The EFG (Edge-Defined Film-Fed Growth) sapphire tube is a high-performance hollow component made from single-crystal aluminum oxide (Al₂O₃). Unlike traditional machining from KY-grown boules, the EFG method enables near-net-shape growth, significantly reducing material waste and machining costs.
With exceptional properties such as extreme hardness (Mohs 9), high-temperature resistance (>2000°C), excellent optical transmission (190 nm – 5 μm), and superior chemical stability, sapphire tubes are widely used in demanding environments where quartz or glass cannot perform reliably.
Key Features & Advantages
1. Near-Net Shape Growth (Cost Efficient)
- Direct tube growth via EFG method
- Reduced material loss and machining time
- Ideal for long-length and large-diameter tubes
2. Outstanding High-Temperature Resistance
- Melting point up to 2050–2100°C
- Stable operation at temperatures up to 2000°C
- Suitable for extreme thermal environments
3. Excellent Optical Properties
- Wide transmission range: 190 nm – 5000 nm (UV to IR)
- High visible light transmittance: ≥85%
- Ideal for optical windows and laser systems
4. Superior Chemical Resistance
- Resistant to acids and alkalis
- Excellent corrosion resistance in harsh environments
- Suitable for semiconductor and chemical industries
5. Exceptional Mechanical Strength
- Hardness: Mohs 9 (second only to diamond)
- High wear resistance and long service life
- Maintains integrity under high stress conditions
Technical Specifications
| Property | Value |
|---|---|
| Material | Single Crystal Al₂O₃ (Sapphire) |
| Growth Method | EFG / KY |
| Purity | ≥99.99% |
| Crystal Structure | Hexagonal |
| Hardness | Mohs 9 |
| Density | 3.97 g/cm³ |
| Melting Point | 2050–2100°C |
| Max Working Temp | ≤2000°C |
| Tensile Strength | 275 – 400 MPa |
| Flexural Strength | 480 – 895 MPa |
| Young’s Modulus | 435 GPa |
| Transmission Range | 190 nm – 5 μm |
| Visible Transmittance | ≥85% |
| Refractive Index | ~1.76 |
| Surface Quality | 20/10 – 80/50 S/D |
| Surface Roughness | <0.3 nm |
Customization Capability
| Parameter | Range |
|---|---|
| Outer Diameter (OD) | 0.1 – 350 mm |
| Inner Diameter (ID) | Customizable |
| Length | 0.1 – 500 mm |
| Wall Thickness | Minimum 0.1 mm |
| Dimensional Tolerance | ±0.1 mm |
| Thickness Tolerance | ±0.01 – 0.10 mm |
| Parallelism | ≤5′ |
| Flatness | λ/4 @ 633 nm |
✔ Available Options:
- Polishing / Grinding / Optical Finishing
- Chamfering & Edge Processing
- Crystal Orientation (C, A, M, R planes)
- Custom shapes and complex geometries
EFG Growth Method (Why It Matters)
The Edge-Defined Film-Fed Growth (EFG) method uses capillary action to draw molten alumina through a shaped die, where crystallization occurs guided by a seed crystal.
Advantages of EFG:
- Direct control over cross-sectional shape
- Continuous crystal growth
- Multi-tube simultaneous production
- Significantly improved production efficiency
- Reduced cost compared to KY machining
EFG vs KY Sapphire Tubes
| Feature | EFG | KY |
|---|---|---|
| Manufacturing | Direct growth | Machined from boule |
| Cost | Lower | Higher |
| Size Capability | Excellent for long tubes | Limited |
| Crystal Uniformity | Good | Excellent |
| Application | Industrial / large-scale | Precision optics |
Applications
- Semiconductor equipment (process tubes, protection tubes)
- Optical systems (windows, lenses, laser components)
- Infrared and UV systems
- High-temperature furnaces
- Chemical processing environments
- Aerospace and defense systems
- Precision mechanical components (including bearings)
FAQ
Q1: What is a sapphire tube?
A sapphire tube is a hollow cylindrical component made from single-crystal Al₂O₃, offering exceptional hardness, thermal stability, and optical transparency.
Q2: What is the advantage of EFG sapphire tubes?
EFG tubes are grown directly into shape, reducing cost and enabling longer lengths compared to traditional KY methods.
Q3: Can you provide custom sizes?
Yes, full customization is available for dimensions, tolerances, surface finish, and crystal orientation.
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