Probing the optimal thermohydrogen processing conditions of titanium alloy shavings via chemisorption method

Due to the high processing cost of recycling industrial titanium alloy shavings wastes, an efficient method to produce TiHX powders from these solid wastes via a combination of thermohydrogen processing (THP) and ball milling treatments is reported in this study. Hydrogen temperature-programmed chemisorption methods (H-2-TPR and TPD) were applied to explore the hydrogen chemisorption behavior (adsorption, consumption, decomposition, and desorption) and determine the optimal processing parameters for THP. The influence of THP temperature and ball mill parameters (speed and time) on the changes for structure and particle size of the TiHX powders was investigated. The phase transition from alpha-Ti to delta-TiHX was observed after THP at 520 degrees C, while metastable gamma-TiHX was detected after THP at 620 degrees C. In according with the H-2-TPR result, 520 degrees C was determined as the optimal THP temperature of titanium alloy shavings, and subsequently to obtain relatively fine titanium hydride powders with uniform particle size. This study establishes H-2-TPR and TPD as chemically sensitive tools for probing and understanding the hydrogenation and dehydrogenation of titanium alloys and beyond. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.