Abstract NaLaS2 powders with various Na/La molar ratios were prepared via a gas-solid reaction method where NaF nanocrystal was used as the sodium source, and CS2 served as the sulfurizing agent. The effective sulfurization parameters were designed based on the thermodynamic properties of the precursor obtained via the reverse coprecipitation way. The phase compositions and morphologies of sulfide powders depended strongly on NaF amount. The powder with a molar ratio of Na/La = 1.3 was selected for sintering NaLaS2 ceramic via hot-pressing process under vacuum due to its highest phase purity and lowest oxidesulfide, fluorosulfide impurities level. As-sintered NaLaS2 ceramic exhibited a consolidated microstructure, a minor amount of oxysulfide impurities and high 8–14 μm mean transmissivity with the maximum transmittance up to 67.5% at 9 μm. Contrasting study proves that NaLaS2 ceramic has the tendency to possess the better IR performance and antioxidation capacity than γ-La2S3 and CaLa2S4 ceramics.

中文翻译：

---

NaLaS 2 透明陶瓷的粉体制备及高红外性能

摘要 以NaF纳米晶为钠源，CS2为硫化剂，采用气固反应法制备了不同Na/La摩尔比的NaLaS2粉体。根据逆共沉淀法获得的前驱体的热力学性质设计了有效硫化参数。硫化物粉末的相组成和形态在很大程度上取决于 NaF 的量。选用摩尔比为 Na/La = 1.3 的粉末在真空下通过热压工艺烧结 NaLaS2 陶瓷，因为它具有最高的相纯度和最低的氧化硫化物、氟硫化物杂质含量。烧结后的 NaLaS2 陶瓷表现出固结的微观结构、少量的氧硫化物杂质和 8-14 μm 的高平均透射率，在 9 μm 处的最大透射率高达 67.5%。