Effects of copper content on the shell characteristics of hollow steel spheres manufactured using an advanced powder metallurgy technique

Metallic hollow spheres are used as base materials in the manufacture of hollow sphere structures and metallic foams. In this study, steel hollow spheres were successfully manufactured using an advanced powder metallurgy technique. The spheres’ shells were character-ized by optical microscopy in conjunction with microstructural image analysis software, scanning electron microscopy (SEM), en-ergy-dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD). The microscopic evaluations revealed that the shells consist of sin-tered iron powder, sintered copper powder, sodium silicate, and porosity regions. In addition, the effects of copper content on various pa-rameters such as shell defects, microcracks, thickness, and porosities were investigated. The results indicated that increasing the copper con-tent results in decreases in the surface fraction of shell porosities and the number of microcracks and an increase in shell thickness.