ASTM_D_8075_-_16_2021.pdf

Designation:D807516(Reapproved 2021)Standard Guide forCategorization of Microstructural and Microtextural FeaturesObserved in Optical Micrographs of Graphite1This standard is issued under the fixed designation D8075;the number immediately following the designation 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.1.Scope1.1 This guide covers the identification and the assignmentof microstructural and microtextural features observed inoptical micrographs of graphite.The objective of this guide isto establish a consistent approach to the categorization of suchfeatures to aid unambiguous discussion of optical micrographsin the scientific literature.It also provides guidance on speci-men preparation and the compilation of micrographs.1.2 The values stated in SI units are to be regarded as thestandard.1.3 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,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.4 This international 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)Committee.2.Referenced Documents2.1 ASTM Standards:2D7219 Specification for Isotropic and Near-isotropicNuclear Graphites3.Terminology3.1 The definitions listed below cover terms used in thisguide and apply specifically to the optical microscopy ofgraphite.Properties and features not apparent under the opticalmicroscope are avoided where possible.Definitions may notexactly match those adopted in general scientific usage butshould not be at variance.General terms have not beenredefinedwithgraphite-specificmeaningsoropticalmicroscopy-specific meanings.As with the identification offeatures in micrographs,some definitions have become unclearto differences in usage and this guide provides the basis for amore consistent approach.3.2 Definitions:3.2.1 accommodation cracks,n(also referred to asMrozowski-like cracks)cracks and voids formed betweenbasal planes and at domain interfaces throughout the graphitemicrostructure from thermal contraction of the graphite duringcarbonization/graphitization(sometimes referred to as calcina-tion cracks),from chemical decomposition of the liquid crystalhydrocarbon precursor in graphite manufacture(also referredto as calcination cracks)and following cooling after graphiti-zation(manufacture).In irradiated graphite,they also comprisecracks arising from anisotropic responses to irradiation.3.2.2 agglomerate,nin manufactured carbon and graph-ite product technology,composite particle containing a numberof grains.3.2.3 binder,nsubstance such as coal tar pitch or petro-leum pitch,used to bond the coke or other filler material priorto baking.3.2.4 crystallite,nin manufactured carbon and graphiteproduct technology,a region of regular crystalline structurehaving parallel basal planes.3.2.5 filler,nin manufactured carbon and graphite prod-uct technology,particles that comprise the base aggregate in anunbaked green-mix formulation(also referred to as cokeparticles,grist particles,or filler grains).3.2.6 filler-binder phase,nin manufactured carbon andgraphite product technology,mix of finely ground filler(flour)and binder comprising the matrix in which the filler is bound.3.2.7 grain,nin manufactured carbon and graphite,par-ticle of filler material(usually coke or graphite)in the startingmix formulation.Also referred to as granular material,fillerparticle,or aggregate material.The term is also used todescribe the general texture of a carbon or graphite body,as inthe descriptions listed below:1This guide is under the jurisdiction of ASTM Committee D02 on PetroleumProducts,Liquid Fuels,and Lubricants and is the direct responsibility of Subcom-mittee D02.F0 on Manufactured Carbon and Graphite Products.Current edition approved April 1,2021.Published May 2021.Originallyapproved in 2016.Last previous edition approved in 2016 as D8075 16.DOI:10.1520/D8075-16R21.2For referenced 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.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,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 Recommendatio