• B S Sheshadri

      Articles written in Journal of Chemical Sciences

    • Effect of dodecyl trimethylammonium bromide on electrocrystallization of copper

      B S Sheshadri P B Rotti

      More Details Abstract Fulltext PDF

      Dodecyl trimethylammonium bromide (DTAB) addition to acidified copper sulphate bath changes the morphology of copper electrodeposits on the copper single crystal planes and increases the cathodic polarization in a current density range of 2–20 mA/cm2. This has been observed in the 100,110 and 111 planes where, under different concentrations and current densities, layer type deposits are transformed to pyramidal growths and finally to polycrystalline forms in the (100) plane, ridges to polycrystalline in the (110) plane, and triangular and hexagonal pyramids become twinned and transform to polycrystalline forms in the (111) plane, in the presence of DTAB.

      On (100) and (110) planes the overpotentials during deposition from pure solution increase with time while on the (111) plane overpotential decreases to a steady value with time. The overpotential values are always higher in the presence of DTAB.

      The observed changes in the morphology and overpotentials are attributed to the adsorption of DTAB on the copper substrate.

    • Inhibitory effect of 2-mercapto pyrimidine on corrosion of copper single crystal planes in 0·1 M H2SO4

      L S Nandeesh B S Sheshadri

      More Details Abstract Fulltext PDF

      Weight loss and polarization techniques have been used to investigate the rates of dissolution of copper single crystal (100), (110) and (111) planes in 0·1 M H2SO4 as well as in the presence of various concentrations (10−5M to 10−2M) of 2-mercapto pyrimidine (2-MP). The corrosion rates of copper single crystal plane were controlled by surface reaction which was found to be a function of crystallographic orientation, temperature and concentration of 2-MP. The stabilities of the crystal planes in pure acid were found to be (111)>(100)>(110). However, at the critical concentration of 2-MP (10−2M) the order of stability was found to be (110)>(100)>(111). The observed corrosion data revealed that inhibition of copper corrosion takes place by surface adsorption of inhibitor molecules, indicating a Bockris-Swinkels type of adsorption isotherm. Inhibitor efficiencies derived from weight loss and polarization techniques showed good agreement. The order of stability of the crystal planes was further confirmed by surface topographical changes during corrosion and also by the thermodynamics of adsorption of inhibitor molecules.

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