Research work on carbon composites could provide answers to sticking points in the rail and solar energy sectors, according to Morgan Advanced Materials.
Carbon composites are in high demand across the globe, particularly in the aerospace, automotive, mechanical engineering and rail sectors. However, as many of these materials were developed decades ago, modern analytical and synthetic techniques have the potential to improve these materials, whilst also lowering production costs and producing greener more energy efficient products.
This is the opinion of Professor Ian Kinloch and his group in the Department of Materials at the University of Manchester, who are collaborating with Morgan Advanced Materials with the aim of creating a deep understanding of the new breed of carbon-carbon composites.
Five Year Project
The Royal Academy of Engineering has awarded Professor Kinloch a research chair, which will help fund the project. Using experimentation, state-of-the-art analysis and analytical models, the five-year project will pave the way to new carbon pantographs, high-temperature thermal insulation materials and improved seals and bearings.
Carbon-carbon composites range from simple unidirectional fibre reinforced structures, to more complex 3-dimensional structures. Their properties mean that they are designed to higher strength and stiffness specifications and, unlike metals, can maintain these properties at high temperatures.
For those who aren’t familiar with carbon, this element forms different structures depending on synthesis conditions. Diamond and graphite are the most familiar forms, but there are also nanotubes, buckyballs (more commonly known as fullerenes), and most recently, graphene. These various forms are what give carbon its huge range of material properties, leading to increased versatility in use.
Funding this research allows Professor Kinloch and Morgan Advanced Materials to discover new ways in which carbon-carbon composites can benefit a large number of industrial applications and use cases.
Railway pantographs take a new direction
One sector which could benefit greatly from improved carbon-carbon composites is rail. Commonly used within the railway sector, pantographs are the apparatus mounted on the roof of an electric train, tram or bus. With an increased demand for greener public transport due to rapidly growing populations, the electrical output needs to increase to accommodate the increased footfall and additional comforts such as air conditioning, Wi-Fi and charging ports.
Morgan already offers a variety of Carbon Current Collector Pantograph Strips for overhead pantograph applications which uniquely allows a reduction in pan head mass, therefore reducing service and maintenance costs. However, as many in the electric train, tram and bus industry will know, energy efficiency needs to be improved to reduce the overall carbon footprint. Thus, more conductive collector strips are continually in demand in transport markets.
In order to find even better efficiency over the lifetime of the pantograph, in-depth research will be conducted on how pantographs made from carbon-carbon composites can offer better electrical conductivity. By doing so, pantograph powered systems will be able to run with less power consumption and under a wider variety of conditions. This includes extremes in temperature, or in adverse weather conditions, which are currently constant challenges for these systems. Other conditions that can affect pantograph performance include the different types of overhead wire system being used, as well as the speed the train is travelling.
Achieving a more environmentally and sustainable composite for pantographs also has benefits in terms of commercial savings, value and global issues. By making trains more energy efficient, cost savings could hopefully be passed on to travellers, while the overall transportation carbon footprint will be reduced.
Turning up the heat
Soft carbon felt has also long been the standard for use as thermal insulation in high temperature vacuum furnaces and inert gas electric furnaces. Once heated to a high temperature, carbon fibre becomes a pure carbon thermal insulator, wrapping the furnace interior like a blanket. During this collaboration, Kinloch and Morgan will be looking into how the carbon can be weaved to reflect the heat more efficiently.
A crucial element of this research project is looking at how to use carbon felt within the solar panel industry, testing graphene or nanotubes to enhance insulating properties. The solar cell market is expanding at a rapid rate; annual worldwide market growth rates are projected at 20% for the foreseeable future. Solar cell production relies on the production of silicon ingots produced in a high-temperature furnace; expansion of ingot production requires larger furnaces, requiring more carbon insulation.
Cost pressures on the steps of solar cell production are intensifying as solar cells become commoditised. For carbon insulation producers like Morgan, that translates into a need to develop more thermally insulating material and at lower cost.
Carbon composites under pressure
Pumping water is a huge industry and quite simply cannot afford to fail without severe social consequences. One of the key areas in keeping the industry’s pumps going are the seals and bearings.
These parts undergo huge amounts of pressure to ensure no leaks occur, while pumping water in high volumes, and are used from large-scale industrial pumps all the way through to pumps in coffee machines.
However, water pumping takes its toll on mechanical systems due to water’s lack of natural lubrication capabilities. This is where carbon materials really excel, as they are self- lubricating. The planar sheets of carbon in graphite structures can slide relative to each other, relieving stress at material interfaces like those at mechanical seal interfaces in pumps. This reduction in friction lowers the required energy to pump the water.
Not only do carbon seals and bearings reduce energy usage during the pumping process, but they are also safer and more hygienic. If carbon materials aren’t used, then invariably a secondary lubricant needs to be added into the pumping process. This brings the risk of mixing chemicals into the solution – for example lubricants mixing into coffee from the coffee machine pose a health risk to the user.
Research shows that 20% of the industrial energy consumption is expended through pumping operations; thus, even incremental improvements in pumping efficiency would result in significant savings. Professor Kinloch’s work will focus on the fundamental mechanisms within carbon materials that dictate friction and wear at the interfaces; Morgan’s strategy is to use this added understanding to create longer lasting seals and bearings.
Diamond in the rough
During this research project, Professor Kinloch will collaborate with Morgan Advanced Materials through its new Carbon Science Centre of Excellence at Penn State University in the USA. Being awarded a research chair is an honour for Professor Kinloch and having the Royal Academy of Engineering offering its resources into this project is an incredible opportunity.
As a strong supporter of manufacturing and education in the UK, Professor Kinloch and Morgan are eager to find carbon-carbon composite materials to help bring step changes across many industries.