[en] Cassava starch graft copolymer (CSGC) was prepared by grafting acryl amide (AA) onto cassava starch (CS). The inhibition effect of CSGC on the corrosion of cold rolled steel (CRS) in 1.0M H_2SO_4 solution was first studied by weight loss, potentiodynamic polarization curves, electrochemical impedance spectroscopy (EIS) and scanning electron microscope (SEM) methods. The results show that CSGC is a good inhibitor, and inhibition efficiency of CSGC is higher than that of CS or AA. The adsorption of CSGC on steel surface obeys Langmuir adsorption isotherm. CSGC is a mixed-type inhibitor at 20 .deg. C, while mainly a cathodic inhibitor at 50 .deg. C.

[en] Highlights: ► Ginkgo leaves extract (GLE) acts as a good inhibitor for steel in HCl and H₂SO₄ media. ► The inhibition efficiency follows the order: HCl > H₂SO₄. ► The adsorption of GLE on steel surface obeys Langmuir adsorption isotherm. ► GLE behaves as a mixed-type inhibitor in 1.0 M HCl, while cathodic inhibitor in 0.5 M H₂SO₄. - Abstract: The inhibition effect of Ginkgo leaves extract (GLE) on the corrosion of cold rolled steel (CRS) in 1.0–5.0 M HCl and 0.5–2.5 M H₂SO₄ solutions was investigated for the first time by weight loss, potentiodynamic polarization curves, electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM) methods. The results show that GLE is a good inhibitor, and exhibits more efficient in 1.0 M HCl than 0.5 M H₂SO₄. The adsorption of GLE on CRS surface obeys Langmuir adsorption isotherm. GLE acts as a mixed-type inhibitor in 1.0 M HCl, while a cathodic inhibitor in 0.5 M H₂SO₄.

[en] Highlights: ► DBLE is a good inhibitor for aluminum in HCl, while a moderate inhibitor in H₃PO₄. ► The inhibition performance between in HCl and in H₃PO₄ is compared in detail. ► The adsorption of DBLE obeys Langmuir adsorption isotherm. ► DBLE acts as a cathodic inhibitor in HCl, while a mixed-type inhibitor in H₃PO₄. ► EIS exhibits an elliptic shape in HCl, while contains three time constants in H₃PO₄. - Abstract: The inhibition effect of Dendrocalamus brandisii leaves extract (DBLE) on the corrosion of aluminum in HCl, H₃PO₄ solutions was studied by weight loss, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM) methods. Effects of temperature, immersion time and acid concentration on corrosion inhibition were fully discussed. The results show that DBLE is a good inhibitor in 1.0 M HCl, while a moderate inhibitor in H₃PO₄. The adsorption of DBLE on aluminum surface obeys Langmuir isotherm in both acids. DBLE acts as a cathodic inhibitor in HCl, while a mixed-type inhibitor in H₃PO₄.

[en] Highlights: ► JNLLE is a new inhibitor for aluminium corrosion in 1.0 M HCl. ► The adsorption of JNLLE obeys Langmuir adsorption isotherm. ► The adsorption of JNLLE is mainly the physical adsorption. ► Effects of immersion time and acid concentration on inhibition are discussed. ► JNLLE behaves as a cathodic inhibitor, EIS exhibits an elliptic shape. - Abstract: The inhibition effect of Jasminum nudiflorum Lindl. leaves extract (JNLLE) on the corrosion of aluminium in HCl solution was studied by weight loss, polarization curves, electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM) methods. The results show that JNLLE is a good inhibitor in 1.0 M HCl, and the adsorption of JNLLE obeys Langmuir adsorption isotherm. Effects of immersion time and acid concentration on inhibitive performance were discussed. Polarization curves reveal that JNLLE acts as the cathodic inhibitor. EIS exhibits a large capacitive loop at high frequencies followed by a large inductive one at low frequency values.

[en] Research highlights: → Two pyrazine derivatives of 2-aminopyrazine (AP) and 2-amino-5-bromopyrazine (ABP) are good inhibitors for the corrosion of steel in 1.0 M HCl solution. → The inhibition efficiency follows the order: ABP > AP. The substitution Br of ABP is the additional centre of adsorption and increases the electron density of pyrazine ring, which can facilitate its adsorption on the metal surface. → For either ABP or AP, the adsorption obeys Langmuir adsorption isotherm. → Both ABP and AP act as mixed-type inhibitors. - Abstract: The inhibition effect of two pyrazine derivatives of 2-aminopyrazine (AP) and 2-amino-5-bromopyrazine (ABP) on the corrosion of cold rolled steel (CRS) in 1.0 M hydrochloric acid (HCl) was studied by weight loss, potentiodynamic polarization curves, and electrochemical impedance spectroscopy (EIS) methods. The results show that both AP and ABP are good inhibitors, and inhibition efficiency follows the order: ABP > AP. The adsorption of each inhibitor on CRS surface obeys Langmuir adsorption isotherm. Potentiodynamic polarization curves show that two pyrazine derivatives act as mixed-type inhibitors. EIS spectra exhibit one capacitive loop and confirm the inhibitive ability.

[en] Research highlights: → Acid violet 6B (AV6B) is found to be a good inhibitor for the corrosion of CRS in 1.0 M HCl. → Effects of hydrochloric acid concentration (1.0 - 5.0 M) and immersion time (2 - 144 h) are discussed in detail. → The corrosion inhibition is satisfactorily discussed by both thermodynamic and kinetic parameters. → AV6B acts as a mixed-type inhibitor. → The adsorption of AV6B obeys Langmuir adsorption isotherm. - Abstract: The inhibition effect of acid violet 6B (AV6B) on the corrosion of cold rolled steel (CRS) in 1.0-5.0 M HCl solution was studied for the first time by weight loss, potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS) methods. The results show that AV6B is a very good inhibitor in 1.0 M HCl, and the adsorption of AV6B on CRS surface obeys Langmuir adsorption isotherm. Polarization curves reveal that AV6B behaves as a mixed-type inhibitor. EIS spectra exhibit one capacitive loop and confirm the inhibitive ability. Effects of immersion time and acid concentration on inhibition performance were also discussed.

[en] Highlights: ► Bamboo leaves extract is a good inhibitor for steel in 1.0 M HCl and 0.5 M H₂SO₄. ► The inhibition efficiency follows the order: HCl > H₂SO₄. ► The adsorption of DSCLE on steel surface obeys Langmuir adsorption isotherm. ► Inhibition efficiency remains constant even at rather long immersion time. ► DSCLE behaves as a mixed-type inhibitor in 1.0 M HCl and 0.5 M H₂SO₄. - Abstract: The inhibition effect of the bamboo of Dendrocalmus sinicus Chia et J.L. Sun leaf extract (DSCLE) on the corrosion of cold rolled steel (CRS) in 1.0–5.0 M HCl, 0.5–5.0 M H₂SO₄ solutions was studied by weight loss, potentiodynamic polarization curves, electrochemical impedance spectroscopy (EIS) and atomic force microscope (AFM) methods. The results show that DSCLE is a good inhibitor in 1.0 M HCl and 0.5 M H₂SO₄, and inhibition efficiency follows the order: HCl > H₂SO₄. The adsorption of DSCLE on CRS surface obeys Langmuir adsorption isotherm, and acts as a mixed-type inhibitor in both acids.

[en] Research highlights: → Triazolyl blue tetrazolium bromide (TBTB) is found to be a novel good inhibitor for the corrosion of CRS in 1.0 M HCl and 0.5 M H₂SO₄ solutions. → The comparison of inhibition performance in HCl and that in H₂SO₄ are discussed in detail. → The corrosion inhibition is satisfactorily discussed by adsorption mode and thermodynamic parameter. → The electrochemical inhibitive mechanism is explained by potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS) results. → The adsorption of TBTB is presented. - Abstract: The inhibition effect of triazolyl blue tetrazolium bromide (TBTB) on the corrosion of cold rolled steel (CRS) in 1.0 M HCl and 0.5 M H₂SO₄ solution was investigated for the first time by weight loss, potentiodynamic polarization curves, and electrochemical impedance spectroscopy (EIS) methods. The results show that TBTB is a very good inhibitor, and is more efficiency in 1.0 M HCl than 0.5 M H₂SO₄. The adsorption of TBTB on CRS surface obeys Langmuir adsorption isotherm. Polarization curves reveal that TBTB acts as a mixed-type inhibitor in both acids.

[en] The inhibition effect of blue tetrazolium (BT) on the corrosion of cold rolled steel (CRS) in 1.0 M HCl solution at 20 ^oC was investigated by weight loss, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), and scanning electron microscopy (SEM) methods. The results show that BT is a very good inhibitor, and the adsorption of BT on CRS surface obeys Langmuir adsorption isotherm. Polarization curves reveal that BT acts as a mixed-type inhibitor. EIS spectra exhibit one capacitive loop and confirm the inhibitive ability. The inhibition action of BT is also evidenced by SEM images.

[en] The synergistic inhibition effect of red tetrazolium (RT) and uracil (Ur) on the corrosion of cold rolled steel (CRS) in 1.0-10.0 M H₃PO₄ solution was first studied by weight loss and potentiodynamic polarization methods. Atomic force microscope (AFM) provided the CRS surface conditions. The results revealed that RT had a moderate inhibitive effect, and the adsorption of RT obeyed the Freundlich adsorption isotherm. Polarization curves showed that RT was a mixed-type inhibitor in phosphoric acid. For the Ur, it had a poor inhibition effect, and acted as a cathodic inhibitor. However, incorporation of RT with Ur improved significantly the inhibition performance. The inhibition efficiency (IE) for RT in combination with Ur was higher than the summation of IE for single RT and single Ur, which was synergism in nature. Polarization studies showed that the RT/Ur mixture acted as a mixed-type inhibitor, which drastically inhibited both anodic and cathodic reactions. The synergistic inhibition effect of RT and Ur could also be evidenced by AFM images. Depending on the results, the synergism mechanism was discussed from the viewpoint of co-adsorption.