Columbium Material Property Data Sheet

Niobium, Nb (Columbium, Cb); Cold-Worked

Subcategory: Metal; Niobium Alloy; Nonferrous Metal; Pure Metallic Element

Component    Wt. % Nb 100

Material Notes:
Cold-worked applies only to tensile and/or hardness values; other property values are typical of the element. The name niobium is used by chemists but the element is generally called columbium by American metallurgists.

Fabrication: good formability, work hardens slowly, cannot be soldered. Joining requires adhesives, rivets, nuts and bolts, or capacitive discharge welding.

Applications: used in aerospace applications (i.e. rocket boosters), sodium vapor lamps, and superconductors.

Physical Properties	Metric	English	Comments
Density	8.6 g/cc	0.311 lb/in³
Mechanical Properties
Hardness, Brinell	126	126	Converted from Vickers for 3000 kg load/10 mm ball Brinell test.
Hardness, Rockwell A	45	45	Converted from Vickers.
Hardness, Rockwell B	71	71	Converted from Vickers.
Hardness, Vickers	130	130
Tensile Strength, Ultimate	600 MPa	87000 psi
Modulus of Elasticity	103 GPa	14900 ksi
Poisson's Ratio	0.38	0.38
Shear Modulus	37.5 GPa	5440 ksi
Electrical Properties
Electrical Resistivity	1.51e-005 ohm-cm	1.51e-005 ohm-cm
Magnetic Susceptibility	2.28e-006	2.28e-006	cgs/g
Critical Magnetic Field Strength, Oersted	2010 - 2110	2010 - 2110
Critical Superconducting Temperature	9.23 - 9.27 K	9.23 - 9.27 K
Thermal Properties
Heat of Fusion	290 J/g	125 BTU/lb
CTE, linear 20°C	7.1 µm/m-°C	3.94 µin/in-°F	over the range 20-100ºC
CTE, linear 250°C	7.38 µm/m-°C	4.1 µin/in-°F	at 300°C
CTE, linear 500°C	7.61 µm/m-°C	4.23 µin/in-°F
CTE, linear 1000°C	8.52 µm/m-°C	4.73 µin/in-°F
Heat Capacity	0.272 J/g-°C	0.065 BTU/lb-°F
Thermal Conductivity	52.3 W/m-K	363 BTU-in/hr-ft²-°F
Melting Point	2468 °C	4470 °F
Optical Properties
Emissivity (0-1)	0.39	0.39	2000°C
Emissivity (0-1)	0.78	0.78	1350°C

References are available for this material.