Adhesion strength and high temperature wear behaviour of ion plating TiN composite coating with electric brush plating Ni-W interlayer deposited on a hot work die steel were investigated using a plate-on-ring test rig. The microstructure and wear characteristics of the coating were analyzed using XRD, TEM, SEM and EDS. The adhesion of the coating to the substrate was determined by scratch test. The results indicated that crystallization and precipitation-hardening in the electric brush plating Ni-W interlayer and formation of interface diffusion layer and duplex composite layer at the interface occurred due to thermal effects during TiN deposition. The Ni-W interlayer could provide an effective support for the TiN coating, thus the adhesion strength and hardness of the TiN composite coating increased significantly. In the temperature range 500-7008C, the TiN composite coating with Ni-W interlayer revealed high wear resistance as compared with the single TiN coating. The coefficient of friction and wear rate of the single TiN coating increased as the temperature increased, while the TiN composite coating exhibited the lowest coefficient of friction and wear rate at 6008C. Abrasive and adhesive wear were the predominant wear mechanisms of the coatings at elevated temperatures.

The aligned film of amorphous carbon (a-C) nanorods was prepared by catalytic chemical vapor deposition (CCVD) on an anodic aluminum oxide (AAO) template at 650 8C. The morphology and microstructure of aligned film of amorphous carbon nanorods were examined by scanning electron microscopy (SEM) and Raman scattering spectroscopy. The friction and wear properties of aligned film of amorphous carbon nanorods on the AAO template in vacuum (1.12

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.

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.

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.