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Keywords:

  • ferroalloy;
  • non-metallic and metallic inclusions;
  • electrolytic extraction;
  • three-dimensional investigations

Abstract

As the requirements on material properties increase, there has been a demand on an additional knowledge on the effect of impurities in the ferroalloys on the properties. Thus, the number, morphology, size, and composition of inclusions in four different ferroalloys (FeTi, FeNb, FeSi, and SiMn) were investigated. This was done in three dimensions (3D) by using scanning electron microscopy in combination with energy dispersive spectroscopy after electrolytic extraction of the ferroalloy samples. The non-metallic and metallic inclusions were successfully analyzed on the surface of film filter. Thereafter, the particle size distribution was plotted for most of the non-metallic inclusions. The non-metallic inclusions were found to be REM oxides in FeTi, FeSi, and SiMn, Al2O3, Ti–Nb–S–O oxides in FeNb and silicon oxides in SiMn. Moreover, the intermetallic inclusions were found to be a Ti–Fe phase in FeTi, Ca–Si, and Fe–Si–Ti phases in FeSi and a Mn–Si phase in SiMn. In addition, the almost pure single metallic phases were found to be Ti in FeTi, Nb in FeNb, and Si in FeSi.