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Nibron Special® and Toughmet®

Nibron Special® and Toughmet®

23 October 2024

Copper alloys have long been valued for their corrosion resistance and excellent friction characteristics, particularly in marine applications and bearing components. However, they often lack the mechanical strength required for high-stress environments.

Over time, alloy development has bridged this gap, leading to the introduction of advanced copper alloys capable of delivering high strength alongside copper’s inherent benefits. Two such alloys – Nibron Special® and Toughmet® – represent significant advancements in the field of copper alloys, offering enhanced performance in demanding engineering applications.

Copper Alloys for High-Strength Applications

While traditional copper alloys perform well in low-stress applications, their use in more demanding environments has historically been limited by lower mechanical strength. The introduction of beryllium copper alloys marked an important step forward, offering improved material strength, though at the cost of safety concerns related to the inhalation of beryllium dust during machining.

Nibron Special® Toughmet®
Nickel
13-16%
15%
Aluminium
2-4%
Iron
0.5-2.5%
Tin
8%
Copper
Balance
Balance

This led to the creation of Nibron Special®, a precipitation-hardened copper-nickel-aluminium alloy, and Toughmet®, a spinodally hardened copper-nickel-tin alloy. Both alloys were designed to provide the high strength needed for more demanding applications, while retaining the key advantages of copper, including corrosion resistance and excellent wear properties.

Nibron Special®: A Balance of Strength and Conductivity

Nibron Special®, developed exclusively by Columbia Metals, is a precipitation-hardened alloy that owes its high strength to the formation of nickel aluminide precipitates in a copper-nickel matrix. These precipitates significantly enhance the alloy’s resistance to deformation, making Nibron Special® particularly suitable for applications where both strength and corrosion resistance are critical.

What distinguishes Nibron Special® is its combination of mechanical strength and conductivity. In addition to its 630MPa yield strength and 850MPa ultimate tensile strength, Nibron Special® offers higher electrical and thermal conductivity compared to some other high-strength copper alloys. This makes it an attractive choice for applications where both strength and conductive properties are required, such as electrical components and marine environments.

Toughmet®: Optimized for Wear Resistance

Toughmet®, by comparison, is a spinodally hardened alloy with a two-phase microstructure of hard nickel-tin (Ni₃Sn) phases within a softer copper-nickel matrix. This unique structure not only increases the material’s strength but also improves its wear resistance by minimizing the formation of debris during frictional wear. Toughmet® is especially well-suited for applications requiring high resistance to wear and reduced maintenance, such as bushings, bearings, and heavy industrial machinery components.

Although Toughmet® has a higher typical yield strength of 760MPa and a slightly higher tensile strength (910MPa), it may not be the optimal choice for applications requiring electrical conductivity, as its conductivity is lower than Nibron Special®‘s.

Nibron Special® Toughmet®
0.2% Proof Strength (typical)
630MPa
760MPa
Tensile Strength (typical)
850MPa
910MPa
Elongation (typical)
12%
10%
Electrical Conductivity (% IACS)
10-12
<7
Thermal Conductivity (W/m/oC)
46
38
Coefficient of Thermal Expansion (m/m/oC
16.4 x 106
16.6 x 106
Density (g/cm3)
8.5
9.0

While both materials perform well under stress, Nibron Special®’s higher electrical and thermal conductivity makes it particularly versatile in applications where heat dissipation or electrical flow is important. This makes it a strong candidate for aerospace, marine, and electrical engineering applications, especially where the combination of strength and conductivity is essential.

Diverse Applications Across Industries

Both Nibron Special® and Toughmet® have found success across a wide range of industries, each alloy playing to its strengths. Nibron Special® has proven itself in areas where a balance of strength, conductivity, and corrosion resistance is necessary, such as:

  • Bearing bushes for aircraft steering and landing gear
  • Subsea fasteners and couplings, ideal for withstanding harsh marine environments
  • Non-magnetic components for remote sensors, ensuring precision in sensitive instrumentation
  • Plastic injection mould tooling and electrical components, leveraging its high conductivity and wear resistance

Toughmet®, with its enhanced wear resistance, is favoured in high-friction environments, such as industrial machinery and bearing components, where reduced maintenance and extended lifespan are critical factors.

Conclusion

The selection of the right alloy for a particular application depends heavily on the specific requirements. Both Nibron Special® and Toughmet® represent significant advancements in copper alloy technology, offering enhanced strength, corrosion resistance, and wear properties. However, Nibron Special®’s combination of strength, thermal and electrical conductivity, and corrosion resistance makes it particularly versatile, especially in applications that demand a balance between mechanical performance and conductive properties.

For design engineers facing complex material challenges, Nibron Special® may offer the flexibility needed to meet a broader range of performance criteria, particularly in industries such as aerospace, marine, and electrical engineering. While Toughmet® excels in specific high-wear applications, Nibron Special® offers an adaptable solution for a wider variety of demanding environments, making it a key consideration for future material needs.

Our Nibron Special® design guide features technical data and discussion of the mechanical performance of the alloy under a range of operating conditions

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