EKasic® SILICON CARBIDE AND EKasin® SILICON NITRIDE GAS SEAL RINGS
For sealing compressors, gas-lubricated mechanical seals have proven to be the most economical solution. They operate on the basis of the contact-free relative movement of the rotor and stator at extremely high speeds and with a minimum gap size. Microstructures introduced into the running surface provide the “air cushion” that allows contact-free rotation. The crucial advantages are no maintenance and minimum leakage:
For this application, ESK offers EKasic® silicon carbide (SiC) or EKasin® silicon nitride (Si3N4) gas seal rings for use in gas-lubricated mechanical seals.
EKasic® T Gas Seal Rings
EKasic® T gas seal rings from ESK offer an impressive combination of properties:
- High mechanical strength
- Excellent thermal conductivity
- High stiffness
- Corrosion resistance
EKasin® Gas Seal Rings
Special high-performance applications can be implemented with the use of EKasin® S (silicon nitride) for the gas seal rings from ESK.
Custom Modifications
As additional services, ESK can microstructure the gas seal rings and perform DLC coating for the start-up phase to customer specifications.
| Silicon Carbide | |||||
| Material properties | Norm | Symbol/Unit | EKasic® F |
EKasic® F plus |
EKasic® T |
| Density | DIN EN 623-2 | ρ [g/cm3] | >3.10 | >3.16 | >3.21 |
| Porosity | DIN EN 623-2 | P [%] | <3.0 | <1.0 | <1.0 |
| Mean grain size | [μm] | <5 | <5 | <2 | |
| Grain size distribution | [μm] | ||||
| Phase composition | α-SiC | α-SiC | α-SiC, YAG |
||
| Vickers hardness | DIN EN 843-4 | HV 1 [GPa] | 25.5 | 25.5 | 22.5 |
| Knoop hardness | DIN EN 843-4 | HK 0.1 [GPa] | 24.5 | 24.5 | 21.0 |
| Young's modulus | DIN EN 843-2 | E [GPa] | 410 | 420 | 420 |
| Weibull modulus | DIN EN 843-5 | m | 10 | 15 | 15 |
| Flexural strength, 4-pt bending |
DIN EN 843-1 | σB [MPa] | 400 | 510 | 550 |
| Compressive strength | σD [MPa] | 2200 | 2200 | 2500 | |
| Poisson ratio | ν | 0.17 | 0.17 | 0.16 | |
| Fracture toughness (SENB) |
Klc [MPa·m0,5] | 4 | 4 | 6 | |
| Coefficient of thermal expansion |
DIN EN 821-1 | ||||
| 20°C - 500°C | α [10-6/K] | 4.1 | 4.1 | 3.5 | |
| 500°C - 1000°C | α [10-6/K] | 5.2 | 5.2 | 5.2 | |
| Specific heat at 20°C | DIN EN 821-3 | cp [J/g K] | 0.6 | 0.6 | 0.6 |
| Thermal conductivity at 20°C |
DIN EN 821-2 | λ [W/mK] | 125 | 125 | 75 |
| Thermal stress parameters |
calculated | ||||
| R1 = σB·(1-ν) / (α·E) | R1 [K] | 198 | 246 | 314 | |
| R2 = R1·λ | R2 [W/mm] | 25 | 31 | 24 | |
| Specific electrical resistance at 20°C |
DIN EN 50359 | ρ [Ω cm] | 106-108 | 106-108 | 102-103 |
| Silicon Carbide | |||||
| Material properties | Norm | Symbol/Unit | EKasic® C |
EKasic® P |
EKasic® G |
| Density | DIN EN 623-2 | ρ [g/cm3] | >3.10 | >2.76- 2.89 |
>3.02 |
| Porosity | DIN EN 623-2 | P [%] | <3.0 | 10-14 | <3.0 |
| Mean grain size | [μm] | bimodal | <5 | bimodal | |
| Grain size distribution | [μm] | 10-1500 | 10-1000 | ||
| Phase composition | α-SiC | α-SiC | α-SiC, graphite |
||
| Vickers hardness | DIN EN 843-4 | HV 1 [GPa] | 25.5 | 23.5 | 24.5 |
| Knoop hardness | DIN EN 843-4 | HK 0.1 [GPa] | 24.5 | 21.6 | 23.0 |
| Young's modulus | DIN EN 843-2 | E [GPa] | 410 | 340 | 390 |
| Weibull modulus | DIN EN 843-5 | m | 10 | 15 | 14 |
| Flexural strength, 4-pt bending |
DIN EN 843-1 | σB [MPa] | 400 | 225 | 230 |
| Compressive strength | σD [MPa] | 2500 | 2000 | 2500 | |
| Poisson ratio | ν | 0.17 | 0.17 | 0.16 | |
| Fracture toughness (SENB) |
Klc [MPa·m0,5] | 3.5 | 3 | 3 | |
| Coefficient of thermal expansion |
DIN EN 821-1 | ||||
| 20°C - 500°C | α [10-6/K] | 4.1 | 3.5 | 4.0 | |
| 500°C - 1000°C | α [10-6/K] | 5.2 | 5.6 | 5.0 | |
| Specific heat at 20°C | DIN EN 821-3 | cp [J/g K] | 0.6 | 0.6 | 0.6 |
| Thermal conductivity at 20°C |
DIN EN 821-2 | λ [W/mK] | 125 | 90 | 110 |
| Thermal stress parameters |
calculated | ||||
| R1 = σB·(1-ν) / (α·E) | R1 [K] | 198 | 157 | 124 | |
| R2 = R1·λ | R2 [W/mm] | 25 | 14 | 14 | |
| Specific electrical resistance at 20°C |
DIN EN 50359 | ρ [Ω cm] | 103-104 | 106-108 | 103-104 |
| Silicon Nitride | |||
| Material properties | Norm | Symbol/Unit | Ekasin®S |
| Density | DIN EN 623-2 | ρ [g/cm3] | >3.24 |
| Porosity | DIN EN 623-2 | P [%] | <0.5 |
| Mean grain size | [μm] | <2 | |
| Aspect ratio (L/D) | 3-5 | ||
| Phase composition | β-Si3N4, Oxide | ||
| Vickers hardness | DIN EN 843-4 | HV 1 [GPa] | 14 |
| Knoop hardness | DIN EN 843-4 | HK 0.1 [GPa] | 13.5 |
| Young's modulus | DIN EN 843-2 | E [GPa] | 300 |
| Weibull modulus | DIN EN 843-5 | m | 15 |
| Flexural strength, 4-pt bending | DIN EN 843-1 | σB [MPa] | 700 |
| Compressive strength | σD [MPa] | >2500 | |
| Poisson ratio | ν | 0.25 | |
| Fracture toughness (SENB) | Klc [MPa·m0,5] | 7 | |
| Coefficient of thermal expansion | DIN EN 821-1 | ||
| 20°C - 500°C | α [10-6/K] | 2.0 | |
| 500°C - 1000°C | α [10-6/K] | 4.0 | |
| Specific heat at 20°C | DIN EN 821-3 | cp [J/g K] | 0.7 |
| Thermal conductivity at 20°C | DIN EN 821-2 | λ [W/m K] | 25 |
| Thermal stress parameters | calculated | ||
| R1 = σB·(1-ν) / (α·E) | [K] | 875 | |
| R2 = R1·λ | [W/mm] | 22 | |
| Specific electrical resistance at 20°C |
ρ [Ω cm] | >1011 | |
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