Tungsten tetraboride is an inexpensive, superhard material easily prepared at ambient pressure. Unfortunately, there are relatively few compounds in existence that crystallize in the same structure as tungsten tetraboride. Furthermore, the lack of data in the tetraboride phase space limits the discovery of any new superhard compounds that also possess high incompressibility and a three-dimensional boron network that withstands shear. Thus, the focus of the work here is to chemically probe the range of thermodynamically stable tetraboride compounds with respect to both the transition metal and the boron content. Tungsten tetraboride alloys with a variable concentration of boron were prepared by arc-melting and investigated for their mechanical properties and thermal stability. The purity and phase composition were confirmed by energy dispersive X-ray spectroscopy and powder X-ray diffraction. For variable boron WBx, it was found that samples prepared with a metal to boron ratio of 1:11.6 to 1:9 have similar hardness values (∼40 GPa at 0.49 N loading) as well as having a similar thermal oxidation temperature of ∼455 °C. A nearly single phase compound was successfully stabilized with tantalum and prepared with a nearly stoichiometric amount of boron (4.5) as W0.668Ta0.332B4.5. Therefore, the cost of production of WB4 can be decreased while maintaining its remarkable properties. Insights from this work will help design future compounds stable in the adaptable tungsten tetraboride structure.

中文翻译：

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不同硼浓度对超硬四硼化钨性能的影响

四硼化钨是一种廉价的超硬材料，易于在环境压力下制备。不幸的是，与四硼化钨以相同结构结晶的化合物相对较少。此外，由于缺乏四硼化物相空间中的数据，因此无法发现任何新的超硬化合物，这些化合物还具有高不可压缩性和可承受剪切的三维硼网络。因此，这里工作的重点是化学探索热力学稳定的四硼化物化合物的范围，包括过渡金属和硼含量。通过电弧熔化制备了具有可变硼浓度的四硼化钨合金，并研究了它们的机械性能和热稳定性。通过能量色散 X 射线光谱和粉末 X 射线衍射确认纯度和相组成。对于可变硼 WBx，发现以 1:11.6 至 1:9 的金属硼比制备的样品具有相似的硬度值（在 0.49 N 负载下~40 GPa）以及~455 的相似热氧化温度℃。几乎单相的化合物用钽成功稳定并用接近化学计量的硼 (4.5) 制备为 W0.668Ta0.332B4.5。因此，可以在保持其卓越性能的同时降低WB4的生产成本。这项工作的见解将有助于设计在适应性强的四硼化钨结构中稳定的未来化合物。结果表明，用 1:11.6 到 1:9 的金属硼比制备的样品具有相似的硬度值（0.49 N 负载下~40 GPa）以及~455°C 的相似热氧化温度。几乎单相的化合物用钽成功稳定并用接近化学计量的硼 (4.5) 制备为 W0.668Ta0.332B4.5。因此，可以在保持其卓越性能的同时降低WB4的生产成本。这项工作的见解将有助于设计在适应性强的四硼化钨结构中稳定的未来化合物。结果表明，用 1:11.6 到 1:9 的金属硼比制备的样品具有相似的硬度值（0.49 N 负载下~40 GPa）以及~455°C 的相似热氧化温度。几乎单相的化合物用钽成功稳定并用接近化学计量的硼 (4.5) 制备为 W0.668Ta0.332B4.5。因此，可以在保持其卓越性能的同时降低WB4的生产成本。这项工作的见解将有助于设计在适应性强的四硼化钨结构中稳定的未来化合物。5) 作为 W0.668Ta0.332B4.5。因此，可以在保持其卓越性能的同时降低WB4的生产成本。这项工作的见解将有助于设计在适应性强的四硼化钨结构中稳定的未来化合物。5) 作为 W0.668Ta0.332B4.5。因此，可以在保持其卓越性能的同时降低WB4的生产成本。这项工作的见解将有助于设计在适应性强的四硼化钨结构中稳定的未来化合物。