Investigating the Effect of Hydroxyapatite (HA) Coating on the Mechanical Properties an‎d Biodegradability of Mg-3Zn-2Sr-1Cu Alloy

1/1/1900 12:00:00 AM

Aiming to enhance the mechanical properties an‎d biodegradability of the magnesium-based alloy Mg-3Zn-2Sr-1Cu, considered a promising can‎didate for temporary orthopedic implants, this study employed hydroxyapatite (HA) coating via the sol-gel method. Following coating, the samples were heat-treated at 300, 350, 400, 450, an‎d 500 °C, an‎d their microstructure, hardness, an‎d corrosion behavior were systematically eva‎luated. Microhardness measurements revealed that the HA coating significantly improved the surface hardness of the alloy, increasing from 88.7 HV in the bare sample to 163.6 HV for the sample heat-treated at 400 °C, an‎d reaching a maximum of 181.8 HV at 450 °C. However, 400 °C was identified as the optimal sintering temperature due to its balanced combination of favorable hardness, uniform coating structure, an‎d superior corrosion performance. In potentiodynamic polarization tests conducted in simulated body fluid (SBF), the corrosion current density (Icorr) decreased from 0.92 μA/cm² in the uncoated alloy to 0.29 μA/cm² in the HA-coated sample sintered at 400 °C. Likewise, the polarization resistance (Rp) increased from 1120.1 Ω to 1348.9 Ω. As a result, the corrosion rate was reduced from 0.114 mm/year for the bare sample to 0.036 mm/year for the coated sample at 400 °C, indicating a more than threefold improvement in biodegradation resistance. In conclusion, HA coating via the sol-gel method combined with heat treatment at 400 °C can simultaneously enhance the mechanical an‎d biological performance of Mg-3Zn-2Sr-1Cu alloy, making it a highly promising material for temporary biomedical implant applications.

پوشش هيدروكسي آپاتيت (HA) , روش سل-ژل , آلياژ Mg-3Zn-2Sr-1Cu , نرخ خوردگي , سنجش سختي در مقياس ميكرو , زيست تخريب پذيري , مقاومت در برابر پلاريزاسيون

Mg-Zn-Sr-Cu alloy , hydroxyapatite coating , sol-gel method , microhardness , corrosion rate , biodegradability , polarization resistance

Erfan Fatehi

Dr. Maryam Salehi