HIGH-QUALITY MIXED-TRANSITION-METAL DICHALCOGENIDES FROM SOLID-STATE EXCHANGE-REACTIONS

High-quality molybdenum-tungsten disulfide solid solutions, (Mo,W)S-2, are rapidly synthesized in self-propagating, solid-state precursor reactions between (MoCl5.WCl6) and Na2S. The mixed-metal dichalcogenide products can be readily reduced in a dilute hydrogen atmosphere at approximately 900 degrees C to the corresponding Mo-W alloys. The metal distribution in the Mo-W alloys is examined using the high-angle 123 powder X-ray reflection and can be correlated to the metal distribution in the metal dichalcogenide product. A comparative study of the peak profiles of several alloys and standards shows that this precursor approach yields mixed-metal dichalcogenide products with a better metal dispersion than the products of long-term, high-temperature reactions between the elements. Powder X-ray diffraction data, as well as elemental and thermogravimetric analyses, are presented.