Tungsten
Tungsten powder is a key raw material used in the production of tungsten-based products such as tungsten carbide, tungsten heavy alloys, and various tungsten compounds. The properties of tungsten powder are critical to the performance of the final product. Key parameters that define tungsten powder’s quality and applicability include:
- Particle Size Distribution: Measured in microns, particle size directly impacts the density, flowability, and sintering behavior of the powder. Fine powders (smaller particles) generally result in higher density products post-sintering, whereas coarser powders may be easier to handle and press.
- Purity: The percentage of tungsten in the powder, excluding impurities such as oxygen, iron, and carbon. High-purity tungsten powder (typically ≥99.95%) is required for applications in electronics, lighting, and aerospace.
- Specific Surface Area (SSA): Reflects the total surface area of all particles per unit mass. A higher SSA indicates smaller particles and can influence the reactivity and compacting properties of the powder.
- Flowability: Determines how easily the powder flows through processing equipment like hoppers and feeders. It’s influenced by particle shape, size distribution, and surface conditions.
- Tap Density: The density achieved when the powder is packed under a defined mechanical impulse. It’s an indicator of how densely the powder can be compacted before sintering.
- Chemical Composition: Apart from tungsten, trace elements like oxygen, nitrogen, and carbon can significantly affect the powder’s properties and the performance of the final product.
- Particle Shape: Can be spherical, irregular, or flake-like, affecting packing efficiency, sintering behavior, and the mechanical properties of the sintered part.
- Sinterability: The ability of the powder to form a dense, strong mass when heated without melting. It depends on particle size, purity, and the presence of sintering aids.
- Dustiness: The tendency of the powder to generate dust during handling, which is a health and safety concern. Lower dustiness is preferred.
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Microstructure: The arrangement and size of grains and phases within the powder particles, which influences the performance of the final product, especially in terms of hardness and toughness.
