Conductivity Loss: Why EMI Gaskets Fail after Thermal Cycling
Problem Statement
EMI gaskets often experience conductivity loss after repeated thermal cycling between -40°C and 150°C. This failure compromises electromagnetic shielding, leading to signal interference in electronic systems.
Material Science Analysis
Conductivity loss occurs due to polymer matrix degradation and filler particle migration. Silicone rubber (VMQ) commonly fails because its low thermal stability accelerates filler oxidation. Fluorocarbon rubber (FKM) outperforms VMQ due to its higher fluorine content (66-70%), which enhances thermal stability and chemical resistance. FKM maintains filler dispersion integrity, ensuring consistent conductivity.
Technical Specs
- Material: FKM (Fluorocarbon Rubber)
- Shore A Hardness: 70 ± 5
- Tensile Strength: 12 MPa
- Elongation at Break: 200%
- Temperature Range: -40°C to 200°C
- Compression Set: 20% (22 hrs at 200°C)
- Chemical Resistance: Resistant to oils, fuels, and acids
Material Comparison
| Material | Temperature Range (°C) | Compression Set (%) | Chemical Resistance | Conductivity Retention |
|---|---|---|---|---|
| FKM | -40 to 200 | 20 | High | 95% |
| VMQ | -60 to 150 | 35 | Moderate | 70% |
| EPDM | -50 to 150 | 30 | Low | 60% |
Standard Compliance
RubberQ adheres to IATF 16949 standards, ensuring batch-to-batch consistency. Our in-house compounding process controls polymer ratios, fillers, and curing agents to meet ASTM D2000 material callouts and ISO 3601 sealing requirements. Each batch undergoes rigorous testing, including ASTM D429 adhesion testing, to guarantee zero-delamination quality.
For custom material compound development or IATF 16949 documentation, consult RubberQ’s engineering department.
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