<p>Scientists, including those of Indian origin, have developed "fuzzy fibres" that act like Velcro and could stand up to the heat and pressure of next-generation rocket engines.<br /><br />The fibres made of of silicon carbide strengthen composites used in advanced rocket engines that have to withstand temperatures up to 1,600 degrees Celsius.<br /><br />Ceramic composites in rockets now being developed use silicon carbide fibres to strengthen the material, but they can crack or become brittle when exposed to oxygen.<br /><br />The researchers from Rice University in the US embedded silicon carbide nanotubes and nanowires into the surface of NASA's fibres.<br /><br />The exposed parts of the fibres are curly and act like the hooks and loops that make Velcro so valuable - but on the nanoscale.<br /><br />The result creates very strong interlocking connections where the fibres tangle; this not only makes the composite less prone to cracking but also seals it to prevent oxygen from changing the fibre's chemical composition.<br /><br />The researchers grew hooks and loops on nanotubes by first bathing silicon carbide fibre in an iron catalyst and then using water-assisted chemical vapour deposition to embed a carpet of carbon nanotubes directly into the surface.<br /><br />These become the template for the final product. The fibres were then heated in silicon nanopowder at high temperature, which converts the carbon nanotubes to silicon carbide 'fuzz'.<br /><br />The researchers, including Pulickel Ajayan from Rice University, hope their fuzzy fibres will upgrade the strong, light and heat-resistant silicon carbide fibres that, when put in ceramic composites, are being tested for robust nozzles and other parts in rocket engines.<br /><br />"The silicon carbide fibre they already use is stable to 1,600 degree Celsius," said Chandra Sekhar Tiwary, a postdoctoral associate at Rice University in the US.<br />"So we are confident that attaching silicon carbide nanotubes and wires to add strength will make it even more cutting-edge," he said.<br /><br />The new materials should also make entire turbo engines significantly lighter, said graduate student Amelia Hart.<br /><br />"Before they used silicon carbide composites, many engine parts were made of nickel superalloys that had to incorporate a cooling system, which added weight to the whole thing," Hart said.<br /><br />"By switching to ceramic matrix composites, they could take out the cooling system and go to higher temperatures," she said.<br /><br />"Our material will allow the creation of larger, longer-lasting turbo jet engines that go to higher temperatures than ever before," she added.<br /><br />The research was published in the journal Applied Materials and Interfaces.</p>
<p>Scientists, including those of Indian origin, have developed "fuzzy fibres" that act like Velcro and could stand up to the heat and pressure of next-generation rocket engines.<br /><br />The fibres made of of silicon carbide strengthen composites used in advanced rocket engines that have to withstand temperatures up to 1,600 degrees Celsius.<br /><br />Ceramic composites in rockets now being developed use silicon carbide fibres to strengthen the material, but they can crack or become brittle when exposed to oxygen.<br /><br />The researchers from Rice University in the US embedded silicon carbide nanotubes and nanowires into the surface of NASA's fibres.<br /><br />The exposed parts of the fibres are curly and act like the hooks and loops that make Velcro so valuable - but on the nanoscale.<br /><br />The result creates very strong interlocking connections where the fibres tangle; this not only makes the composite less prone to cracking but also seals it to prevent oxygen from changing the fibre's chemical composition.<br /><br />The researchers grew hooks and loops on nanotubes by first bathing silicon carbide fibre in an iron catalyst and then using water-assisted chemical vapour deposition to embed a carpet of carbon nanotubes directly into the surface.<br /><br />These become the template for the final product. The fibres were then heated in silicon nanopowder at high temperature, which converts the carbon nanotubes to silicon carbide 'fuzz'.<br /><br />The researchers, including Pulickel Ajayan from Rice University, hope their fuzzy fibres will upgrade the strong, light and heat-resistant silicon carbide fibres that, when put in ceramic composites, are being tested for robust nozzles and other parts in rocket engines.<br /><br />"The silicon carbide fibre they already use is stable to 1,600 degree Celsius," said Chandra Sekhar Tiwary, a postdoctoral associate at Rice University in the US.<br />"So we are confident that attaching silicon carbide nanotubes and wires to add strength will make it even more cutting-edge," he said.<br /><br />The new materials should also make entire turbo engines significantly lighter, said graduate student Amelia Hart.<br /><br />"Before they used silicon carbide composites, many engine parts were made of nickel superalloys that had to incorporate a cooling system, which added weight to the whole thing," Hart said.<br /><br />"By switching to ceramic matrix composites, they could take out the cooling system and go to higher temperatures," she said.<br /><br />"Our material will allow the creation of larger, longer-lasting turbo jet engines that go to higher temperatures than ever before," she added.<br /><br />The research was published in the journal Applied Materials and Interfaces.</p>