Tribology Laboratory

Tribology is the science and technology of controlling friction and wear. The subject originated from the art of lubrication but has since developed to a much broader range of applications. Most mechanical equipment is subject to damage by wear or, else, wastes energy by frictional dissipation. Classic illustrations of this rule are found in the domestic motor vehicle. Almost half of the mechanical power generated by the engine is wasted in friction between pistons and cylinders and within the gearbox and transmission gears. The sole purpose of the complicated system of engine cooling, i.e. a radiator, pump and channels within the engine block, is to provide sufficiently low temperatures for the lubricating oil.

Tribological constraints are not confined only to mechanical equipment; computers and electronic equipment are also a fertile source of tribological problems yet to be solved. A major limitation of data transmission is that for data transfer from a memory disk to a recording head, sliding contact must occur between the disk and the head. If there is, however, true solid to solid contact between these two parts then transferred data will be affected and degraded by wear damage. This problem is minimised in two ways: (i) the iron oxide used for magnetic storage is in the form of spinel, i.e. Fe3O4, which is more wear resistant than red iron oxide, Fe2O3, (ii) the disk and head are separated by a lubricating air film which is a fraction of a micron in thickness.

The human body itself is also prone to friction and wear problems. The skin is continuously supplied with a fatty excretion called sebum to lubricate and prevent sticking wherever contact with a solid surface occurs. The alveoli of the lungs are covered with a layer of surfactants to enable this dense network of branch-form tissue to expand and contract during respiration without tangling. The human joints are perfect bearings lubricated by synovial fluid and operating usually without failure for a very long time. The mechanisms of lubrication operating in this case are extremely reliable, however human joints are well known for failure by rheumatism and in particular arthritis. In a healthy human joint, an extremely low coefficient of friction is maintained, values as low as 0.005 have been measured. It has also been shown that the synovial fluid effectively prevents contact between the joint surfaces. However, when arthritis occurs fragments of cartilage and bone are observed in the synovial fluid. These particles are wear particles generated during the operation of the joint, and the study of wear and lubrication processes in healthy and diseased joints is a major research project. The objective is to be able to predict and prevent wear damage in human joints.

The Tribology Laboratory at Curtin University has an extensive range of industrial expertise on tribology-related problems through consultancy and problem-solving services. The expertise is provided to local, national and international industry and the broader community.

The main areas of expertise are:

• failure analysis of bearings and gears
• wear of materials
• erosive/abrasive wear in slurries
• lubricant selection
• machine condition monitoring based on oil analysis
• material selection for tribological applications

Current research conducted in the Tribology Laboratory is focused on the following areas:

• ReadMYXray
• Development of methods for the trabecular bone texture characterisation from the x-ray images of knee and hand joints for the early detection and prediction of osteoarthritis
• Development of methods for multiscale characterisation of 3D surfaces
• Optimisation of surface textures
• Application of electrochemical methods to study tribocorrosion
• Understanding the synergism between corrosion and abrasive/ erosive wear
• Particle shape effect in abrasion and erosion