STUDY ON ADSORPTION MECHANISM AND CORROSION INHIBITION BEHAVIOR OF DIFFERENT CONCENTRATIONS OF TEA EXTRACTS ON THE SURFACE OF HP13CR STAINLESS STEEL

The effect of tea extract (TE) concentration on the inhibition efficiency and the corrosion behavior of HP13Cr stainless steel in 3.5 wt.% NaCl solutions has been investigated. It was found that the inhibition efficiency was influenced significantly by the addition of different concentration of TE. With the concentration of TE increased from 0.1 g/L to 0.3 g/L, the intermolecular interactions among the TE molecules were mainly characterized by attraction, and the coverage of the inhibition film was increased. However, when the concentration of TE was increased to 0.4 and 0.5 g/L, the intermolecular interactions among the TE molecules were mainly characterized by repulsion, which can result in the desorption of the covered TE molecules and the coverage of the inhibition film was decreased obviously. Therefore, the inhibition efficiency was reduced and the corrosion of HP13Cr was aggravated. The intermolecular interactions of TE are calculated, and the influencing mechanisms of the TE concentration on the inhibition efficiency and corrosion behavior are also discussed.