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Nanocomposites are found in a number of places and the use of nanoparticle-rich materials predates the understanding of the nature of these materials. In recent times nanocomposites have provided the aerospace industry with a variety of material solutions.
Types of Nanocomposites
Three types of nanocomposites include the following:
Ceramic-matrix nanocomposites
Ceramics constitute a major portion of this group of composites. Mostly, ceramic-matrix nanocomposites encompass a metal as the second component. Both the components are finely dispersed in each other. Nanocomposites of these combinations were found to have improved optical, electrical and magnetic properties as well as tribological, corrosion-resistance and other protective properties.
In 2009, GE Aviation, Ohio introduced durable, lightweight ceramic matrix composite components for use in a jet engine. These composites features low mass and greater heat resistance when compared to metals. The ceramic matrix composite engines require less cooling air thereby improving the overall engine efficiency.
Polymer-matrix nanocomposites
Adding nanoparticles to a polymer matrix can enhance its performance. This approach is particularly effective in yielding high performance composites, when the nanoparticles are well dispersed and the properties of the nanoscale filler are substantially different or better than those of the matrix.
Nanoscale dispersion of nanoparticles in the composite can introduce new physical properties such as accelerated biodegradability or fire resistance that are absent in the unfilled matrices, effectively changing the nature of the original matrix.
The use of nanoparticles in these polymer matrices, thus creating a nanocomposite, can yield an optimal multi-functional material for aerospace needs and other applications.
Metal-matrix nanocomposites
Metal matrix nanocomposites (MMC), also known as reinforced metal matrix composites, can be classified as continuous and non-continuous reinforced materials.
Carbon nanotube metal matrix composite (CNT-MMC) are one of the most important nanocomposites for their high tensile strength and electrical conductivity.
Bourque Industries is researching applications of its Kryron technology for the aerospace industry. The Kryronization process develops specialized CNT-MMC materials from a variety of core substrates. High strength to weight ratio, anti-corrosive and non-magnetic qualities, excellent electrical conductivity and heat dissipation properties of these materials make a natural fit for the aerospace industry.
In addition to CNT-MMC, carbon nitride metal matrix composites and boron nitride reinforced metal matrix composites are the new research areas on metal matrix nanocomposites.
Functions of Nanocomposites in Aircraft Construction
The nanocomposite serves as an advanced solution in aircraft construction. Some application areas include the following:
- It acts as strengthening element for the structures such as frames or stringers or as the outer layer for honeycomb type structures used at fuselage and wings.
- Zirconia-based nanocomposites were used as thermal protection for turboengines.
- The nano carbon-carbon composites act as base materials for missiles, space shuttles and re-entry vehicles. It is also used as a brake disk material and brake lining for military and civil aircraft.
- When combined with nanoadditive integrated ceramic matrix, nanocomposites represent a unique solution for the radoms of the hypersonic airplanes.
Recent Development
Aerospace industry is one of the foremost adopters of advanced composite materials, particularly composites reinforced with carbon fiber.
The industry demands for low-weight materials with high strength and stiffness in addition to the ability to mold composite parts and components into curved and complex shapes, which is important for military applications. In fact, composites constitute an average of 25% of aircraft by weight since their introduction.
Recent developments in aircraft design, which can be seen in the Bombardier C-series, Airbus A380 and Boeing B787 airliners, have led to a dramatic rise in the use of composites and a corresponding increase in adhesive bonding of primary structures in aircraft.
References and Further Reading