Krytox Grease: What It Is and Why It's Used in Precision and High-Temperature Applications
Quick Answer: Krytox is a perfluoropolyether (PFPE) grease developed by DuPont — now Chemours — that remains stable from –40°C to 260°C, resists virtually all chemicals and solvents, and does not migrate, evaporate, or decompose under conditions that destroy conventional petroleum or silicone lubricants. Engineers specify it where standard greases fail: high-vacuum systems, oxygen-rich environments, semiconductor equipment, aerospace mechanisms, and precision instruments that cannot tolerate contamination or lubricant breakdown.
Most lubricants work fine under normal conditions. Apply heat, exposure to aggressive chemicals, or vacuum, and the story changes fast — conventional greases oxidize, evaporate, or break down into acidic byproducts that damage the very components they were meant to protect. Krytox was engineered specifically to eliminate those failure modes. It has been the lubricant of choice in NASA programs, semiconductor fabs, and precision instrument manufacturing for decades — not because it's exotic, but because it's the only class of lubricant that reliably handles the combination of temperature, chemical exposure, and contamination sensitivity those environments demand.
What Is Krytox?
Krytox is a brand name for a family of perfluoropolyether (PFPE) lubricants manufactured by The Chemours Company (formerly DuPont). The base fluid is a fully fluorinated synthetic oil — meaning every hydrogen atom in the molecular chain has been replaced with fluorine. That fluorine shell is what gives Krytox its extraordinary stability:
- Fluorine–carbon bonds are among the strongest in chemistry — they don't break down under heat, UV, or oxidation
- The fully fluorinated structure means there's nothing for oxygen, acids, solvents, or reactive chemicals to attack
- PFPE oils have extremely low vapor pressure — they don't evaporate in vacuum or at elevated temperatures
- Non-flammable — suitable for oxygen systems and fire-hazard environments
Krytox greases add a polytetrafluoroethylene (PTFE) thickener to the PFPE base oil to create a grease consistency. The result is a lubricant that handles conditions where both petroleum-based and silicone-based greases fail completely.
Krytox vs. Conventional Lubricants
| Property | Petroleum Grease | Silicone Grease | Krytox (PFPE) |
|---|---|---|---|
| Max continuous temp | ~120°C | ~200°C | 260°C |
| Min temp | ~–20°C | ~–55°C | –40°C to –75°C (grade dependent) |
| Oxygen compatibility | ❌ Flammable | ❌ Not rated | ✅ Oxygen-safe |
| Chemical resistance | Poor–moderate | Moderate | Excellent (resistant to virtually all solvents, acids, bases) |
| Vapor pressure (vacuum) | High — evaporates | Moderate — migrates | Extremely low — suitable for high vacuum |
| Contamination risk | High — outgasses | High — silicone migration notorious in electronics | Very low — inert, non-migrating |
| Flammability | Flammable | Non-flammable | Non-flammable |
| Compatibility with plastics/elastomers | Variable — often degrades rubber | Swells some elastomers | Compatible with most plastics and elastomers |
Krytox GPL 205: General Purpose Grade
The DuPont Krytox GPL 205 is the most widely used general-purpose Krytox grease — a medium-consistency PFPE/PTFE grease suitable for a broad range of precision lubrication applications. It is white in color, compatible with plastics, elastomers, and metals, and provides reliable lubrication across the full –40°C to 260°C operating range.
GPL 205 is the go-to grade when you need Krytox performance without needing a specialized viscosity or additive package. It is used across semiconductor equipment, precision instruments, cleanroom mechanisms, valve stems, O-rings, and any application where contamination sensitivity or temperature demands rule out conventional greases.
Where Krytox Is Specified
Semiconductor and Electronics Manufacturing
Semiconductor fabs are among the most demanding lubrication environments on earth — equipment runs continuously, temperatures fluctuate, and any lubricant that outgasses, migrates, or decomposes can contaminate wafers or sensitive process chemistry. Krytox is used on robot arms, linear actuators, valve stems, bearing assemblies, and O-rings throughout fab equipment precisely because it won't contaminate the process. Silicone grease is explicitly banned from most fab environments because silicone migration causes adhesion failures in coatings and die bonding — Krytox has no silicone and does not migrate.
Aerospace and High-Vacuum Systems
In vacuum environments, conventional lubricants evaporate rapidly — petroleum-based greases can leave abrasive residue as the base oil flashes off. Krytox's extremely low vapor pressure means it stays in place under hard vacuum, making it the lubricant of choice for satellite mechanisms, space instruments, vacuum valves, and turbomolecular pump bearings. It is also specified for liquid oxygen (LOx) service and other oxygen-enriched environments where petroleum or silicone lubricants would create fire or explosion hazards.
Precision Instruments and Optical Equipment
Precision instruments — torque meters, optical mounts, spectrometers, cryogenic equipment — require lubricants that deliver consistent drag characteristics over wide temperature ranges without migrating onto optical surfaces or sensitive components. Krytox's inert, non-migrating chemistry makes it the standard choice for these applications.
Cleanroom Environments
In ISO-rated cleanrooms, lubricant outgassing and particle generation are controlled contaminants. Krytox's extremely low vapor pressure and inert chemistry mean it contributes negligible particle and molecular contamination — an important consideration for ISO 5 and cleaner environments where even trace organic contamination matters.
Chemical Processing and Harsh Industrial Environments
Valves, pumps, and fittings handling aggressive chemicals — strong acids, oxidizers, solvents — need lubricants that won't be attacked by process fluids. Krytox resists virtually all industrial chemicals, including fuming nitric acid, concentrated sulfuric acid, and most organic solvents that would destroy conventional greases in hours.
How to Apply Krytox Grease
- Surface prep: Clean mating surfaces thoroughly — remove existing lubricant, oil, and contamination with IPA or an appropriate cleaner before applying Krytox. Krytox does not bond well over contaminated or oily surfaces.
- Apply sparingly: Krytox is a precision lubricant — a thin, even film is more effective than heavy application. Over-greasing bearings and sliding surfaces wastes material and can actually increase drag.
- Compatibility check: Krytox is compatible with most metals, plastics, and elastomers, but always verify compatibility with specific materials in your assembly, particularly unusual polymers or elastomers.
- Storage: Store in original sealed containers at room temperature. Krytox has an indefinite shelf life when stored properly — it does not oxidize or degrade over time.
Frequently Asked Questions
What does PFPE mean and why does it matter for lubrication?
PFPE stands for perfluoropolyether — a synthetic oil in which every carbon–hydrogen bond has been replaced with a carbon–fluorine bond. Fluorine–carbon bonds are among the strongest in chemistry, which is why PFPE oils are extraordinarily resistant to heat, oxidation, and chemical attack. It's the same chemistry behind PTFE (Teflon) coatings — applied to a lubricant base oil. The practical result is a lubricant that remains stable and effective at temperatures, in environments, and under chemical exposure that would destroy petroleum or silicone lubricants.
Can Krytox be used with oxygen systems?
Yes — Krytox is one of the few lubricants approved for oxygen-enriched and liquid oxygen (LOx) service. Petroleum-based lubricants are fire and explosion hazards in oxygen-rich environments. Krytox is non-flammable and does not react with oxygen even at elevated temperatures and pressures, making it the standard choice for oxygen valves, regulators, fittings, and equipment used in aerospace, medical gas, and industrial oxygen systems.
Why can't I just use silicone grease instead?
Silicone grease handles heat reasonably well (up to ~200°C), but it has two serious drawbacks in precision and electronics applications: silicone migration and poor chemical resistance. Silicone compounds are notorious for migrating onto nearby surfaces — a major problem in electronics assembly where silicone contamination causes adhesion failures in conformal coatings, die bonding, and selective soldering. Silicone grease is also not oxygen-compatible and is not suitable for vacuum applications due to higher vapor pressure. Krytox has none of these issues — it does not migrate, is oxygen-safe, and remains stable under vacuum.
What is the difference between Krytox GPL 205 and other Krytox grades?
Krytox greases are available in a range of grades that differ primarily in base oil viscosity and thickener concentration — which translate to different consistency (NLGI grade), operating temperature range, and load-carrying characteristics. GPL 205 is a medium-consistency general-purpose grease suitable for most standard applications. Higher-numbered grades (GPL 206, 207) are heavier/stiffer for higher-load or slower-speed applications. Lower-numbered grades and the underlying GPL oils are lower viscosity for high-speed bearings or applications requiring minimal drag. For most precision instrument and semiconductor equipment lubrication, GPL 205 is the right starting point.
Does Krytox have a shelf life?
Krytox has an essentially indefinite shelf life when stored in sealed containers at room temperature away from direct sunlight. Unlike petroleum-based greases that can oxidize and petroleum oils that can develop acids over time, PFPE chemistry is inherently stable — it does not react with air, moisture, or light under storage conditions. Opened containers should be resealed after use to prevent particulate contamination.
Shop Krytox at MTE Solutions
MTE Solutions stocks the DuPont Krytox GPL 205 General Purpose Grease (8 oz) — the most widely used Krytox grade for precision lubrication in electronics manufacturing, cleanroom equipment, and industrial applications. If you need a different Krytox grade or viscosity, contact us and we can help source the right specification for your application.
