1、Designation: D4927 14Standard Test Methods forElemental Analysis of Lubricant and Additive ComponentsBarium, Calcium, Phosphorus, Sulfur, and Zinc byWavelength-Dispersive X-Ray Fluorescence Spectroscopy1This standard is issued under the fixed designation D4927; the number immediately following the d
2、esignation indicates the year oforiginal adoption or, in 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.This standard has been approved for use
3、 by agencies of the U.S. Department of Defense.1. Scope*1.1 These test methods cover the determination of barium,calcium, phosphorus, sulfur, and zinc in unused lubricating oilsat element concentration ranges shown in Table 1. The rangecan be extended to higher concentrations by dilution of samplesp
4、ecimens. Additives can also be determined after dilution.Two different methods are presented in these test methods.1.2 Test Method A (Internal Standard Procedure)Internalstandards are used to compensate for interelement effects ofX-ray excitation and fluorescence (see Sections 8 through 13).1.3 Test
5、 Method B (Mathematical Correction Procedure)The measured X-ray fluorescence intensity for a given elementis mathematically corrected for potential interference fromother elements present in the sample (see Sections 14 through19).1.4 The preferred concentration units are mass % barium,calcium, phosp
6、horus, sulfur, or zinc.1.5 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
7、 to use.2. Referenced Documents2.1 ASTM Standards:2D6299 Practice for Applying Statistical Quality Assuranceand Control Charting Techniques to Evaluate AnalyticalMeasurement System Performance3. Summary of the Test Methods3.1 A sample specimen is placed in the X-ray beam and theintensity of the appr
8、opriate fluorescence lines of barium,calcium, phosphorus, sulfur, and zinc are measured. Instrumentresponse factors related to the concentration of standardsenable the determination of the concentration of elements inthe tested sample specimens. Enhancement or depression of theX-ray fluorescence of
9、a given element by an interferingelement in the sample may occur. Two test methods (A and B)are described for compensating any interference effect.3.2 Test Method A (Internal Standard Procedure)Internalstandards are used with the standards and sample specimens tocompensate for the potential interele
10、ment effects.3.2.1 Barium, Calcium, Phosphorus, and ZincA samplespecimen that has been blended with a single internal standardsolution (containing tin or titanium for barium and calcium,zirconium for phosphorus, and nickel for zinc) is poured intoan X-ray cell. Total net counts (peak intensitybackgr
11、ound)for each element and its respective internal standard arecollected at their appropriate wavelengths. The ratios betweenelemental and internal standard counts are calculated andconverted into barium, calcium, phosphorus, or zincconcentrations, or a combination thereof, from calibrationcurves.3.2
12、.2 SulfurA sample specimen is mixed with a leadinternal standard solution and analyzed as described in 3.2.1.3.3 Test Method B (Mathematical Correction Procedure)The measured intensity for a given element is mathematicallycorrected for the interference from other elements in thesample specimen. This
13、 requires that intensities from all ele-ments in the specimen be obtained.3.3.1 The sample specimen is placed in the X-ray beam andthe intensities of the fluorescence lines of barium, calcium,phosphorus, sulfur, and zinc are measured. A similar measure-ment is made away from the fluorescence lines i
14、n order toobtain a background correction. Concentrations of the elementsof interest are determined by comparison of net signals againstappropriate interelement correction factors developed fromresponses of calibration standards.1These test methods are under the jurisdiction of ASTM Committee D02 onP
15、etroleum Products, Liquid Fuels, and Lubricants and are the direct responsibilityof Subcommittee D02.03 on Elemental Analysis.Current edition approved Dec. 1, 2014. Published January 2015. Originallyapproved in 1989. Last previous edition approved in 2010 as D4927 10. DOI:10.1520/D4927-14.2For refer
16、enced ASTM standards, visit the ASTM 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.*A Summary of Changes section appears at the end of this standardCopyri
17、ght ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.3.2 The X-ray fluorescence spectrometer is initially cali-brated with a suite of standards in order to determine byregression analysis, interelement correction factors and instru-ment respon
18、se factors.3.3.3 Subsequent calibration is achieved using a smallernumber of standards since only the instrument response factorsneed to be redetermined. One of these standards (or an optionalsynthetic pellet) can be used to monitor instrumental drift whenperforming a high volume of analyses.3.4 Add
19、itives and additive packages can be determined afterdilution with base oil to place the elemental concentrations inthe range described in 1.1.4. Significance and Use4.1 Some oils are formulated with organo-metallic additiveswhich act as detergents, antioxidants, antiwear agents, and soforth. Some of
20、 these additives contain one or more of theseelements: barium, calcium, phosphorus, sulfur, and zinc. Thesetest methods provide a means of determining the concentrationof these elements which in turn provides an indication of theadditive content of these oils.4.2 Several additive elements and their
21、compounds areadded to the lubricating oils to give beneficial performance (seeTable 2).5. Interferences5.1 The additive elements found in lubricating oils willaffect the measured intensities from the elements of interest toa varying degree. In general for lubricating oils, the X-radiationemitted by
22、the element of interest is absorbed by the otherelements in the sample matrix. Also, the X-radiation emittedfrom one element can further excite another element. Theseeffects are significant at concentrations varying from 0.03mass % due to the heavier elements to 1 mass % for the lighterelements. The
23、 measured intensity for a given element can bemathematically corrected for the absorption of the emittedradiation by the other elements present in the sample specimen.Suitable internal standards can also compensate for X-rayinter-element effects. If an element is present at significantconcentrations
24、 and an interelement correction for that elementis not employed, the results can be low due to absorption orhigh due to enhancement.6. Apparatus6.1 X-Ray Spectrometer, equipped for soft X-ray detectionof radiation in the range from 1 to 10 A. For optimumsensitivity, the spectrometer is equipped with
25、 the following:6.1.1 X-Ray Generating Tube, with chromium, rhodium, orscandium target. Other targets can also be employed.6.1.2 Helium, purgeable optical path.6.1.3 Interchangeable Crystals, germanium, lithium fluo-ride (LiF200), graphite, or pentaerythritol (PET), or a combi-nation thereof. Other c
26、rystals can also be used.6.1.4 Pulse-Height Analyzer, or other means of energydiscrimination.6.1.5 Detector, flow proportional, or scintillation, or flowproportional and scintillation counter.6.2 Shaker, Mechanical Stirrer, or Ultrasonic Bath, capableof handling from 30-mL to 1-L bottles.6.3 X-Ray D
27、isposable Plastic Cells, with suitable filmwindow. Suitable films include Mylar,3polypropylene, orpolyimid with film thicknesses between 0.25 to 0.35 mil (6.3 to8.8 m).NOTE 1Some films contain contamination of the elements of interest(Mylar in particular). The magnitude of the contamination is asses
28、sed andthe same film batch used throughout the entire analysis.7. Purity of Reagents7.1 Reagent grade chemicals shall be used in all tests.Unless otherwise indicated, it is intended that all reagents shallconform to the specifications of the Committee on Analytical3A registered trademark of E. I. du
29、 Pont de Nemours and Co.TABLE 1 Range of ApplicabilityElement Range, Mass %Barium 0.04-8.5Calcium 0.01-1.0Phosphorus 0.01-0.5Sulfur 0.1-4.0Zinc 0.01-0.6TABLE 2 Lubricants and Additive MaterialsElement Compounds Purpose/ApplicationBarium Sulfonates, Phenates Detergent inhibitors, corrosion inhibitors
30、, detergents, rust inhibitors,automatic transmission fluidsCalcium Sulfonates, Phenates Detergent inhibitors, dispersantsPhosphorus Dithiophosphates, Phosphates phosphites Anti-rusting agents, extreme pressure additives, anti-wearSulfur Base oils, sulfonates, thiophosphates, polysulfidesand other su
31、lfurized componentsDetergents, extreme pressure additives, anti-wearZinc Dialkyldithiophosphates, Dithiocarbamates,Phenolates CarboxylatesAnti-oxidant, corrosion inhibitors, anti-wear additives, detergents,crankcase oils, hypoid gear lubricants, aircraft piston engine oils, turbineoils, automatic tr
32、ansmission fluids, railroad diesel engine oils, brakelubricantsD4927 142Reagents of the American Chemical Society, where suchspecifications are available.4Other grades may be used, pro-vided it is first ascertained that the reagent is of sufficientlyhigh purity to permit its use without lessening th
33、e accuracy ofthe determination.TEST METHOD A (INTERNAL STANDARDPROCEDURE)8. Reagents and Materials8.1 Helium, for optical path of spectrometer.8.2 P-10 Ionization Gas, 90 volume % argon and 10 volume% methane for the flow proportional counter.8.3 Diluent Solvent, a suitable solvent free of metals, s
34、ulfur,and phosphorus (for example, kerosine, white oil, or xylenes).8.4 Internal Standard Materials :8.4.1 Nickel Octoate, preferably containing 5.0 6 0.1mass % nickel. If the nickel concentration is higher or lower(minimum concentration that can be used is 2.5 6 0.1 mass %nickel), the laboratory ne
35、eds to adjust the amount of sampletaken in 9.1 to yield an equivalent nickel concentration level inthe internal standard. Other nickel-containing organic matrices(free of other metals, sulfur, and phosphorus) may be substi-tuted provided the nickel is stable in solution, the concentrationis known (2
36、.5 6 0.1 mass % nickel), and the laboratory canadjust the amount of sample taken in 9.1 to yield an equivalentnickel concentration level in the internal standard if the nickelconcentration does not initially contain 5.0 6 0.1 mass %nickel.NOTE 2Many X-ray tubes emit copper X rays which increase inin
37、tensity with age. This does not present a problem when using copper asan internal standard for zinc providing that frequent calibrations areperformed. No problem exists when using nickel as internal for zinc andnickel is the preferred internal standard material.8.4.2 Titanium 2-Ethylhexoide or Tin O
38、ctoate, preferablycontaining 8.0 6 0.1 mass % titanium or tin. If the titanium ortin concentration is higher or lower (minimum concentrationthat can be used is 4.0 6 0.1 mass % titanium or tin), thelaboratory needs to adjust the amount of sample taken in 9.1 toyield an equivalent titanium or tin con
39、centration level in theinternal standard. Other titanium or tin containing organicmatrices (free of other metals, sulfur, and phosphorus) may besubstituted, provided the titanium or tin is stable in solution,the concentration is known (4.0 6 0.1 mass % titanium ortin), and the laboratory can adjust
40、the amount of sample takenin 9.1 to yield an equivalent titanium or tin concentration levelin the internal standard if the titanium or tin concentration doesnot initially contain 8.0 6 0.1 mass % titanium or tin.8.4.3 Zirconium Octoate, preferably containing 12.0 6 0.1mass % zirconium. If the labora
41、tory uses zirconium octoatewith a lower mass % zirconium concentration level, the labo-ratory needs to evaporate away the petroleum solvent to yielda solution that contains 12.0 6 0.1 mass % zirconium. Otherzirconium containing organic matrices (free of other metals,sulfur, and phosphorus) may be su
42、bstituted, provided thezirconium is stable in solution and the concentration is knownand does not exceed 12.0 6 0.1 mass % zirconium. If thezirconium concentration is 12.0 6 0.1 mass %, the laboratoryneeds to evaporate away the petroleum solvent to yield asolution that contains 12.0 6 0.1 mass % zir
43、conium.8.4.4 Lead Naphthenate, containing 24.0 6 0.1 mass %lead.8.5 Calibration Standard Materials:NOTE 3In addition to calibration standards identified in 8.5.1 8.5.5,single-element or multielement calibration standards may also be preparedfrom materials similar to the samples being analyzed, provi
44、ded thecalibration standards to be used have previously been characterized byindependent primary (for example, gravimetric or volumetric) analyticaltechniques to establish the elemental concentration mass % levels.8.5.1 Barium 2-Ethylhexoide or Sulfonate, with concentra-tions 4 mass % barium and cer
45、tified to better than 60.1 %absolute (95 % confidence limit), so that calibration standardscan be prepared as stated in 10.1.1 and 10.1.2.8.5.2 Calcium Octoate or Sulfonate, with concentrations 4mass % calcium and certified to better than 60.1 % absolute(95 % confidence limit), so that calibration s
46、tandards can beprepared as stated in 10.1.1 and 10.1.2.8.5.3 Bis(2-Ethylhexyl)Hydrogen Phosphate, 97 % purity(9.62 mass % phosphorus). Other phosphorus containing or-ganic matrices (free of other metals) may be substitutedprovided the phosphorus is stable in solution and the concen-tration is 4 mass
47、 % phosphorus and certified to better than60.1 % absolute (95 % confidence limit), so that calibrationstandards can be prepared as stated in 10.1.1 and 10.1.2.8.5.4 Zinc Sulfonate or Octoate, with concentration 4mass % zinc and certified to better than 60.1 % absolute (95 %confidence limit), so that
48、 calibration standards can be preparedas stated in 10.1.1 and 10.1.2.8.5.5 Di-n-Butyl Sulfide, 97 % purity, (21.9 mass % sulfur).Other sulfur containing organic matrices (free of metals) maybe substituted, provided the sulfur is stable in solution and theconcentration is 2 mass % sulfur and certifie
49、d to better than60.1% absolute (95 % confidence limit), so that calibrationstandards can be prepared as stated in 10.1.2.8.6 Quality Control (QC) Samples, preferably are portionsof one or more lubricating oils or additives that are stable andrepresentative of the samples of interest. These QC samplescan be used to check the validity of the testing process andperformance of the instrument as described in Section 12.9. Preparation of Internal Standards9.1 Barium, Calcium, Phosphorus, and ZincDispense 2406 0.5 g of nickel octoate (5.0 6 0.1 mass % nickel), 30 6
