The graphite electrodes used in vacuum furnaces are cylindrical conductive heating elements made from ultra-high-purity isostatic pressed graphite as the base material. They are precisely machined and subjected to high-temperature purification treatment to form. These electrodes are specifically designed for high-temperature heating systems in vacuum/inert atmosphere environments. Unlike ordinary arc furnace graphite electrodes, this product adopts a low gas emission formula and high-density structure, possessing the triple functions of conductivity, heating, and load-bearing. It is suitable for high-end thermal equipment such as vacuum heat treatment furnaces, vacuum induction melting furnaces, and vacuum sintering furnaces, and is widely used in fields requiring strict control of purity and temperature, such as the preparation of aerospace alloys, semiconductor material purification, special ceramic sintering, and medical device heat treatment.
Processed by graphitization at temperatures above 2800°C, with fixed carbon content ≥99.995% and total impurities ≤5ppm, the outgassing rate is <1×10⁻⁸ Pa·m³/s in vacuum environment, ensuring no workpiece contamination during heating. They are the core consumables for high-end material preparation.
Advanced aerospace alloy heat treatment (military / aviation core requirements)
For vacuum heat treatment of aerospace materials such as titanium alloys, nickel-based superalloys, and refractory metals, graphite electrodes provide a stable heating solution of 1800-2500℃ for ultra-high temperatures. The electrodes adopt a multi-section connection design, which can be quickly assembled into a 3-8-meter heating system, suitable for large vacuum heat treatment furnaces, achieving uniform heating of the workpiece and temperature uniformity of ±5℃.
Low impurity characteristics (metal impurities such as Fe, Ni, Cr ≤ 1ppm) prevent alloy element contamination, ensuring the mechanical properties of the material; excellent high-temperature strength (bending strength ≥ 35MPa at 2000℃) ensures no deformation during long-term use, with a service life of over 800 furnace cycles, reducing production costs for aerospace enterprises.
Semiconductor and electronic material purification (key applications in the chip / photovoltaic industries)
Serves vacuum zone melting and purification of semiconductor materials such as single-crystal silicon, silicon carbide, and gallium nitride. The graphite electrodes have ultra-low resistivity (≤ 8 μΩ·m at 1000℃) and high conductivity stability, with a 30% increase in heating efficiency and significant energy-saving effects. Customized with cooling structure design, it can precisely control the electrode temperature gradient, meeting the strict temperature field requirements for semiconductor material growth.
Sintering of Special Ceramics and Composites (New Energy / Emerging Demand in Medical Field)
For vacuum sintering of silicon nitride, silicon carbide ceramics, carbon fiber composite materials, etc., graphite electrodes can provide a controllable temperature range of **1200-2000℃**, with a heating rate of up to 50℃/min, significantly shortening the sintering cycle. Customized irregular-shaped electrodes (square, circular, U-shaped) can be adapted to different furnace structures to achieve uniform heat radiation, improving the density and mechanical properties of ceramic materials.
Core Performance and Product Features
Ultra-high purity, ultra-low contamination: Fixed carbon content ≥ 99.995%, total content of metal impurities (Fe, Ni, Cu, Pb) ≤ 5 ppm, single impurity ≤ 1 ppm. No contamination of sensitive materials in a vacuum environment.
Low exhaust rate, high vacuum compatibility: Exhaust rate < 1×10⁻⁸ Pa・m³/s at 2500℃ vacuum environment, ensuring stable vacuum level within 10⁻⁶ Pa in the furnace, meeting the requirements of high-end applications such as semiconductors and aerospace materials.
Ultra-high temperature stable operation: Long-term stable working temperature 1800 - 2500℃, instantaneous tolerance temperature up to 3000℃, far exceeding the temperature limit of metal heating elements.
| No. | Inspection Item | Technical Standard Parameter | Test Method |
|---|---|---|---|
| 1 | Raw Material | Ultra-high Purity Isostatic Graphite | Carbon Purity Analysis |
| 2 | Fixed Carbon Content | ≥99.995% | Combustion Method |
| 3 | Bulk Density | 1.85 – 1.90 g/cm³ | Archimedes Principle |
| 4 | Total Impurity Content | ≤5 ppm (Fe, Ni, Cu, Pb ≤1 ppm each) | ICP-MS Detection |
| 5 | Maximum Long-term Working Temperature | 1800 – 2500 ℃ (Vacuum) | Thermal Stability Test |
| 6 | Instant Heat Resistance Limit | 3000 ℃ | Flash Heating Test |
| 7 | Outgassing Rate (2500℃) | ＜1 × 10⁻⁸ Pa·m³/s | Vacuum Outgassing Measurement |
| 8 | Electrical Resistivity (RT) | 10 – 15 μΩ·m | Four-point Probe Method |
| 9 | Electrical Resistivity (1000℃) | 6 – 8 μΩ·m | High-temperature Resistivity Test |
| 10 | Thermal Conductivity (25℃) | 140 – 160 W/(m·K) | Laser Flash Method |
| 11 | Thermal Expansion Coefficient (25-1000℃) | 3.2 × 10⁻⁶/℃ | Dilatometer Measurement |
| 12 | Thermal Shock Resistance | ≥1000 cycles (RT-2000℃) | Thermal Cycling Test |
| 13 | Flexural Strength (2000℃) | ≥35 MPa | High-temperature Strength Test |
| 14 | Surface Roughness | Ra ≤ 0.8 μm | Surface Profilometer |
| 15 | Connection Type | Thread + Taper Seal (Customizable) | Vacuum Leak Test |
| 16 | Standard Size Range | Diameter: 10-800 mm; Length: 100-3000 mm | Dimension Measurement |
| 17 | Service Life (Vacuum Environment) | 800 – 1200 cycles | Practical Application Test |
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