Custom Sapphire Tubes Semi-Polished Al₂O₃ Single Crystal for
Optical Instruments
Sapphire semi-polished tubes are typically manufactured from
optical-grade sapphire (α-Al₂O₃ single crystal). They undergo
preliminary polishing treatment, resulting in a surface quality
that falls between rough-machined blank tubes and fully polished
tubes with a mirror finish.
The term "semi-polished" indicates that the tubes have undergone
certain polishing processes (which may include rough polishing and
preliminary fine polishing), removing most machining marks and
achieving good surface smoothness, though not yet meeting the
highest surface quality requirements. Depending on specific
applications, subsequent custom finishing may be required.
Sapphire Semi-polished Tubes Key Features
The core characteristics of sapphire semi-polished tubes stem from
the exceptional properties of sapphire material itself and its
semi-polished state:
1. Extreme Hardness & Wear Resistance: Sapphire has a Mohs hardness of 9, second only to diamond. This
makes it highly resistant to wear and scratching, suitable for
high-abrasion environments.
2. Excellent Optical Properties: Sapphire exhibits good light transmission within the 200 nm to
5500 nm spectrum (covering UV, visible, and near-infrared light),
with infrared transmittance remaining stable across temperatures.
3. High Temperature Resistance & Chemical Stability: Sapphire can withstand temperatures up to 1900°C and demonstrates
strong corrosion resistance to most acids and alkalis, making it
suitable for harsh chemical environments and high-temperature
viewports.
4. Specific Advantages of Semi-Polished State:
- Compared to rough blanks: Better surface quality reduces the need
for additional processing time and material allowance.
- Compared to fully polished tubes: Generally more cost-effective,
providing an economical option for applications not requiring a
mirror finish, while retaining allowance for further fine
polishing.
Sapphire Semi-polished Tubes Main Applications
Leveraging these properties, sapphire semi-polished tubes are
widely used in various high-end fields:
- Semiconductor Industry: Used in high-temperature furnace tubes, viewports, carriers, etc.
- Optical Instruments & Equipment: Serving as infrared/UV windows, optical lens base tubes, laser
tubes, etc.
- Industrial Equipment & Sensing: Applied in observation windows under high-temperature and
high-pressure conditions (e.g., chemical pumps, reactors), flow
meter measurement tubes, sensor protection tubes, etc.
- Research & Special Equipment: Utilized in optical windows for high-pressure research chambers,
spectral analysis components, etc.
Sapphire Semi-polished Tubes Key Parameters
The following table summarizes the key technical parameters of
sapphire tubes and semi-polished tubes.
Note: The specific parameters of "semi-polished" tubes (especially
surface roughness and quality) typically fall between the "General
Values" and "High-Precision/Fully Polished" values, depending on
processing levels and customer requirements.
Parameter Name | Description | General Value/Range for Sapphire Tubes | High-Precision/Fully Polished Achievable Value | Typical Value for Semi-Polished Tubes (Reference) |
Material
| Optical-grade sapphire single crystal (α-Al₂O₃) |
Outer Diameter Range (mm)
| Tube outer diameter | 2.0 ~ 300.0 |
| Same as left |
Outer Diameter Tolerance (mm)
| Allowable deviation of outer diameter | ±0.02 | < ±0.02 | ±0.02 ~ ±0.05 |
Inner Diameter Range (mm)
| Tube inner bore diameter | 0.2 ~ 100.0 |
| Same as left |
Inner Diameter Tolerance (mm)
| Allowable deviation of inner bore diameter | ±0.02 | < ±0.02 | ±0.02 ~ ±0.05 |
Length Range (mm)
| Tube length | 2.0 ~ 100.0, up to 250 |
| Same as left |
Length Tolerance (mm)
| Allowable deviation of length | ±0.02 |
| Same as left |
Wall Thickness Deviation
| Uniformity of tube wall |
|
| Consult supplier |
Concentricity Error (mm)
| Offset between inner and outer wall centers |
| ≤ 0.05 | > 0.05 |
Straightness Tolerance (mm)
| Axial straightness of the tube |
| 0.005 ~ 0.01 | > 0.01 |
Surface Roughness (Ra)
| Microscopic surface unevenness |
| ≤ 0.1 μm (Rz ≤ 0.1) | > 0.1 μm |
Surface Quality
| Scratch/Dig Standard (MIL-O-13810) | 40/20 ~ 80/50 | 20/10 or better | 60/40 or 40/20 |
Clear Aperture (%)
| Percentage of effective light-transmitting area | 80 ~ 99 |
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Q1: What is a semi-polished sapphire tube?
A1: A semi-polished sapphire tube is made from optical-grade
α-Al₂O₃ single crystal, featuring a surface finish between
rough-machined and fully polished states, achieved through
preliminary polishing steps to improve smoothness while remaining
cost-effective38.
Q2: What are the key advantages of semi-polished sapphire tubes?
A2: They offer high hardness (Mohs 9), excellent optical
transmission from UV to NIR (200-5500 nm), and superior
chemical/thermal resistance (up to 1900°C), making them ideal for
optical instruments, semiconductor equipment, and high-temperature
viewports35.
Tags: #Sapphire Tubes, #Custom, #High Hardness, #Semi-Polished, #High Hardness, #Infrared Windows, #Al₂O₃ Single Crystal, #Optical Instruments
