Gravimetric and data analysis of the corrosion resistance behaviour and inhibition of C26000 brass in dilute HNO3 solution

Abstract

The corrosion resistance of as-received and heat treated C26000 brass (annealed and quenched) was evaluated by gravimetric analysis in 0.5 M, 1 M, 1.5 M, 2 M, 2.5 M, 3 M and 3.5 M HNO3 solution. Generally, corrosion rate of C26000 increased with increase in HNO3 concentration and varies significantly with respect to observation time. Results showed that heat treatment has no influence on the corrosion resistance of the brass heat treated brass compared to the as-received sample. Application of garlic extracts in HNO3 solution at 0.5 M significantly decreased the corrosion rate of C26000 60% concentration with inhibition value of 79.46%. The garlic extract exhibited significant concentration dependent behaviour and its inhibition performance varies with observation time. Statistical evaluation showed the standard deviation values of as-received and heat treated C26000 varied with respect to mean inhibition data. However, variation increased with HNO3 concentration due to thermodynamic instability with respect to observation time. In the presence of the garlic extracts, the high standard deviation values at the lowest and highest garlic concentration signify significant variation with observation time and thermodynamic instability. Evaluation through analysis of variance shows HNO3 concentration and observation are statistically irrelevant to the corrosion rate output of as-received and heat treated C26000. In the presence of garlic extracts only the extract concentration is statistically relevant with value of 90.52%.