Carbon fibre's wonder strength once helped push Rolls-Royce into nationalisation
In the late 1960s Rolls-Royce bet on a new British material, carbon fibre, to win American airliner business with compressor blades for its RB-211 engine. The blades turned out to be vulnerable to bird strikes, and that problem, among others, set the company back so badly that it was nationalised in 1971.
The story starts with light bulbs. Joseph Swan made carbon fibres in 1860 for lamps, Thomas Edison carbonised cotton thread and bamboo slivers into filaments in 1879, and Lewis Latimer developed a dependable carbon filament in 1880. Modern high-performance fibre dates to 1958, when Roger Bacon at Union Carbide near Cleveland heated rayon until it carbonised, though the result was only about 20 percent carbon. Akio Shindo in Japan used polyacrylonitrile, or PAN, in the early 1960s, and in 1963 researchers at the Royal Aircraft Establishment at Farnborough found how to unlock the material's full strength.
Britain licensed that process to Rolls-Royce, Morganite and Courtaulds, but the lead soon shifted. Japan took charge of PAN-based fibre in the late 1960s with strong government backing, as firms such as Toray, Toho Rayon and Mitsubishi built production. Courtaulds, the last big British maker, quit in 1991 because its water-based process let in impurities. Later yarns kept climbing in performance, from Toray's T400 at 4,000 megapascals of tensile strength to intermediate fibres reaching 6,000, and aircraft makers adopted them first in secondary parts, later in primary structures.
Each fibre is only 5 to 10 micrometres across and made almost entirely of carbon, its crystals lined up along the length to give great strength for its size. Thousands are bundled into a tow, which can be woven into fabric or soaked in resin and baked into carbon-fibre-reinforced polymer: very stiff and light, but somewhat brittle. Fibres made from PAN have crumpled sheets of atoms and excel in tensile strength, while pitch-based fibres heated beyond 2200 degrees Celsius become graphitic and extremely stiff.
Cost remains the brake. For cars, carbon fibre may be 10 to 12 times pricier than steel, down from roughly 35 times in the early 2000s. It also forms a galvanic corrosion cell when touching metal unless a sealant separates them. Unusual uses include heated airport pavements, where current through carbon-laced asphalt melts snow and ice.
Source: Carbon fibers
