摘要
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.
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
Supported by the Fundamental Research Funds for the Central Universities(04040022212005)
