Jul 282015
 

Researchers predict material with record-setting melting point

Highly steeped in the hypothetical, but it looks like a material made from the right amounts of hafnium, nitrogen, and carbon (HfN0.38C0.51) would have a melting point of 4,400 kelvin = 7,460 F. No data yet on the mechanical properties. If it’s a powder, that’s not so helpful, but if it’s a reasonably strong solid, it’d be handy for heat shields and the like. It’d be really nice if this could be used to make rocket engines.

 Posted by at 4:09 pm
  • Jandanagger Laterobinson

    But obtaining a block of the stuff, how could we form it

    • Scottlowther

      Depends entirely on the mechanical properties, which seem to be unknown. Perhaps a block of it could be machined. Perhaps it could be hammered into shape. We might get lucky and the stuff comes in the form of fibers.

      • sferrin

        Any idea on the density?

      • publiusr

        What about borazon?

        “it can withstand temperatures greater than 2000 °C (3632 °F), much higher than that of a pure diamond at 871 °C (1600 °F).”

  • p1t1o

    Powders don’t necessarily cause a problem, tungsten carbide powder is sintered into shape without melting it for example.

    • Scottlowther

      Yeah, but try as you might, talcum powder is hard to form into meaningful structural elements. Imagine if this stuff was essentially unmeltable… and shared talcum powders mechanical properties.

      • p1t1o

        Sure, but I think its more likely that its physical properties will be closer to Tungsten Carbide than talcum powder…

        • Scottlowther

          Maybe. It might end up like titanium oxide. Who knows.

          • p1t1o

            Seems unlikely from the stoichiometry, which implies a carbide-like solid solution, rather than an oxide form.

  • Herp McDerp

    There’s interesting information in NIAC 7600-039 Final Report: NASA Institute for Advanced Concepts – A Realistic Interstellar Explorer, 14 October 2003 [PDF] regarding the use of hafnium carbide, tantalum carbide, and tantalum hafnium carbide in nuclear rocket engines (start at page 52).

    The nitrogen in HfN0.38C0.51 might be a problem, though — I have no idea how the stuff might react with very very hot hydrogen. Very very hot ammonia is another possible propellant. You might not want to expose it to other hot gases; Wikipedia notes that hafnium carbide “has a low oxidation resistance, with the oxidation starting at temperatures as low as 430 °C.”

  • publiusr