The corrosion rate and interface capacity of steel in 0.5mol/L H 2SO 4+0 5mol/L Na 2SO 4 solution containing methyl red were measured by curve-fitting method of polarization data and Ac impedance technique at 20℃.The...The corrosion rate and interface capacity of steel in 0.5mol/L H 2SO 4+0 5mol/L Na 2SO 4 solution containing methyl red were measured by curve-fitting method of polarization data and Ac impedance technique at 20℃.The degree of coverage of methyl red on steel surface was calculated.The degree of coverage was found to increase with the increasing of concentration of methyl red.The experimental data were treated with adsorption kinetic theory,too.It was found that adsorption of methyl red on steel surface in the acidic solutions was a substitution adsorption process and one water molecule was displaced by each adsorbed methyl molecule.The experimental result shows that at 20℃ the adsorption behavior follows the isotherm θ/ =1/55.5exp[27808-972 θ)/RT ].The ideal surface adsorption free energy was calculated.The interface capacity of steel decreases with the increasing of the degree of surface coverage in acidic solutions at 20℃.展开更多
为探究酸性溶液作用下花岗岩力学特性损伤机制,在pH值分别为7、5、3的化学溶液中对花岗岩试件进行72 d饱和处理,然后对饱和试件和自然干燥试件进行三轴压缩试验、核磁共振试验、电镜扫描试验(scanning electron microscope, SEM)及X射...为探究酸性溶液作用下花岗岩力学特性损伤机制,在pH值分别为7、5、3的化学溶液中对花岗岩试件进行72 d饱和处理,然后对饱和试件和自然干燥试件进行三轴压缩试验、核磁共振试验、电镜扫描试验(scanning electron microscope, SEM)及X射线衍射试验,并对比分析不同化学溶液作用下花岗岩试件三轴抗压强度损伤、变形特征及力学参数的变化规律。试验结果表明:1)花岗岩试件的三轴抗压强度、弹性模量及黏聚力随酸性溶液pH值降低而减小,泊松比随着pH值的降低而增大;2)在酸性溶液的腐蚀作用下,试件内斜长石及方解石等矿物成分的消耗导致试件内部结构疏松程度增加,强酸作用下伴有微裂隙产生;3)与自然干燥状态下的试件相比,在围压20 MPa的条件下经pH=3的酸性溶液酸化处理后的试件,其偏应力峰值强度降幅达39.94%;4)花岗岩在酸性溶液作用下,部分矿物溶解、迁出,使得孔隙结构不断劣化产生大量次生孔隙,且酸性溶液pH值越低,中、大孔隙占比越高。展开更多
文摘The corrosion rate and interface capacity of steel in 0.5mol/L H 2SO 4+0 5mol/L Na 2SO 4 solution containing methyl red were measured by curve-fitting method of polarization data and Ac impedance technique at 20℃.The degree of coverage of methyl red on steel surface was calculated.The degree of coverage was found to increase with the increasing of concentration of methyl red.The experimental data were treated with adsorption kinetic theory,too.It was found that adsorption of methyl red on steel surface in the acidic solutions was a substitution adsorption process and one water molecule was displaced by each adsorbed methyl molecule.The experimental result shows that at 20℃ the adsorption behavior follows the isotherm θ/ =1/55.5exp[27808-972 θ)/RT ].The ideal surface adsorption free energy was calculated.The interface capacity of steel decreases with the increasing of the degree of surface coverage in acidic solutions at 20℃.
