Mechanochemical interaction of titanium powder with organic liquids

作者：Dorofeev G A^*; Lad'yanov V I; Lubnin A N; Mukhgalin V V; Kanunnikova O M; Mikhailova S S; Aksenova V V

来源：International Journal of Hydrogen Energy, 2014, 39(18): 9690-9699.

DOI：10.1016/j.ijhydene.2014.04.101

• Titanium
• Liquid hydrocarbons
• Ball milling
• Nanostructures
• Stacking faults
• Metastable carbohydrides

The formation of the nanocrystalline cubic titanium-based phase under high energy ball milling of alpha-Ti (hcp) in the presence of liquid hydrocarbons (toluene or n-heptane) used as a process control agent (PCA) has been studied by X-ray diffraction, X-ray photoelectron spectroscopy and chemical analysis in detail. The state of the PCA during ball milling has been examined by IR-spectroscopy, densitometry and refractometry. It has been shown that the formation of the nanocrystalline structure and the generation of deformation stacking faults in hcp Ti as well as the appearance of the titanium-based amorphous phase take place at the early stage of ball milling. The fcc nanocrystalline phase which the nucleation sites are stacking faults is found to be formed under longer-term (up to 50 min) ball milling when the amorphous phase vanishes. The atomic ratio of H/C in as-milled samples agrees well with that in toluene and n-heptane. The ball milling in toluene leads to more particle dispersivity than that in n-heptane. Most probably, the fcc phase is metastable titanium carbohydride with deficiency of carbon and hydrogen in comparison with stable titanium carbohydrides. The metastable titanium carbohydride transforms to stable titanium carbide and stable titanium carbohydride at low-temperature (550 degrees C) annealing under vacuum and argon respectively. In the latter case the beta-Ti phase precipitates too. The milling has caused no changes of the PCA structure and physical properties. The mechanism of the mechanochemical interaction of titanium with PCA is considered. It involves repeated fracture, adsorption of the PCA molecules on newly formed surfaces and cold welding of powder particles. As a result, the absorption of carbon and hydrogen inside the titanium particles takes place.

• 出版日期2014-6-15