1、Designation: D6375 09 (Reapproved 2014)Standard Test Method forEvaporation Loss of Lubricating Oils by ThermogravimetricAnalyzer (TGA) Noack Method1This standard is issued under the fixed designation D6375; the number immediately following the designation indicates the year oforiginal adoption or, i
2、n the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the procedure for determiningthe Noack evaporation loss of
3、 lubricating oils using a thermo-gravimetric analyzer test (TGA). The test method is applicableto base stocks and fully formulated lubricant oils having aNoack evaporative loss ranging from 0 to 30 mass %. Thisprocedure requires much smaller specimens, and is faster whenmultiple samples are sequenti
4、ally analyzed, and safer than thestandard Noack method using Woods metal.1.2 The evaporative loss determined by this test method isthe same as that determined using the standard Noack testmethods.1.3 The values stated in SI units are to be regarded asstandard. No other units of measurement are inclu
5、ded in thisstandard.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to
6、 use.2. Referenced Documents2.1 ASTM Standards:2D5800 Test Method for Evaporation Loss of LubricatingOils by the Noack MethodD6299 Practice for Applying Statistical Quality Assuranceand Control Charting Techniques to Evaluate AnalyticalMeasurement System PerformanceD6792 Practice for Quality System
7、in Petroleum Productsand Lubricants Testing LaboratoriesE1582 Practice for Calibration of Temperature Scale forThermogravimetry3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 Noack reference oilthe oil provided by Noack equip-ment manufacturers to check proper operation of the
8、 Noackevaporation tester.3.1.2 Noack reference timethe time (in minutes) requiredfor the Noack reference oil to reach its known Noack evapo-rative loss under the conditions used in this test method.3.1.3 TGA Noack volatilitythe evaporative loss (in masspercent) of a lubricant as determined in this t
9、est method.4. Summary of Test Method4.1 A lubricant specimen is placed in an appropriate TGAspecimen pan. The pan is placed on the TGA pan holder andquickly heated to between 247 and 249C under a stream of air,and then held isothermal for an appropriate time. Throughoutthis process, the TGA monitors
10、 and records the mass lossexperienced by the specimen due to evaporation. The Noackevaporation loss is subsequently determined from the specimenweight percent loss versus time curve (TG curve) as the masspercent lost by the specimen at the Noack reference timedetermined under the same TGA conditions
11、.5. Significance and Use5.1 This test method is a safe and fast alternative fordetermination of the Noack evaporation loss of a lubricant.5.2 The evaporation loss of a lubricant is important in thehot zones of equipment where evaporation of part of thelubricant may increase lubricant consumption.5.3
12、 Some lubricant specifications cite a maximum allowableevaporative loss.6. Apparatus6.1 Thermogravimetric Analyzer , with the capability tomeet all the conditions required for this test method, along withthe software necessary to complete the required analyses.6.2 Aluminum Specimen PanThis shall be
13、cylindrical, andhave a minimum inside diameter/height ratio of 0.45 and avolume of 50 6 3 L. If the pans provided by the particularTGA manufacturer do not meet these criteria, alternative pans1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products, Liquid Fuels, and Lu
14、bricants and is the direct responsibility ofSubcommittee D02.06 on Analysis of Lubricants.Current edition approved May 1, 2014. Published July 2014. Originally approvedin 1999. Last previous edition approved in 2009 as D6375 09. DOI: 10.1520/D6375-09R14.2For referenced ASTM standards, visit the ASTM
15、 website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United
16、States1may be used and adapted to fit the pan holder of the TGA.Examples of some of the adaptations used during the evalua-tion of this test method are shown in Fig. 1.6.3 Pressure Regulator, capable of maintaining air deliverypressure at the level required by the TGA instrument.6.4 Flowmeter, with
17、a flow control valve capable of settingand measuring the air throughput required by the TGA instru-ment.7. Reagents and Materials7.1 TGA Temperature Calibration StandardsThese mate-rials will depend on the particular TGA apparatus and itscapabilities. The TGA manufacturer typically provides themand
18、describes their use in the operating manual for theinstrument.7.2 Compressed air at a pressure suitable for operation ofthe TGA instrument. Reagent grade air is not necessary butmay be used if there are concerns over possible contaminationof the internal parts of the TGA.7.3 Noack Reference OilOil h
19、aving a known Noackevaporative loss, the value of which is provided by themanufacturer.8. TGA Preparation and Calibration (see Note 1)NOTE 1This section only needs to be done if TGA has been idle foran extended period of time, has had significant repairs made to it, or hasbeen mishandled or its loca
20、tion changed.8.1 Check the temperature correlation between the speci-men and control temperatures in accordance with TGA manu-facturers recommendations or Practice E1582. Use calibrationstandards that will bracket 250C. When necessary, recalibrate,and regenerate correlation.8.2 When necessary, burn
21、out the TGA to remove anycondensed liquids or deposits, which may have formed on itsinside surfaces. Generally, burn out is accomplished by raisingthe temperature of the TGAto a minimum of 800C with an airpurge from 200 to 500 mL/min, and by maintaining it at thishigh temperature until no smoke is d
22、etected from the TGA gasexhaust tube. Normally 15 to 20 min at these conditions areenough to remove most deposits. (WarningDo not place aspecimen pan in the TGAduring this operation. It will melt andmay damage the balance or furnace mechanisms.)8.3 Check operation of TGA balance and adjust whenneces
23、sary. Follow manufacturers procedure and recommenda-tions.9. Procedure9.1 Determination of Specimen Mass :9.1.1 Determine the nominal internal diameter (in centime-tres) of the specimen pans by measuring the internal diameterof 10 different pans and averaging the results.Acaliper shall beused to mak
24、e this measurement.9.1.2 Calculate the specimen mass using following equa-tion:Ms5 350 ID!3(1)Ms= Specimen mass, mg (round to closest whole mg.)ID = Nominal inside diameter of specimen pan, cm (see9.1.1).9.2 Air Flowrate Set air flowrate to that recommended bythe TGA manufacturer or higher if during
25、 the initial tests withthe Noack reference oil there appears to be condensation onany part of the TGA balance mechanism or furnace lining.Repeat 8.1 with the new flow rate.9.3 Temperature Program (see Note 2):NOTE 2This section only needs to be done during the initial set up ofthe method in the TGA.
26、9.3.1 Using the correlation from 8.1, determine the finalprogram temperature required to obtain a final specimentemperature of 249C.9.3.2 Program the TGA to heat the specimen from 50C tothe final program temperature determined in 9.3.1 at heatingrate(s) that will simulate the specimen heating rate o
27、f thestandard Noack methods (;100C/min to 220C and 10C/minfrom 220C to 249C). Some guidance on how to achieveacceptable heating rates can be obtained from the examplesshown in Fig. 2. Maintain the final program temperature for30 min (see Note 3).NOTE 3The 30 min isothermal hold may be adjusted after
28、 the Noackreference oil has been tested and the Noack reference time for theinstrument has been established (see 9.4). The isothermal hold can then beset to be 2 min longer than the measured Noack reference time.9.3.3 Tare an empty specimen pan in accordance with theTGA operating manual.9.3.4 Add th
29、e required mass (6 3 mg) (as determined in9.1) of the Noack reference oil to the tared pan.9.3.5 Place the pan on the TGA pan holder, and runspecimen through the temperature program, as described in9.3.2.9.3.6 From the data obtained in 9.3.5, generate a plot of timeversus specimen temperature. Deter
30、mine whether at any timeFIG. 1 Examples Showing Adaptation of Alternative Sample PansD6375 09 (2014)2the specimen temperature was above 249C. When this occurs,proceed to 9.3.8. When it does not occur, proceed to 9.3.7.9.3.7 Temperature not over 249C: Determine the Noackreference time in accordance w
31、ith 9.4.6. When the Noackreference time is less than 7 min, return to 9.3.2 and the reduceheating rate to extend the Noack reference time beyond 7 min.Check the specimen temperature at the Noack reference time tobe sure it is between 248 and 249C. When it is lower,determine how much lower than 248.5
32、C and increase the finalprogram temperature by this amount. Go to 9.4.9.3.8 Temperature over 249C: Modify the TGA tempera-ture program to eliminate the temperature overshoot. This isgenerally accomplished by splitting the program into twostages, by reducing the heating rate by the final programtempe
33、rature, or by a combination thereof. An example of howtemperature overshoot was eliminated in a particular instru-ment is shown in Fig. 3. Repeat 9.3.3 9.3.6 until anappropriate temperature program has been obtained.9.4 Determination of Noack Reference Time:NOTE 4Important: This determination shall
34、be completed each dayprior to evaluating any test specimens.9.4.1 Set air flowrate in accordance with 9.2.9.4.2 Enter final temperature program established in 9.3.9.4.3 Tare an empty specimen pan in accordance with theTGA operating manual.9.4.4 Add the required mass (as determined in 9.1)oftheNoack
35、reference oil to the tared pan. Whether specimen isadded volumetrically or gravimetrically, the actual mass shallbe within 63 mg of the calculated specimen mass. Adjustspecimen mass to meet this requirement.9.4.5 Place the pan on the TGA pan holder, and runspecimen.9.4.6 From the thermogravimetric c
36、urve generated in 9.4.5,determine the time (if possible to the closest 0.01 min) requiredfor the Noack reference oil to reach its Noack evaporative loss.This time is the Noack reference time. Record this time, as itwill be used in 9.5 to determine the TGA Noack volatility ofthe test lubricants. An e
37、xample of a TG curve for the Noackreference oil and how to use it to determine the Noackreference time is shown in Fig. 4 (Curve 1). The isothermalhold of the TGA temperature program can now be modified tothe Noack reference time plus 2 min. This will expedite futuredeterminations.9.4.7 Check that t
38、he specimen temperature at the Noackreference time is between 247 and 249C. When the tempera-ture is outside this range, burn out TGA in accordance with 8.2and repeat 9.4.9.4.8 Compare the measured Noack reference time to thosemeasured in prior days. When the difference is more than 10 %,check opera
39、tion of the TGA in accordance with Section 8.When significant repairs or modifications, such as replacementof the balance mechanisms, temperature sensor, and so forth,have been made to the TGA since the previous time the Noackreference time was measured, the test method shall be repeatedstarting wit
40、h Section 8.9.5 Determination of TGA Noack Volatility of Test Lubri-cant:9.5.1 Using a new specimen pan, repeat 9.4.1 9.4.5 usingthe test lubricant in place of the Noack reference oil.9.5.2 Using the TG curve for the test lubricant and theNoack reference time from 9.4.6, determine the mass loss (inm
41、ass %) of the test lubricant at the Noack reference time. Thisis the TGA Noack volatility for the test lubricant. Examples ofhow to determine the TGA Noack volatility of test lubricantsare shown in Fig. 4 (Curves 2 and 3). Check that the specimentemperature at the Noack reference time is between 247
42、 and250C. When it is not, reinitiate the test starting with Section8.9.5.3 The TGA shall be burned out (see 8.2) on a regularbasis. An estimate of how many tests can be done on aparticular TGAbefore it needs to be burned out can be obtainedby performing consecutive tests with the Noack reference oil
43、until the difference in the Noack reference time between any ofthe determinations is greater than 10 %. The number of testsbetween burn outs may be increased by operating at a higherair flowrate (see 9.2).FIG. 2 TGA Noack Programs and Resulting Specimen Heating RatesD6375 09 (2014)310. Report10.1 Re
44、port the TGA Noack volatility of the test lubricant,as determined in 9.5.2, to the closest 0.01 mass percent.11. Quality Control (QC)11.1 Confirm the performance of the instrument or the testprocedure by analyzing a QC sample.11.1.1 If a suitable QC oil or basestock sample is notavailable, prepare Q
45、C sample from a stock of such material.11.1.2 When QC/Quality Assurance (QA) protocols arealready established in the testing facility, they may be usedwhen they confirm the reliability of the test result.11.1.3 When there is no QC/QA protocol established in thetesting facility, Appendix X1 can be us
46、ed as the QC/QAsystem.12. Precision and Bias312.1 On the basis of an interlaboratory round robin consist-ing of nine laboratories testing eight oils with TGAinstrumentsfrom five different manufacturers, the following precision andbias were determined for this procedure.12.2 Repeatability Two determi
47、nations made on the samesample within a short interval of time, by the same operatorusing the same TGA equipment, in the normal and correctoperation of this test method, should differ by more than thefollowing value only in one case in twenty.Repeatability 5 0.31 TGA Noack Volatility!0.60(2)3Support
48、ing data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR:D02-1447.FIG. 3 TGA Noack Programs and Resulting Specimen Heating Rates Showing Modification of TGA Program to Eliminate Overshoot inSpecimen TemperatureFIG. 4 Determination of Noack Refer
49、ence Time and Test Oils Evaporative LossD6375 09 (2014)412.3 Reproducibility Two determinations made on thesame sample by different operators or using different TGAequipment, in the normal and correct operation of this testmethod, should differ by more than the following value only inone case in twenty.Reproducibility 5 0.39 TGA Noack Volatility!0.60(3)12.4 BiasWithin the repeatability of this test method, nosignificant bias was found between the Noack volatility deter-mined by this test method and those determined using TestMethod D580
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