Abstract
In this current work, nanocrystalline calcium-deficient hydroxyapatite (CDHA) was synthetically produced using calcium hydroxide and diammonium phosphate through a wet chemical synthesis route. X-ray diffraction (XRD) analysis and electron microscopy demonstrated the nano-level (~47 nm) of the produced CDHA. Then, the nano-CDHA was reinforced into ZE41 Mg alloy by friction stir processing (FSP) aimed at manufacturing degradable bone implants. Microstructures clearly demonstrated the development of a fine-grained structure (7.4 ± 6.9 µm) in addition to incorporating nano-CDHA into ZE41 Mg alloy. FSP resulted in decreased intermetallic phases, which suggests increased solubility of zinc into magnesium due to FSP. XRD analysis of the composite confirms the development of a basal-dominated texture in the composite. From the potentiodynamic polarization studies, corrosion performance was assessed using simulated body fluid (SBF). The composite exhibited noble behavior by demonstrating a lower corrosion current density (-1.23 ± 0.8 × 10-4 A/cm2) compared with ZE41 alloy (-4.75 ± 1.1 × 10-4 A/cm2). Lower weight loss was observed for the composite after 72 hours of immersion in SBF, indicating improved degradation resistance due to the incorporated nano-CDAH and grain refinement. The lower corrosion rate measured for the composite (11.4 ± 2.1 mm/year) is 40% lower compared with ZE41 alloy (19.3 ± 1.8 mm/year) based on weight loss data. The results demonstrate the feasibility of FSP to develop ZE41-nano-CDHA composite with better corrosion control.