Effect of carbon on the growth of TaC crystal derived from organometallic precursors |
Yoonjoo Lee1, Philjae Kang2, Sooyong Jung2, Seonggun Bae3, Joungil Kim4, Manyoung Lee5, Dong-Geun Shin3 |
1Energy and Environment Division, Korea Institute of Ceramic Engineering and Technology, Jinju 52851, Korea 2Department of Chemistry and Molecular Structure Laboratory, Yonsei University, Seoul 03722, Korea 3Convergence R&D Division, Korea Institute of Ceramic Engineering and Technology, Jinju 52851, Korea 4R&D Center, DACC Carbon Co. Ltd., Jeonju 54853, Korea 54th Directorate, Agency for Defense Development, Daejeon 34186, Korea |
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Received: February 21, 2020; Revised: June 26, 2020 Accepted: August 10, 2020. Published online: January 31, 2021. |
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ABSTRACT |
TaC, which is an ultra-high-temperature structural material, was derived from two types of organometallic precursors: Me3CCH = Ta(CH2CMe3)3 and Cp*-TaMe4. Both compounds are kinds of single-source precursors composed only of tantalum, carbon, and hydrogen, which should be converted into carbide material without oxygen contamination. The carbide material was formed through several processes such as pyrolysis, nucleation, and crystal growth, which are dependent on heat treatment temperature. However, organometallic precursor usually leaves residual carbon, and the crystallization of carbide is affected by the carbon. In this study, two types of organometallic precursors containing different amounts of carbon in the organic part were used to prepare TaC, and the crystallization behavior of TaC in rich carbon was investigated. The amount of residual carbon was estimated by thermogravimetry (TG) analysis, and the TaC crystals were characterized using X-ray diffraction (XRD) and transmission electron microscopy (TEM). Nano-sized TaC particles were obtained by heat treatment without any by-products but with excess carbon. The TaC crystal was formed starting from 1300 °C, but the crystals grew better with less carbon, while the carbon barrier prevented agglomeration of the atoms. |
Key words:
TaC · Tantalium carbide · Residual carbon · Crystal growth |
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