The interaction mechanism of dolomite mineral and phosphoric acid and its impact on the Ti alloy corrosion.

The interaction mechanism of dolomite rock mineral as a novel corrosion inhibitor for titanium alloy in phosphoric acid (0.001-0.5 M) has been investigated for the first time using electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization measurements. Unlike prior studies on synthetic inhibitors, this work uniquely highlights the potential of a naturally abundant, eco-friendly mineral for corrosion mitigation. EIS results reveal a distinctive shift in the inhibition mechanism-from adsorption to diffusion-controlled processes-with increasing phosphoric acid concentration, corroborated by in-situ Raman spectroscopy. This is the first report showing that dolomite effectively reduces the corrosion rate of titanium alloy by forming a stable passive film, with optimal performance observed in low acid concentrations (0.001-0.01 M). Furthermore, at higher acid concentrations (0.1-0.5 M), the mechanism transition influences the film performance. Surface characterization using SEM, EDS, FTIR, XRD, XRF, and in-situ Raman spectroscopy confirms the protective film formation and elucidates the interaction chemistry. The study establishes dolomite as a sustainable alternative to synthetic inhibitors, offering new insights into corrosion protection strategies for titanium alloys.