Carbohydrate biopolymer for corrosion control of 6061 Al-alloy and 6061Aluminum-15%(v) SiC(P) composite-Green approach

The acid corrosion control of 6061Aluminum alloy and 6061Al-15%(v) SiC(P) composite material (Al-CM) was carried by using inulin - a carbohydrate polymer as a green inhibitor. Potentiodynamic polarization (PDP) and Electrochemical Impedance Spectroscopy (EIS) techniques were adopted. Concentration of inulin was in the range of 0.2 gL−1-1.0 gL−1, and studies were done in the temperature range of 303-323 K. The adsorption of inhibitor on the surface of Al alloy and Al-CM was confirmed by physical techniques such as Scanning electron microscopy (SEM), energy-dispersive X-Ray analysis (EDX), and atomic force microscopy (AFM) analysis. The studies showed that inhibition efficiency of inhibitor increased with increase in concentrations of inulin and decreased with increase in temperature. The adsorption of inulin on metal surface obeyed Langmuir adsorption isotherm through physical adsorption on both alloy and on Al-CM. Results obtained from potentiodynamic polarization method and electrochemical impedance spectroscopic methods were in good agreement with one another.