TY - JOUR
T1 - Effect of Reheating and Quenching on the Cathodoluminescence Intensity of Free Lime in Steelmaking Slag
AU - Imashuku, Susumu
AU - Nagasako, Makoto
AU - Wagatsuma, Kazuaki
N1 - Funding Information:
This study was supported by Steel Foundation for Environmental Protection Technology. We thank Nippon Steel Corp. for the supplies of steelmaking slag sample and for the determination of its free lime content. The authors thank Mr. Shun Itoh and the Kaori Sato of Tohoku University for helping us perform TEM observation and FIB fabrication, respectively.
Publisher Copyright:
Copyright © The Author(s), 2021. Published by Cambridge University Press on behalf of the Microscopy Society of America.
PY - 2021/6
Y1 - 2021/6
N2 - Determining free lime content in steelmaking slag is crucial for its safe reuse in road construction. A simple method has been recently developed to rapidly derive this value via cathodoluminescence (CL) imaging of steelmaking slag, previously quenched from 1,000°C to room temperature, according to the illuminated areas corresponding to free lime (luminescence peak at 600 nm). This quenching is required to obtain intense CL from free lime, but the mechanism of such signal enhancement is still unknown. Therefore, the present study investigated the mechanism by comparing the microstructures, CL images, and CL spectra of free lime in quenched and unquenched steelmaking slag. Large amounts of defects, including dislocations, were observed in the free lime emitting intense luminescence at 600 nm, whereas the samples without clear CL exhibited only a few defects. These results and previous studies suggest that the luminescence at 600 nm from free lime is enhanced by the CL originating from oxygen vacancies (380 nm); therefore, the enhancement of the intensity of the free lime CL peak could be attributed to the increase in the oxygen vacancies via quenching from 1,000°C to room temperature.
AB - Determining free lime content in steelmaking slag is crucial for its safe reuse in road construction. A simple method has been recently developed to rapidly derive this value via cathodoluminescence (CL) imaging of steelmaking slag, previously quenched from 1,000°C to room temperature, according to the illuminated areas corresponding to free lime (luminescence peak at 600 nm). This quenching is required to obtain intense CL from free lime, but the mechanism of such signal enhancement is still unknown. Therefore, the present study investigated the mechanism by comparing the microstructures, CL images, and CL spectra of free lime in quenched and unquenched steelmaking slag. Large amounts of defects, including dislocations, were observed in the free lime emitting intense luminescence at 600 nm, whereas the samples without clear CL exhibited only a few defects. These results and previous studies suggest that the luminescence at 600 nm from free lime is enhanced by the CL originating from oxygen vacancies (380 nm); therefore, the enhancement of the intensity of the free lime CL peak could be attributed to the increase in the oxygen vacancies via quenching from 1,000°C to room temperature.
KW - cathodoluminescence
KW - free lime
KW - luminescence enhancement
KW - oxygen vacancy
KW - quench
KW - scanning electron microscopy-cathodoluminescence system
KW - scanning transmission electron microscopy
KW - steelmaking slag
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U2 - 10.1017/S1431927621000374
DO - 10.1017/S1431927621000374
M3 - Article
AN - SCOPUS:85106183287
VL - 27
SP - 484
EP - 490
JO - Microscopy and Microanalysis
JF - Microscopy and Microanalysis
SN - 1431-9276
IS - 3
ER -