Ammonium fluoride-activated synthesis of cubic δ-TaN nanoparticles at low temperatures
1 Graduate School of Green Energy Technology, Chungnam National University, Daejeon 305-764, Republic of Korea
2 Graduate School of Department of Metallurgical Engineering, Chungnam National University, Daejeon 305-764, Republic of Korea
3 Korea Institute of Energy Research, 152 Gajeong-ro, Yuseong-gu, Daejeon 305-343, Republic of Korea
Nanoscale Research Letters 2013, 8:126 doi:10.1186/1556-276X-8-126Published: 15 March 2013
Cubic delta-tantalum nitride (δ-TaN) nanoparticles were selectively prepared using a K2TaF7 + (5 + k) NaN3 + kNH4F reactive mixture (k being the number of moles of NH4F) via a combustion process under a nitrogen pressure of 2.0 MPa. The combustion temperature, when plotted as a function of the number of moles of NH4F used, was in the range of 850°C to 1,170°C. X-ray diffraction patterns revealed the formation of cubic δ-TaN nanoparticles at 850°C to 950°C when NH4F is used in an amount of 2.0 mol (or greater) in the combustion experiment. Phase pure cubic δ-TaN synthesized at k = 4 exhibited a specific surface area of 30.59 m2/g and grain size of 5 to 10 nm, as estimated from the transmission electron microscopy micrograph. The role of NH4F in the formation process of δ-TaN is discussed with regard to a hypothetical reaction mechanism.