The ethanolic extract of Kleinia grandiflora leaves was characterized and tested for its potential anticorrosion properties on mild steel in 1 M H2SO4 medium using mass-loss analysis, potentiodynamic polarization meas...The ethanolic extract of Kleinia grandiflora leaves was characterized and tested for its potential anticorrosion properties on mild steel in 1 M H2SO4 medium using mass-loss analysis, potentiodynamic polarization measurements, electrochemical impedance spectroscopy, Fourier-transform infrared spectroscopy, scanning electron microscopy, UV–visible spectroscopy, and X-ray diffraction analysis. The effect of temperature on the corrosion behavior of mild steel was studied in the range of 308 to 328 K. The inhibition efficiency was observed to increase with increasing concentration of the extract. Polarization curves revealed that the Kleinia grandiflora leaf extract is a mixed inhibitor. Impedance diagrams revealed that an increase of Kleinia grandiflora leaf extract concentration increased the charge transfer resistance and decreased the double-layer capacitance. The adsorption process obeys Langmuir＇s model, with a standard free energy of adsorption（ΔGads） of-18.62 k J/mol. The obtained results indicate that the Kleinia grandiflora leaf extract can serve as an effective inhibitor for the corrosion of mild steel in a sulfuric acid medium.展开更多
The corrosion inhibition of cold rolled steel(CRS) in 7.0 mol·L^(-1) H_2 SO_4 solution by red tetrazolium(RTZ) was carefully investigated using both experimental procedures and theoretical techniques. The results...The corrosion inhibition of cold rolled steel(CRS) in 7.0 mol·L^(-1) H_2 SO_4 solution by red tetrazolium(RTZ) was carefully investigated using both experimental procedures and theoretical techniques. The results show that RTZ acts as an effective inhibitor for the corrosion of CRS in 7.0 mol·L^(-1) H_2SO_4, and the maximum inhibition efficiency is higher than 95% with a RTZ concentration of 2.0 mmol·L^(-1). The adsorption of RTZ on CRS surface follows Langmuir isotherm. RTZ effectively retards both cathodic and anodic reactions, and acts as a mixed-type inhibitor. EIS exhibits two capacitive loops, and their resistances increase drastically in the presence of RTZ. SEM and AFM confirm that the addition of RTZ could significantly retard the corrosion of CRS surface. A series of characterizations like FTIR, RS, XRD and XPS reveal that the corrosion CRS surface is composed of the corrosion products of iron sulfates, iron oxides and iron hydroxide, as well as inhibitor. Theoretical results of quantum chemical calculation and molecular dynamics(MD) indicate that the adsorption center of RTZ+(organic cationic part of RTZ) mainly relies on its tetrazole ring,and the adsorption of RTZ+on Fe(001) surface is in a nearly flat orientation mode.展开更多
Corrsion inhibition of Aloe lateritia gel for Mild steel in 2 M HNO<sub>3</sub> and 1 M H<sub>2</sub>SO<sub>4</sub> solutions was investigated by potentiodynamic polarization, Scann...Corrsion inhibition of Aloe lateritia gel for Mild steel in 2 M HNO<sub>3</sub> and 1 M H<sub>2</sub>SO<sub>4</sub> solutions was investigated by potentiodynamic polarization, Scanning electron microscopy (SEM) and Foutier transform infrared (FT-IR). Inhibition efficiency increased with the increase of the concentration of the gel. The optimal concentration of the gel gives maximum inhibition efficiency of 77.4% and 70.3% in 1 M H<sub>2</sub>SO<sub>4</sub> and 2 M HNO<sub>3</sub> respectively. Polarization plots shows that, the gel works as a mixed type inhibitor altering both cathodic and anodic reaction. SEM proves the uniform and pitting corrosion at the surface of Mild steel in 1 M H<sub>2</sub>SO<sub>4</sub> and 2 M HNO<sub>3</sub> respectively. Using FT-IR potential function groups from pure gel and some stretch shift was observed from corrosion product and some stretch shift from corrosion products was observed.展开更多
文摘The ethanolic extract of Kleinia grandiflora leaves was characterized and tested for its potential anticorrosion properties on mild steel in 1 M H2SO4 medium using mass-loss analysis, potentiodynamic polarization measurements, electrochemical impedance spectroscopy, Fourier-transform infrared spectroscopy, scanning electron microscopy, UV–visible spectroscopy, and X-ray diffraction analysis. The effect of temperature on the corrosion behavior of mild steel was studied in the range of 308 to 328 K. The inhibition efficiency was observed to increase with increasing concentration of the extract. Polarization curves revealed that the Kleinia grandiflora leaf extract is a mixed inhibitor. Impedance diagrams revealed that an increase of Kleinia grandiflora leaf extract concentration increased the charge transfer resistance and decreased the double-layer capacitance. The adsorption process obeys Langmuir＇s model, with a standard free energy of adsorption（ΔGads） of-18.62 k J/mol. The obtained results indicate that the Kleinia grandiflora leaf extract can serve as an effective inhibitor for the corrosion of mild steel in a sulfuric acid medium.
基金Supported by the National Natural Science Foundation of China(51361027)the Training Program of Young and Middle Aged Academic and Technological Leaders in Yunnan Province(2015HB049)
文摘The corrosion inhibition of cold rolled steel(CRS) in 7.0 mol·L^(-1) H_2 SO_4 solution by red tetrazolium(RTZ) was carefully investigated using both experimental procedures and theoretical techniques. The results show that RTZ acts as an effective inhibitor for the corrosion of CRS in 7.0 mol·L^(-1) H_2SO_4, and the maximum inhibition efficiency is higher than 95% with a RTZ concentration of 2.0 mmol·L^(-1). The adsorption of RTZ on CRS surface follows Langmuir isotherm. RTZ effectively retards both cathodic and anodic reactions, and acts as a mixed-type inhibitor. EIS exhibits two capacitive loops, and their resistances increase drastically in the presence of RTZ. SEM and AFM confirm that the addition of RTZ could significantly retard the corrosion of CRS surface. A series of characterizations like FTIR, RS, XRD and XPS reveal that the corrosion CRS surface is composed of the corrosion products of iron sulfates, iron oxides and iron hydroxide, as well as inhibitor. Theoretical results of quantum chemical calculation and molecular dynamics(MD) indicate that the adsorption center of RTZ+(organic cationic part of RTZ) mainly relies on its tetrazole ring,and the adsorption of RTZ+on Fe(001) surface is in a nearly flat orientation mode.
文摘Corrsion inhibition of Aloe lateritia gel for Mild steel in 2 M HNO<sub>3</sub> and 1 M H<sub>2</sub>SO<sub>4</sub> solutions was investigated by potentiodynamic polarization, Scanning electron microscopy (SEM) and Foutier transform infrared (FT-IR). Inhibition efficiency increased with the increase of the concentration of the gel. The optimal concentration of the gel gives maximum inhibition efficiency of 77.4% and 70.3% in 1 M H<sub>2</sub>SO<sub>4</sub> and 2 M HNO<sub>3</sub> respectively. Polarization plots shows that, the gel works as a mixed type inhibitor altering both cathodic and anodic reaction. SEM proves the uniform and pitting corrosion at the surface of Mild steel in 1 M H<sub>2</sub>SO<sub>4</sub> and 2 M HNO<sub>3</sub> respectively. Using FT-IR potential function groups from pure gel and some stretch shift was observed from corrosion product and some stretch shift from corrosion products was observed.
