Influence of henna extract on the Inhibition efficiency of Diethylene Triamine penta (methylenephospphonic Aicd)DTPMP- Zn~2+ System

摘要

The Inhibition efficiency (IE) of various concentrations of a DTPMP - Zn~2+-henna system in controlling corrosion of mild steel immersed in well water was evaluated by a mass - loss study. The formulation consisting of 50 ppm of DTPMP and 25 ppm of Zn~2+ and 1 ml of henna showed 90% Inhibition efficiency. A synergistic effect was noticed between DTPMP - Zn~2+- henna system. In the presence of henna DTPMP- Zn~2+ system has excellent inhibition efficiency. Polarization studies reveal that DTPMP - Zn~2+- henna functions as a mixed type inhibitor. AC impedance spectra suggest that a protective film is formed on the metal surface. The protective film was analyzed by Fourier transform infrared spectroscopy. The film consisted of Fe~2+ DTPMP complex and zinc hydroxide [Zn (OH)-2]. SEM micrographs reveals that a protective film was formed on the metal surface by the inhibitor and therefore corrosion is prevented