Vol. 2, Issue 4 (2016)
Evaluation of dwarf ixora coccinea extract in corrosion inhibition of mild steel in an acidic medium
Author(s): Ntunde DI, Okoye OA
Abstract: The efficacy of the dwarf ixora coccinea extract in corrosion inhibition of mild steel in an acid medium was evaluated using a mild steel specimen of dimensions 10cm x 1cm x 1cm obtained locally and analysed for its constituent composition using spectrometer. The mild steel bar was cut into 61 pieces and notched into appropriate shape suitable for impact test. The samples were degrease using ethanol and immersed for two minutes in 10% HNO3 to activate the surface. The bars were dried to prevent the formation of a passivation layers that may interfere with the results. The leaves of coccinea plant were dried and ground to fine powder and the extraction was done using soxhlet extractor. Twelve (12) glass jars of the extracts were used for the experiment. Six of which contain 500ml of the corrosive media (0.5, 1.0M, 1.5M, 2M of HCL, sea water and distilled water without Ixora coccinea extract while the other six contain the mixture of the corrosive media and the extract. Five specimens were completely immersed in each jar and allowed to stand for 35 days (840hrs); after 7 days interval (168hrs), the specimens were removed, washed, dried and evaluated for corrosion. Results obtained showed that strength of mild steel in various media (0.5M, 1M, 1.5M, 2.0M HCL, sea water and distilled water) without the extract after 35 days exposure period were 53, 52, 47, 43, 58 and 59j respectively; and the corresponding impact strength for the mild steel in the ixora coccinea extract were 57,55, 52, 51,59 and 61j respectively. It was also observed that the impact strength is dependent on the thickness of the mild steel. Generally, ixora coccinea extract inhibited the corrosion of mild steel in HCL acid and failed to inhibit corrosion in sea and distilled water media.