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Unique Preparation of Hexaboride Nanocubes: A First Example of Boride Formation by Combustion Synthesis
Author(s) -
Kanakala Raghunath,
RojasGeorge Gabriel,
Graeve Olivia A.
Publication year - 2010
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1551-2916.2010.03853.x
Subject(s) - carbohydrazide , x ray photoelectron spectroscopy , scanning electron microscope , combustion , boride , materials science , chemical engineering , differential scanning calorimetry , boron , chemistry , metallurgy , composite material , organic chemistry , physics , engineering , thermodynamics
Nanocubes of LaB 6 and Sm 0.8 B 6 have been synthesized using low‐temperature combustion synthesis, a technique that had only been used previously for the preparation of oxides. The hexaboride nanocubes were prepared using lanthanum nitrate or samarium nitrate, carbohydrazide, and boron powders. The furnace temperature for synthesis was kept at 320°C, lower than the typical temperature values used in combustion processes for the preparation of oxides. After synthesis, the nanocubes were characterized using X‐ray diffraction, scanning electron microscopy, and X‐ray photoelectron spectroscopy. The combustion process was analyzed using differential scanning calorimetry, which shows that the formation of the carbohydrazide and nitrate melts as well as the formation of a complex between metal ions and carbohydrazide are crucial steps for the reaction. The technique results in high‐purity powders with a unique cubic morphology, in which the corners of the cubes can be used as point sources for efficient electron emission.