Corrosion Resistance Of A3 Carbon Steel Luan Leaves, Pods Son, Seed Extract In 5% H ₂ SO ₄ In

The inhibition efficiency of plant corrosion inhibitors extracted from Koelreuteria paniculata leaves、legumen and seeds on A3steel in5%H2SO4before and after synergy with TEMAB、SMPAB,which two new quaternary ammonium salts, were studied by electrical impedance spectroscopy(EIS), polarization curves(PC), differential polarization curves(DPC) and gravimetric methods.The structure of plant extract were characterized by FT-IR and GC-MS,and combined SEM exploring the inhibition mechanism.The results of electrochemical methods showed that:the effect of liquid corrosion inhibitor was nearly as same as the solid corrosion inhibitor in preventing corrosion,but the extraction technology of liquid inhibitor was simpler,which is the best extraction technology. The inhibition efficiency of Koelreuteria paniculata leaves、legumen and seeds extract increased with the concentration of the tested inhibitor.The highest efficiency91.43%,91.31%,91.51%were obtained at15g/L of Koelreuteria paniculata leaves、legumen and seeds extract at25℃by PC as same as EIS.The results of gravimetric methods showed that:The highest efficiency91.76%、93.69%、93.88%were obtained at15g/L of Koelreuteria paniculata leaves、legumen and seeds extract at25℃.The result were consistent with the electrochemical results.The results of synergy showed that:the inhibition efficiency of TEMAB、SMPAB were up to the highest efficiency95.69%and96.10%respectively at25℃,1×10-2mol/L. When15g/L of Koelreuteria paniculata leaves、legumen and seeds extract at25℃mixed with5×10-4mol/L TEMAB, the inhibition efficiency were up to96.99%,98.73%,94.54%respectively by EIS; when it mixed with5×10-4mol/L SMPAB, the inhibition efficiency were up to97.29%,99.48%,96.78%respectively by EIS. EIS and PC method results are basically similar.Koelreuteria paniculata leaves、legumen and seeds extract were characterized by FT-IR and GC-MS from the structure to inhibit corrosion. Excellent inhibition effect on the surface of carbon steel in the presence of corrosion inhibitor and compound was observed by SEM experimental results.The electrochemical corrosion mechanism of the extracts was studied by EIS, PC and DPC, thermodynamic and kinetic parameters that come form gravimetric methods...