High-quality hafnium disilicide (HfSi₂) has been successfully synthesized using a high-pressure and high-temperature (HPHT) method at 3 GPa and 1573 K in a DS6 × 10 MN cubic press. The modest synthesis temperature is aided by significant decreases in both liquidus and solidus temperatures at high pressure for the Si-rich portion of the Hf–Si binary system. The in situ high-pressure X-ray diffraction study yielded a bulk modulus of B₀ = 124.4 ± 0.8 GPa with a fixed B₀^′ = 4.0 for HfSi₂, which exhibits a dramatically anisotropic compressibility, with a and c axes nearly twice as incompressible as the b axis. The bulk HfSi₂ as synthesized has a Vickers hardness of 6.9 ± 0.1 GPa and high thermal stability of 1163 K in air, indicating its hard and refractory ceramic properties. The core-level XPS data of Hf 4f and Si 2p have been collected on the bulk samples of HfSi₂, HfSi, and Hf, as well as Si powder to examine the Hf–Si bonding in hafnium silicides. The Hf 4f_7/2 binding energies are 15.0 and 14.8 eV for bulk HfSi₂ and HfSi, respectively.

中文翻译：

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HfSi2的高压高温合成及原位高压同步辐射X射线衍射研究

使用高压高温 (HPHT) 方法在 3 GPa 和 1573 K 条件下，在 DS6 × 10 MN 立方压机中成功合成了高质量的二硅化铪 (HfSi ₂ )。对于 Hf-Si 二元体系的富硅部分，高压下液相线和固相线温度的显着降低有助于适度的合成温度。原位高压X射线衍射研究，得到的体积弹性模量乙₀ = 124.4±0.8 GPA具有固定乙₀ ^' = 4.0 HfSi ₂，其表现出显着的各向异性可压缩性，与一个和ç轴近两倍不可压缩为b轴。散装 HfSi合成后的₂具有 6.9 ± 0.1 GPa 的维氏硬度和在空气中 1163 K 的高热稳定性，表明其具有坚硬和耐火的陶瓷特性。Hf 4f 和 Si 2p 的核心级 XPS 数据已在 HfSi ₂、HfSi 和 Hf 以及 Si 粉末的大块样品上收集，以检查铪硅化物中的 Hf-Si 键合。Hf 4f _7/2结合能对于块状 HfSi ₂和 HfSi 分别为 15.0 和 14.8 eV 。