ASTM D8075-16

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Designation: D8075 − 16
Standard Guide for
Categorization of Microstructural and Microtextural Features
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Observed in Optical Micrographs of Graphite
This standard is issued under the fixed designation D8075; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 3.2 Definitions:
3.2.1 accommodation cracks, n—(also referred to as
1.1 This guide covers the identification and the assignment
Mrozowski-like cracks) cracks and voids formed between
of microstructural and microtextural features observed in
basal planes and at domain interfaces throughout the graphite
optical micrographs of graphite. The objective of this guide is
microstructure from thermal contraction of the graphite during
to establish a consistent approach to the categorization of such
carbonization/graphitization (sometimes referred to as calcina-
features to aid unambiguous discussion of optical micrographs
tioncracks),fromchemicaldecompositionoftheliquidcrystal
in the scientific literature. It also provides guidance on speci-
hydrocarbon precursor in graphite manufacture (also referred
men preparation and the compilation of micrographs.
to as calcination cracks) and following cooling after graphiti-
1.2 The values stated in SI units are to be regarded as the
zation(manufacture).Inirradiatedgraphite,theyalsocomprise
standard.
cracks arising from anisotropic responses to irradiation.
1.3 This standard does not purport to address all of the
3.2.2 agglomerate, n—in manufactured carbon and graph-
safety concerns, if any, associated with its use. It is the
ite product technology,compositeparticlecontaininganumber
responsibility of the user of this standard to establish appro-
of grains.
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use. 3.2.3 binder, n—substance such as coal tar pitch or petro-
leum pitch, used to bond the coke or other filler material prior
2. Referenced Documents
to baking.
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2.1 ASTM Standards:
3.2.4 crystallite, n—in manufactured carbon and graphite
D7219 Specification for Isotropic and Near-isotropic
product technology, a region of regular crystalline structure
Nuclear Graphites
having parallel basal planes.
3. Terminology 3.2.5 filler, n—in manufactured carbon and graphite prod-
uct technology,particlesthatcomprisethebaseaggregateinan
3.1 The definitions listed below cover terms used in this
unbaked green-mix formulation (also referred to as coke
guide and apply specifically to the optical microscopy of
particles, grist particles, or filler grains).
graphite. Properties and features not apparent under the optical
microscope are avoided where possible. Definitions may not
3.2.6 filler-binder phase, n—in manufactured carbon and
exactly match those adopted in general scientific usage but
graphite product technology, mix of finely ground filler (flour)
should not be at variance. General terms have not been
and binder comprising the matrix in which the filler is bound.
redefined with graphite-specific meanings or optical
3.2.7 grain, n—in manufactured carbon and graphite, par-
microscopy-specific meanings. As with the identification of
ticle of filler material (usually coke or graphite) in the starting
featuresinmicrographs,somedefinitionshavebecomeunclear
mix formulation. Also referred to as granular material, filler
to differences in usage and this guide provides the basis for a
particle, or aggregate material. The term is also used to
more consistent approach.
describe the general texture of a carbon or graphite body, as in
the descriptions listed below:
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This guide is under the jurisdiction of ASTM Committee D02 on Petroleum
3.2.7.1 coarse grained, adj—containing grains in the start-
Products, Liquid Fuels, and Lubricants and is the direct responsibility of Subcom-
ing mix that are substantially greater than 4 mm in size.
mittee D02.F0 on Manufactured Carbon and Graphite Products.
Current edition approved Dec. 15, 2016. Published February 2017. DOI:
3.2.7.2 medium coarse grained, adj—containing grains in
10.1520/D8075-16.
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the starting mix that are generally less than 4 mm in size.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
3.2.7.3 medium grained, adj—containing grains in the start-
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. ing mix that are generally less than 2 mm in size.
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