The physical properties of black tungsten wire include a high melting point (3422°C), high density (19.25 g/cm³), high mechanical strength, good electrical and thermal conductivity, low thermal expansion coefficient, and excellent high-temperature creep resistance. These characteristics make black tungsten wire widely used in lighting, electronics, and high-temperature industrial applications.
High Melting Point:
- Value: Approximately 3422°C (tungsten’s melting point, one of the highest among naturally occurring metals).
- Characteristics: Enables black tungsten wire to operate in extremely high-temperature environments, widely used in incandescent lamp filaments, high-temperature furnace heating elements, etc.
High Density:
- Value: Approximately 19.25 g/cm³ (close to the density of pure tungsten).
- Characteristics: High density provides black tungsten wire with greater mass and mechanical stability but makes it heavier, requiring consideration in lightweight applications.
Mechanical Strength:
- Tensile Strength: Tungsten wire has extremely high tensile strength, maintaining excellent mechanical properties at high temperatures (specific values vary depending on diameter and doping).
- Characteristics: Black tungsten wire has strong resistance to deformation at high temperatures, suitable for prolonged exposure to mechanical and thermal stress.
Hardness and Brittleness:
- Hardness: Tungsten has a Mohs hardness of approximately 7.5, indicating high hardness.
- Characteristics: Black tungsten wire is brittle at room temperature and prone to breaking, requiring careful handling; however, its ductility improves at high temperatures (>1000°C), facilitating wire-drawing processes.
Electrical Conductivity:
- Resistivity: Approximately 5.5 μΩ·cm (at 20°C, for pure tungsten).
- Characteristics: Black tungsten wire has good electrical conductivity, making it suitable for use as filaments, heating elements, and conductive materials in electronic devices, though resistivity increases with temperature.
Thermal Conductivity:
- Value: Approximately 173 W/(m·K) (thermal conductivity of pure tungsten at room temperature).
- Characteristics: High thermal conductivity allows effective heat transfer, suitable for high-temperature heating applications, though attention to uniform heat distribution is needed.
Thermal Expansion Coefficient:
- Value: Approximately 4.5 × 10⁻⁶ /K (from room temperature to 1000°C).
- Characteristics: Tungsten’s extremely low thermal expansion coefficient ensures minimal dimensional changes at high temperatures, making black tungsten wire suitable for applications requiring thermal stability.
Surface Characteristics:
- Roughness: The surface of black tungsten wire is rough due to the application of graphite milk, remaining unpolished, in contrast to the smooth surface of cleaned tungsten wire.
- Characteristics: The graphite milk coating (primarily carbon-based) gives the wire its black appearance, slightly affecting surface friction and electrical contact performance, but it does not impact functionality in most applications.
High-Temperature Creep Resistance:
- Characteristics: By doping with trace elements (e.g., potassium, aluminum, silicon), black tungsten wire exhibits excellent creep resistance at high temperatures, reducing deformation during prolonged high-temperature operation, making it particularly suitable for filaments and heating elements.
Optical Characteristics:
- Appearance: Dark black due to the graphite milk coating.
- Characteristics: The graphite milk coating does not affect the intrinsic physical properties of the tungsten wire, but its non-smooth appearance may need consideration in optical or surface-sensitive applications.
Size Range:
- Diameter: Black tungsten wire typically ranges from a few micrometers to several millimeters, depending on the application (e.g., fine wires for filaments or thicker wires for heating elements).
- Characteristics: The diameter can be precisely controlled through the wire-drawing process to meet the needs of various applications.
More details of tungsten wire, please visit website: http://www.tungsten-wire.com.cn/
Please contact CHINATUNGSTEN for inquiry and order of tungsten wire:
Email: sales@chinatungsten.com
Tel.: +86 592 5129595
