[57]Fe Mossbauer spectroscopy and complementary analysis of tin coated steel.

[57]Fe Conversion Electron Mossbauer Spectroscopy (CEMS) has been used to identify intermetallic products in commercially and laboratory produced tinplated steels. By removing the tin overlayers using a potassium iodate / sodium hydroxide solution any intermetallics from the uppermost surface layer of the samples and can be identified. Commercially produced DWI tinplate shows some signs of FeSn2 on the ironed walls where temperatures reach 200°C, and no intermetallics on the base where compressive force has been used to compact the tinplate to a required thickness. By heat treating laboratory produced tin electroplated steel, intermetallics have been formed and identified as FeSn[2] using CEMS. The formation of these intermetallics at heat treatments of different temperatures and times has been investigated. The effect of steel surface roughness on the electrodeposition and subsequent identification of the intermetallics formed has also been investigated and increased substrate roughness was found to effectively increase the substrate signal. Carbon coating of the DWI can wall after etching was carried out. Such a technique is shown to be useful when analysing the samples using CEMS as there is an increased differentiation of signal between the substrate and the intermetallics dwelling on the surface.