Precise fabrication of open porous Mg scaffolds using NaCl templates: Relationship between space holder particles, pore characteristics and mechanical behavior

Mg-based scaffolds have great potential of application for bone defect repair due to their biodegradability and the excellent osteoinductivity, yet currently the fabrication of Mg-based porous materials is still a challenge. In this study, a new fabrication method was proposed to produce porous Mg scaffolds, which could be achieved by three steps: (1) defectless NaCl open porous template with enhanced relative density was prepared with NaCl particles by hot press sintering (HPS) process; (2) green compact of Mg and the NaCl template was produced by infiltration casting; (3) open porous Mg scaffold was achieved after leaching out the template. By using spherical NaCl particles and irregular polyhedral NaCl particles, respectively, two different types of templates were prepared, and correspondingly Mg scaffolds with spherical and irregular pores were respectively fabricated. The irregular-pore scaffold (I-scaffold) exhibited higher yield strength, while the spherical-pore scaffold (S-scaffold) showed superior interconnectivity and more stable compressive deformability due to the uniform spatial structure. Keywords: Mg scaffold, Infiltration casting, NaCl template, Interconnectivity, Mechanical properties, Microstructural evolution