Space & Astronomy Applications
Customized ceramic technology for satellite components, space observation and astronomy
SPACE & ASTRONOMY MATERIALS
Cordierite (CO720)
Cordierite is an extremely low thermal expansion ceramic which was developed over two decades back, and we have been constantly improving on its characteristics since.
Characteristics
- Minimal temperature deformation due to unique material composition with an extremely low thermal expansion rate
- Approx. 70% weight reduction when compared to low CTE glass* with a slim ribbed structure design featuring high rigidity
- Rapid process time even for complex designs due to good machinability
Structural parts made of ceramics in a satellite
* based on Kyocera's research
Temperature dependency graph < Cordierite CO720 >
Material characteristics comparison with Low CTE glass
| Low CTE glass | ||
|---|---|---|
| Density [g/cm3] | 2.53 | 2.55 |
| CTE** [ppm/K] | 0.02 | 0.02 |
| Elasticity modulus [GPa] | 90 | 145 |
| Specific rigidity | 36 | 57 |
The values are typical material properties and may vary according to product configuration and manufacturing process.
** temperature dependency graph
Displacement map***
3-point supported deflection***
Comparison conditions:
- Product size: Ø1020 x 120mm (rib structure)
- Supported points: outside 3 points
- Load: self-weight
*** based on Kyocera's research
Silicon-infiltrated Silicon Carbide (SiSiC)
Proprietary joining and manufacturing technology combined with our excellent StarCeram® materials enables high precision components with unique design features.
- Hidden internal cavities possible (e.g. cooling channels)
- Complex and fine detailed structures below 1mm achievable
- Large-scale parts monolithically up to 950mm x 950mm x 650mm and
larger via proprietary joining technologies - High strength, extreme stiffness and reliability components at lowest weight
- Joining areas with identical material properties, such as E Modulus and strength
Characteristics
- Closed porosity for water and gas tightness requirements
- Superior impurity levels by utilization of semiconductor grade constituents
- Extremely homogeneous material through large-scaled part
| StarCeram® Si SiSiC | |
|---|---|
| SiC | > 85 wt% |
| Si | balance |
| Cu | < 3 ppm |
Silicon Carbide (SiC)
- Excellent chemical resistance from basic to acidic materials allowing applications in harsh environments
- Large-scaled parts with outstanding high-temperature performance answering the demanding needs of the aerospace industry
Chemical resistance
Material characteristics
| StarCeram® S SSiC | StarCeram® Si SiSiC | |
|---|---|---|
| Density [g/cm³] | 3.13 | 3.05 |
| Fracture strength RT [MPa] | 373 | 300 |
| Young’s modulus RT [GPa] | 395 | 380 |
| Thermal conductivity RT [W/mK] | 125 | 200 |
| CTE (RT -1,000C°) [x10-6K-1] | 4.5 | 4.0 |
| Resistivity RT [Ωm] | 104 | 10-2 |
| Thermal shock coefficient R1 [K] | 180 | 190 |
| Max. working temperature [°C] | 1,600 | 1,350 |
Alumina (Al2O3) and Zirconia (ZrO2)
Kyocera’s oxide ceramics display operational safety, reliability and long lifetime based on the following physical characteristics:
- Mechanical strength
- High chemical resistance
- Good thermal shock resistance at high and low temperatures
- Good thermal conductivity
- Excellent electrical resistance
- Low dielectric loss at high frequency
Brazed oxide ceramic-to-metal assemblies outreach the excellent properties of ceramics and metal. Ceramics show electrical insulation; metal components feature weldability. This advantageous combination enables a wide range of vacuum, high-voltage and high-pressure applications.
| Alumina F99.7 α-Al2O3 | Zirconia FZM ZrO2 MgO | |
|---|---|---|
| Purity [wt-%] | > 99.7 | > 99.7 |
| Apparent density [g/cm³] | ≥ 3.90 | ≥ 5.70 |
| Bending strength [N/mm² (MPa)] | 350 | 500 |
| Maximum operating temperature [°C] | 1,950 | 900 |
SPACE & ASTRONOMY APPLICATIONS
Camera lens spacer
Subaru Telescope is an 8.2-meter (320 in) optical-infrared flagship telescope operated by the National Astronomical Observatory of Japan (NAOJ), located at the Mauna Kea Observatory on Hawaii.
In 2012, when NAOJ installed a new super wide angle camera “Hyper Suprime-Cam (HSC)” into the SUBARU Telescope, there were two design requirements for adaptive optics. One was to make a larger lens aperture and the other was to make the lens lighter.
Kyocera’s cordierite was chosen as the best material to achieve the two design requirements for the lens support. Cordierite’s superior characteristics enabled a slim design with enough material strength and rigidity to support the lens structure as well as minimal deformation due to temperature fluctuations.
Video
Fine Ceramics technology supporting space observation 13 billion light years away
Optical systems including mirrors
We have developed diffraction-limited off-axis reflective optical systems (mirrors, mirror holders, and optical benches) made entirely of cordierite materials, with Kyocera’s high accuracy assembling technology.
Cordierite was used as it has a great “athermal property” whereby the optical performance does not degrade under varying temperature conditions owing to its monoclinic nature. We were able to process this extremely low thermal expansion ceramic to include cordierite mirrors coated with metal (Au), as seen in the pictures. Alternatively, larger cordierite mirrors of over 1 meter diameter, can be produced with a light weight design and the required surface roughness.
Such structures are expected to be installed in large telescopes (30 meters) and space telescopes in the coming years.
Optical bench from different perspectives
Camera housing made of F99.7 for aerospace industry
In-house 5-axis CNC machining supported by ultrasonic processing allows the manufacture of complex components such as camera housing. The permeability of ceramics for electromagnetic radiation takes effect in this type of application: the electromagnetic waves of the sensors inside the housing can pass through to the outside, while radar beams from outside are hardly reflected thus impeding detection of aircraft.
Insulators for ion thrusters
High electrical insulation and thermal strength of our F99.7 alumina material allow its use in components of ion thrusters. Excellent performance in ultra-high vacuum is guaranteed by minimal desorption and leakage rate. When required, we combine ceramics with metals.
Customized parts
Low weight and high corrosion resistance combined with high mechanical strength make our ceramic materials perfectly suitable for space applications. We excel in specific solutions. Our years of experience as a manufacturer of customized and standard components guarantee superior solutions to accomplish a variety of tasks.
