ASTM F109-21

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Designation: F109 − 12 (Reapproved 2018) F109 − 21
Standard Terminology Relating to
Surface Imperfections on Ceramics
This standard is issued under the fixed designation F109; the number immediately following the designation indicates the year of original
adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript
epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This terminology describes and illustrates imperfections observed on whitewares and related products. For additional
definitions of terms relating to whitewares and related products, refer to Terminology C242. To observe these defects, examination
shall be performed visually, with or without the aid of a dye penetrant, as described in Test Method C949. Agreement by the
manufacturer and the purchaser regarding specific techniques of observation is strongly recommended.
1.2 This terminology does not cover every defect or imperfection possible for whitewares or related products. The standard is not
intended to be an all inclusive document for ceramic imperfections. New defect types may be created as ceramic processes,
materials, and technology evolve.
1.3 Some of the imperfection photos utilize magnification for clarity in documentation. Unless otherwise noted, typical
observation conditions for detection of tile imperfections/defects shall consist of current ANSI A137.1 viewing criteria for the
specific defect type
1.4 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
C242 Terminology of Ceramic Whitewares and Related Products
C485 Test Method for Measuring Warpage of Ceramic Tile
C949 Test Method for Porosity in Vitreous Whitewares by Dye Penetration
E165E165/E165M Practice for Liquid Penetrant Testing for General Industry
2.2 ANSI Standard:
ANSI A137.1 American National Standards Specifications For Ceramic Tile
3. Terminology
blemish—strained or discolored area attributable to normal composition or forming, or both. (See also inclusion.
This terminology is under the jurisdiction of ASTM Committee C21 on Ceramic Whitewares and Related Products and is the direct responsibility of C21.01Editorial
and Terminology on Nomenclature.
Current edition approved Feb. 1, 2018Feb. 1, 2021. Published February 2018March 2021. Originally approved in 1969. Last previous edition approved 20122018 as
F109 – 12.F109 – 12 (2018). DOI: 10.1520/F0109-12R18.10.1520/F0109-21.
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 Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036, http://www.ansi.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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)
3.1 Definitions:
blemish—strained or discolored area attributable to normal composition or forming, or both; see Fig. 1 in addition to the image
below. (See also inclusion.)
blister—bubble or gaseous inclusion at the surface which if broken could form a pit, pock, or hole; see Fig. 2 in addition to the
image below.
FIG. 1 Blemish
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FIG. 2 Blister
burr—fragment of excess material or foreign particle adhering to the surface; the photographed example was the re-
sult of debris from a ware explosion during firing; see Fig. 3 in addition to the image below.
camber—a single arch of curvature; also called warpage when related to ceramic tile and defined as ANSI A137.1; warpage
measurement for ceramic tile shall be evaluated with Test Method C485; see Fig. 4 in addition to the image below. (See also
waviness.)
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FIG. 3 Burr
chip, basic—area along an edge or corner where the material has broken off; see Fig. 5 in addition to the image below.
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FIG. 4 Camber
where:
w = width
l = length, and
d = depth.
chip, closed —fractured area on the edge or corner when the material has not broken off; see Fig. 6 in addition to the image
below. (Syn. potential chip)
where:
W = width
l = length, and
d = depth.
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FIG. 5 Chip, Basic
chip, pre-print or pre-glaze—Surface damage that occurs prior to decorative glazing or printing; these may occur before or
after the base color; the photographed examples in Fig. 7 show chips that were printed over with graphic, making them more
difficult to detect; the upper picture of in Fig. 7 is a tile that was chipped after the base glaze, but prior to printing; the lower
picture in Fig. 7 is a tile that was chipped prior to the initial glaze.
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FIG. 5 Chip, Basic (continued)
crack, basic—line of fracture without complete separation; see Fig. 8 in addition to the image below.
crack, (cooling) dunting—a type of fracture that consists of long curving cracks with smooth and shiny edges; these tend to
happen in the cooling area of the kiln; this is most often caused by the beta to alpha quartz transition around 573 °C; the
transition causes a volume change between the crystal structures and corresponding internal stresses can lead to cracking; the
fracture face tends to be smooth and slightly glossy compared to other types of fractures; these may or may not originate from
a pre-existing flaw in the product; these are similar in appearance and cause to a crack, (cooling) thermal shock; see Fig. 9
in addition to the image below.
crack, (cooling) thermal shock—a cracky very similar in appearance to crack, (cooling) dunting as it is also the result of
internal stress; however, this type of crack requires a thermal gradient in the ware to occur; the result of low thermal conductivity
and high thermal expansion; the resultant stresses cause cracking when the stress exceed the tensile strength of the material; this
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FIG. 6 Chip, Closed
may occur on the cooling cycle of product in a kiln; the photographs in Fig. 10 were the result of a forced thermal shock test
that was conducted around 400 °C to avoid the quartz inversion effect.
crack, liquid contamination in greenware—water, oil, or other liquid gets into a localized region of the title prior to firing;
on drying or firing it can cause an area of localized cracking; see Fig. 11.
crack, drying—typically small fissures that form 90 °C to the tile edge; these can occur when the greenware drying is uneven
or too rapid; these may only be present on the glazed surface, or span through the body as well; the image at the bottom is a
forced drying crack in a clay sample; see Fig. 12.
crack green—typically a fissure that does not extend far into the body; the causes can be impact damage, flexing, or other
stresses to the pre-fired piece prior to firing; the crack tends to widen during the firing; the fracture edges tend to be rougher
than other types of cracks (see Fig. 13, bottom photo); this may or may not seed a cooling crack.
crawling—a parting and contraction of the glaze on the surface of ceramic ware during drying or firing, resulting in unglazed
areas bordered by coalesced glaze; see Fig. 14 in addition to the image below.
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FIG. 7 Chip, Pre{print or Pre-glaze
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FIG. 8 Crack, Basic
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FIG. 9 Crack, (Cooling) Dunting
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FIG. 9 Crack, (Cooling) Dunting (continued)
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FIG. 10 Crack, (Cooling) Thermal Shock
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FIG. 11 Crack, Liquid Contaminaon in Greenware
crazing—the cracking that occurs in fired glazes or other ceramic coatings as a result of tensile stresses; some surfaces are
intentionally crazed for aesthetic reasons; in these cases crazing would not be considered an imperfection or defect; see Fig. 15
in addition to the image below.
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FIG. 11 Crack, Liquid Contaminaon in Greenware (continued)
delaminaon—cracks that tend to run horizontal to the tile thickness; they may or may not break the surfaces; when broken, the
areas tend to shale off in large flakes; this defect occurs during the body forming process (pressing or extrusion); see Fig. 16.
divot—a shallow depression; this can be the result of a pinhole or pit that was subjected to polishing; the result is a roughly
circular halo effect; the phenomena can occur flat or as a very shallow depression; this defect is often more visible under glare
conditions; see Fig. 17.
fin—fine feather-edge protrusion from the surface; on tile this can occur when the edges miss cleaning after pressing; on glazed
products, the fin can shear off and expose the layer underneath the glaze; see Fig. 18 in addition to the following image. (Syn.
flash)
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FIG. 12 Crack, Drying
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FIG. 12 Crack, Drying (continued)
flow line—one or more streaks distinguished by a difference in light reflectance from the surrounding area, charateristic of
injection-molded parts. (See also weld mark.)
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FIG. 13 Crack, Green
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FIG. 13 Crack, Green (continued)
FIG. 14 Crawling
grinding mark—a pattern of fine striations or scoring, usually directional, resulting from machining, as distinct from surface
marks; see Fig. 19.
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FIG. 15 Crazing
FIG. 16 Delaminaon
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FIG. 16 Delaminaon (continued)
hole—a deep depression or void, the bottom of which is not visible by normal (20/20) vision under 200 fc illumination; see Fig.
20 in addition to the image below.
inclusion—embedded foreign material or a stain other than from normal composition or forming, or both; see Fig. 21. (See also
blemish).
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FIG. 17 Divot
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FIG. 18 Fin
kink—a type of waviness occurring interior to the edges, not to be confused with the more abrupt departures as ridges or surface
marks. (See also waviness.)
lump—a raised area on the surface having the appearance of being solid; see Fig. 22.
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FIG. 18 Fin (continued)
metal marks—lines on the surface of a ceramic body or glaze caused by drawing a hard metal, such as a knife, across the
surface; see Fig. 23 in addition to the image below.
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FIG. 19 Grinding Mark
peeling—compressive stresses in a fired glaze or other ceramic coating of sufficient magnitude to exceed the strength of
adhesion between the glaze and the body.
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This photography is a magnified hole that was formed during the burn of a contaminant.
FIG. 20 Hole
FIG. 21 Inclusion
pinholes—imperfections in the surface of a ceramic glaze resembling pin pricks; these tend to be shallow and the bottom may
be visible; visibility is sometimes enhanced under glare like conditions; see Fig. 24 in addition to the image below.
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FIG. 21 Inclusion (continued)
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FIG. 22 Lump
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FIG. 23 Metal Marks
pit—a shallow depression or crater in which all surfaces are visible by normal (20/20) vision under 200 fc of illumination; the
images in Fig. 25 are magnified for publication; the top photo is a cross section of a pit, the bottom photo is a top view.
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The bottom image is magnified for clarity in this publication.
FIG. 24 Pinholes
pock—a partially closed surface cavity; see Fig. 26 in addition to the image below.
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The top photo is a cross section of a pit, the bottom picture is a top view.
FIG. 25 Pit
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FIG. 26 Pock
where:
w = width.
pore—an internal cavity which may be exposed by cutting, grinding, or polishing to become a pit, pock, or hole; see Fig. 27
in addition to the image below.
This photograph is a cross section of a pore in a porcelain body.
FIG. 27 Pore
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porous area—an area that will retain dye when tested in accordance with Practice E165/E165M and, if broken through at the
porous area, will show evidence of dye penetration into the body; see Fig. 28 in addition to the image below.
FIG. 28 Porous Area
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ridge—long, narrow protrusion on any surface.
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rim—a protrusion, usually of base material, bordering either partially or completelly a hole, pit, or pock; see Fig. 29 in addition
to the image below.
speck—a discrete particle of unreacted or unwanted material in a ceramic body or glaze; see Fig. 30 in addition to the image
below.
FIG. 29 Rim
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FIG. 30 Speck
straightness of sides—the deviation from straightness of the center of the side in the plane of the tile, as measured by a wedgi
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