Liquid Cooling Sealing Guide: Solving Leakage Risks for AI Data Centers & Semiconductor Equipment

As AI supercomputing centers and 800V fast-charging systems push thermal densities to their absolute limits, liquid cooling has evolved from an option to a necessity. However, the integrity of these advanced systems often rests on a single, critical variable: sealing reliability.

A micro-leakage in a high-value AI server rack or a semiconductor manufacturing line can lead to catastrophic downtime and multi-million dollar losses. Choosing the right material—whether it’s the cost-effective EPDM, the resilient FKM, or the ultimate FFKM—is no longer just a procurement choice; it’s a strategic decision for system longevity.

Before we dive into the deep technical analysis, here is a quick summary to help you navigate the performance boundaries of each solution.

Quick Summary: Scenario, Challenge, and Sealing Solution Comparison

EPDM—The Cost-Effective “Basic Defense Line”

As the mainstream material choice for cold-plate liquid cooling, EPDM dominates the core market in general application scenarios such as data centers and base station cooling with well-balanced performance and cost advantages. It features a temperature resistance range of -50℃ to 150℃, which is perfectly compatible with conventional coolants including water-glycol and fluorinated liquids. It also offers excellent flexibility with a minimum bending radius of only twice the pipe diameter, allowing flexible layout and installation within the compact space of 1U servers.

In terms of performance optimization, peroxide-vulcanized EPDM can prevent sulfate leaching and avoid coolant contamination. When combined with a polyester braided reinforcement layer, it can withstand working pressure above 0.6 MPa, fully meeting the typical server pressure requirement of 0.1–0.3 MPa. With a cost approximately 60% lower than fluoroplastic pipes, EPDM becomes the preferred option for mid-to-basic liquid cooling scenarios and laboratory test platforms. It is widely used in server cold plate connections, general sealing for energy storage systems, and liquid cooling loops of 5G base station AAUs.

[Problems Solved by This Solution] 

• • • Coolant Conductivity Fluctuation: Through high-purity vulcanization processes, it thoroughly solves the media contamination problem caused by sulfate leaching.
  • • Compact Space Wiring: Utilizing its superior bending radius, it solves the challenge of piping layout within the extremely tight spaces of 1U servers.
  • • Cost vs. Reliability Conflict: While maintaining 0.6 MPa pressure, it provides a more economical choice for large-scale liquid cooling deployment.

FKM—The Corrosion-Resistant Guardian for Harsh Working Conditions

For mid-to-high-end scenarios such as vehicle power batteries and immersion liquid cooling that face challenges of corrosion and high temperatures, FKM (fluoroelastomer) stands out with outstanding chemical resistance. Its temperature resistance ranges from -20℃ to 200℃, providing reliable resistance against erosion from fuel, organic solvents and partial fluorinated liquids. Reinforced with a steel wire braided layer, it achieves a pressure resistance of over 4 MPa and withstands broadband vibration of 10–2000 Hz, perfectly adapting to sealing connection requirements at vibrating parts of vehicle power batteries.

In immersion liquid cooling scenarios, FKM resists long-term immersion in low-concentration fluorinated liquids to avoid swelling and aging. In the 800V high-voltage fast charging system of new energy vehicles, it withstands instantaneous high temperatures and electrical treeing risks, ensuring sealing safety of high-voltage circuits. At present, FKM has become the core material for liquid cooling pipelines of vehicle power batteries, auxiliary sealing of immersion liquid cooling, and industrial high-temperature oil cooling systems, serving as a key transition material connecting general and extreme working conditions.

[Problems Solved by This Solution]:

• • • EV Power Battery Failure: Solves the hidden danger of fatigue leakage at connections under strong vibration of 10–2000 Hz.
  • • Immersion Swelling and Aging: Effectively solves the problem of volume changes and performance degradation caused by long-term immersion in fluorinated liquids.
  • • Electrical Safety Risk: In high-voltage fast charging scenarios, it solves problems related to electrical treeing and sealing safety caused by temperature rise.

FFKM—The Ultimate Sealing Solution for Extreme Environments

In fields with stringent requirements for sealing reliability such as semiconductor manufacturing, high-end immersion liquid cooling and aerospace, FFKM (perfluoroelastomer) breaks the performance limits of conventional sealing materials with its unique perfluorocarbon chain structure, making it an irreplaceable top-tier sealing material. It covers a temperature resistance range of -10℃ to 320℃ and resists more than 2,000 types of highly corrosive media, including 98% concentrated sulfuric acid, hydrofluoric acid and electronic fluorinated liquids. With a compression set rate ≤ 10% and gas permeability only 1/300 of EPDM, it fundamentally eliminates risks of medium migration and micro-leakage.

In the liquid cooling industry, FFKM is mainly used for static sealing of high-end immersion liquid cooling cabinets, liquid cooling loop sealing of semiconductor equipment, and liquid cooling interfaces of core AI supercomputing components. The leakage rate is controlled within 0.1 mL/h, meeting the ultra-high standard for helium leak testing at 1×10⁻⁹ Pa·m³/s. Despite its high price, FFKM significantly reduces operation and maintenance costs in high-end scenarios requiring zero leakage and long service life, achieving optimal comprehensive benefits over the entire life cycle.

[Problems Solved by This Solution]:

• • • Strong Acid/Alkali Corrosion: Solves the instantaneous destruction of ordinary seals by extreme media such as 98% sulfuric acid in semiconductor conditions.
  • • Downtime Caused by Micro-leakage: With 1/300 gas permeability and helium-grade sealing standards, it solves the “zero-leakage” demand of high-value AI supercomputing components.
  • • Frequent Maintenance Costs: Solves the huge economic losses brought by short service life and frequent replacement of ordinary seals in extreme conditions.

Conclusion and Future Trends

Currently, the liquid cooling sealing market presents a distinct pattern: EPDM consolidates the basic market, FKM expands the mid-end market, and FFKM breaks through high-end technical barriers. Cold-plate liquid cooling still adopts EPDM as the mainstream material; in immersion liquid cooling, FKM and FFKM are gradually replacing traditional materials; high-end scenarios such as AI supercomputing and semiconductor manufacturing have fully adopted FFKM for core sealing solutions.

As liquid cooling systems develop toward higher power density, diversified cooling media and longer service life, sealing materials continue to upgrade in the direction of high performance, specialization and compounding. In the future, through material modification and structural optimization, EPDM will further enhance medium resistance, FKM will iterate toward high purity and low compression set, and FFKM will expand its application scope via cost optimization. Complementary and coordinated with each other, the three major materials will provide a solid material foundation for the large-scale popularization and high-quality development of the liquid cooling industry.

Still debating between FKM and FFKM for your immersion system? Don’t risk a micro-leakage failure. Click below to get a free Material Compatibility Consultation and our signature “Sealing Reliability Analysis Report” within 24 hours.