2024/10/16 by D. Sivaprahasam, Sivaprahasam, D., R. Preyadarshini +3
Engineering · Materials Science · Physics and Astronomy · #Boron and Carbon Nanomaterials Research #FOS: Physical sciences #Intermetallics and Advanced Alloy Properties #Materials Science (cond-mat.mtrl-sci) #Semiconductor materials and interfaces
paper · pdf · doi:10.48550/arxiv.2410.12314
openalex publication_date 2024/10/16 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
AlFe2B2, a ternary transition metal boride doped with Ag, Ni, Sb, Ga, and Ge was investigated for the phase constituents, microstructure, and thermoelectric properties. The parent compound with 20% excess Al (Al1.2Fe2B2) prepared by vacuum arc melting contains orthorhombic AlFe2B2 and FeB upon doping form additional phases such as Ag5Al, AlNi3, Al3Ni2, AlSb, and AlB2. The structural parameters of the AlFe2B2 phase in Ag, Ni, and Sb-doped samples are nearly the same as the un-doped one. The lattice parameters and cell volume increase noticeably in Ga and Ge-doped compounds. The Ga-doped sample shows only FeB as a secondary phase; however, the AlB2 phase is observed in Ge-doped AlFe2B2. The microstructure investigated in FEG-SEM with EDS shows the AlFe2B2 matrix is chemically homogenous in all samples, except the Ga-doped one, with uniformly distributed single or multiple secondary phases. The DSC-TG results show that all the dopants decrease the AlFe2B2 phase peritectic decomposition reaction temperature, indicating the structure destabilizes. The thermoelectric properties measured show that AlFe2B2 is an n-type compound with electrical conductivity in the range of 0.35-0.46×106 S/m. The addition of Ag, Ni, Ga, and Ge marginally alters the Seebeck and electrical conductivity. The noticeable improvement in Seebeck coefficient and with negligible change in electrical conductivity resulted in a highest power factor of 0.4 mW/mK2 for Sb-doped sample. The thermal conductivity of AlFe2B2, which is in the range of 6.4-9.1 W/m-K between 300 to 773 K, decreases with Sb doping to 5.2-8.5 W/m-K resulting in a maximum zT of 0.04 at 773K.