The automotive industry today is driven by the need to reduce fuel consumption and emissions whilst improving safety and reliability standards, and to reduce manufacturing and servicing costs. This can be achieved by lowering the weight of the vehicle by using materials such as aluminium, aluminium alloys, metal matrix composites and polymers. These materials are lightweight and can be very cost effective but their surface properties sometimes leave a lot to be desired. However, thermal spray technology can help by engineering the surface with a functional coating specifically designed to meet the in-service demands. Thermally sprayed coatings have been used for many years on high volume automotive components such as piston rings, synchronisation rings, lambda sensors and alternator covers. More recently this technology has been increasingly used on lightweight components such as: - 1. Aluminium metal matrix composite brake discs - these are coated with a ceramic material to give the desired frictional characteristics for road vehicles and high performance motor cycles. 2. Lightweight cylinder block bores are successfully coated with a 150 μ coating to replace cast iron cylinder liners. There is a range of materials that can be tailored to suit standard production or high performance applications. 3. Aluminium alloy valve lifters have their outside diameters coated to give protection against wear and scuffing. The use of thermally sprayed coatings on lightweight components is discussed in detail together with an indication of the special purpose machines used for the high volume production of these components.
展开▼
