Industrial Production of Nanofibers
Nanofiber technology can provide many benefits to the advanced ceramic composite industry.
Materials science is the grandfather of nanotechnology. Industrial materials companies are hot on the heels of the latest nanotechnology research in the ever-
present quest for a competitive advantage that can help their products perform better, last longer and cost less.
Early examples of nanotechnology-based advanced ceramics can be seen on display in the British Museum. The ancient Roman Lycurgus Cup, dating from the 4th century, is one of the finest and earliest examples of advanced ceramics using nanotechnology as a core component of the finished product. In this case, nanoparticles were used to affect the way light passes through the cup, causing the color to change from green to red. In their search for the ability to turn base metals into gold, alchemists carried on the tradition of materials research through the Middle Ages, while today’s “alchemists” are at the forefront of materials science design and applications engineering.
The world market for advanced ceramics is projected to exceed $68 billion by the year 2018.1 This will be driven by a number of factors, including technical innovation in materials, reduced production costs, increased demand from a number of market segments, and supportive environmental and energy regulatory frameworks.
The largest end-user market segments for advanced ceramics will remain the IT and electronics industries, but significant growth opportunities can be expected in a number of other end-user segments as governments tighten energy efficiency and environmental harm reduction policies and regulation. Such segments include medical devices, military and commercial aircraft coatings, filters and membranes, and fuel cell technologies.
In the long term, it is forecast that ceramic matrix composites (CMCs) will witness strong growth, expanding at an estimated compound annual growth rate (CAGR) of 8.3% through 2015, reaching nearly $1.3 billion in total revenues,2 driven by increased use of CMCs in high-temperature and high-corrosion applications. In this area, aluminum oxide (alumina) nanofibers have the potential for significant market penetration due to their excellent performance as a thermal insulation composite material ingredient, among other characteristics. Areas of concern in the advanced ceramics industry that nanofibers could help resolve include brittleness, high-temperature instability, susceptibility to abrasion and susceptibility to chemicals/bio-compatibility.
With their performance-boosting capabilities, such nanofibers will enable advanced ceramics to step up to the challenges of a new era. Nanofibers have the
Nanofibers have the potential to change the direction of many industries, opening up new possibilities in end-user applications.
potential to change the direction of many industries, opening up new possibilities in end-user applications. Researchers are only now beginning to scratch the surface of the potential.
The atmosphere of ingenuity and innovation created by carbon fibers and carbon nanotubes (CNTs) some 20 years ago helped pave the way to the game-changing materials that are being tested in R&D today. On the supply side, the key challenge now is taking those technologies from the lab and into mass production.
The demand side is certainly growing and will continue to accelerate as the developed world moves out of recession and back into the next growth cycle. Key applications for advanced ceramics materials that are reinforced with nanofibers are expected to be identified in a number of sectors.
Nanofibers come at a time when the advanced ceramics sector is at a turning point in its development. Looking to the future, advanced ceramics will come to play an even larger role in the everyday life of machines, industry and humans. For example, the intertwined issues of global warming and environmental protection will likely help drive the uptake of advanced ceramics solutions in the aviation and aerospace industries. Nanofibers are currently being tested in a range of composites for a variety of applications, including energy, aerospace, manufacturing, military and more.
The energy industry alone offers many potential applications for nanofibers, ranging from catalysts, filters and membranes in industrial and chemical processes to insulation materials and boosting of tensile strength in wind or sea turbine blades.
In the aerospace, automotive and aviation industries, advanced ceramic composites will play a role in reducing weight, increasing material strength, and increasing fuel efficiency. One area of interest is in transparencies (windows). Jet or turbine gas engines that include higher levels of CMCs would weigh considerably less than today’s engines and operate at much higher temperatures, resulting in far greater fuel efficiencies and reduced pollution.
In manufacturing, applications include filters and membranes, paints and coatings, insulation, wear-resistant coatings, ceramic and polymer composite materials, and metal matrix composites.
Applications include power systems, from fuel cell linings and components to lithium-ion battery components (heat resistant layers), as well as microwave and radio frequency applications.
Applications include chemical- and corrosion-resistant coatings, ceramic implants and medical devices, and coatings for medical instruments. Another area of interest is bioactive nanomaterials for biomedical devices.
Demand is growing for advanced ceramic composites in body armor for military applications.
Advanced ceramic composite materials are an important and evolving solution to many of the issues facing a broad range of end-user markets. However, some challenges remain.
While traditional ceramics can withstand temperatures that would melt most metals, they have suffered from an Achilles’ heel in terms of performance, namely brittleness. Developments in advanced ceramic composite materials are seeking to address this problem by testing the reinforcing properties of fibers when included into the composite mix. Similar to human bones, these composite structures exhibit hierarchical, hybrid microstructures that help impede localized damage and reduce the risk of catastrophic fracturing/cracking.
While it has been reduced, the risk of micro-fractures still exists within the composite. This is important for many end-user applications, and researchers are working hard to improve this area of advanced ceramic composite performance. In the aviation industry, for example, such micro-fractures are an unacceptable risk. Likewise, in environments where hazardous and corrosive gases and liquids are processed, these micro-fractures present a challenge to advanced ceramic composite producers.
For ceramic composites in ultra-high-temperature applications, especially where corrosive species in the environment must be kept out of the material, relatively small cracks (e.g., in the order of a single micron) can be unacceptable. Exactly how micro-cracks are restrained by the tailored microstructures of a ceramic composite is the central question for the materials scientists seeking the optimal composition or architecture.
Production Quality Control
Significant and positive developments have been made in the scientific understanding of the production processes of advanced ceramic composites. The production process can have a significant influence on the properties of advanced ceramics. Research shows that small changes in production settings and systems can lead to great changes in end user product reliability and performance, so this is a key area of concern and focus at both the R&D and production level.
Further refining of production processes will help companies address some of the concerns regarding reliability of their end-user products.In situ testing and analysis of the production process chain are helping advanced ceramics companies to fine-tune their production to minimize faults and increase overall quality control.
The issue of quality control is therefore essential to companies buying into nanofiber solutions. Consistency is absolutely paramount if nanofibers are to become the “inside solution” equivalent to Intel Inside’s famous microprocessor chip. Without this, companies will be wary of investing heavily in the technology. In this respect, nanofiber companies themselves have a large part to play in actively communicating innovation to the advanced ceramic composites sector.
A key issue concerning any business in any sector is cost. The advanced ceramic composites industry is no different in this respect. Until recently, the benefits of nanofiber ingredients have come at a price point that has prohibited large-scale uptake of the technology. Pricing had previously been too high to translate the R&D results into production reality.
Nanofiber production companies have had to step up to this challenge and find new ways of producing fibers while bringing costs into line with customer expectations. New synthesizing processes enable manufacturers to offer truly scalable industrial quantities of alumina nanofiber at commercially viable prices, while maintaining the superior-grade quality (99.7%) demanded by many of the growth territory end-user applications.
The physical and mechanical properties of nanofibers show outstanding potential for advanced ceramic composites seeking reinforcing and performance-boosting raw nanotech ingredients. Research performed by MISiS (Moscow University), Cambridge University and the Fraunhofer Institute has shown that alumina nanofibers can increase tensile strength, Young’s modulus and compressive strength in certain composite materials by up to 100%, while providing significant increases in heat resistance to temperatures well above 1,000°C.
Using nanofibers can also increase chemical and radiation resistance in the end composite product. This is a key performance attribute in some of the environments where advanced ceramics play an integral part in industrial processes.
The global nanotechnology market is projected to grow at a CAGR of around 19% during 2011-2013, with the expected market for nanotechnology-based manufactured goods to be worth $1.6 trillion, representing a CAGR of around 50% during the 2009-2013 period.3
Nanofiber technology has the flexibility to be used in other materials aside from ceramic composites. With further research, manufacturers hope to be able to target specific product manufacturers in the polymer sector and develop new product solutions involving alumina nanofibers and powders.
While the ceramics market is a hugely important market, it is also important to explore the opportunities in a range of business sectors where nanofiber technology has the power to unlock innovation and capture a growing market share. Another area of cooperation is in the field of thermal insulation for industrial ceramic kilns, where increases in thermal efficiency offer energy savings and increased productivity.
When creatively used, advanced ceramic composite materials could help to expand resources, protect the environment, and create new technological opportunities for innovation. Yet the responsibility is a shared one, so advanced ceramic composite manufacturers and nanofiber producers need to cooperate and share knowledge and expertise in order to engineer the best possible products and solutions for the market.
Without deep R&D partnerships and networks of technical knowledge, companies will struggle to advance fast enough to keep pace with end-user demands from industry and society. Those that can collaborate successfully will survive into the next generation of leading advanced ceramic composite materials.
A concentration effect is likely as certain companies and partnerships prosper thanks to growing demand for their products. As more and more of the benefits of nanotechnology become apparent, and as production costs are reduced, products that incorporate nanotechnology will likely play a greater part in the daily lives of the world’s population.
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1. “Global Advanced Ceramics Market to Exceed US$68 Billion by 2018,” Global Industry Analysts, Inc., www.prweb.com/releases/advanced_ceramics/engineered_ceramics/prweb9940291.htm.
2. “Ceramic Matrix Composites: Technologies and Global Markets,” BCC Research, www.bccresearch.com/report/ceramic-matrix-composites-avm014d.html
3. Nanotechnology Market Projected to Grow 19% Annually Through 2013, RNCOS, www.marketresearch.com/corporate/aboutus/press.asp?view=3&article=1944&g=1.