Characterization and separation resistance of an in-situ 2D nanocarbon/calcium aluminate composite synthesized via a combustion method. Issue 3 (3rd July 2021)

• Record Type: Journal Article
• Authors: Yang, Shoulei; Xiao, Guoqing; Ding, Donghai
• Is Part Of: Journal of Asian ceramic societies. Volume 9:Issue 3(2021)
• Page Start: 1038
• Page End: 1045
• Publication Date: 2021-07-03
• Subjects: Combustion synthesis -- calcium aluminate -- in-situ nanocarbon -- separation resistance; Ceramics -- East Asia -- Periodicals; Materials science -- Periodicals; 620.1405
• DOI: 10.1080/21870764.2021.1935122
• Languages: English
• ISSNs: 2187-0764

Abstract

ABSTRACT: In-situ 2D nanocarbon/calcium aluminate composite (NCAC) was synthesized via a combustion method designed based on aluminothermic reduction using calcium carbonate (CaCO3 ) as carbon source. The results demonstrate that compared with the pristine product, when the molar substitution rate of CaCO3 for CaO2 in the reactants was 25%, the contents of CaAl2 O4 (CA), CaAl4 O7 (CA2 ) and Ca12 Al14 O33 (C12 A7 ) in the combusted product did not change substantially and were close to those of Secar71. When the molar substitution rate was increased to 50%, the contents of CA and CA2 decreased, and that of C12 A7 increased substantially. Interestingly, the nanocarbons generated in-situ in the combusted composite were embedded in calcium aluminate and had a nanoflake morphology (2D) with a thickness of approximately 50 nm, few defects and high graphitization degree. The results of the suspension experiment demonstrate that the floating ratio of NCAC in the suspension after ultrasonic vibration for 10 min was approximately 5.5 wt.%, which is much lower than that (78.8 wt.%) of a carbon black/Secar71 composite powder; thus, the in-situ 2D nanocarbon/aluminate composite had strengthened interfacial bonds and satisfactory separation resistance. These would be favorable for the uniform dispersion of nanocarbons within the matrix, improving the performance of cement-based composites.