As power density increases in modern electronics, long-term thermal interface reliability becomes a critical design requirement. Conventional thermal greases can experience pump-out under repeated thermal cycling, which raises thermal resistance and reduces product lifetime. GOOD GI Phase Change Materials (PCM) are engineered to stabilize the thermal interface over the full lifecycle.
What Causes Pump-Out?
Pump-out occurs when thermal grease migrates away from the contact area due to thermal expansion/contraction, material flow, and mechanical stress during long-term operation and thermal cycling.
- Repeated thermal expansion and contraction
- Material flow under mechanical stress
- Long-term thermal cycling
The result is higher interface thermal resistance, uneven contact, localized hotspots, and accelerated component aging.
Why Use PCM Instead of Thermal Grease?
PCM is solid at room temperature and softens only at a designed transition temperature. During operation, PCM flows just enough to fill microscopic gaps and then re-solidifies upon cooling, providing a stable interface.
- Effective pump-out mitigation
- Consistent interface thickness
- Stable thermal resistance over time
- Clean, grease-free handling and assembly
Comparison of Thermal Interface Materials
| Comparison Item | Thermal Grease | Thermal Pad | PCM (Phase Change Material) |
|---|---|---|---|
| Application Method | Dispensing or screen spreading required | Cut and place | Solid sheet at room temperature, direct placement |
| Production Line Friendliness | ❌ Risk of overflow, stencil cleaning required | ✅ Clean and easy handling | ✅ Clean handling similar to thermal pads |
| Gap-Filling Capability | ✅ Excellent flowability | ⚠️ Depends on material softness | ✅ Softens when heated to fill micro-gaps |
| Typical Thermal Resistance | ⭐ Low (approx. 0.03–0.10 ℃·cm²/W) | ⚠️ Medium to high (thickness-dependent) | ⭐ Low (as low as 0.05 ℃·cm²/W) |
| Thermal Conductivity | 3–12 W/m·K (high-performance grades) | 1–8 W/m·K | 2–8.5 W/m·K |
| Long-Term Reliability | ⚠️ Susceptible to pump-out | ✅ Stable | ✅ Re-solidifies after phase change, minimal migration |
| Electrical Insulation | Formulation dependent | Generally good | Can be designed for high insulation (≥8 kV) |
| Clamping Pressure Required | Recommended | Recommended | Required (5–20 psi) |
| Applicable Heat Flux | High | Low to medium | Medium-high to ultra-high |
GOOD GI PCM Engineering Advantages
GOOD GI PCM series are designed for high-reliability electronics and deliver both thermal performance and electrical safety.
- Thermal conductivity up to 8.5 W/m·K
- Electrical insulation up to 8 kV
- Excellent durability under thermal cycling
- Improved long-term reliability for high power-density designs
Typical Applications
- HPC and AI servers
- Power modules and industrial electronics
- Automotive electronics and ADAS
- Display panels and consumer electronics
For datasheets, sample evaluation, or engineering consultation, please contact GOOD GI via the inquiry form or email.