore-forming agent

Abstract

Open-cell ceramic foams with controllable cell connectivity were fabricated by polymethyl methacrylate (PMMA) microspheres as pore-forming agent combined with particle-stabilized foaming method. In order to adjust the open-cell structures of ceramic foams, PMMA microspheres with distinct particle sizes and contents were used. The results indicate that the bubble-derived pores in the prepared ceramic foams were interconnected by microsphere-derived pores within cell walls, and the average size and volume fraction of microsphere-derived pores and bubble-derived pores could be tailored by adjusting the particle size and content of PMMA microspheres. The impacts of open-cell structures on connectivity were described in terms of permeability in this study. The open-cell ceramic foams obtained using larger PMMA particle size and content exhibited larger Darcian and non-Darcian permeability constants due to the increase of the size and volume fraction of microsphere-derived pores. The ratio of Darcian and non-Darcian permeability constant represents the individual contribution of viscous and inertial effects to the total pressure drop during the permeation process that are strongly dependent on the microsphere-derived pore size and pore volume fraction. The Darcian and non-Darcian constants in this study were in the range of 3.54 × 10⁻¹² to 4.09 × 10⁻¹¹ m² and 3.05 × 10⁻⁷ to 5.10 × 10⁻⁶ m, respectively. These results are of practical value for the preparation and optimization of ceramic foams in applications requiring open-cell structures.