Niobium
Niobium belongs to an elite class of refractory metals built for temperatures beyond the reach of conventional structural alloys. Its combination of high-temperature capability and relatively favorable density makes it critical in applications where strength, stiffness and dimensional stability have to endure extraordinary heat.
But making a refractory metal useful is the hard part. Niobium is highly sensitive to impurities, difficult to process and, like other refractory metals, requires protection from oxidation in many high-temperature environments. Performance depends not simply on the element, but on purity, alloy design and the manufacturing path used to turn it into an engineered material. That is where ATI stands apart.
Learn More About Niobium
Niobium Alloys
Niobium is a highly ductile, soft refractory metal. The machining characteristics of niobium and its common alloys are similar to those of 316 stainless steel, and in lathe turning they behave much like soft copper. The chemical compositions, along with the physical and mechanical properties of niobium and its two most common alloys are listed in Tables 1 and 2. Guidelines and recommendations for specific machining and forming operations are given below. The advice and data should be used as starting points for working with niobium and its alloys. Fine chips and grinding dust of niobium and niobium-based alloys may burn and sustain combustion.
Niobium is a highly ductile, soft refractory metal. The machining characteristics of niobium and its common alloys are similar to those of 316 stainless steel, and in lathe turning they behave much like soft copper. The chemical compositions, along with the physical and mechanical properties of niobium and its two most common alloys are listed in Tables 1 and 2. Guidelines and recommendations for specific machining and forming operations are given below. The advice and data should be used as starting points for working with niobium and its alloys. Fine chips and grinding dust of niobium and niobium-based alloys may burn and sustain combustion.
It was discovered that the addition of 1% zirconium to niobium greatly improved the creep strength over the soft pure metal. Thus ATI Nb1Zr™ Alloy became the replacement for pure niobium in applications requiring the chemical resistance of niobium and a material with high melting temperature. In addition to greatly increasing the strength of pure niobium at higher temperatures, ATI Nb1Zr™ Alloy also has low thermal nuclear capture cross-section properties. This alloy has been closely associated with the nuclear industry, which requires specified elevated temperature strength in the range of 1800º F to 2200º F. Because of the increasing need for better strengths, as technology has advanced, ATI Nb1Zr™ Alloy has been replaced in some applications by alloys such as ATI C103™ Alloy, which has greater strength and thus improved reliability, but still retains all the desirable characteristics of ATI Nb1Zr™ Alloy. ATI Nb1Zr™ Alloy has the advantage of being less expensive than the higher strength alloys, and can be used in applications where a high temperature material is needed with low loads such as a loadfree thermal shield. Due to the excellent fabricability and ductility, this material is readily available in all desired mill product forms.
ATI C103TM is used in aerospace and defense propulsion applications requiring strength at sustained high operating temperatures. ATI C103TM is now offered in spherical powder for use with electron beam, laser powder bed, direct energy deposition and cold spray technologies for additive manufacturing of complex geometries. ATI C103™ Spherical Powder is offered in fine and coarse sizes. Fine is defined as nominal 15-63 µm with coarse being defined as 63-180 µm. Other particle sizes are offered by request.
Originally developed for application as an aerospace alloy because of its relative ease of formability, high strength and ductility at temperatures up to 427°C (801°F), ATI 45Nb™ Alloy is an ideal candidate for rivets that secure aluminum aircraft panels, particularly in areas exposed to high engine exhaust temperatures.
This alloy has been used as welded flange components that secure high energy physics RF linear accelerator cavities (made from high purity niobium), and has been drawn into superconductivity wire. It is used as a medical device material for cochlear hearing implants and its low elastic modulus makes the material a consideration for a variety of medical and dental devices.
ATI 45Nb™ Alloy is easily fabricated into structures and components. Although it is considered a refractory metal, processing techniques are the same as those for other titanium alloys. Parts are typically welded using the GTAW process but require the addition of trailing and backing shields and due to its simple metallurgical structure there is no requirement for post weld heat treatment. Machining requires the use of solid fixture setups, high torque at low RPM ridge machine tools with sharp high rake cutters.
With an exceptionally small bend radius capability (down to a bend radius of 1t where t=sheet thickness) and low modulus of elasticity, ATI 45Nb™ Alloy is highly formable and yet still retains excellent tensile and elongation properties. It can also be cast into shapes with the same processes used to cast CP titanium.
ATI 45Nb™ Alloy readily accepts surface oxidation treatment to enhance its hardness and wear resistance. “Nobelizing” is a common commercially available process to apply this type of surface treatment.
ATI 45Nb™ Alloy provides improved corrosion resistance along with higher strength compared to that of Ti-7, 12, 16, and 26 in many chemical environments. ATI 45Nb™ Alloy has also proven to be a great success in the autoclave processing of gold ore. For many years gas vents, oxygen lances, steam spargers, valves and other pressure oxidation reactor components have been produced, put into service, and survived hot, concentrated sulfuric or hydrochloric acid. In addition the metal has been shown to have higher ignition resistance when compared to CP Ti, thereby allowing further process optimization.
Another chemical processing applications for ATI 45Nb™ Alloy is the oxygen-based, low-pressure, wet oxidation process (LoProx*) for the treatment of waste water and sludge. Because of its corrosion and higher ignition resistance this material is an ideal candidate for the 200°C (392°F), 20 bar pressure with oxygen environment. The superior corrosion resistance of ATI 45Nb™ Alloy makes it well suited for service in a variety of environments including most organic and mineral acids below 150°C (302°F). Because of its stable oxide film, ATI 45Nb™ Alloy has excellent resistance to oxidizing acids including mixtures of HNO3 and HCL; however it is susceptible to attack from HF and other fluoride ions.
Niobium is a highly ductile, soft refractory metal. The machining characteristics of niobium and its common alloys are similar to those of 316 stainless steel, and in lathe turning they behave much like soft copper. The chemical compositions, along with the physical and mechanical properties of niobium and its two most common alloys are listed in Tables 1 and 2. Guidelines and recommendations for specific machining and forming operations are given below. The advice and data should be used as starting points for working with niobium and its alloys. Fine chips and grinding dust of niobium and niobium-based alloys may burn and sustain combustion.
Niobium is a highly ductile, soft refractory metal. The machining characteristics of niobium and its common alloys are similar to those of 316 stainless steel, and in lathe turning they behave much like soft copper. The chemical compositions, along with the physical and mechanical properties of niobium and its two most common alloys are listed in Tables 1 and 2. Guidelines and recommendations for specific machining and forming operations are given below. The advice and data should be used as starting points for working with niobium and its alloys. Fine chips and grinding dust of niobium and niobium-based alloys may burn and sustain combustion.
Niobium is a highly ductile, soft refractory metal. The machining characteristics of niobium and its common alloys are similar to those of 316 stainless steel, and in lathe turning they behave much like soft copper. The chemical compositions, along with the physical and mechanical properties of niobium and its two most common alloys are listed in Tables 1 and 2. Guidelines and recommendations for specific machining and forming operations are given below. The advice and data should be used as starting points for working with niobium and its alloys. Fine chips and grinding dust of niobium and niobium-based alloys may burn and sustain combustion.
Niobium is a highly ductile, soft refractory metal. The machining characteristics of niobium and its common alloys are similar to those of 316 stainless steel, and in lathe turning they behave much like soft copper. The chemical compositions, along with the physical and mechanical properties of niobium and its two most common alloys are listed in Tables 1 and 2. Guidelines and recommendations for specific machining and forming operations are given below. The advice and data should be used as starting points for working with niobium and its alloys. Fine chips and grinding dust of niobium and niobium-based alloys may burn and sustain combustion.
Niobium is a highly ductile, soft refractory metal. The machining characteristics of niobium and its common alloys are similar to those of 316 stainless steel, and in lathe turning they behave much like soft copper. The chemical compositions, along with the physical and mechanical properties of niobium and its two most common alloys are listed in Tables 1 and 2. Guidelines and recommendations for specific machining and forming operations are given below. The advice and data should be used as starting points for working with niobium and its alloys. Fine chips and grinding dust of niobium and niobium-based alloys may burn and sustain combustion.
ATI produces niobium powder in two compositions: Grade 1 and Grade 2, with Grade 1 being lower in tantalum.
Applications for niobium powders include:
• High-temperature components, especially for the aerospace industry
• Alloy additions, including some for superconducting materials
• Plasma spray coatings
• Filters
• Certain corrosion-resistant applications
