Three types of anodic films(unsealed,hot water sealed and agent sealed)were prepared to study the effects of anodic film structure on the adhesive bonding performance of AA5754 automotive sheets.The morphology of the ...Three types of anodic films(unsealed,hot water sealed and agent sealed)were prepared to study the effects of anodic film structure on the adhesive bonding performance of AA5754 automotive sheets.The morphology of the anodic films was examined by using scanning electron microscope(SEM)and the composition was examined by glow discharge optical emission spectroscopy(GDOES).The adhesive bonding strength and the durability in corrosive environment were investigated by using single lap-hear test and salt spray test(SST),respectively.The results showed that the unsealed sample could provide high initial bonding strength,but the durability was poor in corrosive environment.The hot water sealed sample could provide high durability,but the bonding strength was low.In contrast,the agent sealed sample displayed porous structure at outer layer and partially plugged nano pores structure at inner layer,providing both excellent bonding strength and durability.展开更多
In this paper,effects of conditions in phenol sulfonic acid(PSA) plating for tin coating of MR low carbon aluminum killed steel on trace Pb were examined.Trace Pb was measured by atomic absorption spectrometry(AAS)and...In this paper,effects of conditions in phenol sulfonic acid(PSA) plating for tin coating of MR low carbon aluminum killed steel on trace Pb were examined.Trace Pb was measured by atomic absorption spectrometry(AAS)and glow discharge spectrometry,and coating morphology was observed by scanning electronic microscopy(SEM).Corrosion resistance of the tin coating was analyzed by electrochemical methods.The results indicated that Pb content in the tin coating reduced as bath temperature increased.When the temperature exceeded40 ℃,the grains in the coating were coarse and loose,reducing the corrosion resistance.As current density increased,Pb content increased rapidly,while low current density plating could lead to drain regions.The plating speed had no obvious effect on trace Pb in tin coating.In the tin plating layer,Pb was enriched at the surface and gradually reduced to zero along the depth.At bath temperature of 40 ℃ and current density of 20 A·dm^(-2),the amount of Pb could be less than 100 mg·kg^(-1) with excellent corrosion resistance.展开更多
A distributed feedback laser with a wavelength of 2.8μm was used to measure the species produced by water vapor glow discharge.Only the absorption spectra of OH radicals and transient H2O molecules were observed usin...A distributed feedback laser with a wavelength of 2.8μm was used to measure the species produced by water vapor glow discharge.Only the absorption spectra of OH radicals and transient H2O molecules were observed using concentration modulation(CM)spectroscopy.The intensities and orientations of the absorption peaks change with the demodulation phase,but the direction of one absorption peak of H2O is always opposite to the other peaks.The different spectral orientations of OH and H2O reflect the increase or the decrease of the number of particles in the energy levels.If more transient species can be detected in the discharge process,the dynamics of excitation,ionization,and decomposition of H2O can be better studied.This study shows that the demodulation phase relationship of CM spectrum can be used to study the population change of molecular energy levels.展开更多
The surface morphology of alloy layer of tinplate was studied by means of scanning electron microscopy. By using the layer on layer debonding technology of glow discharge spectrum, the contents of C and O at the bound...The surface morphology of alloy layer of tinplate was studied by means of scanning electron microscopy. By using the layer on layer debonding technology of glow discharge spectrum, the contents of C and O at the boundary of alloy layer and black plate were analyzed. And the corrosion characteristic of cavity of tinplate alloy layer was studied on-line and in-situ by means of electrochemical atomic force microscope. The corrosion depth of cavity of alloy layer in-situ after different corrosion time was measured. The results show that the cavity of alloy layer is a critical factor causing rapid decline of corrosion resistance of tinplate, and the formation of cavity of alloy layer is due to incorrect pretreatment of black plate before electrotinning. The cavity of alloy layer is the internal factor causing pitting corrosion of tinplate when the tinplate is applied to food packaging material. And the dynamic equation of pitting corrosion generated in the cavity of alloy layer conforms to logarithm law.展开更多
基金Project(2018MXJH17)supported by the Technology Foundation of Aluminum Corporation of China
文摘Three types of anodic films(unsealed,hot water sealed and agent sealed)were prepared to study the effects of anodic film structure on the adhesive bonding performance of AA5754 automotive sheets.The morphology of the anodic films was examined by using scanning electron microscope(SEM)and the composition was examined by glow discharge optical emission spectroscopy(GDOES).The adhesive bonding strength and the durability in corrosive environment were investigated by using single lap-hear test and salt spray test(SST),respectively.The results showed that the unsealed sample could provide high initial bonding strength,but the durability was poor in corrosive environment.The hot water sealed sample could provide high durability,but the bonding strength was low.In contrast,the agent sealed sample displayed porous structure at outer layer and partially plugged nano pores structure at inner layer,providing both excellent bonding strength and durability.
基金Supported by the Fundamental Research Funds for the Central Universities(04040022212005)
文摘In this paper,effects of conditions in phenol sulfonic acid(PSA) plating for tin coating of MR low carbon aluminum killed steel on trace Pb were examined.Trace Pb was measured by atomic absorption spectrometry(AAS)and glow discharge spectrometry,and coating morphology was observed by scanning electronic microscopy(SEM).Corrosion resistance of the tin coating was analyzed by electrochemical methods.The results indicated that Pb content in the tin coating reduced as bath temperature increased.When the temperature exceeded40 ℃,the grains in the coating were coarse and loose,reducing the corrosion resistance.As current density increased,Pb content increased rapidly,while low current density plating could lead to drain regions.The plating speed had no obvious effect on trace Pb in tin coating.In the tin plating layer,Pb was enriched at the surface and gradually reduced to zero along the depth.At bath temperature of 40 ℃ and current density of 20 A·dm^(-2),the amount of Pb could be less than 100 mg·kg^(-1) with excellent corrosion resistance.
基金the National Natural Science Foundation of China(No.61625501,No.61427816)the Open Fund of the State Key Laboratory of High Field Laser Physics(SIOM)the Open Fund of the State Key Laboratory of Precision Spectroscopy。
文摘A distributed feedback laser with a wavelength of 2.8μm was used to measure the species produced by water vapor glow discharge.Only the absorption spectra of OH radicals and transient H2O molecules were observed using concentration modulation(CM)spectroscopy.The intensities and orientations of the absorption peaks change with the demodulation phase,but the direction of one absorption peak of H2O is always opposite to the other peaks.The different spectral orientations of OH and H2O reflect the increase or the decrease of the number of particles in the energy levels.If more transient species can be detected in the discharge process,the dynamics of excitation,ionization,and decomposition of H2O can be better studied.This study shows that the demodulation phase relationship of CM spectrum can be used to study the population change of molecular energy levels.
文摘The surface morphology of alloy layer of tinplate was studied by means of scanning electron microscopy. By using the layer on layer debonding technology of glow discharge spectrum, the contents of C and O at the boundary of alloy layer and black plate were analyzed. And the corrosion characteristic of cavity of tinplate alloy layer was studied on-line and in-situ by means of electrochemical atomic force microscope. The corrosion depth of cavity of alloy layer in-situ after different corrosion time was measured. The results show that the cavity of alloy layer is a critical factor causing rapid decline of corrosion resistance of tinplate, and the formation of cavity of alloy layer is due to incorrect pretreatment of black plate before electrotinning. The cavity of alloy layer is the internal factor causing pitting corrosion of tinplate when the tinplate is applied to food packaging material. And the dynamic equation of pitting corrosion generated in the cavity of alloy layer conforms to logarithm law.
