Researchers from the National Institute for Materials Science in Tsukuba, Japan, have used nanoparticles to reinforce steel and make it 100 times more creep resistant than any other steel.
Steel is normally made more creep resistant by dispersing various oxides throughout the metal but this process is expensive and unsuitable to large scale manufacturing processes.
Currently the strengthening additives have a particle diameter around 100 to 300 nanometres. The Japanese researchers added material with very fine, 5 to 10 nanometres, particle sizes. At 923 Kelvin, they found an addition of 0.002% carbon to martensitic steel with 9% chromium, increased the time-to-rupture by a factor of 100 over the strongest creep-resistant steel. This steel has around 0.08% carbon. The added material formed into carbon-nitrogen metal alloy nanoparticles that strengthened the material by linking vulnerable areas in the steel such as grain boundaries.