Hanadi Salem: Nanotech Cars are Safer, Glossier, More Durable
Studies show that people are replacing their cars less frequently than in the past, meaning that the average age of cars on the road has increased considerably.
In the United States, the lifespan of vehicles on the road reached an all-time high of 11.4 years at the end of 2013 and is likely to rise to 11.7 years by 2019, according to IHS Automotive. In the United Kingdom, it is 7.7 years, according to a study by the Society of Motor Manufacturers and Traders; in Canada it is 9.26 years, as relayed by the Automotive Industries Association of Canada. And in Egypt, cars are on the road for decades. While this may be partly due to financial constraints, experts have affirmed that the increase in the average age of modern cars on the road is largely due to their higher quality and improved durability.
Automobile longevity depends on a number of factors, including how the car is driven and maintained, but high-quality components are also necessary to reduce wear and tear. As a result, manufacturers are increasingly fabricating mechanical components in vehicles such as automobiles, buses, trains, aircrafts and even space shuttles, that include nanoscale structures or nanoparticles, which improve the overall mechanical properties of these components, with enhanced durability so that they are longer lasting, more cost effective and, ultimately, safer.
“Gears in engine cylinders, ignition relays, brake pads and braking systems are subject to surface-to-surface contact and friction as part of regular use, which causes mild or severe erosion,” explained Hanadi G. Salem, professor of mechanical engineering and director of AUC’s nanotechnology graduate program. “Over time, mechanical components wear out due to erosion of the softest and weakest rubbing surfaces, removal of the coating or structural detritions associated with the overheating caused by friction. Nanostructured composites with high-wear resistance and self-lubricants offer a more durable and reliable alternative than conventional engine parts,” noted Salem.
Such work, she explained, falls under the discipline of tribology, an interdisciplinary field between materials science and mechanical engineering, whereby interacting surfaces in motion, application of friction principles, lubrication and wear are examined.
In addition to enhancing durability, studies have shown that nanotechnology will soon become an essential part of the automotive industry in the future. A global study titled NanoCar, conducted by Helmut Kaiser Consultancy, examined and forecasted the changes in the automotive industry in 2008, 2010 and 2015 through the integration of nanotechnology in 70 leading car manufacturers worldwide. It concluded that, in 10 years, the design and manufacture of cars, trucks, buses and other vehicles would be affected by nanotechnology by up to 60 percent based on miniaturization, lighter and stronger materials, and new energy systems. It also showed that almost all parts of a vehicle could benefit from nanotechnology, from the engine, transmission system, suspension, brakes and chassis to the mirrors, side panels, tires and paint.
Experts have contended that the use of nanotechnology in cars would result in more flexible design and manufacturing; a lighter engine, suspension and exterior body; stronger material; improved coating due to scratch-resistant paint; as well as greater fuel and cost efficiency. “Nanotechnology is a ‘must’ for the automobile companies,” the NanoCarstudy reported. “The competition in 10 years could well depend on the development and application of nanotechnology by manufacturers in their automobiles.”
One of the primary uses of nanomaterials, or nanocomposites, in the production of vehicle components is decreasing erosion and rust. This is done by increasing hardness and softening the temperature of coatings, as well as creating self-lubricating mechanical components. “The production of self-lubricating solids enables the friction between two rubbing surfaces to be reduced, without the need for a liquid medium,” said Salem, who presented her findings at the 2013 TMS Annual Meeting and Exhibition in the United States, one of the premiere international conferences for materials scientists and engineers. “Self-lubricating materials are necessary for components that operate in high temperatures and severe conditions, such as those in advanced engines like airplanes and automobiles.”
However, the benefits of nanostructured materials to mechanical components can be lost during the manufacturing process. Researchers are, thus, developing novel ways to produce nanomaterials whose properties are retained throughout production and in service. “One of the major issues with nanostructured materials, specifically metallic ones, is that during the processing of these materials, they suffer from coarsening of the structure,” Salem noted. “The destruction of the nanostructure (the tiny, internal structure of the material that should make the overall material behavior stronger and harder and, hence, provide enhanced performance) means that the main benefit of having nanomaterials versus conventional ones is lost. Accordingly, the main challenge is to retain the synthesized nanostructure while processing to achieve the aspired outstanding performance in service.”
To combat this issue, scientists are working with different processing techniques that can preserve the high performance and high reliability of nanoscale internal-structured materials. One such technique is consolidating powders to a nanoscale, after their internal structure has been refined, then using these nanopowders to produce better mechanical components. “My research team has been working on consolidation of powders, suitable for wear-resistant components that could be used in airplane or automobile engines; high wear-resistant coating; insulation bricks in fusion nuclear power stations and machine tools that shape and cut metal parts,” said Salem, adding that her team also uses advanced processing techniques, such as sever plastic deformation, additive manufacturing and spark plasma sintering, for the fabrication of high-performance nanostructured mechanical components.
Developing production methods by which various mechanical components maintain the nanostructure that enables superior wear resistance is just one side of the problem. Nanoscale structure can also be lost as a result of overheating while in service . “Surface rubbing is one of the major sources of generated heat induced by friction, which ultimately causes coarsening and, as a result, less wear resistance,” Salem said. “To protect the nanostructure of materials from overheating, we use a ceramic nanocomposite that allows the creation of mechanical components with four times greater hardness and a higher softening temperature compared to conventional materials, hence much higher wear resistance and tribological properties.”
In addition to the ceramic nanocomposite, coating can also insulate materials from overheating, allowing them to maintain their nanostructure. However, to ensure that this coating is efficiently operating with “outstanding wear resistance,” as Salem put it, an optimum combination of coating hardness and toughness should be achieved. To this effect, Salem and her team are working on laser coating treatment as a novel method for eliminating porosity and producing a homogeneous surface layer of thermal barrier coating, which is commonly used for the coating of blades in jet engines to protect them from high temperatures.
“In the automotive and aircraft industry, there is a rising demand for high-efficiency, high-performance materials, and that’s where nanotechnology comes in,” said Salem. “Our ultimate aim is for car, airplane and train engines to last longer and be less likely to fail, cutting maintenance costs and improving safety. Nanotechnology is changing the world in many ways, big and small, and for the automotive industry, in particular, it marks a new, promising future.”