Corrosion inhibition study and statistical data of thymus mastichina and alicium verum oil on low carbon steel in dilute H2SO4 and HCl solution

Abstract

Data on the corrosion inhibition of thymus mastichina and alicium verum (TA) on mild steel in H2SO4 and HCl solution was evaluated by coupon measurement and statistically through analysis of variance. The inhibition performance of TA was observed to decrease significantly with exposure time at 1% TA, beyond which the extent of decrease reduced. In HCl solution TA inhibition efficiency varied significantly with exposure time from 1%-4% TA concentration. Data showed TA effectively inhibited the mild steel after 1% concentration with optimal value of 81.24% and 5% TA concentration. TA performed poorly in HCl with optimal value of 68.33% at 5% TA concentration. Standard deviation showed variation of TA inhibition efficiency from mean inhibition value was significant at 1-5% TA concentration in HCl and at 1% TA concentration in H2SO4. 88% of TA inhibition data were above 70% inhibition with respect to exposure time and TA concentration at margin of error of +0.09% compared to 53% in HCl at margin of error of +0.1%. Analysis of variance showed TA concentration is the dominant source of variation responsible for the inhibition performance of TA with statistical relevance value of 88.83% while TA concentration and exposure time were both influential in HCl solution with values of 67.96% and 26.97%.