Extraction of Nonmetallic Inclusion Particles Containing MgO from Steel

Extraction of inclusion particles from a metal matrix allows for accurate three-dimensional estimation of their morphology, size, and composition. In this study, the stability of MgO and MgAl2O4 particles was examined using acid, halogen-methanol, and nonaqueous electrolytes. These particles hardly dissolved in a 2% TEA-Ba (2 v/v% triethanolamine-1 w/v% tetramethylammoniumchloride-methanol containing 0.05–0.20 w/v% Ba) electrolyte. The potentiostatic extraction method using nonaqueous electrolytes with various Ba and H2O contents was examined for the extraction of MgO inclusion particles from metals. The O content of the extracted MgO and MgAl2O4 inclusion particles agreed approximately with the analyzed total O content of the metal. The Mg contents of the extracted inclusion particles were in agreement with those calculated using the results of two-dimensional measurements. Finally, it was concluded that 2% TEA-Ba was the most suitable for the electrolytic extraction of MgO and MgAl2O4 inclusion particles from steel.