Al-Ru Intermetallics Fabricated By Mechanical Alloying And Annealing Treatment

The catalyst of skeletal Ru is a hydrogenation catalyst with high activity, which can catalyze the hydrogenation reaction on many unsaturated bands, and it has been considered to be with a very wild application prospect in many high economic add-ons such as the medication and fine chemistry, because of its high activity and selectivity. However, Ru is a noble metal and has a high melting temperature. It is very difficulty to prepare the metal alloy of Al-Ru by custom technique, and it also suffers a complicated process and high cost by special preparation method.In order to develop a low cost technique to produce the metal alloy of skeletal Ru, the mechanical alloying (MA) and following anneal have been used to try to prepare the Al-Ru alloy containing 50wt.% Ru. The optimizing MA parameter as well as the effect of milling time and anneal temperature on the alloy has been investigated. The results have been shown as follows:(1) When considering the cost of noble metal Ru, during the optimization of MA parameter, the Al-Ni alloy powder has been used to study the influences of the ratios of milling ball to the powder and the process controlling addition (PCA) on the MA course. The result shows that the best ratio of the milling ball to powder is 20:1, and the best volume of ethanol addition as the PCA is 2 ml. In these conditions, the milling time has been saved and the product efficiency has also been improved.(2) The Al-Ru alloy powder with 50wt.% Ru has been made after the optimized parameter, and the effects of milling time on the crystal size, microstrain and heat stability have been observed. The results have illustrated the crystal size firstly decreases with the increase of milling time and gradually tend to arrive at a minimal size. The microstrain increases to a maximal value with 4.584% after milling for 30h, and then decreases as the milling time. From the heat stability experiment, it can be seen that the Ru(Al) supersaturated solute formed by MA can transfer at low temperature.(3) The powder after MA has been annealed at 550℃and 700℃, the effect of temperature and time on the phase component has been investigated. The result suggests that the alloy anneal at 550℃are mainly composed of Al₂Ru, Al₅Ru₂ and a little of Al₁₃Ru₄. The heat preservation time has slight effect on the phase transformation. While when the powder was annealed at 700℃, the formed intermetallics in the alloy are primary Al₂Ru, Al₁₃Ru₄ and Al₅Ru₂. The Al₅Ru₂ intermetallic changes into Al₂Ru and Al₁₃Ru₄ as the prolonging of heating preservation. However, the holding time at this temperature has no obvious influence on the growth of crystal grains.In this paper, the Al-Ru alloy containing 50 wt.% Ru has been made by MA and following anneal. This technique has reduced the cost of Al-Ru preparation, and it is hoped to be a effective metal alloy preparation of the skeletal Ru catalyst.