Mechanochemical Synthesis and Characterization of Cerium Monosulfide

Cerium monosulfide (CeS) has desirable refractory properties such as high melting point (2445 °C) and high thermal conductivity, but it is not commercially available. CeS has been used for high temperature crucibles for molten metals or nuclear fuels due to its non-wetting nature. In the past, CeS has been synthesized using temperatures greater than 1700 ^o C, which is expensive and hazardous. In this work, CeS was synthesized by high-energy planetary ball milling of elemental cerium and sulfur. The reaction was monitored at ambient conditions, using in situ temperature and pressure. Using a similar approach, CeS was also prepared from a commercially available sulfide, Ce ₂ S ₃ , by mixing stoichiometric amounts of cerium. After CeS was synthesized using both approaches, the resulting powders were characterized using X-ray diffraction (XRD) and scanning electron microscopy (SEM), coupled with energy dispersive X-ray spectroscopy (EDS). The CeS powder was then sintered in an inert atmosphere and the thermal conductivity was measured.