Effect of methanolic plant extract on copper electro-polishing in ortho-phosphoric acid

Abstract

The behavior of copper electro-polishing in ortho-phosphoric acid using the galvanostatic polarization method was ascertained. This was examined via measuring and comparing anode potential –limiting current relationship in solution of regularly mounting concentrations (from 50 to 1800 ppm of methanolic Allium sativum (garlic extract), Tilia cordata (Tilia leafs), Foeniculum vulgare (fennel seeds), and Lablab purpureus (Dolichos lablab extract) and weight loss method. Influence of temperature on the dissolution kinetics were investigated. First order kinetic is applicable to the copper dissolution in solution containing plant extracts. Surface morphologies, brightness and roughness of polished specimens were examined with a scanning electron microscope (SEM), reflectance and atomic force microscope (AFM). Addition of methanolic plant extract to electro-polishing solution produce a lesser limiting current. According to SEM, UV–VIS-NIR spectra and surface roughness measurements, addition of high concentration (1800 ppm) of methanolic plant extract to the electrolytic solution is highly effective to enhance surface quality. High reflection property is obtained when the different type of methanolic plant extract is added to the electro-polishing electrolyte. The minimum Ra and PV values are achieved by garlic extract, which records the highest reflectance value and inhibition efficiency. Weight loss data obtained is excellent conformity with the result obtained by electrochemical measurements.

Keywords

• Copper
• Electro-polishing
• Scanning electron microscope (SEM)
• Methanolic plant extract