SUPERSiC® Silicon Carbide Materials
SUPERSiC® is a high-purity silicon carbide (SiC) material created and customized precisely for specific applications including industrial, photovoltaic, semiconductor and aerospace optics. Entegris provides an array of infiltration materials, cleaning options, and coatings to create the material specifications that meet precise needs.
Entegris' unique conversion process starts with graphite material specially designed and manufactured for use as the precursor in the conversion process.
Near-net shaped parts are machined in graphite in a similar way that aluminum is machined in conventional 3, 4, and 5-axis CNC mills and lathes. This allows engineers and designers greater flexibility to optimized designs for weight and strength. After machining, the articles are purified, then subjected to a proprietary chemical vapor conversion (CVC) process that substitutes pure silicon atoms for carbon atoms. The conversion process enables the creation of extremely complex, lightweight structures for aerospace optics such as spaceflight, closed-back, off-axis, or aspherical mirrors for satellite systems.
SUPERSiC MATERIALS
Our unique conversion process produces the highest quality silicon carbide products available on the market today. We offer a range of SUPERSiC grades to meet your demanding requirements.
Christa - what are the grades we are promoting, what needs to be added/subtracted, and do the corresponding two data sheets need to be edited? What about SUPERSiC H?
The data sheets in question are:
SUPERSiC
SUPERSiC silicon carbide is our base SiC converted graphite. This material is ideal for high-temperature and atmospheric processes and harsh process environments..
SUPERSiC-3C
SUPERSiC-3C grade is SUPERSiC silicon carbide that has been coated with a 75 μm CVD SiC coating, which encapsulates the substrate and seals the surface. This material is ideal for low-cost optics and structures.
SUPERSiC-Si
SUPERSiC-Si grade is SUPERSiC silicon carbide that has been infiltrated with high-purity silicon, giving it improved mechanical properties over SUPERSiC material. This grade is ideal for CVD SiC coating or silicon cladding.
SUPERSiC-Si-3C
SUPERSiC-Si-3C grade is SUPERSiC silicon carbide that has been infiltrated with silicon and then coated with a 75 μm CVD SiC coating, sealing the porosity. This material is ideal for space-based optics and structures.
SUPERSiC-Si-8C
SUPERSiC-Si-8C grade is SUPERSiC silicon carbide that has been infiltrated with silicon and then coated with a 200 μm CVD SiC coating. This material is ideal for large optics and lithography components.
SUPERSiC-Si-4S
SUPERSiC-Si-4S grade is SUPERSiC silicon carbide that has been infiltrated with silicon and then selectively clad with a 100 μm silicon cladding. This material is ideal for single-point diamond turning (SPDT), for reduced lead time and total cost.
SUPERSiC-SP
SUPERSiC-SP grade is the newest grade in our family of silicon carbide materials. This product improves on the mechanical properties of SUPERSiC-Si material by changing the densification material from silicon to silicon carbide.* The result is a material that is stronger in flex and tensile load. Further, the monolithic material ensures an even more uniform response to thermal loading.
* Some trace amounts of free silicon will remain
Typical Material Properties
(Christa, the table below is pulled off data sheet 10995, but the table on data sheet 7062 is different.)
Property |
SUPERSiC | SUPERSiC-3C | SUPERSiC-Si | SUPERSiC-Si-3C | SUPERSiC-SP |
Apparent density | 3.13 g/cm3 (0.113 lb/in3) |
3.15 g/cm3 (0.114 lb/in3) |
3.01 g/cm3 (0.109 lb/in3) |
3.03 g/cm3 (0.110 lb/in3) |
3.04 g/cm3 (0.110 lb/in3) |
Bulk density | 2.53 g/cm3 (0.092 lb/in3) |
2.55 g/cm3 (0.092 lb/in3) |
2.93 g/cm3 (0.106 lb/in3) |
2.95 g/cm3 (0.107 lb/in3) |
3.00 g/cm3 (0.109 lb/in3) |
Total porosity: % of volume | 20% | 20%† | 4% | 4%† | 5% |
Open porosity: % of total | 19% | 0%†† | 1% | 0%†† | 1% |
Total impurity level | < 10 ppm | < 10 ppm | < 10 ppm | < 10 ppm | < 10 ppm |
Flexural strength | 155 MPa (22,400 psi) |
155 MPa (22,400 psi) |
192 MPa (27,900 psi) |
192 MPa (27,900 psi) |
220 MPa (31,900 psi) |
Tensile strength | 129 MPa (18,700 psi) |
129 MPa (18,700 psi) |
124 MPa (17,940 psi) |
124 MPa (17,940 psi) |
162 MPa (23,510 psi) |
Elastic modulus | 217 GPa (31x106 psi) |
217 GPa (31x106 psi) |
331 GPa (48x106 psi) |
331 GPa (48x106 psi) |
373 GPa (54x106 psi) |
Specific stiffness | 86 kN.m/g | 85 kN.m/g | 113 kN.m/g | 112 kN.m/g | 124 kN.m/g |
Poisson’s ratio | 0.17 | 0.17 | 0.17 | 0.17 | 0.17 |
Dynamic shear modulus | 97 GPa (14x106 psi) |
97 GPa (14x106 psi) |
138 GPa (20x106 psi) |
138 GPa (20x106 psi) |
159 GPa (23x106 psi) |
Fracture toughness | 2.44 MPa.m0.5 | 2.44 MPa.m0.5 | 3.78 MPa.m0.5 | 3.78 MPa.m0.5 | N/A |
Hardness knoop | 1992 kg/mm2 | N/A | 1643 kg/mm2 | N/A | N/A |
Thermal diffusivity | 100 mm2/s | 100 mm2/s | 115 mm2/s | 115 mm2/s | 111 mm2/s |
Thermal conductivity |
170 W/(cm·K) (98 Btu/hr/ft°F) |
170 W/(cm·K) (98 Btu/hr/ft°F) |
220 W/(cm·K) (127 Btu/hr/ft°F) |
220 W/(cm·K) (127 Btu/hr/ft°F) |
224 W/(cm·K) (129 Btu/hr/ft°F) |
Electrical resistivity | 0.009 Ω-cm (3700 μΩ-in) |
N/A | 0.010 Ω-cm (4000 μΩ-in) |
N/A | 0.008 Ω-cm (3280 μΩ-in) |
Instantaneous coefficient of thermal expansion at RT |
2.4x10-6/K (1.3x10-6/°F) |
2.4x10-6/K (1.3x10-6/°F) |
2.4x10-6/K (1.3x10-6/°F) |
2.4x10-6/K (1.3x10-6/°F) |
2.4x10-6/K (1.3x10-6/°F) |
† Porosity is sealed under the dense coating; porosity is not exposed to the process.
†† Porosity sealed off by CVD SiC coating.