1、Designation:D518721Standard Test Method forDetermination of Crystallite Size(Lc)of Calcined PetroleumCoke by X-Ray Diffraction1This standard is issued under the fixed designation D5187;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,
2、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.Scope*1.1 This test method covers the determination of the meancrystallite thickness of a representative,pulverized samp
3、le ofcalcined petroleum coke by interpretation of a X-ray diffractionpattern produced through conventional X-ray scanning tech-niques.1.2 Calcined petroleum coke contains crystallites of differ-ent thicknesses.This test method covers the determination ofthe average thickness of all crystallites in t
4、he sample byempirical interpretation of the X-ray diffraction pattern.Thecrystallite diameter(La)is not determined by this test method.1.3 The values stated in SI(metric)units are to be regardedas the standard.The inch-pound units given in parentheses areprovided for information purposes only.1.4 Th
5、is 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,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.5 This i
6、nternational standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)
7、Committee.2.Referenced Documents2.1 ASTM Standards:2D6969 Practice for Preparation of Calcined Petroleum CokeSamples for AnalysisD6970 Practice for Collection of Calcined Petroleum CokeSamples for AnalysisE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Metho
8、d3.Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 crystallites,nstacks of graphitic carbon plateletslocated parallel to one another.3.1.2 Lc,nthe mean or average thickness of crystallites ina sample.It is expressed as a linear dimension in angstromunits,A(101nm).3.1.3 hkl(002),n
9、the Miller indices of the crystallineplanes of graphite corresponding to a lattice spacing(d)of3.35.3.1.4 Theta angle,nthe glancing angle produced whena parallel beam of uniform X-rays impinges upon a crystallinelattice.This angle is measured by the X-ray goniometer and isusually expressed in degree
10、s TwoTheta (2).4.Summary of Test Method4.1 A packed sample pulverized to less than 75 m issubjected to a monochromatic X-ray beam and rotated toproduce a diffraction pattern under specific conditions.Thelocation and shape of the peak with hkl=(002)at d=3.35 Ais used to calculate the Lcby manual inte
11、rpretation of the peakor by computer simulation.5.Significance and Use5.1 The crystallinity of petroleum coke,as reflected by theLcvalue,is a general measure of quality affecting suitability forend use and is a function of the heat treatment.5.2 The crystallite thickness is used to determine the ext
12、entof such heat treatment,for example,during calcination.Thevalue of the Lcdetermined is not affected by coke microporo-sity or the presence of foreign,non-crystalline materials suchas dedust oil.6.Apparatus6.1 X-Ray Powder Diffractometer,equipped with an X-raysource,a monochromator or filter for re
13、stricting the wave-length range,a sample holder,a radiation detector,a signalprocessor,and readout(chart or computer memory).The1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products,Liquid Fuels,and Lubricants and is the direct responsibility ofSubcommittee D02.05 on
14、 Properties of Fuels,Petroleum Coke and Carbon Material.Current edition approved Jan.1,2021.Published January 2021.Originallypublished in 1991.Last previous edition approved in 2015 as D5187 10(2015)1.DOI:10.1520/D5187-21.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact A
15、STM 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 standardCopyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocke
16、n,PA 19428-2959.United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.1diffractometer must be capable of rate scanning at 1 2 minor incrementally step scanning at 0.2 2 steps.6.2 Sample Holders,as specified by the manufacturer
