Development of MgAl₂O₄ grain refiner in Al in-situ composite through H₃BO₃ addition

In the present work, a novel approach has been made for synthesis of in-situ Magnesium Aluminate (MgAl2O4) particles in the Al-4Mg alloy by Boric Acid (H3BO3) precursor addition (1 wt %, 1.5 wt % and 2 wt %) during the casting process. The developed composite has been investigated for its microstructural characteristics and corrosion performance. Scanning Electron Microscopy and Energy Dispersive Spectroscopy examination revealed the formation of MgAl2O4 particles in the composite. Potentiodynamic polarization corrosion experiments were performed on the Al-4Mg/H3BO3 composite specimens (1 wt %, 1.5 wt % and 2 wt %) in three different medium (3.5 % Sodium Chloride-NaCl, 1 M Sulphuric Acid-H2SO4 and 1 M Hydrochloric Acid-HCl). Corrosion results showed that Al-4Mg/1.5 wt % H3BO3 composite specimen exhibited better corrosion resistance in 3.5 % NaCl, 1 M H2SO4 and 1 M HCl medium due to the significant grain refinement produced by MgAl2O4 particles. The developed composite with better corrosion properties can be utilized for marine and naval application.