Investigating the effects of shot peening and Polycaprolactone (PCL) electrospinning surface treatments on the corrosion properties of Mg-2.5٪HA biocomposite

Due to its biocompatibility and biodegradability, magnesium has become a very suitable candidate for orthopedic implant applications. However, its high corrosion rate leads to rapid deterioration in corrosive environments, resulting in premature failure of the implant before sufficient bone healing. In this regard, surface modifications are required to improve corrosion resistance. This research investigates the effect of two surface modifications, shot peening and electrospinning, on the corrosion properties of magnesium/hydroxyapatite composite. Shot peening was performed using glass beads at an Almen intensity of 0.3 mmN and with 100٪ coverage on the surface of the composite. Electrospinning was carried out using Polycaprolactone (PCL) nanofibers at 18 kV for 30 minutes. Tensile-compressive tests were performed on the composite specimens. Also, pH monitoring and weight loss tests were conducted on the shot peened and electrospun samples. The results show that electrospinning decreased the corrosion rate of magnesium by 75٪ and 40٪ after 1 day and 7 days of immersion, respectively. Shot peening also reduced the corrosion rate by 35٪ and 20٪, respectively. Electrospinning reduced the corrosion rate by limiting the contact surface area between the corrosive solution and magnesium due to its high specific surface area for calcium-phosphate absorption. Shot peening, on the other hand, delayed the corrosion by accelerating the formation of a passive layer, leading to increased corrosion resistance in short periods.