The effect of ball milling on the ph of Mg-based metals, oxides and Zn in aqueous media

The pH variation induced electrochemical reactions for Zn, Mg, MgO and the mixture MgMgO (25 wt.% Mg and 75 wt.% MgO) fabricated by high-energy mechanical ball milling in 3.5 wt.% NaCl have been investigated using the potentiodynamic method and electrochemical impedance spectroscopy to control the rate of magnesium dissolution as cathodic protection. It is known that pH variation is a good measurement of dissolution for cathodic protection materials. The pH of Zn was modestly increased because of the formation of ZnO. Mg showed a relatively high pH value when forming as Mg(OH)(2). Highly activated MgMgO showed the highest pH value, located between Mg and MgO, of equilibrium potentials and impedance. This indicates that the electrochemical reaction in 3.5 wt.% NaCl has been changed by mechanical ball milling. This implies that the dissolution rate can be controlled by high-energy mechanical ball milling.