VERIFICATION OF SANDELIN PHENOMENA IN MECHANICALLY ALLOYED FE-ZN AND FE-ZN-SI

Mechanical alloying through the ball-milling of elemental powders to f orm the zinc-rich zeta binary Fe-Zn alloy, and the ternaries consistin g of 0.12 mass%Si, 1.2 mass%Si, and 2.4 mass%Si, based on the same Fe/ Zn ratio was performed. These materials have been designated as zeta, zeta + 0.12 mass%Si, zeta + 1.2 mass%Si, and zeta + 2.4 mass%Si and me chanically alloyed to form their metastable states, eta-Zn, FeSi and z eta phases. Differential scanning calorimetry (DSC) measurements of th e materials show the presence of characteristic exothermic and endothe rmic reactions during their continuous transformation to stable equili brium states. In the zeta + 0.12 mass%Si material composition (i.e., S andelin region), wt: observe an invariant reaction peak at around 422 degrees C, corresponding to both the eutectic reaction in the Zn-Si an d the melting of Zn in the Fe-Zn systems. The observation of the FeSi phase for all the compositions, while absent in coatings of Si bearing steels suggests a relationship between the Sandelin effect and its fo rmation.