This study investigated the effects of the Al2O3/SiO2 mass ratio and gas composition on the viscosity and structure of Cr-containing CaO-SiO2-MgO-Al2O3-CrOx stainless steel slags. The wet chemical analysis method was used to identify the Cr3+/Cr2+ ratio, and XPS (X-ray photoelectron spectroscopy) and 27Al MAS NMR (magic angle spinning nuclear magnetic resonance) were used to correlate the structural units comprising the melt to the viscosity measurements. The results showed that the break temperature (TBr) corresponded to the temperature when the crystallization fraction increased rapidly. When the Al2O3/SiO2 mass ratio was in the range between 0.125 and 1.0, the viscosity gradually increased as the Al2O3/SiO2 mass ratio increased. Similar viscosity trends were observed for gas compositions with higher oxygen partial pressures, which was correlated to an increased degree of polymerization (DOP) of the slag structure. In addition, the variation in the Cr3+/Cr2+ ratio, which decreased with increasing Al2O3/SiO2 mass ratios and increased with higher oxygen partial pressures, correlated well with the viscous behavior of the slags, the variation trends of [AlO4]- and [AlO5]-structural units, and the increased DOP of the slags.
Bibliographical noteFunding Information:
This work was supported by the third stage of the Brain Korea 21 Plus Project of the Division of Creative Materials in 2018 and the National Research Foundation of Korea (NRF) grant funded by the Korean government (MSIT) (No. 2018R1A2B2006609 ).
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Ceramics and Composites
- Process Chemistry and Technology
- Surfaces, Coatings and Films
- Materials Chemistry