Investigation of the Potential of Some Plant ...

The inhibitive effect of some natural organic compounds on the corrosion behaviour of duplex stainless steel was investigated. Inhibitors studied include natural honey and natural oils from various plant extracts. The honey was obtained from two sources, namely the blue gum tree (honey BG) and honey from orange blossoms (honey OB), while the oils consisted of rosemary, jojoba, eucalyptus, and mugwort oils. The inhibitory effects were studied on two different types of duplex stainless, namely steels 2205 and 2507, in 1 M hydrochloric acid and 1 M sulphuric acid solutions, using a potentiodynamic polarization method and varying concentrations of inhibitors (2.5, 5.0 and 10.0 g of inhibitors per litre of acid). Mugwort oil was found to be the best and effective inhibitor in hydrochloric acid media on both types of duplex stainless steels, while honey BG and honey OB showed good inhibitive effects in a 1 M sulphuric acid solution for 2205 and 2507 respectively. Inhibition was found to increase with increasing concentration of honey and the oils.