Ultrapure niobium RRR for superconductor applications

In the fundamental research of high-energy physics, scientists use superconductive particle accelerators to penetrate deep into the material. Investigating fundamental interactions and the smallest possible structures, they generate new knowledge and approaches. They lay the foundation for new technologies and sustainable solutions for future concerns: energy supply, climate protection, and health.

Powerful accelerators rank among their most important research tools. Depending on the discipline, they use a wide variety of superconducting structures for particle acceleration and collision.

The metal niobium is distinguished by high thermal conductivity and superconductive properties, as well as easy workability. It is therefore particularly well-suited for the construction and development of a wide variety of structures or cavities, such as elliptical cavities, single spoke resonators (SSR), and half-wave resonators (HWR).

Heraeus offers you grades specially developed for superconductive cavities. You receive the niobium as an ingot or semi-finished product (sheets, plates, tubes, rings, flanges, disks sliced directly from the ingot, HOM coupler housing, HOM coupler port, rods).

Our many years of experience and in-depth expertise in processing the material allow you to develop individual solutions. We provide custom-tailored solutions and work with you to master your challenges.


Heraeus is a qualified manufacturer of high purity niobium. With our many years of experience and our technical expertise, we work directly with your scientists to develop individual solutions to meet your requirements.


We offer niobium in various ultra-pure quality grades:

  • Reactor grade niobium in accordance with ASTM B 391
  • Ultrapure niobium RRR 40 – niobium RRR 300, repeatedly melted by electron beam
  • Large-grain or fine-grain grades
  • You receive the material as a melt – ingot (Ø approx. 300 mm – weight approx. 1 t) or semi-finished product:
    • Sheets and plates
    • Disks sliced directly from ingot
    • Round blanks / disks, rolled
    • Seamless tubes (end tubes / HOM coupler ports)
    • HOM coupler housing (blank or machined)
    • Flanges and support rings (blank or machined)
    • Round materials, rods

Technical data

  • Melting point 2,468 °C
  • Density at room temperature 8.57 [g/cm³]
  • Transition point Tc 9.2K / – 264°C
  • High thermal conductivity at cryogenic temperatures: 20 W/(m*K) @ 4 K and 10 W/(m*K) @ 2 K
  • Low tantalum content (< 500 µg/g) of niobium metal through liquid-liquid extraction of concentrate ore
  • Low level of interstitial impurities (C, O, H, N, S): Repeated electron beam melting reduces content to 5% of the content of standard niobium
  • RRR values of 40 – 300 (the RRR value is a reference value for thermal conductivity. It is the ratio between the electrical resistance (room temperature) and the electrical resistance taken just above the critical temperature.)
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