Gasparrini Claudia, Rana Dhan-Sham, Le Brun Niccolò, Horlait Denis, Markides Christos N, Farnan Ian, Lee William E
Centre for Nuclear Engineering (CNE) & Department of Materials, Imperial College London, South Kensington Campus, London, SW7 2AZ, UK.
Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EQ, UK.
Sci Rep. 2020 Apr 14;10(1):6347. doi: 10.1038/s41598-020-63037-0.
The dependencies of the enhanced thermomechanical properties of zirconium carbide (ZrC) with sample purity and stoichiometry are still not understood due to discrepancies in the literature. Multiple researchers have recently reported a linear relation between the carbon to zirconium atomic ratio (C/Zr) and the lattice parameter, in contrast with a more established relationship that suggests that the lattice parameter value attains a maximum value at a C/Zr ~ 0.83. In this study, the relationship between C/Zr atomic ratio and the lattice parameter is critically assessed: it is found that recent studies reporting the thermophysical properties of ZrC have unintentionally produced and characterised samples containing zirconium oxycarbide. To avoid such erroneous characterization of ZrC thermophysical properties in the future, we propose a method for the accurate measurement of the stoichiometry of ZrC using three independent experimental techniques, namely: elemental analysis, thermogravimetric analysis and nuclear magnetic resonance spectroscopy. Although a large scatter in the results (ΔC/Zr = 0.07) from these different techniques was found when used independently, when combining the techniques together consistent values of x in ZrC were obtained.
由于文献中的差异，碳化锆（ZrC）增强热机械性能与样品纯度和化学计量比之间的依赖关系仍未明确。最近，多位研究人员报告了碳与锆原子比（C/Zr）与晶格参数之间的线性关系，这与一种更为公认的关系相反，后者表明晶格参数值在C/Zr约为0.83时达到最大值。在本研究中，对C/Zr原子比与晶格参数之间的关系进行了严格评估：发现最近报道ZrC热物理性质的研究无意中制备并表征了含有碳氧化锆的样品。为了避免未来对ZrC热物理性质的此类错误表征，我们提出了一种使用三种独立实验技术准确测量ZrC化学计量比的方法，即：元素分析、热重分析和核磁共振光谱。尽管单独使用这些不同技术时结果存在较大分散性（ΔC/Zr = 0.07），但将这些技术结合在一起时，获得了ZrC中x的一致值。
