ASTM D7098-05
(Test Method)Standard Test Method for Oxidation Stability of Lubricants by Thin-Film Oxygen Uptake (TFOUT) Catalyst B
Standard Test Method for Oxidation Stability of Lubricants by Thin-Film Oxygen Uptake (TFOUT) Catalyst B
SCOPE
1.1 This test method covers the oxidation stability of lubricants by thin-film oxygen uptake (TFOUT) Catalyst B. This test method was originally developed as a screening test to indicate whether a given re-refined base stock could be formulated for use as automotive engine oil particularly in relationship with Engine Test Sequence IIID (Test Method D 4742). More recently, another catalyst has been developed using engine oils characterized by oxidation resistance in Engine Test Sequence IIIE. In addition, the test method has since been found broadly applicable as an oxidation test of petroleum products.
1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are provided for information purposes only.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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Standards Content (Sample)
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An American National Standard
Designation: D 7098 – 05
Standard Test Method for
Oxidation Stability of Lubricants by Thin-Film Oxygen
,
1 2
Uptake (TFOUT) Catalyst B
This standard is issued under the fixed designation D 7098; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope A 314 Specification for Stainless Steel Billets and Bars for
Forging
1.1 This test method covers the oxidation stability of lubri-
B211 Specification for Aluminum and Aluminum-Alloy
cants by thin-film oxygen uptake (TFOUT) Catalyst B. This
Bar, Rod, and Wire
test method was originally developed as a screening test to
D 664 TestMethodforAcidNumberofPetroleumProducts
indicate whether a given re-refined base stock could be
3 by Potentiometric Titration
formulated for use as automotive engine oil particularly in
D 1193 Specification for Reagent Water
relationship with Engine Test Sequence IIID (Test Method
D 2272 Test Method for Oxidation Stability of Steam-
D 4742). More recently, another catalyst has been developed
Turbine Oil by Rotating Pressure Vessel
using engine oils characterized by oxidation resistance in
4 D 4742 Test Method for Oxidation Stability of Automotive
Engine Test Sequence IIIE. In addition, the test method has
Engine Oils by Thin Film Oxygen Uptake (TFOUT)
since been found broadly applicable as an oxidation test of
E1 Specification for ASTM Thermometers
petroleum products.
E 144 Practice for Safe Use of Oxygen Combustion Bombs
1.2 The values stated in SI units are to be regarded as the
standard. The values given in parentheses are provided for
3. Terminology
information purposes only.
3.1 Definitions of Terms Specific to This Standard:
1.3 This standard does not purport to address all of the
3.1.1 break point—the precise point of time at which rapid
safety concerns, if any, associated with its use. It is the
oxidation of the oil begins.
responsibility of the user of this standard to establish appro-
3.1.2 oxidation induction time—the time until the oil begins
priate safety and health practices and determine the applica-
to oxidize at a relatively rapid rate as indicated by the decrease
bility of regulatory limitations prior to use.
of oxygen pressure.
2. Referenced Documents 3.1.3 oxygen uptake—oxygen absorbed by oil as a result of
oil oxidation.
2.1 ASTM Standards:
4. Summary of Test Method
This test method is under the jurisdiction of ASTM Committee D02 on 4.1 The test oil is mixed in a glass container with four other
Petroleum Products and Lubricants and is the direct responsibility of Subcommittee
liquids used to simulate engine conditions: (1) an oxidized/
D02.09 on Oxidation.
nitrated fuel component (Annex A3), (2) a mixture of soluble
Current edition approved April 1, 2005. Published May 2005.
metal naphthenates (lead, iron, manganese, and tin naphthen-
While Catalyst B can be used for testing oxidation stability of many lubricant
types, the mixture of fuel, nitro-paraffin, and catalyst components used in this test
ates (AnnexA4), (3) a nitro-paraffinic compound, and (4)Type
method simulates the Sequence IIIE Engine Test. Test results on several ASTM
II reagent water.
reference oils have been found to correlate with Sequence IIIE engine tests in hours
2 4.2 The glass container holding the oil mixture is placed in
for a 375 % viscosity increase.
apressurevesselequippedwithapressuresensor.Thepressure
Ku, C. S. and Hsu, S. M., “A Thin Film Uptake Test for the Evaluation of
Automotive Lubricants,” Lubrication Engineering, 40, 2, 1984, pp. 75–83.
vessel is sealed, charged with oxygen to a pressure of 620 kPa
Ku, Chia-Soon, Pei, Patrick T., and Hsu, Stephen M., “A Modified Thin-Film
(90 psig), and placed in an oil bath at 160°C at an angle of 30°
Oxygen Uptake Test (TFOUT) for the Evaluation of Lubricant Stability in ASTM
from the horizontal. The pressure vessel is rotated axially at a
Sequence IIIE Test, SAE Technical Paper Series 902121, Tulsa, OK, Oct. 22-25,
1990. speed of 100 r/min forming a thin film of oil within the glass
Selby, Theodore W., “Oxidation Studies with a Modified Thin-Film Oxygen
containerresultinginarelativelylargeoil-oxygencontactarea.
Uptake Test”, SAE Technical Paper Series 872127, Toronto, Ontario, Nov. 2-5,
4.3 The pressure of the pressure vessel is recorded continu-
1987.
ously from the beginning of the test and the test is terminated
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
when a rapid decrease of the pressure vessel pressure is
Standards volume information, refer to the standard’s Document Summary page on
observed (Point B, Fig. 1). The period of time that elapses
the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D7098–05
all reagents shall conform to the specifications of the Commit-
teeonAnalyticalReagentsoftheAmericanChemicalSociety.
7.2 Purity of Water—Unless otherwise indicated, references
to reagent water shall be understood to mean distilled water
meeting requirements of reagent water as defined byType II of
Specification D 1193.
7.3 Acetone,CH COCH .
3 3
7.4 Air, containing 2000 ppm nitrogen dioxide,
NO (commercially available compressed gas mixture, certi-
fied within 65 %).
7.5 Cyclo-hexane,C H , Practical Grade or other suitable
6 12
hydrocarbon solvent. (Warning—Highly flammable. Skin ir-
ritant on repeated contact. Aspiration hazard.)
7.6 Isopropyl Alcohol,CH CH(CH )OH.
3 3
7.7 Oxygen, 99.8 %.
FIG. 1 Pressure versus Time Diagram of the Oxidation Test
8. Materials
between the time when the pressure vessel is placed in the oil
8.1 TFOUT Catalyst B Package:
bath and the time at which the pressure begins to decrease
8.1.1 Fuel Component—The fuel component is a nitrated
rapidly is called the oxidation induction time and is used as a
gasoline fraction or organic equivalent. This component may
measure of the relative oil oxidation stability.
be prepared in accordance with the procedures described in
Annex A3.
5. Significance and Use
8.1.2 Soluble Metal Catalyst Mixture—This catalyst is a
5.1 This test method was originally developed to evaluate
mixture of soluble metal catalysts (lead, iron, manganese, and
oxidation stability of lubricating base oils combined with
tin). The catalyst may be prepared according to the procedures
additives chemistries similar to those found in gasoline engine
described in Annex A4.
oils and service.
8.1.2.1 Other oxidation stability test methods have demon-
5.2 This test method is useful for screening formulated oils
strated that soluble metal catalyst supplies may be inconsistent
before engine tests. Within similar additive chemistries and
and have significant effects on the test results. Thus, for test
base oil types, the ranking of oils in this test appears to be
comparisons, the same source and same batch of metal
predictive of ranking in certain engine tests. When oils having
naphthenates shall be used.
different additive chemistries or base oil type are compared,
NOTE 2—Itisgoodresearchpracticetousethesamebatchesofcatalyst
results may or may not reflect results in engine tests. Only
components when closely comparing engine oils.
gasoline engine oils were used in generating the precision
NOTE 3—Slow, steady reactivity of some of the catalyst chemicals can
statements in this test method.
beaproblem.Suchproblemscanbereducedbystoringtheclosedcatalyst
vials in a refrigerator at approximately 5°C.
6. Apparatus
8.1.3 Nitro-paraffın—This compound is made up of a nitri-
6.1 Oxidation Bath and Pressure Vessel—See appropriate
alkane blend.
Annex (Annex A1 or Annex A2) for detailed description of
NOTE 4—Suitably prepared catalyst packages may be purchased from
apparatus and accessories for equipment described in this test
Tannas Co.
method.
8.2 Varnish and Deposit Remover, water-soluble varnish
NOTE 1—To reduce vapor odors when opening pressure vessel after
remover or other engine varnish/deposit removers.
use, a hood may be desirable.
6.2 Precision Pressure Gage—Use a certified precision
pressure gage to accurately control the oxygen feed to the
Reagent Chemicals, American Chemical Society Specifications, American
Chemical Society, Washington, DC. For suggestions on the testing of reagents not
pressure vessel. The gage shall have a sufficient range to
listed by the American Chemical Society, see Analar Standards for Laboratory
encompass 0 to 650 kPa (~90 psig) required by the test method
Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
withdivision2.0kPa(~0.5psig)orbettertoenablereadingsto
and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,
be made to 2.0 kPa (~0.25 psig).
MD.
The sole source of supply of the apparatus known to the committee at this time
7. Reagents is Tannas Co., 4800 James Savage Rd., Midland, MI 48642. If you are aware of
alternative suppliers, please provide this information to ASTM International
7.1 Purity of Reagents—Reagent grade chemicals shall be
Headquarters.Your comments will receive careful consideration at a meeting of the
used in all tests. Unless otherwise indicated, it is intended that
responsible technical committee, which you may attend.
D7098–05
8.3 Silicone Stopcock Grease. 10.2 Pressure Vessel Assembly and Charging—Immediately
and rapidly assemble and charge the pressure vessel in accor-
dance with apparatus type (see A1.2 or A2.7).
9. Preparation of Apparatus
9.1 Glass Sample Container—A clean glass sample con-
NOTE 8—Avoid releasing the oxygen too rapidly by decreasing the
pressure to atmospheric in no less than 1 min to avoid possible foaming
tainer is important for obtaining repeatable results. Thorough
and overflow of the sample from the glass sample container.
cleaningcanbeaccomplishedby(a)rinsingwithcyclo-hexane
or other suitable hydrocarbon solvent, (b) soaking in concen-
10.3 Oxidation—Before starting the test, bring the heating
trated solution of a water-soluble varnish remover, (c) thor-
bath to the test temperature at 160°C and insert the pressure
oughly rinsing with water, (d) rinsing with acetone, (e) and
vessel(s) in accordance with apparatus type (seeA1.3 orA2.8).
permitting to dry.
10.3.1 Allow the bath temperature to level out at the test
temperature, which must occur within 15 min after insertion of
NOTE 5—A segmented glass reaction dish has been found suitable to
thepressurevessel.Maintainingthetesttemperaturewithinthe
prevent premature mixing of the catalyst components (see Fig. A2.4)
specified limits of 160 6 0.3°C during the entire test run is the
9.2 Cleaning of Pressure Vessel—Fill with concentrated
most important single factor ensuring both repeatability and
solution of a water-soluble varnish remover and soak for
reproducibility of test results. If the test temperature cannot be
suitable time, rinse with water, rinse with acetone, and permit
maintained as specified, the test results shall not be considered
to dry.
valid.
9.3 Cleaning of Pressure Vessel Stem—Periodically disas-
NOTE 9—The time for the bath to reach the operating temperature after
semble, inspect, and clean the pressure vessel stem. Rinse the
insertion of the pressure vessel may differ for different apparatus assem-
inside of the stem with isopropyl alcohol and blow dry with oil
blies and shall be observed for each unit (a unit may carry one, two, three,
free compressed air. For users of apparatus described inAnnex
orfourpressurevessels).Theobjectiveistofindasetofconditions,which
A1, periodically insert a dry pipe cleaner into the transducer
does not permit a drop of more than 2°C after insertion of the pressure
line opening for removal of potential residue buildup. vessel(s) and allows the pressure vessel pressure to reach plateau within
15 min.
NOTE 6—Replace O-rings when reassembling the pressure transducers.
10.4 Keep the pressure vessel completely submerged and
9.4 Periodicallypressuretestthepressurevesselsat690kPa
maintain continuous and uniform rotation throughout the test.
(~100 psi) with air or oxygen. If the pressure drops more than
A standard rotational speed of 100 6 5 r/min is required; any
0.690 kPa (~0.1 psi) on the pressure gage within 60 s, replace
variation in this speed could cause erratic results.
the O-ring seals and inspect the valve seals according to
10.5 Monitor the pressure of the pressure vessel preferably
manufacturer’sdirections.Iftheproblemcontinues,contactthe
using a strip chart or some other form of electronic data
specific equipment manufacturer.
collection program. If a dial pressure gage is used, make
readings at least every 5 min. (The maximum pressure must be
NOTE 7—Previous versions of this test method have called for hydro-
reachedwithin15min.)Afteratestperiod(theinductiontime),
static testing of the pressure vessel. This was found unnecessary at the
relatively low pressures involved in running this test method. thepressuredecreasesbecauseofoxygenabsorptionbyoil(the
break point).
9.5 Cleaning of Catalyst Syringes—Use individual catalyst
10.5.1 When the oil reaches the break point, the pressure
syringes for each catalyst component. Thoroughly clean and
decreases rapidly as oxygen is absorbed rapidly by the test oil.
dry syringes prior to each use. (See Annex A5 for recom-
Thetestcanbeterminatedassoonassufficientinformationhas
mended procedure.)
been collected to form a tangent to the decreasing pressure
trace (see 10.6) or, if desired, continued until pressure de-
10. Procedure
creases to some further level.
10.1 Weighing and Mixing Sample and Catalyst Compo-
NOTE 10—The pressure within the pressure vessel increases at the
nents:
beginning because of gas expansion accompanying the temperature
10.1.1 Place the clean glass sample container onto the
increase of the pressure vessel. Following this rise, the pressure reaches a
precision balance and tare. plateau as shown in Fig. 1. This pressure may gradually drop slightly
during the test.Agradual decrease of the pressure is not unusual and does
10.1.2 Weigh 1.500 6 0.001 g of oil sample into the
not invalidate the test. The time between initiating the test and the break
container and tare.
point is called the oxidation induction time.
10.1.3 Add 0.045 6 0.001 g of the soluble metal catalyst
NOTE 11—If a break in pressure does not occur within 300 to 500 mins,
mixture into the glass sample container and tare.
the operator may elect to terminate the test. A slow decrease
...
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