Spinel LiMn2O4 materials were synthesized via sintering of a precursor which was obtained from the solution of the corresponding metal acetate by a spray-drying method. Following sintering at 600 C for 15h, the spinel LiMn2O4 particles that are formed are fine, narrowly distributed, and well crystallized. The synthesized material has excellent electrochemical properties as a cathode, delivering an initial discharge capacity of 137mA h/g and exhibiting good cycle stability.

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.

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.

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.

Amorphous carbon nanofiber arrays were synthesized in porous anodic aluminum oxide templates by pyrolysis of acetylene with cobalt nanoparticles as catalyst at 640 8C. The carbon nanofibers have amorphous structures under high-resolution transmission electron microscopy and Raman spectroscopy examination. The aligned amorphous carbon nanofibers grown within the pores of the aluminum oxide membranes are uniform with lengths of about 2μm and outer diameters of about 85 nm. The frictional properties of the array film of amorphous carbon nanofibers were investigated using an atomic force and friction force microscopy (AFM-FFM) and a ball-on-disk machine in air. The adhesion between the amorphous carbon nanofiber arrays and the anodic aluminum oxide membrane remained intact at relatively low loads. The AFM-FFM measurements indicated that the friction forces on the array film of amorphous carbon nanofibers were uniform. The array film had low friction coefficient and high wear resistance under the micro friction tests. The friction coefficient of the array film dry sliding against a corundum counterface was observed to be constant after an initial transient period and decreased with increasing the sliding velocity.