If you are sourcing components for liquid cooling systems, material compatibility is not optional. The wrong material can corrode, degrade, or contaminate the coolant.
This article covers two common coolant types and what materials work with each.
Ethylene Glycol-Based Coolants
Ethylene glycol is the most common coolant in data center liquid cooling. Mixed with water and corrosion inhibitors, it provides freeze protection and heat transfer efficiency.
Compatibility
| Material | Compatibility |
|---|---|
| SS304 | Good |
| SS316L | Excellent |
| Nickel-plated brass | Good |
| Aluminum (6061) | Limited – requires anodizing |
| Copper | Good – but rarely used in fittings |
Key Risk
Glycol degrades over time. As it oxidizes, it becomes acidic. Corrosion inhibitors deplete. When that happens, the coolant attacks unprotected metal surfaces.
SS316L is the safest choice because its molybdenum content resists this degradation better than SS304.
Dielectric Fluids
Immersion cooling uses dielectric fluids—non-conductive liquids that transfer heat without electrical conductivity.
Common Types
| Fluid Type | Examples |
|---|---|
| Synthetic hydrocarbons | Mineral oils, PAO |
| Silicone-based | Silicone oils |
| Fluorocarbons | 3M Novec, Fluorinert |
Compatibility
| Material | Compatibility |
|---|---|
| SS304 | Good |
| SS316L | Excellent |
| Nickel-plated brass | Good |
| Aluminum | Varies by fluid |
| Seals (EPDM, FKM) | Check fluid compatibility |
Key Risk
Different dielectric fluids have different chemistries. Some are aggressive toward seals. Some attack aluminum. SS316L provides the broadest compatibility across all fluid types.
Factors That Affect Corrosion
Fluid temperature
Higher temperature = faster corrosion
Fluid velocity
Higher velocity = erosion-corrosion risk
Fluid contamination
Particles or moisture accelerate corrosion
Fluid chemistry
Some inhibitors protect, some do not
What to Specify
| Coolant Type | Recommended Material |
|---|---|
| Ethylene glycol/water | SS316L |
| Propylene glycol/water | SS316L |
| Dielectric fluid (synthetic) | SS316L |
| Dielectric fluid (fluorocarbon) | SS316L + compatible seals |
For stainless steel, always require:
Sulfur content <0.03%
Passivation or electropolishing
96-hour salt spray test
Final Thought
Material compatibility is simple: when in doubt, specify SS316L. It works with glycols. It works with dielectrics. It holds tight tolerances. It does not corrode.
If your cooling loop uses a fluid you are unsure about, ask your supplier for material compatibility verification.
Need SS316L components for your cooling system? Send your drawings for a quote.
