Abrasive Wear Studies Research Articles

Influence of fillers and fibre reinforcement on abrasive wear resistance of some polymeric composites

Fillers and fibre reinforcement increase the strength and stiffness of a polymer, and hence are effective in reducing wear in dry sliding conditions involving adhesion transfer or fatigue. However, in abrasive wear, such reinforcements are less effective and, in some cases, increase the abrasive wear rate. For a better understanding of this, abrasive wear studies were carried out on four types of polymers and their filler- and/or fibre-reinforced composites, abrading the polymer pins against an abrasive surface of silicon carbide paper of a fixed grit size. In most cases, the specific wear rate decreased with an increase in load. Except for bronze-filled polytetrafluoroethylene (PTFE), all the fillers (carbon, graphite, PTFE and MoS2) as well as short glass fibres increased abrasive wear. These results may be attributed to the reinforcement greatly reducing the ultimate elongation to fracture which in turn is a key factor in abrasive wear performance. The extent of counterface modification in multipass studies was observed to be another important factor in the abrasive wear performance of the composites. Worn pin and paper surfaces were also studied with scanning electron microscopy.

Abrasive wear study of laser surface alloying of chromium onto AISI 1018 steel

The abrasive wear properties of the alloys produced by the laser surface alloying of chromium onto AISI 1018 steel substrates were studied in the present paper. The low carbon steel samples were chromium electro-deposited using conventional electroplating techniques and a laser beam was used to melt the surfaces to produce the alloying effects. The chromium coating thickness, laser power and working speed were varied and their effects on the wear resistance of the alloying produced were investigated. The conducting dry sand-rubber wheel abrasion test was adopted and the weight loss measured to evaluate the wear properties. Scanning electron microscopy was used to characterize the worn surfaces of the alloyed specimens. The results show that the weight loss decreases with increasing chromium content, melted depth and hardness. The width and depth of the wear scratches decrease as the wear resistance properties increase.

Abrasive wear studies of nitrogen-implanted aluminium and titanium

Disks of commercial grade aluminium and titanium were implanted at room temperature with nitrogen ions to doses ranging from 1 × 10 16 to 5 × 10 17 ions cm -2. The abrasive wear resistance of the implanted layer was tested using a modified polishing machine. The relative wear resistance (RWR) was measured along the wear depth. For both aluminium and titanium an appreciable decrease in wear rate was observed for sample surfaces implanted to doses higher than 1 × 10 17 cm -2. The RWR reaches a maximum value of about 4 in the implanted layer close to the sample surface and gradually drops to unity when the implanted layer is removed. X-ray diffraction using Seemann-Bohlin geometry reveals the formation of AIN and TiN in aluminium and titanium respectively after high dose implantation. We attribute the ennoblement of the surface after implantation to the classic hardening mechanisms of solid solution and fine dispersion strengthening. Abrasive wear testing appears to be an appropriate method of evaluating the hardness of the thin surface layer and the effectiveness of implantation.