The corrosion behaviors and electrochemical properties of Q235 A steel in the treated water containing corrosive halide anions(F-, Cl-) have been investigated with corrosion tests of static coupon and dynamic coupon t...The corrosion behaviors and electrochemical properties of Q235 A steel in the treated water containing corrosive halide anions(F-, Cl-) have been investigated with corrosion tests of static coupon and dynamic coupon testing, electrochemical measurement of open-circuit potential and linear sweep voltammetry. The results reveal that the existence of F-and Cl-ions in the simulated treated water accelerate the corrosion rate of Q235 A steel. The corrosion rate reaches maximum with F-concentration of 50 mg/L, Cl-concentration of 200 mg/L, respectively. However, Q235 A steel would passivate when an applied potential is added to the system. Meanwhile, the initiating passive potential becomes positive with F-, Cl-concentration increasing. There is a little influence of F-, Cl-concentration on the initiating passivation current density. Therefore, it is necessary to control F-, Cl-concentration in the treated water when it is recycled by the pipelines made of Q235 A steel.展开更多
The corrugated packing is prone to break down easily, which can affect the tower efficiency substantially. It is the inner environment of the vacuum distillation tower including the temperature and chemical nature of ...The corrugated packing is prone to break down easily, which can affect the tower efficiency substantially. It is the inner environment of the vacuum distillation tower including the temperature and chemical nature of fluid that lead to the packing damage. The theoretical analysis indicates that it is the inner material flow of vacuum distillation tower that leads to the vibration of packing, which can affect the corrosion fatigue of packing significantly. Meanwhile, the modal shape and inherent frequency of packing under prestress can be obtained by means of mathematical analysis. Based on the two kinds of analysis, the flow induced vibration and corrosion fatigue are accountable for the failure of packing.展开更多
The results of experimental works aimed on finding the optimal composition of concretes containing alternative materials as mineral additives for assurance their high resistance to chemical aggressive attack are prese...The results of experimental works aimed on finding the optimal composition of concretes containing alternative materials as mineral additives for assurance their high resistance to chemical aggressive attack are presented in the paper. 4 kinds of additives （blast furnace slag, fly ash, non-treated and treated serpentinite waste） and 4 kinds of aggressive environments （distilled water, HCI, MgSO4 and NaOH） representing the concrete corrosive processes was checked within experimental process. The open laboratory curing was used as a reference environment. Moreover, the amounts of additives were varied, so 16 various recipes were checked on the whole. The resistance of samples was tested in the terms of flexural strength, compressive strength and evaluation of decrease/increase of strengths after long time （28 months） exposition in monitored aggressive media. Based on obtained results, it is possible for each of aggressive environments recommend the most promising recipe from various points of view, in accordance with user＇s priorities. From the percentage increase of 28-day compressive strengths point of view, there are： for HCI action - recipe with 20% of non treated serpentinite waste with plasticizer application, for MgSO4 action - recipe with 20% of blast furnace slag without plasticizer application and for NaOH action - recipe with 10% of non treated serpentinite waste without plasticizer application. Application of alternative materials as partial substitution of cement appears to be beneficial for achievement the resistance to aggressive chemical actions. With the keeping or enhancement of technical parameters it extra represents both the environmental and economic benefit.展开更多
In this paper the corrosion characteristics of Silicon carbide particulate-reinforced 6061 aluminum composite （ 6061 AI/SiCp composite ） and the base alloy are experimentally assessed. The corrosion tests are carrie...In this paper the corrosion characteristics of Silicon carbide particulate-reinforced 6061 aluminum composite （ 6061 AI/SiCp composite ） and the base alloy are experimentally assessed. The corrosion tests are carried out at different temperatures in the concentration range of 0.01N to 1N sulphuric acid as corrosion media using Tafel extrapolation technique and Electrochemical Impedance Spectroscopy （EIS）. The results obtained from Tafel extrapolation technique and Electrochemical Impedance Spectroscopy are in good agreement. The results show an increase in the corrosion rate with increase in temperature as well as with increase in the concentration of the corrosion media. The thermodynamic parameters like energy of activation are calculated using Arrhenius theory equation and, enthalpy of activation and entropy of activation are calculated using transition state theory equation.展开更多
基金Project(2018YFC1900304)supported by the National Key R&D Program of ChinaProject(2018SK2026)supported by the Key R&D Program of Hunan Province,ChinaProject(2017SK2420)supported by the Science and Technology of Hunan Province,China。
文摘The corrosion behaviors and electrochemical properties of Q235 A steel in the treated water containing corrosive halide anions(F-, Cl-) have been investigated with corrosion tests of static coupon and dynamic coupon testing, electrochemical measurement of open-circuit potential and linear sweep voltammetry. The results reveal that the existence of F-and Cl-ions in the simulated treated water accelerate the corrosion rate of Q235 A steel. The corrosion rate reaches maximum with F-concentration of 50 mg/L, Cl-concentration of 200 mg/L, respectively. However, Q235 A steel would passivate when an applied potential is added to the system. Meanwhile, the initiating passive potential becomes positive with F-, Cl-concentration increasing. There is a little influence of F-, Cl-concentration on the initiating passivation current density. Therefore, it is necessary to control F-, Cl-concentration in the treated water when it is recycled by the pipelines made of Q235 A steel.
文摘The corrugated packing is prone to break down easily, which can affect the tower efficiency substantially. It is the inner environment of the vacuum distillation tower including the temperature and chemical nature of fluid that lead to the packing damage. The theoretical analysis indicates that it is the inner material flow of vacuum distillation tower that leads to the vibration of packing, which can affect the corrosion fatigue of packing significantly. Meanwhile, the modal shape and inherent frequency of packing under prestress can be obtained by means of mathematical analysis. Based on the two kinds of analysis, the flow induced vibration and corrosion fatigue are accountable for the failure of packing.
文摘The results of experimental works aimed on finding the optimal composition of concretes containing alternative materials as mineral additives for assurance their high resistance to chemical aggressive attack are presented in the paper. 4 kinds of additives （blast furnace slag, fly ash, non-treated and treated serpentinite waste） and 4 kinds of aggressive environments （distilled water, HCI, MgSO4 and NaOH） representing the concrete corrosive processes was checked within experimental process. The open laboratory curing was used as a reference environment. Moreover, the amounts of additives were varied, so 16 various recipes were checked on the whole. The resistance of samples was tested in the terms of flexural strength, compressive strength and evaluation of decrease/increase of strengths after long time （28 months） exposition in monitored aggressive media. Based on obtained results, it is possible for each of aggressive environments recommend the most promising recipe from various points of view, in accordance with user＇s priorities. From the percentage increase of 28-day compressive strengths point of view, there are： for HCI action - recipe with 20% of non treated serpentinite waste with plasticizer application, for MgSO4 action - recipe with 20% of blast furnace slag without plasticizer application and for NaOH action - recipe with 10% of non treated serpentinite waste without plasticizer application. Application of alternative materials as partial substitution of cement appears to be beneficial for achievement the resistance to aggressive chemical actions. With the keeping or enhancement of technical parameters it extra represents both the environmental and economic benefit.
文摘In this paper the corrosion characteristics of Silicon carbide particulate-reinforced 6061 aluminum composite （ 6061 AI/SiCp composite ） and the base alloy are experimentally assessed. The corrosion tests are carried out at different temperatures in the concentration range of 0.01N to 1N sulphuric acid as corrosion media using Tafel extrapolation technique and Electrochemical Impedance Spectroscopy （EIS）. The results obtained from Tafel extrapolation technique and Electrochemical Impedance Spectroscopy are in good agreement. The results show an increase in the corrosion rate with increase in temperature as well as with increase in the concentration of the corrosion media. The thermodynamic parameters like energy of activation are calculated using Arrhenius theory equation and, enthalpy of activation and entropy of activation are calculated using transition state theory equation.
