Synthesis of Mg–Zn–Ca alloy by the spark plasma sintering

Mechanical alloying (MA) and spark plasma sintering (SPS) was employed to synthesize the Mg₆₀Zn₃₅Ca₅ alloy. SPS, which is also known as the field-assisted sintering technique, plasma-activated sintering, pulsed electric current sintering, or plasma pressure-compaction, appears to be promising for manufacturing a biodegradable Mg₆₀Zn₃₅Ca₅ alloy. SPS is a sintering technology that utilizes Joule heating via a pulsed electric current to achieve densification. SPS allows very fast heating and cooling rates, very short holding time, and the possibility of obtaining fully dense samples at comparatively low sintering temperatures, typically a few hundred degrees lower than normal hot pressing. The Joule heating could lead to further improved densification via localized plastic flow at the necks of connected particles during sintering. The structure and compressive strength of the Mg₆₀Zn₃₅Ca₅ alloy were investigated. In the X-ray diffraction (XRD) patterns of the representative Mg₆₀Zn₃₅Ca₅ powder after 13 h of MA, a broad diffraction peak corresponding to the amorphous phase is noticed. The results by XRD show that the Mg₆₀Zn₃₅Ca₅ alloy after sintering has a multiphase structure. The investigated alloy shows a slightly higher compressive strength (264–300 MPa) compared to the crystalline Mg-based alloy (250 MPa) and exhibits properties appropriate for medical applications.