Novel synthesis of nitride powders by microwave-assisted combustion

A novel and simple microwave-assisted combustion procedure for the synthesi s of a number of technologically important metal nitrides was demonstrated. The method involves the combustion reaction of a porous metal powder compa ct with N-2 gas in the microwave field and provides phase-pure metal nitrid e products (consisting of fine particles, fibers, and whiskers) within minu tes. The ignition and combustion temperatures of the reaction were found to vary as a function of compaction pressure. The microwave-prepared nitrides were characterized using x-ray diffraction, scanning electron microscopy e nergy dispersive spectroscopy, thermogravimetric analysis, and infrared spe ctroscopy. The present microwave-assisted hybrid-heating procedure allows t he preparation of nitrides with good crystallinity, structural uniformity, and phase purity, and appears to have general applicability for the prepara tion of metal nitrides (using the respective metals or even their oxides).