The Effect of Heat Treatment on the Fe—Sn Alloy System

Autor: J. P. G. Farr, T. J. Crichton
Rok vydání: 2004
Předmět:
Zdroj: Transactions of the IMF. 82:169-173
ISSN: 1745-9192
0020-2967
DOI: 10.1080/00202967.2004.11871585
Popis: The diffusion reaction of tin into pre-flow melted bright tinplate has been studied. It has been shown that the power index for the diffusion of tin to form the intermetallic layer increases from approximately 2 below 232°C to 5.6 at 350°C. Furthermore, the rate constant for alloy formation increases from I at 100°C to 331 at 225°C and to 2 x 10 6 at 250°C. At 350°C it reaches 6.3 × 10 6 . The activation energy for the formation of FeSn 2 is reduced from 19 kJ mol -1 K -1 for temperatures below the melting point of tin, to 7 kJ mol -1 K -1 for those above the melting point. Evidence for the presence of iron-tin alloys other than FeSn 2 is also presented. These alloys are only formed when the processing temperature exceeds 350°C and all the free tin has been depleted. These results provide a better understanding of the diffusion reaction between tin and iron when hot processing is used on tinplate and can be used to give better control to some processes. This improved control will minimise the adverse affects of heat treatment of tinplate that can result in both greying of the surface and maximise the amount of tin that can be reclaimed from scrap used tinplate.
Databáze: OpenAIRE