Krytox® MIL PRF-27617 Greas es Meet Type I, II, and III Specifications

GREASE, AIRCRAFT AND INSTRUMENT, FUEL AND OXIDIZER RESISTANT
DuPont™ Krytox® oils and greases are based on 
perfluoropolyether (PFPE) oils. These synthetic fluorinated 
lubricants are used in extreme conditions such as continuous 
high temperatures up to 300 °C (572 °F) and higher 
temperatures for shorter periods, depending on product grade 
limits. Chemically inert and safe for use around hazardous 
chemicals, these lubricants are nonflammable and are safe for 
use in oxygen service. Krytox® oils and greases are silicone free 
and do not damage plastics or elastomers or cause corrosion 
to metals. They are commonly used as lubricants in aerospace, 
automotive, industrial and semiconductor applications as well as 
solving many other routine lubrication problems.
Krytox® greases are the original products that this military 
specification was written for and have been certified 
continuously since the specification was originally written. 
This is the latest data from the recertification that is required 
every five years. Krytox® greases are standard as NLGI Grade 
2 penetration. If the 240 AZ is ordered to meet MIL-SPEC 
requirements, it must be ordered as NLGI Grade 1 to meet 
the specification.
Krytox® Grade 240 AZ 240 AB 240 AC
Qualification Reference Number, 1 Oct 2008 AFPET/PTPT 08-011 AFPET/PTPT 08-012 AFPET/PTPT 08-013
Grease Type/Operating Range, °C Type I (–54 to 149) Type II (–40 to 204) Type III (–34 to 288)
NATO Number G-397 G-398 G-399
Penetration Grade NLGI 1 NLGI 2 NLGI 2
Change in Worked Penetration (30 max.) +13 +3 –3
Corrosion on Copper (2b max.) 1b 1b 1b
High Temperature Bearing Performance 
(500 hr min. at 10,000 RPM, 204 °C)
— Stopped at 1320 hr Stopped at 1685 hr
Evaporation ASTM D-2595, % 12.9 10.1 0.2
Oil Separation, % — 14.2 15.5
Solubility in Fuel (20% max.), % — 0.3 0.1
Liquid Oxygen Impact Sensitivity
20 impacts at 43.3 in, no reaction 
No Reaction No Reaction No Reaction
Water Washout Characteristics (20% max.), % — 0.25 —
Oxidation Stability (5 max.), psi — 0.5 —
Dirt Count 
75 μ and larger (0 per cc max.)
25 to 74 μ (1000 per cc max.)
0/26 0/0 0/0
Resistance to Aqueous Solution
Distilled Water
50/50 Distilled Water/Ethanol
Pass
Pass
Pass
Pass
Pass
Pass
Film Stability and Corrosion on Steel Pass Pass Pass
Krytox® Base Oil Viscosity, 40 °C, cSt 22.8 77.8 243
Krytox® Useful Range, °C –57 to 149 –40 to 232 –34 to 288
Determination of % TML and CVCM from Thermal Outgassing — — TML = 0.141; CVCM = 0.051
*These values are typical properties and are not specifications
CAGE No.: 43S57 SIC Code: 2992 Lubricating Oils and Greases
NAICS Code: 324191 Lubricating Oils and Greases Manufacturing DUNS: 557214574Copyright © 2011 DuPont. The DuPont Oval Logo, DuPont™
, The miracles of science™
 and 
Krytox® are registered trademarks or trademarks of E.I. du Pont de Nemours and Company 
or its affiliates. All rights reserved.
K-20068-2 (01/11) Printed in the U.S.A.
The information set forth herein is furnished free of charge and based on technical data that DuPont believes 
to be reliable. It is intended for use by persons having technical skill and at their own discretion and risk. 
Because conditions of use are outside our control, DuPont makes no warranties, express or implied, and 
assumes no liability in connection with any use of this information. Nothing herein is to be taken as license to 
operate under or a recommendation to infringe any patents or trademarks.
Typical Applications 
Applications for DuPont™ Krytox® lubricants are generally of 
a critical nature with temperatures in all industries reaching 
extremes for conventional lubricants. They are expected to 
be durable in the most aggressive environments and are now 
often considered an integral part of the design. Where failure 
of components is not an option, whether because of durability, 
warranty, safety, loss of productivity or down time, Krytox®
is the lubricant of choice in a wide range of industries and 
applications. 
In the aerospace industry, Krytox® oils and greases are 
applied on various settings spanning from bearings and 
sealants to o-rings and oxygen systems. Krytox® is a valuable 
asset to the aerospace industry due to its superior performance 
in a wide range of temperatures scaling from 70 to 399 ºC 
(–100 to 750 ºF). In addition, it is robust in harsh environments 
and has excellent frictional properties, allowing it to resist 
change in properties over time, provide longer wear, and lower 
energy consumption. Krytox® lubricants are compatible with 
all metals, elastomers, plastics, paints and finishes. Due to the 
intense and severe circumstance of the aerospace industry, 
it can be expected that Krytox® delivers a high level of 
product excellence.
DuPont™ Krytox® 240 AC, 240 AB and 240 AZ gr-1 greases 
now have NSF approval for incidental food contact (H-1) 
in and around food processing areas.
Preparation Before Packing Bearings With Grease
New bearings and equipment that are not lubricated often have 
rust preventive oils in them to prevent damage while they are 
in storage before use. New bearings should be inspected for 
damage and cleanliness before use. The greases or preservative 
oils need to be removed when using Krytox® as a lubricant. 
Failure to do so could result in reduced bearing life. Bearing life 
tests on uncleaned bearings have shown reduced life in high 
temperature, high speed tests where the bearing was filled with 
a minimum amount of grease. The preservatives coat the metal 
surface to prevent rusting so they can also prevent the grease 
from adhering, causing them to be thrown off by the action of 
the bearing. They also will oxidize and harden and can create 
debris which will contaminate the grease.
Storage and Shelf Life
Krytox® grease and oil lubricants have an indefinite shelf life if 
unopened and stored in a clean dry location.