Effect of Fixed Sample Length Conditions and Mechanical Activation of the Starting Mixture on Combustion in the Ti + C System

This paper examines the effect of fixed sample length conditions and mechanical activation of the starting mixture on the combustion rate and sample elongation during the synthesis process and the phase composition and morphology of the combustion products in the Ti + C system. Milling for 9 min in air in an AGO-2 mill at an acceleration of 90g with 9-mm-diameter steel balls as grinding media led to partial mechanochemical synthesis: the resultant mixture contained TiC along with unreacted titanium and carbon. After ball milling for 9 min, the mixture became pyrophoric and occasionally ignited when withdrawn from the grinding vial. Mechanical activation for less than 9 min led to an increase in the combustion rate of the mixture and a decrease in particle size in comparison with the combustion rate and particle size of the starting mixture. Increasing the MA time from 1 to below 9 min caused an increase in the amount of impurity gas in the mixture, resulting in a larger sample elongation. Mechanical activation for a relatively long time led to disintegration of the sample during the combustion process. Keeping the sample length fixed led to a considerable increase in combustion rate, but had no effect on the phase composition of the synthesis products, as did mechanical activation of the starting mixture.