A type of nanocrystalline Mg Ni Cr/TiO composite was prepared by ball-milling alloy with different amounts of (0.5, 1.5, 2.5 2 0.75 0.25 2 wt%) TiO nanoparticles. The microstructures of the nanocomposites were examined by XRD and TEM. The effects of the addition of transition metal oxide TiO2 nanoparticles on the absorption and desorption properties of the nanocrystalline Mg2Ni0.75Cr0.25 alloy were investigated. The TiO2 nanoparticles could act as catalyst and the nanocomposites showed rapid absorption and desorption kinetics and good thermodynamic properties. The absorption temperatures of the nanocomposites were greatly decreased and the rates of hydriding were increased. In comparison with the nanocrystalline Mg2Ni0.75Cr0.25 alloy, the enthalpy of hydride formation for the nanocomposite was small, but the absorption capacity was reduced.

Sub-micro spinel-structured LiMn1.5Ni0.5O4 material was prepared by a spray-drying method. The electrochemical properties of LiMn1.5Ni0.5O4 were investigated using Li ion model cells, Li/LiPF6 (EC+DMC)/LiMn1.5Ni0.5O4. It was found that the first reversible capacity was about 132 mAh g−1 in the voltage range of 3.60-4.95V. Ex situ X-ray diffraction (XRD) analysis had been used to characterize the first charge/discharge process of the LiMn1.5Ni0.5O4 electrode. The result suggested that the material configuration maintained invariability. At room temperature, on cycling in high-voltage range (4.50-4.95 V) and low-voltage range (3.60-4.50 V), the discharge capacity of the material was about 100 and 25 mAh g−1, respectively, and the spinel LiMn1.5Ni0.5O4 exhibited good cycle ability in both voltage ranges. However, at high temperature, the material showed different electrochemical characteristics. Excellent electrochemical performance and low material cost make this spinel compound an attractive cathode for advanced lithium ion batteries.

Sliding wear behavior of in situ Cu-TiB2 nanocomposites fabricated by reaction of pure titanium and copper-boron melts were investigated on a pin-on-disk wear tester under dry sliding conditions, rubbing against medium carbon steel disk at sliding speeds range from 0.089 to 0.445ms−1 and at loads between 20 and 140 N. The hardness, yield strength and wear resistance of the in situ composites increased with the content (from 0.5 to 2.5 wt.%) of TiB2 nanoparticles in the copper matrix. Owing to the good interfacial bonding between uniformly dispersed TiB2 nanoparticles and the copper matrix, there was no transition from mild wear to severe wear over the applied load range. While the electrical conductivity of the in situ composites decreased considerably with the content of TiB2 nanoparticles, the wear resistance made the material a potential candidate for sliding electrical contacts.

The slurry erosion-corrosion behaviour of TiN coated α-Ti alloy in aqueous silica slurry ontaining 3.5% NaCl has been investigated using a jet-in-slit rig. Erosion- orrosion tests were performed with slurry having jet velocity range 4.8-12.8 m s-1 and at normal impact angle. Because of synergistic effects between erosive wear and flow-induced corrosion, the erosion-corrosion rates of the TiN coating and a-Ti substrate were higher than the sum of erosive wear rates and flow-induced corrosion rates. At the lower slurry velocity, the TiN coating deposited on the a-Ti substrate presented better slurry erosion-corrosion resistance. With increasing slurry velocity, however, perforating, cracking and fragmenting of the hard TiN coating occurred and the protection effect of the coating layer reduced with the erosion-corrosion duration. And then the volume loss of the a-Ti substrate was enhanced through cracking of flakes induced by stress and corrosion.

Steady-state friction and wear behaviour of as-cast and T6-treated hypoeutectic Al-Si-Mg-matrix composites reinforced with 19.5 vol.% of Al18B4O33 whiskers dry sliding against 5CrNiMo steel counterface have been investigated as a function of applied load and sliding speed. Owing to the severe interfacial cracking and fracture of whiskers which occurs under higher applied load conditions, the composites exhibited a transition from mild wear to severe wear over the applied load range from 45 to 230 N. By comparison with the as-cast composite, the T6-treated composite, with reduced whisker strength and weak whisker/matrix inter-face, had relatively low wear resistance. Under low applied loads, increasing sliding speed caused deep surface damage, thus indu-cing an increase in wear rate and coefficient of friction. As the sliding speed further increased, the formation of a mainly Al2O3 transfer layer on the worn surface and the strain-hardening of the subsurface layer contributed to decreases in wear rate and coef-ficient of friction of the composites.