Porous ceramics have been extensively used in diverse fields, for examples, as scaffolds for bone regeneration, components for thermal insulation and filters, and preforms for structural composites [1] and [2]. Fundamentally, the functions of porous ceramics are strongly affected not only by their porous structure (e.g., overall porosity, pore size, pore geometry, and pore interconnectivity), but also by the distribution of those pores. Thus, considerable effort has been made to locally tune the porous structure of porous materials for the creation of porosities and pore sizes which vary throughout a porous material. Materials featuring such gradient porous structures can have their functions tailored for specific applications [3]. For instance, gradient porous ceramics mimicking the architecture of natural bone comprised of a relatively dense outer layer and a highly porous core can provide excellent biomechanical functions with outstanding bone regeneration ability in vivo when used as bone scaffolds [4] and [5]. In particular, a porous core should have good interconnection between pores with sizes >100 µm to provide a favorable environment for bone ingrowth into pores and controlled pore configuration to provide high mechanical strengths [1].