Three benzoxazole corrosion inhibitors, namely 2-(benzo [d]oxazol-2-yl)phenol (BOP), 6-(benzo [d]oxazol-2-yl)pyridin-2-ol (BOPO), and 2-(quinolin-2-yl) benzo [d]oxazole (QBO), were synthesized. Moreover, their corrosi...Three benzoxazole corrosion inhibitors, namely 2-(benzo [d]oxazol-2-yl)phenol (BOP), 6-(benzo [d]oxazol-2-yl)pyridin-2-ol (BOPO), and 2-(quinolin-2-yl) benzo [d]oxazole (QBO), were synthesized. Moreover, their corrosion inhibition performance for N80 steel in 1 M HCl solution at 303 K was measured by the electrochemical measurements and surface analysis studies. The results show that the inhibition efficiency of all corrosion inhibitors increases with the increase of concentration. At the same concentration, the order of inhibition efficiency is BOP < BOPO < QBO. Moreover, the studied inhibitors act as mixed-type inhibitors, and the adsorption of all inhibitors on N80 steel followed the Langmuir adsorption isotherm. Further, we have examined the effect of iodide ions on inhibition efficiency. The results show that BOP and KI are synergistic, BOPO and QBO are competitive adsorptions with KI. The quantum chemical parameters such as highest occupied molecular orbital, lowest unoccupied molecular orbital energy levels, and energy gap were calculated by the density functional theory (DTF). The relations between the inhibition efficiency and some quantum parameters have been discussed. The protective effect of the three inhibitors followed the sequence of BOP < BOPO < QBO. The results obtained from quantum chemicals and electrochemical were in reasonable agreement.展开更多
A novel and effective water-soluble aldehydes(β-HA)as corrosion inhibitor was synthesized for N80 steel corro-sion in 15%HCl solution,and the corrosion inhibition performance was evaluated by using weight loss,electr...A novel and effective water-soluble aldehydes(β-HA)as corrosion inhibitor was synthesized for N80 steel corro-sion in 15%HCl solution,and the corrosion inhibition performance was evaluated by using weight loss,electro-chemical measurements,scanning electron microscope(SEM),quantum chemical calculation and molecular dynamics simulation(MDS).The results show that synthesizedβ-HA showed excellent corrosion performance compared with MHB and PE for carbon steel in 15%HCl solution compared with MHB and PE,and the inhibi-tion efficiency increased with increasing concentration of the inhibitor.The inhibition efficiency of β-HA at 8 mmol/L reached the maximum value 94.08%.The inhibitor acted as mixed-type inhibitor via blocking both the anodic and cathodic reaction.The adsorption of inhibitors on N80 steel surface obeyed Langmuir adsorption isotherm,and the process contained chemisorption and physisorption.TheΔG ads of β-HA was−28.81 kJ·mol^(-1)der the standard atmospheric pressure.Moreover,the theoretical calculation parameters revealed stronger combination and higher interaction energy for inhibitor β-HA comparing with MHB and PE,further demonstrat-ing the correlation between the theoretical and experimental results.展开更多
To investigate the correlation between structure characteristics and wear resistance of CO2 corrosion product scales at high temperature and high pressure, an autoclave was used to prepare CO2 corrosion product scales...To investigate the correlation between structure characteristics and wear resistance of CO2 corrosion product scales at high temperature and high pressure, an autoclave was used to prepare CO2 corrosion product scales on N80 steel in carbon dioxide corrosion environment. The correlation between wear resistance of the scales and many other factors, such as temperature, pressure, morphology, structure, velocity of fluid medium, sand grain size, and so on, was comparatively analyzed by a self assembled wear device, and the scale morphologies before or after being worn were observed by scanning electron microscope （SEM）. And then the surface grain size and thickness of scale were measured. The results showed that the cross-section of the corrosion scale was of a double-layer structure, the outer layer of which was composed of regular crystals, whereas the inner layer was a thin scale of fine grains. The outer grain size and thickness of scale varied with temperature, and the initial wear loss was consistent with the surface grain size; at the same time, the total wear loss corresponded to the thickness of scale. Compared to wear resist- ance in different depths of the scale, it was found that the structure of scale was a double-layer structure in cross-section, and the wear resistance of inner layer was better than that of the outer layer; the closer the scale to the matrix, the greater was the wear resistance of scale; and the larger the size or the higher the rotary speed of solid grain in multiphase flowing medium, the more was the wear loss of scale.展开更多
A novel imidazoline compound SEI was synthesized from benzaldehyde,triethylenetetramine and crylic acid.Its structure was characterized by IR spectrum.The corrosion-inhibition was studied through electrochemical imped...A novel imidazoline compound SEI was synthesized from benzaldehyde,triethylenetetramine and crylic acid.Its structure was characterized by IR spectrum.The corrosion-inhibition was studied through electrochemical impedance spectroscopy(EIS),potentiodynamic polarization curves and gravimetric measurements.The obtained results showed that SEI revealed a good corrosion-inhibitor and performed pretty inhibiting efficiency for N-80 steel in 1mol/L HCl solution.The inhibition efficiency was high with addition of 10 mg/L SEI in 1 mol/L HCl solution.The effect of temperature for inhibition efficiency was also studied,the result show the inhibition efficiency decreased with the increased of temperature,but the inhibition efficiency was over 80% when the temperature was 50℃.展开更多
The relationship between microstructures and mechanical properties of a medium carbon V-N microalloyed steel used for N80 seamless oil-well tubes of hot rolling non-quenched/tempered (non-Q and T) was investigated.The...The relationship between microstructures and mechanical properties of a medium carbon V-N microalloyed steel used for N80 seamless oil-well tubes of hot rolling non-quenched/tempered (non-Q and T) was investigated.The results have shown that volume percentages of upper bainite,modified bainite and ferrite have a decisive influence on impact energies of steel tubes.When the total volume percentage of bainite is larger than 5%,the impact energy of tubes can not satisfy with the industrial criteria.Moreover,if the total volume percentage of bainite is smaller than 5%,then the impact energy of steel tubes enhances with volume percentage of ferrite increasing.The final microstructures have closely relation with tube billet quality,controlled cooling temperature after tube rolling and cooling method after stretch-reduction-diameter.High quality of medium carbon V-N microalloyed steel for non-Q and T oil-well tubes can be produced through comprehensive control of microstructures and mechanical properties in sub-procedures,especially for tube billet quality and controlled cooling parameters.展开更多
文摘Three benzoxazole corrosion inhibitors, namely 2-(benzo [d]oxazol-2-yl)phenol (BOP), 6-(benzo [d]oxazol-2-yl)pyridin-2-ol (BOPO), and 2-(quinolin-2-yl) benzo [d]oxazole (QBO), were synthesized. Moreover, their corrosion inhibition performance for N80 steel in 1 M HCl solution at 303 K was measured by the electrochemical measurements and surface analysis studies. The results show that the inhibition efficiency of all corrosion inhibitors increases with the increase of concentration. At the same concentration, the order of inhibition efficiency is BOP < BOPO < QBO. Moreover, the studied inhibitors act as mixed-type inhibitors, and the adsorption of all inhibitors on N80 steel followed the Langmuir adsorption isotherm. Further, we have examined the effect of iodide ions on inhibition efficiency. The results show that BOP and KI are synergistic, BOPO and QBO are competitive adsorptions with KI. The quantum chemical parameters such as highest occupied molecular orbital, lowest unoccupied molecular orbital energy levels, and energy gap were calculated by the density functional theory (DTF). The relations between the inhibition efficiency and some quantum parameters have been discussed. The protective effect of the three inhibitors followed the sequence of BOP < BOPO < QBO. The results obtained from quantum chemicals and electrochemical were in reasonable agreement.
基金This work was supported by the National Science and Technology Major Project of China(Grant No.2016ZX05028–004)the Fundamental Research Funds for the Central Universities(Grant No.FRF-IC-18–007).
文摘A novel and effective water-soluble aldehydes(β-HA)as corrosion inhibitor was synthesized for N80 steel corro-sion in 15%HCl solution,and the corrosion inhibition performance was evaluated by using weight loss,electro-chemical measurements,scanning electron microscope(SEM),quantum chemical calculation and molecular dynamics simulation(MDS).The results show that synthesizedβ-HA showed excellent corrosion performance compared with MHB and PE for carbon steel in 15%HCl solution compared with MHB and PE,and the inhibi-tion efficiency increased with increasing concentration of the inhibitor.The inhibition efficiency of β-HA at 8 mmol/L reached the maximum value 94.08%.The inhibitor acted as mixed-type inhibitor via blocking both the anodic and cathodic reaction.The adsorption of inhibitors on N80 steel surface obeyed Langmuir adsorption isotherm,and the process contained chemisorption and physisorption.TheΔG ads of β-HA was−28.81 kJ·mol^(-1)der the standard atmospheric pressure.Moreover,the theoretical calculation parameters revealed stronger combination and higher interaction energy for inhibitor β-HA comparing with MHB and PE,further demonstrat-ing the correlation between the theoretical and experimental results.
基金Item Sponsored by National Natural Science Foundation of China (50231020) , National Basic Research Programof China(G1999065004) ,2001'Key Laboratory Opening Fund of Corrosion and Protection of Tabular Goods Research Center of ChinaNational Petroleum Corporation (ZYT-01070)
文摘To investigate the correlation between structure characteristics and wear resistance of CO2 corrosion product scales at high temperature and high pressure, an autoclave was used to prepare CO2 corrosion product scales on N80 steel in carbon dioxide corrosion environment. The correlation between wear resistance of the scales and many other factors, such as temperature, pressure, morphology, structure, velocity of fluid medium, sand grain size, and so on, was comparatively analyzed by a self assembled wear device, and the scale morphologies before or after being worn were observed by scanning electron microscope （SEM）. And then the surface grain size and thickness of scale were measured. The results showed that the cross-section of the corrosion scale was of a double-layer structure, the outer layer of which was composed of regular crystals, whereas the inner layer was a thin scale of fine grains. The outer grain size and thickness of scale varied with temperature, and the initial wear loss was consistent with the surface grain size; at the same time, the total wear loss corresponded to the thickness of scale. Compared to wear resist- ance in different depths of the scale, it was found that the structure of scale was a double-layer structure in cross-section, and the wear resistance of inner layer was better than that of the outer layer; the closer the scale to the matrix, the greater was the wear resistance of scale; and the larger the size or the higher the rotary speed of solid grain in multiphase flowing medium, the more was the wear loss of scale.
文摘A novel imidazoline compound SEI was synthesized from benzaldehyde,triethylenetetramine and crylic acid.Its structure was characterized by IR spectrum.The corrosion-inhibition was studied through electrochemical impedance spectroscopy(EIS),potentiodynamic polarization curves and gravimetric measurements.The obtained results showed that SEI revealed a good corrosion-inhibitor and performed pretty inhibiting efficiency for N-80 steel in 1mol/L HCl solution.The inhibition efficiency was high with addition of 10 mg/L SEI in 1 mol/L HCl solution.The effect of temperature for inhibition efficiency was also studied,the result show the inhibition efficiency decreased with the increased of temperature,but the inhibition efficiency was over 80% when the temperature was 50℃.
基金financial support from Chinese National Nature Science Fund(Project No.50271009and No.51071019)Wuxi Seamless Steel Tube Company,Ltdthe Vanadium International Technical Committee via the CSM
文摘The relationship between microstructures and mechanical properties of a medium carbon V-N microalloyed steel used for N80 seamless oil-well tubes of hot rolling non-quenched/tempered (non-Q and T) was investigated.The results have shown that volume percentages of upper bainite,modified bainite and ferrite have a decisive influence on impact energies of steel tubes.When the total volume percentage of bainite is larger than 5%,the impact energy of tubes can not satisfy with the industrial criteria.Moreover,if the total volume percentage of bainite is smaller than 5%,then the impact energy of steel tubes enhances with volume percentage of ferrite increasing.The final microstructures have closely relation with tube billet quality,controlled cooling temperature after tube rolling and cooling method after stretch-reduction-diameter.High quality of medium carbon V-N microalloyed steel for non-Q and T oil-well tubes can be produced through comprehensive control of microstructures and mechanical properties in sub-procedures,especially for tube billet quality and controlled cooling parameters.
