ASTM D7412-09
(Test Method)Standard Test Method for Condition Monitoring of Phosphate Antiwear Additives in In-Service Petroleum and Hydrocarbon Based Lubricants by Trend Analysis Using Fourier Transform Infrared (FT-IR) Spectrometry
Standard Test Method for Condition Monitoring of Phosphate Antiwear Additives in In-Service Petroleum and Hydrocarbon Based Lubricants by Trend Analysis Using Fourier Transform Infrared (FT-IR) Spectrometry
SIGNIFICANCE AND USE
Antiwear additives are commonly used in petroleum and hydrocarbon based lubricants to prevent machinery wear by forming a chemical barrier activated by frictional heat. Antiwear additives that are phosphate based can be measured by FT-IR spectroscopy using the phosphate absorption band. Initially, phosphate antiwear additives will decompose and form a protective film by binding to metal surfaces and through oxidative mechanisms, and so a decrease in the level of phosphate antiwear additive relative to that in the new oil is expected during normal machinery operation. Subsequently, significant depletion of phosphate antiwear additives due to oxidation or hydrolysis can occur when the lubricant is subjected to high temperatures and high levels of moisture. This usually occurs prior to the point where the oxidation of the lubricant begins to accelerate—making trending of phosphate antiwear additives a useful indicator of the lubricant’s remaining in-service life. Monitoring of phosphate antiwear additive depletion is therefore an important parameter in determining overall machinery health and should be considered in conjunction with data from other tests such as atomic emission (AE) and atomic absorption (AA) spectroscopy for wear metal analysis (Test Method D 5185), physical property tests (Test Methods D 445, D 2896, and D 6304) and other FT-IR oil analysis methods for oxidation (Test Method D 7414), sulfate by-products (Test Method D 7415), nitration, breakdown products and external contaminants (Practice E 2412), which also assess elements of the oil’s condition, see Refs (1-6).
SCOPE
1.1 This test method covers monitoring phosphate antiwear additives in in-service petroleum and hydrocarbon based lubricants such as various types of engine oils, hydraulic oils, and other lubricants that are formulated for protection against wear. Typical phosphate antiwear additives include zinc dialkyldithiophosphates, trialkyl phosphates and triaryl phosphates.
1.2 This test method uses Fourier Transform Infrared (FT-IR) spectrometry for monitoring of phosphate antiwear additive depletion in in-service petroleum and hydrocarbon based lubricants as a result of normal machinery operation. Monitoring the depletion of phosphate antiwear additives in in-service lubricants can indicate unusual wear or severe operating conditions of the machine. This test method is designed as a fast, simple spectroscopic check for monitoring of phosphate antiwear additives in in-service petroleum and hydrocarbon based lubricants with the objective of helping diagnose the operational condition of the machine based on measuring the level of phosphate antiwear additives in the oil.
1.3 Acquisition of FT-IR spectral data for measuring phosphate antiwear additives in in-service oil and lubricant samples is described in Practice D 7418. In this test method, measurement and data interpretation parameters for phosphate antiwear additives using both direct trend analysis and differential (spectral subtraction) trend analysis are presented.
1.4 This test method is based on trending of spectral changes associated with phosphate antiwear additives in in-service petroleum and hydrocarbon based lubricants. Warnings or alarm limits can be set on the basis of a fixed minimum value for a single measurement or, alternatively, can be based on a rate of change of the response measured, see Ref (1).
1.4.1 For direct trend analysis, values are recorded directly from absorption spectra and reported in units of absorbance per 0.1 mm pathlength.
1.4.2 For differential trend analysis, values are recorded from the differential spectra (spectrum obtained by subtraction of the absorption spectrum of the reference oil from that of the in-service oil) and reported in units of 100*absorbance per 0.1 mm pathlength (or equivalently absorbance units per centimeter).
1.4.3 In either case, maintenance action limits should be determined through statisti...
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Designation: D7412 − 09
Standard Test Method for
Condition Monitoring of Phosphate Antiwear Additives in
In-Service Petroleum and Hydrocarbon Based Lubricants by
Trend Analysis Using Fourier Transform Infrared (FT-IR)
1
Spectrometry
This standard is issued under the fixed designation D7412; 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 (´) indicates an editorial change since the last revision or reapproval.
1. Scope value for a single measurement or, alternatively, can be based
2
on a rate of change of the response measured, see Ref (1).
1.1 This test method covers monitoring phosphate antiwear
1.4.1 For direct trend analysis, values are recorded directly
additives in in-service petroleum and hydrocarbon based lubri-
fromabsorptionspectraandreportedinunitsofabsorbanceper
cants such as various types of engine oils, hydraulic oils, and
0.1 mm pathlength.
otherlubricantsthatareformulatedforprotectionagainstwear.
1.4.2 For differential trend analysis, values are recorded
Typical phosphate antiwear additives include zinc dialkyl-
from the differential spectra (spectrum obtained by subtraction
dithiophosphates, trialkyl phosphates and triaryl phosphates.
of the absorption spectrum of the reference oil from that of the
1.2 This test method uses Fourier Transform Infrared (FT-
in-service oil) and reported in units of 100*absorbance per 0.1
IR) spectrometry for monitoring of phosphate antiwear addi-
mm pathlength (or equivalently absorbance units per centime-
tive depletion in in-service petroleum and hydrocarbon based
ter).
lubricants as a result of normal machinery operation. Monitor-
1.4.3 In either case, maintenance action limits should be
ing the depletion of phosphate antiwear additives in in-service
determined through statistical analysis, history of the same or
lubricants can indicate unusual wear or severe operating
similar equipment, round robin tests or other methods in
conditions of the machine. This test method is designed as a
conjunction with the correlation of changes in the level of
fast, simple spectroscopic check for monitoring of phosphate
phosphate antiwear additives to equipment performance.
antiwear additives in in-service petroleum and hydrocarbon
NOTE 1—It is not the intent of this test method to establish or
based lubricants with the objective of helping diagnose the
recommend normal, cautionary, warning or alert limits for any machinery.
operational condition of the machine based on measuring the
Suchlimitsshouldbeestablishedinconjunctionwithadviceandguidance
level of phosphate antiwear additives in the oil.
from the machinery manufacturer and maintenance group.
1.3 Acquisition of FT-IR spectral data for measuring phos-
1.5 This test method is for petroleum and hydrocarbon
phate antiwear additives in in-service oil and lubricant samples
based lubricants and is not applicable for ester based oils,
is described in Practice D7418. In this test method, measure-
including polyol esters or phosphate esters.
mentanddatainterpretationparametersforphosphateantiwear
1.6 The values stated in SI units are to be regarded as
additives using both direct trend analysis and differential
standard. No other units of measurement are included in this
(spectral subtraction) trend analysis are presented.
standard.
-1
1.4 This test method is based on trending of spectral
1.6.1 Exception—The unit for wave numbers is cm .
changes associated with phosphate antiwear additives in in-
1.7 This standard does not purport to address all of the
service petroleum and hydrocarbon based lubricants. Warnings
safety concerns, if any, associated with its use. It is the
or alarm limits can be set on the basis of a fixed minimum
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica-
1
This test method is under the jurisdiction of ASTM Committee D02 on
bility of regulatory limitations prior to use.
Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of
Subcommittee D02.96.03 on FTIR Testing Practices and Techniques Related to
In-Service Lubricants.
2
Current edition approved July 1, 2009. Published August 2009. DOI: 10.1520/ The boldface numbers in parentheses refer to a list of references at the end of
D7412-09. this standard.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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D7412 − 09
2. Referenced Documents 5. Significance and Use
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2.1 ASTM Standards: 5.1 Antiwearadditivesarecommonlyusedinpetroleumand
D445 Test Method for Kinematic Viscosity of Transparent hydrocarbo
...
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