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 m 2 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.