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Technologically viable principles have been developed for the preparation of titanium and zirconium powders via reduction of metal oxides. We have studied the effect of synthesis conditions (starting-mixture composition and relationships between reactants) on the composition, structure, and particle size of the powders. The results demonstrate that the addition of excess magnesium to the starting mixture leads to the complete reduction of the oxides and that reducing the combustion temperature of the starting mixture leads to an increase in the percentage of zirconium oxide in the final product. The titanium and zirconium powders prepared in the combustion regime with a reduction stage consist of agglomerates of particles ranging widely in size: from large (several microns) to ultrafine and nanoscale particles. The use of magnesium perchlorate as a heating additive leads to the formation of a titanium–zirconium solid solution. The composition of the powders has been determined by chemical analysis, microstructural analysis, and X-ray diffraction. [ABSTRACT FROM AUTHOR]

Technologically viable principles have been developed for the preparation of the MAX phase Ti2AlC by self-propagating high-temperature synthesis (SHS) with a reduction step, using titanium dioxide. We have studied the influence of synthesis conditions (starting-mixture composition and ratio of reactants) on the composition, structure, and particle size of Ti2AlC powders. The results demonstrate that an excess of magnesium in the starting mixture leads to a decrease in the percentage of MgAl2O4 (spinel), and carbon deficiency in the starting mixture reduces the percentage of titanium carbide in the final product. The Ti2AlC powders prepared by SHS consist of agglomerates of layered particles differing in size: from coarse (several microns) to ultrafine and nanometer-sized particles. The composition of the powders was confirmed by chemical analysis, microstructural examination, and X-ray diffraction. [ABSTRACT FROM AUTHOR]