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® C |
| Density | DIN EN 623-2 | ρ [g/cm3] | >3.10 | >3.16 | >3.10 |
| Porosity | DIN EN 623-2 | P [%] | <3.0 | <1.0 | <3.0 |
| Mean grain size | [μm] | <5 | <5 | bimodal | |
| Grain size distribution | [μm] | 10-1500 | |||
| Phase composition | α-SiC | α-SiC | α-SiC | ||
| Vickers hardness | DIN EN 843-4 | HV 1 [GPa] | 24.5 | 24.5 | 24.5 |
| Knoop hardness | DIN EN 843-4 | HK 0.1 [GPa] | 24.5 | 24.5 | 24.5 |
| Young's modulus | DIN EN 843-2 | E [GPa] | 430 | 430 | 430 |
| Weibull modulus | DIN EN 843-5 | m | 10 | 10 | 10 |
| Flexural strength, 4-pt bending |
DIN EN 843-1 | σB [MPa] | 400 | 510 | 400 |
| Compressive strength | σD [MPa] | > 2500 | > 2500 | > 2500 | |
| Poisson ratio | ν | 0.17 | 0.17 | 0.17 | |
| Fracture toughness (SENB) |
Klc [MPa·m0,5] | 4 | 4 | 3.5 | |
| Coefficient of thermal expansion |
DIN EN 821-1 | ||||
| 20°C - 500°C | α [10-6/K] | 3.8 | 3.8 | 3.8 | |
| 500°C - 1000°C | α [10-6/K] | 5.1 | 5.1 | 5.1 | |
| Specific heat at 20°C | DIN EN 821-3 | cp [J/g K] | 0.69 | 0.69 | 0.69 |
| Thermal conductivity at 20°C |
DIN EN 821-2 | λ [W/mK] | 130 | 130 | 130 |
| Thermal stress parameters |
calculated | ||||
| R1 = σB·(1-ν) / (α·E) | R1 [K] | 203 | 259 | 203 | |
| R2 = R1·λ | R2 [W/mm] | 26 | 34 | 26 | |
| Specific electrical resistance at 20°C |
DIN EN 50359 | ρ [Ω cm] | > 108 | > 108 | 104-105 |
| Silicon Carbide | |||||
| Material properties | Norm | Symbol/Unit | EKasic® P |
EKasic® G |
EKasic® T |
| Density | DIN EN 623-2 | ρ [g/cm3] | >2.76- 2.89 |
>3.02 | >3.21 |
| Porosity | DIN EN 623-2 | P [%] | 10-14 | <3.0 | <1.0 |
| Mean grain size | [μm] | <5 | bimodal | <2 | |
| Grain size distribution | [μm] | 10-1000 | |||
| Phase composition | α-SiC | α-SiC, graphite |
α-SiC, YAG |
||
| Vickers hardness | DIN EN 843-4 | HV 1 [GPa] | 24.5 | 24.5 | 22.5 |
| Knoop hardness | DIN EN 843-4 | HK 0.1 [GPa] | 24.0 | 24.0 | 22.5 |
| Young's modulus | DIN EN 843-2 | E [GPa] | 340 | 390 | 420 |
| Weibull modulus | DIN EN 843-5 | m | 15 | 15 | 15 |
| Flexural strength, 4-pt bending |
DIN EN 843-1 | σB [MPa] | 225 | 250 | 550 |
| Compressive strength | σD [MPa] | > 2000 | > 2200 | > 2500 | |
| Poisson ratio | ν | 0.13 | 0.15 | 0.17 | |
| Fracture toughness (SENB) |
Klc [MPa·m0,5] | 3 | 3.5 | 6 | |
| Coefficient of thermal expansion |
DIN EN 821-1 | ||||
| 20°C - 500°C | α [10-6/K] | 3.8 | 3.8 | 4.1 | |
| 500°C - 1000°C | α [10-6/K] | 5.1 | 5.1 | 5.3 | |
| Specific heat at 20°C | DIN EN 821-3 | cp [J/g K] | 0.69 | 0.69 | 0.71 |
| Thermal conductivity at 20°C |
DIN EN 821-2 | λ [W/mK] | 110 | 130 | 80 |
| Thermal stress parameters |
calculated | ||||
| R1 = σB·(1-ν) / (α·E) | R1 [K] | 152 | 143 | 265 | |
| R2 = R1·λ | R2 [W/mm] | 17 | 19 | 21 | |
| Specific electrical resistance at 20°C |
DIN EN 50359 | ρ [Ω cm] | > 108 | 104-105 | 103-106 |
| 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] | 15 |
| Knoop hardness | DIN EN 843-4 | HK 0.1 [GPa] | 15 |
| 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] | 800 |
| Compressive strength | DIN 51104 | σD [MPa] | >2500 |
| Poisson ratio | DIN EN 843-2 | ν | 0.28 |
| Fracture toughness (SENB) | Klc [MPa·m0,5] | 7 | |
| Coefficient of thermal expansion | DIN EN 821-1 | ||
| 25°C - 500°C | α [10-6/K] | 2.5 | |
| 500°C - 1000°C | α [10-6/K] | 3.9 | |
| Specific heat at 25°C | DIN EN 821-3 | cp [J/g K] | 0.65 |
| Thermal conductivity at 25°C | DIN EN 821-2 | λ [W/m K] | 27 |
| Thermal stress parameters | calculated | ||
| R1 = σB·(1-ν) / (α·E) | [K] | 768 | |
| R2 = R1·λ | [W/mm] | 21 | |
| Specific electrical resistance at 25°C |
DIN EN 50359 | ρ [Ω cm] | >1011 |

