The EFG (Edge-Defined Film-Fed Growth) sapphire tube is a single-crystal aluminum oxide component produced through the advanced EFG crystal growth process. Unlike conventional sapphire fabrication methods that rely on bulk crystal cutting and subsequent machining, the EFG technique enables the direct formation of long, uniform, and hollow sapphire structures. This method significantly improves dimensional stability, minimizes material waste, and delivers high structural integrity suitable for demanding industrial environments.

This product features an unpolished (as-grown) inner and outer surface, retaining the natural crystalline texture formed during the EFG growth process. It suits a wide range of applications where optical transparency is not required but extreme durability, chemical resistance, and thermal stability are critical.

1. Key Material Advantages

High-Purity Single-Crystal Sapphire (99.99% Al₂O₃)

The tube is made from high-purity, defect-controlled sapphire crystal with excellent physical properties:

• Mohs hardness of 9 for outstanding abrasion resistance

• High compressive strength and structural rigidity

• Exceptional dimensional stability even at elevated temperatures

• Complete chemical inertness to acids, alkalis, and high-purity process gases

These characteristics make the unpolished sapphire tube far more durable and stable than quartz, ceramics, metals, or glass alternatives.

2. Unpolished (As-Grown) Surface – Functional and Cost-Effective

The unpolished EFG sapphire tube retains the natural matte crystal surface, with no optical grinding or polishing applied. This brings several engineering benefits:

• Lower production cost – Avoids expensive optical finishing processes

• Stronger surface adhesion – Ideal for coating, metallization, or bonding

• Reduced internal stress – No post-machining stress introduced

• Suitable for structural and protective roles rather than optical transmission

• Easier secondary processing – Customers may perform post-polishing only on critical sections if needed

This makes the unpolished tube especially suitable for furnace components, chemical transport, and semiconductor processing equipment.

3. Advantages of the EFG Growth Process

Compared with C-axis-cut tubes, KY-grown sapphire, or machined sapphire cylinders, the EFG method offers:

• Long continuous tube lengths (up to 1000 mm or more)

• Excellent wall thickness uniformity

• Superior concentricity due to simultaneous inner/outer wall formation

• Flexible geometry design: round, square, oval, multi-bore tubes

• Higher yield and better cost performance

These advantages make EFG sapphire tubes a preferred choice for industrial customers requiring reliable, consistent, and customizable crystal components.

4. High Temperature & Chemical Stability

Sapphire’s physical robustness enables the tube to withstand:

• >1500°C in oxidizing environments

• >2000°C in inert or vacuum atmospheres

• Rapid thermal cycling without cracking

• Long-term exposure to corrosive media, including:

  • Hydrochloric, sulfuric, and nitric acids

  • Strong alkalis such as NaOH and KOH

  • Chlorine-bearing gases

  • Plasma and reactive ion atmospheres

This level of resistance is unmatched by quartz, technical ceramics, or most specialty metals.

5. Typical Applications

Thanks to its excellent combination of thermal, chemical, and mechanical properties, the unpolished EFG sapphire tube is widely used in:

Semiconductor & Optoelectronic Equipment

• MOCVD/PECVD protective tubes

• High-temperature reaction chambers

• Laser and LED protection sleeves

• Plasma-resistant pipeline components

High-Temperature Industrial Processes

• Furnace protection tubes

• Thermocouple shielding components

• Chemical vapor and gas flow channels

Chemical and Corrosive Fluid Handling

• Acid/alkali-resistant pipelines

• High-purity fluid transport

• Oxidizing gas distribution systems

Mechanical & Structural Components

• Wear-resistant sleeves and liners

• High-strength insulating elements

• Support structures in harsh environments

Scientific & Vacuum Equipment

• Vacuum system observation ports

• Corrosion-resistant experimental chambers

• High-temperature containment structures

6. Customizable Specifications

We offer a wide range of customization options:

• Outer Diameter (OD): 3–80 mm

• Inner Diameter (ID): 1–70 mm

• Wall Thickness: 1–10 mm

• Length: up to 1000 mm

• Cross-Section: round / square / oval / multi-channel

• End Finish: unpolished / ground / chamfered

• Surface Condition: as-grown (unpolished) or semi-finished

• Crystal Orientation: standard EFG orientation

Custom engineering samples and mass-production batches are available.

7. Why Choose Unpolished EFG Sapphire Tubes?

• More economical compared to polished sapphire tubes

• High structural integrity and long service life

• Suitable for extreme temperatures and corrosive environments

• Ideal for mechanical, chemical, and protective applications

• Compatible with downstream machining and coating processes

FAQ – EFG Sapphire Tube (Unpolished)

1. What is an EFG sapphire tube?

An EFG sapphire tube is a hollow single-crystal aluminum oxide component manufactured using the Edge-Defined Film-Fed Growth method. This technique allows the tube to grow directly in its final shape, offering excellent dimensional stability and uniform wall thickness.

2. What is the difference between unpolished and polished sapphire tubes?

• Unpolished (as-grown): The tube surface maintains the natural matte crystal texture, suitable for mechanical, chemical, and high-temperature applications.

• Polished: The surface is optically ground and polished for transparency, used for optical or imaging applications.
  Unpolished tubes are significantly more cost-effective.

3. What are the advantages of using sapphire instead of quartz or ceramics?

Sapphire offers superior:

• Hardness (Mohs 9)

• High-temperature resistance (>1500°C)

• Chemical resistance to acids, alkalis, plasma, and solvents

• Mechanical strength and wear resistance

• Long service lifetime

It outperforms quartz and most technical ceramics in harsh environments.

4. Can the unpolished tube withstand high-temperature environments?

Yes. Sapphire tubes can operate at:

• Over 1500°C in oxidizing atmosphere

• Up to 2000°C in inert/vacuum conditions
  They also have excellent thermal shock resistance.

Related Products

Sapphire tube EFG double side polish for Laser and Optical Systems

High Purity Sapphire Tube With Extreme Heat Resistance 99 995% Length 1-1500mm EFG Technology

About Us

ZMSH specializes in high-tech development, production, and sales of special optical glass and new crystal materials. Our products serve optical electronics, consumer electronics, and the military. We offer Sapphire optical components, mobile phone lens covers, Ceramics, LT, Silicon Carbide SIC, Quartz, and semiconductor crystal wafers. With skilled expertise and cutting-edge equipment, we excel in non-standard product processing, aiming to be a leading optoelectronic materials high-tech enterprise.