Electrochemically Prepared Precursors for the Formation of Non-Oxides

Various metals, such as Ca, Mg, A1, Ti, Cr, Y, Zr, and Ta were anodically dissolved in an organic electrolyte composed of propylamine, acetonitrile, and tetrabutylammonium bromide. The electrode reactions were completely irreversible. At the cathode, the organic amine was reduced to the corresponding anion and gaseous hydrogen, at the anode the metals were oxidized and metal-amino compounds were formed. The solvent and excess amine could be evaporated from the elec-trolytes and amorphous solids were formed which were pyrolyzed into metal nitrides or carbides by calcination i dried ammonia, nitrogen or argon at temperatures in the range of 600-1400~ In the last few years, many pyrolytic routes for the pro-duction of ceramic powders, fibers, and coatings have been developed. 1-3 Conventional routes for the formation of non-oxides, such as the carbothermic reduction ~ or the direct nitridation of metal powders 5 require high temperature processes and are not suitable for the production of ce-ramic fibers or coatings. Pyrolytic routes generally enable the formation of ceramic powders at relatively low temper