Thermal Evaporation Coating tungsten wires
Evaporation-coated thermal evaporation coating tungsten twisted wires (vacuum evaporation tungsten coil) is the core heating evaporation source in the vacuum thermal evaporation and PVD vacuum metallization process. The product is made by twisting multiple high-purity potassium-doped tungsten wires together in a precise manner.
comparison of product parameters
| Products name | Thermal Evaporation Coating tungsten wires |
| Products model | WAL1 |
| Products material | Tungsten |
| Density | 19.2g/cm3 |
| Tungsten Wire Melting Point | 3422 ℃ |
| Thermal Conductivity | 173 W/(m·K) |
| Wire Diameter | 0.3mm,0.4mm,0.5mm,0.6mm,0.7mm,0.8mm,1.0mm or as request |
| Strand Options | 2-strand /3-strand /4-strand twisted |
| Coil Shape | Funnel type, Gate type, Custom forming |
How can tungsten wires be used in vacuum thermal evaporation coating to extend the tungsten heating wires lifespan, and can reduce tungsten heated wire breakage, thereby reducing furnace chamber contamination and improving coating production efficiency?
Material selection is very important and crucial. It is necessary to reduce wire breakage and contamination at the source and improve lifespan.
01.Doped tungsten wire / Non-sagging tungsten
suitable for continuous production and multiple cycles of coating.
Compared to pure tungsten W1: Pure tungsten rapidly grows grains at high temperatures and becomes brittle. After multiple temperature rises, it is prone to sagging, breaking, and dropping aluminum droplets.
Suitable for short-term, small-batch experiments, but not recommended for mass production.
02.Purity indicators
for ultra-clean requirements, select 99.99% (4N), strictly controlling O, C, Fe, Ni impurities.
Impurities can create local hotspots, causing local melting and brittle fracture;
impurities volatilize at high temperatures, being one of the main pollution sources in the vacuum furnace.
03.Wire diameter and twisting structure selection
Twisting structure: Multi-strand twisting is common, with 3 or 4 strands being more common; the pitch is uniform, and the shape is stable; perform stress-relieving annealing during production to eliminate residual stress from winding and prevent deformation and wire breakage at high temperatures.
Surface condition: Acid wash clean / electrolytic polishing tungsten wire, removing graphite lubricants and surface oxide layers; black wires have a graphite lubricating layer, and the graphite will volatilize at high temperatures and pollute the furnace chamber, and black wires are prohibited in clean coating scenarios.
04.Structural selection
for aluminum evaporation, the funnel type is preferred, as the aluminum material is evenly wrapped, reducing aluminum balls rolling and dripping onto the workpiece or furnace bottom.
Process optimization during use
Installation and pre-treatment precautions:
1) Do not touch the wire with bare hands;
hand oils volatilize at high temperatures, polluting the furnace chamber and causing local burnout.
2) Fixture installation: The electrode clips should be moderately tightened; too tight will cause micro-cracks due to pressure on the tungsten wire;
too loose will result in high contact resistance, local heating, and wire breakage, forming hot spots.
3) Pre-burning to remove gas: Slowly heat to slightly red in a vacuum environment, maintain for gas removal, releasing oxygen, water vapor, and surface residual impurities inside the material;
avoid direct full-power heating at once, as it can cause instantaneous oxidation and slagging, polluting the chamber.
Temperature control during heating
1) Use a stepwise, slow increase in power; strictly avoid full-power shock.
Tungsten has high brittleness at low temperatures, and rapid thermal expansion and contraction will cause thermal fatigue cracks, and it will break after several cycles.
2) Control the maximum working temperature; do not overheat.
High temperature: The evaporation loss of tungsten increases, and the evaporation metal melts excessively and aggregates, forming metal droplets that fall from the wire, polluting the substrate and the furnace chamber.
3) Vacuum level guarantee: It is recommended that the vacuum level before evaporation should be better than 1×10⁻³Pa;
When the vacuum level is insufficient, the residual gas will react with the high-temperature tungsten, generating harmful substances.
Evaporation material filling
The filling amount of aluminum wire / material particles should not be excessive. After melting, the molten metal exceeds the wire's carrying capacity and drips, causing workpiece damage and accumulation of metal pollutants in the furnace.  • The purity of the evaporation material should be high; low-purity aluminum contains impurities that will alloy with tungsten, corroding the wire and causing the wire to break prematurely.  • Do not completely evaporate the material at once; after the material is exhausted, the tungsten wire is directly exposed to high temperatures, accelerating wear.
Equipment Maintenance
Regularly clean the shielding baffle to prevent the formation of excessive metal film layers that may flake off and cause particle contamination.  • Check the electrode contact: Oxidized electrodes may cause poor contact and local overheating, leading to the burnout of the wire.
Contact Person: Tracy
Our address
Baoji city, shaanxi province ,China
Phone Number
0086-18291730106
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