University of Oulu

Gyakwaa, F.; Aula, M.; Alatarvas, T.; Vuolio, T.; Shu, Q.; Huttula, M.; Fabritius, T. Application of Raman Spectroscopy for Characterizing Synthetic Non-Metallic Inclusions Consisting of Calcium Sulphide and Oxides. Appl. Sci. 2020, 10, 2113.

Application of Raman spectroscopy for characterizing synthetic non-metallic inclusions consisting of calcium sulphide and oxides

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Author: Gyakwaa, Francis1; Aula, Matti1; Alatarvas, Tuomas1;
Organizations: 1Process Metallurgy Research Unit, University of Oulu, P.O. Box 4300, FI–90014 Oulu, Finland
2Nano and Molecular Systems Research Unit (NANOMO), University of Oulu, P.O. Box 4300, FI–90014 Oulu, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 6.2 MB)
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Language: English
Published: Multidisciplinary Digital Publishing Institute, 2020
Publish Date: 2020-06-23


The presence of non-metallic inclusions (NMI) such as sulphides and oxides may be detrimental to the control of the steel casting process and product quality. The need for their identification and characterization is, therefore, urgent. This study uses time-gated Raman spectroscopy for the characterization of synthetic duplex oxide-sulphide phases that contain CaS and the oxide phases of Al₂O₃, CA, C12A7, C3A, and MgO·Al₂O₃ (MA). Binary phase samples of CaS–MA, C3A–CaS, C12A7–CaS, Al₂O₃–CaS, and MA–CaS were prepared with varying phase contents. The relative intensities of the Raman peaks were used to estimate the samples’ phase content. For a quantitative estimation, linear regression calibration models were used to evaluate the change in phase content in the samples. The most suitable Raman peak ratios had mean absolute error (MAE) values ranging from 3 to 7 wt. % for the external validation error, and coefficients of determination (R²) values between 0.94 and 0.98. This study demonstrated the use of Raman spectroscopy for the characterization of the calcium sulphide, magnesium aluminate spinel, Al₂O₃, and calcium aluminate phases of CA, C3A, and C12A7 in a duplex oxide-sulphide system, and it offers potential for inclusion characterization in steel.

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Series: Applied sciences
ISSN: 2076-3417
ISSN-E: 2076-3417
ISSN-L: 2076-3417
Volume: 10
Issue: 6
Article number: 2113
DOI: 10.3390/app10062113
Type of Publication: A1 Journal article – refereed
Field of Science: 216 Materials engineering
114 Physical sciences
Funding: Research is funded due I4Future doctoral program funded by the European Union’s H2020 under the Marie Skłodowska-Curie grant agreement No. 713606 and the Academy of Finland Profilation Project (Academy of Finland, No. 311934).
EU Grant Number: (713606) I4FUTURE - Novel Imaging and Characterisation Methods in Bio, Medical, and Environmental Research and Technology Innovations
Copyright information: © 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (