Silicon Carbide (SiC) Mirrors
Silicon carbide (SiC) mirrors are advanced optical components known for their exceptional properties, making them ideal for various applications, including larger telescopes, high-speed scanning systems, and space applications. Here is an overview of SiC mirrors, including their properties, manufacturing methods, and Avantier’ capabilities in producing custom SiC mirrors:
Properties of Silicon Carbide (SiC) Mirrors
Silicon carbide mirrors offer several key advantages:
- Lightweight: SiC is known for its low density, making SiC mirrors significantly lighter than traditional glass mirrors. This property is particularly important for space applications and larger telescopes, where weight reduction is critical.
- High Strength and Stiffness: SiC exhibits high mechanical strength and stiffness, providing excellent structural integrity even in demanding environments.
- High Thermal Conductivity: SiC has high thermal conductivity, enabling it to dissipate heat effectively. This property is essential for maintaining optical performance in high-temperature environments.
- Thermal Stability: SiC mirrors can withstand high temperatures, making them suitable for use in applications where temperature fluctuations occur.
- Thermal Shock Resistance: SiC mirrors are highly resistant to thermal shock, making them durable in conditions with rapid temperature changes.
- Oxidation and Chemical Resistance: SiC is resistant to oxidation and chemical degradation, ensuring long-term stability in harsh environments.
- Low Thermal Expansion: SiC has a low coefficient of thermal expansion, which minimizes the impact of temperature changes on mirror performance.
- Mechanical Strength: While SiC is generally mechanically strong, it can be brittle, so careful handling is required.
Manufacturing of Silicon Carbide
There are three primary methods for producing Silicon Carbide for optical applications:
- Reaction Bonding: This method involves casting a mixture of alpha Silicon Carbide and carbon, followed by firing. Liquid silicon is then infiltrated into the porous mixture, reacting with carbon to form dense SiC. Reaction bonded Silicon Carbide is cost-effective and suitable for lightweight optical designs.
- Sintering: SiC powder is sintered at high temperatures (above 2000°C) with non-oxide sintering additives in an inert atmosphere and high pressure. Sintered SiC results in a very hard ceramic suitable for optical mirrors but requires extensive machining to eliminate surface roughness.
- Chemical Vapor Deposition (CVD): CVD is used to produce very pure SiC in a face-centered cubic crystal form. This type of SiC has exceptionally high thermal conductivity but is more expensive to produce.
The choice of manufacturing method can impact the physical properties of the SiC, such as density and Young’s modulus.
Specifications
Size | 25 mm – 800 mm |
Surface Shape | Flat (typical), Sphere, Aspheric |
Surface Flatness | up to λ/100 RMS |
Coatings | Al, Ag, Au & High Laser Damage Threshold Dielectric Coatings as needed |
Lightweight SiC Mirror Applications | Telescopes, Laser Scanning Systems, etc. |
Tailored Design Example
Dimensions: Length 379 mm, Width 260 mm, Thickness 85 mm
Dimension Tolerance: ±0.1 mm
Clear Aperture (CA): 90%
Surface Quality: 80-50
Surface Accuracy: RMSI < 16 nm
Coating: Protective gold
Reflectance (Rabs): >95% @ 400-12,000 nm
Angle of Incidence (AOI): 0-4.5°
Custom Silicon Carbide Mirrors at Avantier
Avantier specializes in producing custom Silicon Carbide Mirrors tailored to specific customer requirements. These mirrors are designed to meet the needs of applications such as larger telescopes, high-speed scanning systems, and space missions.
Avantier utilizes precision machining processes and state-of-the-art metrology equipment to ensure the highest quality Silicon Carbide Mirrors. Our capabilities allow with various specifications, including size, shape, and optical coatings.
If you require custom Silicon Carbide Mirrors or need design assistance, you can contact Avantier to discuss your specific requirements and explore their manufacturing capabilities. Their expertise can help meet the demands of your unique optical application.
WE CAN HELP YOU!
Contact us NOW for sales & expert advice.