Status of Development of Fluoroiodocarbon (FIC) Solvents as Environmentally Safe, Nonflammable, Drop-in Replacements for Chlorinated Solvents

Jon Nimitz, Ph.D.
Environmental Technology & Education Center (ETEC)
4500-B Hawkins St. NE
Albuquerque, NM 87109-4541
Phone: (505) 345-2707; Fax: (505) 345-4884

This paper describes progress to date on the testing of solvents based on fluoroiodocarbons (FICs). This work is supported under a small business innovation research (SBIR) contract from the U.S. Air Force Wright Laboratories at Wright-Patterson AFB in Dayton, Ohio. Topics discussed include cleaning performance, flammability, materials compatibility, ozone-depletion and global warming potentials, toxicology, and costs. Results with both pure FICs and nonfractionating (near-azeotropic) blends with conventional (flammable) solvents are covered. The FICs under investigation include perfluoro-n-propyl iodide (CF₃CF₂CF₂I, abbreviated 1-C₃F₇I, bp 40°C), perfluoro-n-butyl iodide (CF₃CF₂CF₂CF₂I abbreviated 1-C₄F₉I, bp 67°C), and perfluoro-n-hexyl iodide (CF₃CF₂CF₂CF₂CF₂CF₂I, abbreviated 1-C₆F₁₃I, bp 117°C). For simplicity these compounds are sometimes abbreviated in this paper as C3, C4, and C6, based on the number of carbon atoms.
FIC solvents possess the unusual combination of attractive physical properties, excellent cleaning ability, nonflammability, low toxicity, and extremely low environmental impact. If they can be manufactured cheaply they show great promise as drop-in replacements for chlorinated solvents including 1,1,1-trichloroethane, CFC-113, trichloroethylene, perchloroethylene, and methylene chloride. FICs appear suitable for use in high-value applications where cleaning with aqueous solutions or flammable solvents has not proven satisfactory. The current drawbacks to these solvents include high cost and the development of traces of iodine on storage. Efforts are underway to overcome these drawbacks.
ETEC Mission
The mission of ETEC is to help organizations prevent pollution while improving productivity. ETEC reviews, assesses, and screens alternative chemicals and processes to eliminate usage of environmentally harmful chemicals. ETEC helps organizations find the highest-performing, lowest-cost, least hazardous, most environmentally safe alternative chemicals. When needed, ETEC also develops new alternative chemicals for a variety of applications. Successful efforts to date have included solvents, refrigerants, foam blowing agents, aerosol propellants, and firefighting agents, plus effective chemicals for several smaller niche applications.
Properties of Fluoroiodocarbons
The FICs under investigation as solvents are odorless, nonflammable liquids that evaporate quickly and cleanly and appear to have generally low toxicity and negligible environmental impact. Because carbon-to-iodine bonds are photolyzed rapidly in sunlight, FICs have atmospheric lifetimes of about two days and very low GWPs of about 6 (relative to CO₂ = 1). The ODPs of FICs are currently calculated to be less than 0.0025, below any level of concern (Ref. 1). Previous work by the author and colleagues has shown that FICs can provide attractive high-performance replacements for CFCs, HCFCs, and halons in many applications (Refs. 2-9).
Attractive Uses for Fluoroiodocarbon Solvents
FIC-based solvents appear suitable for spray, wipe, and immersion cleaning applications. They appear particularly appropriate for closed-loop cleaning of high-value items that cannot be cleaned satisfactorily by aqueous or other methods. Some possible cleaning applications include surface-mount electronics, semiconductor wafers, optics, gyroscopes, and gaseous/liquid oxygen systems.
Previous Work on Fluoroiodocarbon Solvents
The overall goal of the current effort is to provide a set of high-performance, nonflammable, low toxicity, environmentally safe, clean-evaporating solvents at reasonable cost. In Phase I of this project the properties of FICs and potential blending solvents were tabulated and laboratory tests of thermal stability, cleaning effectiveness, and materials compatibility were conducted on three pure FICs (1-C₃F₇I, 1-C₄F₉I, and 1-C₆F₁₃I). All three FICs were found to have excellent thermal stability, excellent materials compatibility, and high cleaning effectiveness on a variety of difficult soils. FICs are particularly effective at removing perfluorinated greases. Pure FICs undergo less than 0.6% decomposition when exposed to 175°C for four months in sealed tubes. Neither air, water, nor moderate amounts of light affect FIC stability. The most attractive FIC solvent appears to be 1-C₄F₉I, because of its physical properties and high cleaning performance. The results have demonstrated the technical feasibility of FIC solvents as "drop-in" replacements for CFC-113, 1,1,1-trichloroethane (TCA), trichloroethylene (TCE), and perchloroethylene (PCE).
In an interim task performed between Phase I and Phase II, the properties of blends containing fluoroiodocarbons (FICs) and conventional solvents were examined and the most promising blends for Phase II laboratory studies were identified. Two objectives were met: (1) identification of likely azeotropic or near-azeotropic solvent blends containing FICs, and (2) selection of optimal blends containing FICs for Phase II laboratory testing. Optimal solvent blends were selected, based on the properties of the pure components and the calculated properties of the blends determined by the proprietary AZEO computer program (Refs. 2, 5, 7). Factors considered in ranking blends were: health considerations, environmental impact, fractionation, cost, and stability. Tabulated data were converted into numerical scores in each category and the scores were combined accounting for the relative weights assigned to each category. A set of top-ranking blends was selected, representing a wide range of volatilities, chemical classes, and cleaning performance characteristics. All of these blends appeared to have high potential to provide useful clean-evaporating, environmentally safe, nonflammable, nonfractionating, low-toxicity, nonaqueous solvents.
The tasks undertaken in the current Phase II effort include:

Experimental identification of azeotropic or near-azeotropic FIC blends
Flammability testing of FIC blends
Fractionation testing of blends
Compatibility testing of blends
Measurement of selected properties of pure FICs and blends
Cleaning ability testing
Stability testing of FIC blends
Determination of environmental effects (ODP, GWP, biodegradability, and VOC issues)
Toxicity testing

Status of Tasks
Measurement of selected properties is underway, and stability testing is planned in the near future. The status of several of the other tasks is discussed below.

Identification of Azeotropes or Near-Azeotropes
Fourteen binary and one ternary blend of pure FICs with fifteen conventional (flammable) solvents were examined for formation of azeotropes or near-azeotropes by fractional distillation with gas chromatographic analysis. The conventional solvents were chosen for blending on the basis of their physical and environmental properties, low toxicity, and low cost. Out of the fifteen combinations tested, six provided azeotropic or near-azeotropic blends at certain compositions at atmospheric pressure.
In a practical sense, as long as a blend does not fractionate enough to become flammable or change properties significantly, it is enough that it is near-azeotropic. A true azeotrope, which exists only at one specified temperature, pressure, and composition, is not required.

Flammability Testing
The six near-azeotropic blends identified were tested for flammability. Flammability tests were conducted by four methods: (1) Setaflash open-cup, (2) Setaflash closed cup, (3) aerosol spray, and (4) autoignition. Three of the blends proved to be fire-resistant by all of these methods. We prefer use of the term fire-resistant over nonflammable, since any material (including, for example, copper and stainless steel) may be caused to ignite under extreme conditions.
Because patents are pending on these solvent blends, the compositions are not revealed at this time. However, their properties will be discussed and it is anticipated that their compositions will be revealed in future publications. For the purpose of this paper, the blends will be labeled Blend A, Blend B, and Blend C.

Fractionation Testing
Fractionation tests were conducted on the three fire-resistant blends to make sure they never formed a flammable vapor or liquid at any point during evaporation. Samples were placed in beakers and allowed to evaporate as the composition of the remaining liquid was monitored by GC.

Compatibility Testing
Compatibility of solvents with polymers was tested based on ASTM methods. The weights, dimensions, and hardnesses of samples of the polymers were recorded, the samples were immersed for 10 days, and the properties were remeasured. The results are shown in Table 1.

Table 1. Compatibilities of C4 and FIC Blends with Polymers

Polymer Type Compatible with

C4 Blend A Blend B Blend C

Acrylic Yes Yes No No

Aflas No No No No

Buna-N Yes No Yes Yes

Cyanate Ester Yes Yes Yes Yes

EPDM Yes No Yes Yes

Fluorosilicone Yes No No No

FR4 Yes Yes Yes Yes

Hi-temp Glass Epoxy Yes Yes Yes Yes

Neoprene Yes Yes No Yes

Nylon Yes Yes Yes Yes

Phenolic Yes Yes Yes Yes

Polyimide Yes Yes Yes Yes

Polystyrene No No No No

PVC type 1 Yes Yes Yes Yes

Silicone No No No No

Teflon Yes Yes Yes Yes

Urethane No No No Marginal

Viton Yes Yes Marginal No

Table 1 shows that C4 is compatible with all polymers tested except Aflas, polystyrene, silicone, and urethane. The differences between Blend A and C4 are that Blend A is also incompatible with Buna-N, EPDM, and fluorosilicone. Except for Aflas, polystyrene, and urethane, FIC-based solvents can be found that are compatible with all the other polymers tested.
Compatibility tests of solvents with selected metals were also carried out based on ASTM methods. The results are shown in Table 2.
Table 2 shows that pure C4 and Blend A were compatible with all metals tested. Blend B was incompatible with aluminum and magnesium, compatible with the other metals. Blend C was incompatible with aluminum 7075 T6 and magnesium, compatible with the other metals.

Table 2. Compatibilities of C4 and FIC Blends with Metals

Metal Compatible with

C4 Blend A Blend B Blend C

Aluminum 2024 T3 Yes Yes No Yes

Aluminum 5052 H32 Yes Yes No Yes

Aluminum 6061 T6 Yes Yes No Yes

Aluminum 7075 T6 Yes Yes No No

Brass Yes Yes Yes Yes

Bronze SAE 660 Yes Yes Yes Yes

Cast Iron Yes Yes Yes Yes

Copper Yes Yes Yes Yes

Magnesium Yes Yes No No

Stainless Steel 303 Yes Yes Yes Yes

Stainless Steel 416 Yes Yes Yes Yes

Titanium Yes Yes Yes Yes

Cleaning Abilities
Results of cleaning tests of various soils on aluminum coupons are shown in Table 3. Cleaning tests were conducted following protocols developed at Sandia National Labs (Ref. 10). For each test a set of four 1" by 3" aluminum coupons were weighed to the nearest 0.1 mg on an analytical balance, soiled on the lower 1/3 of one face, reweighed, then immersed in a magnetically stirred solvent bath consisting of 100 mL of solvent in a 150-mL beaker. The soiled faces of the coupons faced inward and coupons were clamped to keep them from touching each other. Coupons were removed after 0.5, 1.0, 2.0, and 5.0 minutes, dried, reweighed, and examined. The percentage of soil removal was plotted versus time. For baseline comparison, cleaning tests were also conducted using CFC-113, TCA, and TCE.

Table 3. Summary of Cleaning Abilities of FIC and Chlorinated Solvents

SOIL CFC-113 TCA TCE 1-C₃F₇I 1-C₄F₉I 1-C₆F₁₂I

AFFF (aqueous film-forming foam) excellent very good very good excellent excellent excellent

BEESWAX good good very good poor poor poor

CASTOR OIL very good very good excellent excellent very good fair

EDM (electric discharge machining) OIL excellent excellent excellent excellent excellent excellent

GREASE PENCIL fair fair fair fair fair poor

HYDRAULIC FLUID MIL-H-5606 excellent excellent excellent excellent excellent excellent

HYDRAULIC FLUID MIL-H-83282 excellent excellent excellent excellent excellent excellent

HYDR. FLUID SKYDROL 500B4 excellent excellent excellent excellent excellent excellent

JET FUEL A excellent very good excellent excellent excellent excellent

JET FUEL JP-4 excellent excellent very good excellent excellent excellent

LANOLIN very good very good excellent poor fair fair

MOLY GREASE very good very good excellent very good good fair

MOLY SPRAY LUBE excellent excellent excellent fair poor poor

MOTOR OIL 10W30 excellent poor excellent excellent excellent excellent

OIL WD-40 excellent excellent excellent excellent excellent excellent

PERFLUORINATED GREASE very good poor poor excellent very good very good

SILICONE SEALANT fair poor good poor fair poor

SILICONE SPRAY excellent excellent very good excellent excellent excellent

SUPERSOIL very good excellent very good very good very good excellent

For soiling samples with supersoil (designed to approximate shop scenarios), the following procedure was followed (all soiling refers to only the lower 1/3 of the coupon): (1) one face of the coupon was marked with an X with marker pen, (2) the coupon was dipped into a 5% solution of salt in water and oven-dried at 250°F for 15 minutes, (3) the coupon was dipped into a vigorously agitated supersoil solution (consisting of 1% by volume EDM oil, 1% by volume hydraulic fluid MIL-H-83282, 0.5% by weight shop dust, and 0.25% by weight aluminum oxide powder in hexanes) and oven-dried.
The results of these tests are summarized in Table 3 with short descriptions of the cleaning abilities of each solvent on each soil tested (excellent, very good, good, fair, or poor). These terms are defined in Table 4.

Table 4. Definitions of Cleaning Abilities of Solvents

Category % Soil removal
within 0.5 minutes % Soil removal
within 1 minute % Soil removal
within 5 minutes

excellent >80 >95

very good >40 >85

good >20 >70

fair >30

poor <30

The data in Table 3 show that FICs are excellent solvents, quite similar to CFC-113, TCA, and TCE in cleaning ability for most soils, including AFFF, EDM oil, hydraulic fluids, jet fuels, motor oil, WD40 oil, silicone sealant, silicone spray, and supersoil. FICs are superior to the conventional chlorinated solvents in removal of perfluorinated greases, and are inferior in removal of beeswax, grease pencil, lanolin, and molybdenum spray lubricant.
FICs are virtually identical to the chlorinated solvents in removal of supersoil (from which all solvents were effective at removing the EDM oil and hydraulic fluid, but ineffective on salt). All solvents gave similar results with AFFF, removing the organic components but not the small amount of water contained in AFFF, which evaporated after the cleaning. The most difficult soils to remove of the 19 tested were beeswax, castor oil, grease pencil, lanolin, molybdenum grease, molybdenum spray lubricant, and silicone sealant.
It should be noted that even if a solvent performed poorly in removing a particular soil in this test, it is expected that in most cases satisfactory removal could be obtained by using some combination of longer soaking times, ultrasonic agitation, and physical methods such as wiping or brushing. In addition, some new formulations of greases and oils are available that are easier to remove.
CFC-113, pure C4, and the three blends were tested for removal of some additional soils from aluminum coupons. The results shown in Table 5 show that Blend A is a superior cleaner for these soils to Blends B and C. None of the FIC solvents are as effective at removing cosmoline as CFC-113.

Table 5. Summary of Cleaning Abilities of C4 and Blends on Additional Soils

SOIL CFC-113 1-C₄F₉I BLEND A BLEND B BLEND C

COSMOLINE very good fair fair poor fair

ESTER-BASED GAS TURBINE
ENGINE OIL MIL-L-7808 excellent excellent excellent excellent excellent

ESTER-BASED GAS TURBINE
ENGINE OIL MIL-L-2369 excellent excellent excellent excellent very good

PFPAE (perfluoropolyalkylether)
DENMUM S-65 excellent excellent excellent excellent very good

PFPAE FOMBLIN Z-04 excellent excellent excellent excellent excellent

PFPAE KRYTOX excellent excellent excellent excellent very good

SILICONE GREASE good good very good poor very good

Toxicity
Previous studies indicate that FICs have relatively low toxicities (Refs. 9, 12). All three pure FICs in this study are undergoing the Ames and human lymphocyte chromosome aberration tests to determine mutagenicity and clastogenicity. The top-ranking pure FIC will undergo the following additional tests: (1) acute aquatic toxicity to fathead minnows and Daphnia and (2) a 4-week subchronic rat inhalation study.

Economic Considerations
Until recently, all FICs were made only in small quantities and, like other custom-made research chemicals, were relatively expensive. In 1992, for example, CF₃I was $600/lb. Now, because of development of this material as a Halon 1301 replacement by the author and others, it is being produced in larger quantities and the price has already dropped to about $50/lb (Refs. 2-4,11,12). Significant further cost reductions on this material are expected.
The world price for iodine varies from about $10 to 20 per kg ($4 to 8 per lb). Pure FICs range from about 30% to 60% by weight iodine. For example, 1-C₄F₉I contains 37% by weight iodine. Thus the cost of the iodine in a pound of 1-C₄F₉I is about $1.50 to $3.00. Although FIC solvents are still only made in small quantities and are quite expensive (about $250/lb) it is believed that with larger volumes and improved methods FIC solvents can be manufactured at costs competitive with other high-tech fluorinated solvents. Blending with inexpensive materials also lowers costs. FIC-based solvents are easily reclaimed, and by using proper techniques and closed systems evaporative losses can be minimized.
Conclusions
FICs appear promising as high-performance, nonflammable, low toxicity, environmentally safe nonaqueous solvents for high-value applications. In terms of physical properties and manufacturability, perfluoro-n-butyl iodide appears more attractive than perfluoro-n-propyl iodide or perfluoro-n-hexyl iodide. Three fire-resistant nonfractionating (near-azeotropic) blends with conventional flammable solvents have been identified. The cleaning abilities of these blends on selected soils and their compatibilities with polymers and metals have been investigated.
FICs have two disadvantages as solvents: (1) high cost and (2) the fact that a trace of elemental iodine develops on storage, giving the solution a pink, purple, or brown coloration. If these disadvantages can be overcome the solvents appear quite attractive for a variety of cleaning applications. ETEC is working on methods to manufacture the chemicals more economically and to remove traces of iodine continuously.
Availability of solvents for testing
ETEC can provide small samples of the solvents to a limited number of interested parties for testing. Appropriate applications include, for example, cleaning of electronics, gyroscopes, liquid/gaseous oxygen systems, and optical surfaces. To supply solvent for testing we require a completed application form, access to all test data obtained, and a deposit equal to the value of the solvent. This deposit is returned when the used solvent is returned for reclamation. Please contact the author to find out more about this offer.
Acknowledgments
The author is grateful for support of this work by the U.S. Air Force Wright Materials Laboratories under Small Business Innovation Research (SBIR) program contract F33615-95-C-5026. The capable assistance of our technical advisor at Wright Labs, Carl E. Snyder, is greatly appreciated. The valuable laboratory work of Linda Sick on this effort is also gratefully acknowledged.
References

Personal communication from Dr. Don Wuebbles, Dept. of Atmospheric Sciences, Univ. of Illinois, Urbana, IL to Dr. Jon Nimitz, ETEC, Albuquerque, NM, September 1996
Nimitz, J. S. "The Ultimate Halon Replacements are in Sight," Proceedings of the 1993 Halon Alternatives Working Conference, University of New Mexico, Albuquerque, NM, May 11-13, 1993.
Nimitz, J. S., and Lankford, L. H., "Fluoroiodocarbons as Halon Replacements," Proceedings of the 1993 International CFC and Halon Alternatives Conference, Washington DC, October 20-22, 1993.
Nimitz, J. S., High-Performance, Environmentally Sound Replacements for Halon 1301, Prepared for McClellan AFB under contract F04699-93-C-0004, December 1993, ETEC 93-3
Lankford, L. H., and Nimitz, J. S., "A New Class of High-Performance, Environmentally Sound Refrigerants" Proceedings of the 1993 International CFC and Halon Alternatives Conference, Washington DC, October 20-22,1993.
Nimitz, J. S., and Lankford, L. H., "A New Class of Nonflammable, Environmentally Safe Solvents," Fourth Annual International Workshop on Solvent Substitution, Phoenix, AZ, Dec. 7-10, 1993.
Nimitz, J. S., and Lankford, L. H., "Refrigerants Containing Fluoroiodocarbons (FICs)" Proceedings of the 1994 ASHRAE International Compressor Engineering Conference, Purdue University, W. Lafayette, IN, July 19-22, 1994
Nimitz, J. S., Development of Nonflammable, Environmentally Compliant Fluoroiodocarbon Solvents: Report on Interim Tasks, Prepared for U.S.A.F. Wright Laboratories under contract F33615-94-C-5003, ETEC 95-2, March 1995.
Nimitz, J. S., Development of Nonflammable, Environmentally Compliant Fluoroiodocarbon Solvents: Phase I Final Report, Prepared for U.S.A.F. Wright Laboratories under contract F33615-94-C-5003, ETEC 95-1, January 1995.
Lopez, E. P., Peebles, D. E., Reich, J. E., and Smith, M. E., The Effect of Environmentally Compatible, Alternative Cleaners on Solder Flux and Silicone Mold Release Removal, Sandia Report 92-1030 prepared under contract DE-AC04-76DP00789, 1992
Skaggs, S. R., Dierdorf, D. S., and Tapscott, R. E., "Update on Iodides as Fire Extinguishing Agents," Proceedings of the 1993 CFC and Halon Alternatives Conference, Washington, DC, October 20-22, 1993, pp. 800-809.
Skaggs, S., "Interpreting the Toxicology of CF₃I," prepared for Pacific Scientific, HTL/Kin Tech, September 1994

Polymer Type	Compatible with
C4	Blend A	Blend B	Blend C
Acrylic	Yes	Yes	No	No
Aflas	No	No	No	No
Buna-N	Yes	No	Yes	Yes
Cyanate Ester	Yes	Yes	Yes	Yes
EPDM	Yes	No	Yes	Yes
Fluorosilicone	Yes	No	No	No
FR4	Yes	Yes	Yes	Yes
Hi-temp Glass Epoxy	Yes	Yes	Yes	Yes
Neoprene	Yes	Yes	No	Yes
Nylon	Yes	Yes	Yes	Yes
Phenolic	Yes	Yes	Yes	Yes
Polyimide	Yes	Yes	Yes	Yes
Polystyrene	No	No	No	No
PVC type 1	Yes	Yes	Yes	Yes
Silicone	No	No	No	No
Teflon	Yes	Yes	Yes	Yes
Urethane	No	No	No	Marginal
Viton	Yes	Yes	Marginal	No

Metal	Compatible with
C4	Blend A	Blend B	Blend C
Aluminum 2024 T3	Yes	Yes	No	Yes
Aluminum 5052 H32	Yes	Yes	No	Yes
Aluminum 6061 T6	Yes	Yes	No	Yes
Aluminum 7075 T6	Yes	Yes	No	No
Brass	Yes	Yes	Yes	Yes
Bronze SAE 660	Yes	Yes	Yes	Yes
Cast Iron	Yes	Yes	Yes	Yes
Copper	Yes	Yes	Yes	Yes
Magnesium	Yes	Yes	No	No
Stainless Steel 303	Yes	Yes	Yes	Yes
Stainless Steel 416	Yes	Yes	Yes	Yes
Titanium	Yes	Yes	Yes	Yes

SOIL	CFC-113	TCA	TCE	1-C₃F₇I	1-C₄F₉I	1-C₆F₁₂I
AFFF (aqueous film-forming foam)	excellent	very good	very good	excellent	excellent	excellent
BEESWAX	good	good	very good	poor	poor	poor
CASTOR OIL	very good	very good	excellent	excellent	very good	fair
EDM (electric discharge machining) OIL	excellent	excellent	excellent	excellent	excellent	excellent
GREASE PENCIL	fair	fair	fair	fair	fair	poor
HYDRAULIC FLUID MIL-H-5606	excellent	excellent	excellent	excellent	excellent	excellent
HYDRAULIC FLUID MIL-H-83282	excellent	excellent	excellent	excellent	excellent	excellent
HYDR. FLUID SKYDROL 500B4	excellent	excellent	excellent	excellent	excellent	excellent
JET FUEL A	excellent	very good	excellent	excellent	excellent	excellent
JET FUEL JP-4	excellent	excellent	very good	excellent	excellent	excellent
LANOLIN	very good	very good	excellent	poor	fair	fair
MOLY GREASE	very good	very good	excellent	very good	good	fair
MOLY SPRAY LUBE	excellent	excellent	excellent	fair	poor	poor
MOTOR OIL 10W30	excellent	poor	excellent	excellent	excellent	excellent
OIL WD-40	excellent	excellent	excellent	excellent	excellent	excellent
PERFLUORINATED GREASE	very good	poor	poor	excellent	very good	very good
SILICONE SEALANT	fair	poor	good	poor	fair	poor
SILICONE SPRAY	excellent	excellent	very good	excellent	excellent	excellent
SUPERSOIL	very good	excellent	very good	very good	very good	excellent

Category	% Soil removal within 0.5 minutes	% Soil removal within 1 minute	% Soil removal within 5 minutes
excellent	>80		>95
very good		>40	>85
good		>20	>70
fair			>30
poor			<30

SOIL	CFC-113	1-C₄F₉I	BLEND A	BLEND B	BLEND C
COSMOLINE	very good	fair	fair	poor	fair
ESTER-BASED GAS TURBINE ENGINE OIL MIL-L-7808	excellent	excellent	excellent	excellent	excellent
ESTER-BASED GAS TURBINE ENGINE OIL MIL-L-2369	excellent	excellent	excellent	excellent	very good
PFPAE (perfluoropolyalkylether) DENMUM S-65	excellent	excellent	excellent	excellent	very good
PFPAE FOMBLIN Z-04	excellent	excellent	excellent	excellent	excellent
PFPAE KRYTOX	excellent	excellent	excellent	excellent	very good
SILICONE GREASE	good	good	very good	poor	very good

For more information regarding this subject, please contact Dr. Nimitz at mailto:jnimitz@etec-nm.com

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