ASTM C242-01(2007)
(Terminology)Standard Terminology of Ceramic Whitewares and Related Products
Standard Terminology of Ceramic Whitewares and Related Products
SCOPE
1.1 This terminology pertains to the terminology used in ceramic whitewares and related products.
1.2 Words adequately defined in standard dictionaries are not included. Included are words that are peculiar to this industry. Double words, hyphenated words, or phrases are listed alphabetically under the first word; additional important words are cross-referenced.
1.3 For definitions of terms relating to surface imperfections on ceramics, refer to Terminology F 109.
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Designation: C242 − 01(Reapproved 2007)
Standard Terminology of
Ceramic Whitewares and Related Products
This standard is issued under the fixed designation C242; 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 absorbance—the logarithm of that fraction of an incident light
beam that is dissipated in the sample, being neither trans-
1.1 This terminology pertains to the terminology used in
mitted nor reflected.
ceramic whitewares and related products.
absorbed moisture—water held mechanically in the material
1.2 Words adequately defined in standard dictionaries are
and having physical properties not substantially different
not included. Included are words that are peculiar to this
from ordinary water at the same temperature and pressure.
industry. Double words, hyphenated words, or phrases are
listed alphabetically under the first word; additional important
absorption—(1) the relationship of the weight of the water
words are cross-referenced.
absorbed by a ceramic specimen, subjected to prescribed
immersion procedure, to the weight of the dry specimen.
1.3 For definitions of terms relating to surface imperfec-
tions on ceramics, refer to Terminology E109. (2) the capacity of a substance to take up a substance,
usually a liquid or gas, with the formation of an apparently
homogeneous mixture.
2. Referenced Documents
2.1 ASTM Standards:
adsorption—the capacity of a substance to accept and retain
D1129 Terminology Relating to Water
on its surface a layer of another substance, usually a gas or
E109 Method for Dry Powder Magnetic Particle Inspection;
a liquid.
Replaced by E 709 (Withdrawn 1981)
agglomerate—a jumbled mass or collection of two or more
E180 Practice for Determining the Precision of ASTM
particles or aggregates, or a combination thereof, held
Methods for Analysis and Testing of Industrial and Spe-
together by relatively weak cohesive forces caused by weak
cialty Chemicals (Withdrawn 2009)
chemical bonding or an electrostatic surface charge gener-
F465 Practice for Developing Precision and Accuracy Data
ated by handling or processing.
on ASTM Method for the Analysis of Meat and Meat
DISCUSSION—Common usage in powder technology (and British
Products (Withdrawn 1993)
Standard BS 2955BS 2955Glossary of Terms Relating to Powders) has
2.2 British Standard:
the terms “aggregate” and “agglomerate” interchanged in meaning
BS 2955 Glossary of Terms Relating to Powders
from the definitions presented here, and care must be taken to
determine in context which definition is in use.
3. Terminology
aggregate—a dense mass of particles held together by strong
intermolecular or atomic cohesive forces that is stable to
absolute or true density—See absolute or true density under
normal mixing techniques, including high-speed stirring and
density.
ultrasonics.
alumina porcelain—See alumina porcelain under porcelain.
This terminology is under the jurisdiction of ASTM Committee C21 on
alumina whiteware—See alumina whiteware under ceramic
Ceramic Whitewares and Related Productsand is the direct responsibility of
whiteware.
Subcommittee C21.01 on Editorial and Teminology.
Current edition approved Nov. 1, 2007. Published January 2008. Originally andalusite—a polymorph, along with sillimanite and kyanite,
approved in 1950. Last previous edition approved in 2001 as C242 – 01. DOI:
of composition Al O ·SiO which on firing dissociates to
2 3 2
10.1520/C0242-01R07.
yield principally mullite.
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
apparent or pycnometric density—See apparent or pycnomet-
Standards volume information, refer to the standard’s Document Summary page on
ric density under density.
the ASTM website.
The last approved version of this historical standard is referenced on
apparent porosity—See apparent porosity under porosity.
www.astm.org.
average particle size—a single value representing the entire
Available from British Standards Institute, 2 Park St., London, England
W1A 2B5. particle-size distribution.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C242 − 01 (2007)
DISCUSSION—It is essential to specify the basis under which the
bright glaze—See bright glaze under glaze.
average is obtained.
calcine—aceramicmaterialormixturefiredtolessthanfusion
for use as a constituent in a ceramic composition.
ball clay—a secondary clay, commonly characterized by the
presence of organic matter, high plasticity, high dry strength,
capillary action—thephenomenonofintrusionofaliquidinto
long vitrification range, and a light color when fired.
interconnected small voids, pores, and channels in a solid,
resulting from surface tension.
ball milling—a method of grinding and mixing material, with
or without liquid, in a rotating cylinder or conical mill
cassiterite (SnO )—an inorganic mineral of the tetragonal
partially filled with grinding media such as balls or pebbles.
form used as a source of tin and tin oxide.
basalt ware—a black unglazed vitreous ceramic ware having
casting—a process for forming ceramic ware by introducing a
the appearance of basalt rock.
body slip into a porous mold which absorbs sufficient water
(or other liquid) from the slip to produce a semirigid article.
Belleek china—a highly translucent whiteware composed of a
drain casting (hollow casting)—forming ceramic ware by
body containing a significant amount of frit and normally
introducing a body slip into an open porous mold, and then
having a luster glaze.
draining off the remaining slip when the case has reached the
bentonite—a distinct type of fine-grained clay containing not
desired thickness.
less than 85 % montmorillionite clay having the formula
solid casting—forming ceramic ware by introducing a body
(OH) Si Al O nH O and composed of units made up of
4 8 4 20 2
slip into a porous mold which usually consists of two major
two silica tetrahedral sheets with a central alumina octahe-
sections,onesectionformingthecontouroftheoutsideandthe
dral sheet.
other forming the contour of the inside of the ware and
allowing a solid cast to form between the two mold faces.
beryllium oxide (beryllia) (BeO)—an inorganic material of
exceptionally high thermal conductivity which is toxic in the
ceramic article—an article having a glazed or unglazed body
powder form.
of crystalline or partly crystalline structure, or of glass,
which body is produced from essentially inorganic, nonme-
bias—a constant or systematic error, as opposed to a random
tallic substances and either is formed from a molten mass
error, manifesting itself as a persistent positive or negative
which solidifies on cooling, or is formed and simultaneously
deviation of the method average from the accepted reference
or subsequently matured by the action of the heat.
value. E180; F465
ceramic mosaic tile—an unglazed tile formed by either the
binder—a cementing medium; either a material added to the
1 3
dust-pressedorplasticmethod,usually ⁄4to ⁄8in.(6.4to9.5
mixture to increase the green or dry strength as compacted,
mm) thick, and having a facial area of less than 6 in. (39
and which may be expelled during sintering or calcining, or
cm ) and which is usually mounted on sheets approximately
a material added to a mixture for the purpose of cementing
1 by 2 ft (0.3 by 0.6 m) to facilitate setting.
together particles.
DISCUSSION—Ceramic mosaic tile may be of either porcelain or
DISCUSSION—A binder may be either a permanent addition, or a
natural clay composition and may be either plain or with an abrasive
temporary additive to a ceramic product.
mixture throughout.
bisque fire—See bisque fire under firing.
ceramic paste—a French term synonymous with “ceramic
blackbody—the ideal, perfect emitter and absorber of thermal
body.”
radiation which emits radiant energy at the maximum rate
ceramic process—the production of articles or coatings from
possible,asaconsequenceofitstemperature,andabsorbsall
essentially inorganic, nonmetallic materials, the article or
incident radiation.
coating being made permanent and suitable for utilitarian
blistering—the development during firing of enclosed or
anddecorativepurposesbytheactionofheatattemperatures
broken macroscopic vesicles or bubbles in a body, or in a
sufficient to cause sintering, solid-state reactions, bonding,
glaze or other coating.
or conversion partially or wholly to the glassy state.
bloating—substantial swelling produced by a heat treatment
ceramics—a general term applied to the art or technique of
that causes the formation of a vesicular structure.
producing articles by a ceramic process, or to the articles so
produced.
blunging—the wet process of blending, or suspending ceramic
material in liquid by agitation.
ceramic whiteware—a fired ware consisting of a glazed or
unglazedceramicbodywhichiscommonlywhiteandoffine
body—the structural portion of a ceramic article, or the
texture, designating such product classifications as tile,
material or mixture from which it is made.
china, porcelain, semivitreous ware and earthenware.
bone ash—calcined bone consisting essentially of calcium
alumina whiteware— any ceramic whiteware in which
phosphate.
alumina (Al O ) is an essential crystalline phase.
2 3
bone china—a translucent china made from a ceramic white- cordierite whiteware—any ceramic whiteware in which
ware body composition containing a minimum of 25 % bone cordierite (2MgO·2Al O ·5SiO ) is the essential crystalline
2 3 2
ash. phase.
C242 − 01 (2007)
forsterite whiteware—any ceramic whiteware in which for- comminution—the act or process of reduction of particle size
sterite (2MgO·SiO ) is the essential crystalline phase. with attendant increase in surface area and population of
particles, usually but not necessarily by grinding, milling, or
steatite whiteware—any ceramic whiteware in which mag-
pulverizing.
nesium metasilicate (MgO·SiO ) is the essential crystalline
phase.
conductive ceramic tile—tile made from special body com-
titania whiteware—any ceramic whiteware in which titania positions or by methods that result in specific properties of
(TiO ) is the essential crystalline phase. electrical conductivity while retaining other normal physical
properties of ceramic tile.
zircon whiteware—any ceramic whiteware in which zircon
(ZrO ·SiO ) is the essential crystalline phase.
2 2
connected porosity—See connected porosity under porosity.
cordierite porcelain—See cordierite porcelain under porce-
chemical porcelain—See chemical porcelain under porcelain.
lain.
china—aglazedorunglazedvitreousceramicwhitewaremade
cordierite whiteware—See cordierite whiteware under ce-
by the china process and used for nontechnical purposes,
ramic whiteware.
designating such products as dinnerware, sanitary ware, and
corundum—a naturally occurring hexagonal mineral of the
artware when they are vitreous. (See also bone china.)
compositionAl O ,whichcanalsobepreparedsynthetically
2 3
china clay—See kaolin.
to high purity; noted for its hardness (9 on Mohs scale) and
china process—the method of producing glazed ware by
refractoriness (M.P. = 2045°C).
which the ceramic body is fired to maturity, following which
DISCUSSION—It forms the gem varieties ruby and sapphire with
the glaze is applied and matured by firing at a lower
appropriate impurities. It may contain associated minerals such as
diaspore or various silicates, or both. Commonly coarsely crystalline,
temperature.
sometimes microcrystalline.
china sanitary ware (sanitary plumbing fixtures)—glazed,
covering power—the ability of a glaze to cover the surface of
vitrified whiteware fixtures having a sanitary service func-
the fired ware uniformly and completely.
tion.
crawling—apartingandcontractionoftheglazeonthesurface
clay—a natural mineral agglomerate, consisting essentially of
of ceramic ware during drying or firing, resulting in un-
hydrousaluminumsilicates;plasticwhensufficientlywetted,
glazed areas bordered by coalesced glaze.
rigid when dried en masse, and vitrified when fired to a
sufficiently high temperature.
crazing—the cracking that occurs in fired glazes or other
ceramic coatings as a result of tensile stresses. May also
clear glaze—See clear glaze under glaze.
occur in the surface portion of uncoated (unglazed) white-
closed porosity—See closed porosity under porosity.
ware bodies.
coefficient of friction—the ratio of the parallel component of
force required to overcome or have a tendancy to overcome
crystalline glaze—See crystalline glaze under glaze.
the resistance to relative motion of two surfaces in physical
deagglomeration—the process of breaking down, usually by
contact one with another, but otherwise unconstrained, to the
physicalmeans,themassesofparticlesthatareheldtogether
normal component of the force—usually the force as a result
by relatively weak cohesive forces resulting in a final system
of gravity—applied through the object which tends to cause
of aggregates or primary particles, or both.
the friction.
deairing—the process of removing entrapped air, or absorbed
color difference—(1) the magnitude and character of the
airfromamassorslurry,usuallybyapplicationofavacuum.
difference between two colors, described by such terms as
decorated—adorned, embellished, or made more attractive by
redder, bluer, lighter, darker, grayer, or cleaner. (2) the
means of color or surface detail.
magnitude and direction of the difference between a sample
and a standard, computed from tristimulus values, or chro-
decorating fire—See decorating fire under firing.
maticity coordinates and luminance factor, by means of a
decoration:—
specified set of color difference equations.
inglaze decoration—a ceramic decoration applied on the
surface of an unfired glaze and matured with the glaze.
color space—a three dimensional arrangement for represent-
ing all possible colors; for example, in the color space
overglaze decoration—a ceramic or metallic decoration
defined by the color scales L, a, and b used to describe the
applied and fired on the previously glazed surface of ceramic
color of opaque specimens, scale L is a measure of lightness,
ware.
a is a measure of redness (plus) or greenness (minus), and b
polychrome decoration—a multicolor decoration.
is a measure of yellowness (plus) or blueness (minus).
underglaze decoration—a ceramic decoration applied di-
color standard—a plaque or other physical standard of estab-
rectlyonthesurfaceofceramicwarean
...
This document is not anASTM standard and is intended only to provide the user of anASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation:C242–00a Designation:C242–01 (Reapproved 2007)
Standard Terminology of
Ceramic Whitewares and Related Products
This standard is issued under the fixed designation C 242; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This terminology pertains to the terminology used in ceramic whitewares and related products.
1.2 Words adequately defined in standard dictionaries are not included. Included are words that are peculiar to this industry.
Double words, hyphenated words, or phrases are listed alphabetically under the first word; additional important words are
cross-referenced.
1.3 For definitions of terms relating to surface imperfections on ceramics, refer to Terminology F 109.
2. Referenced Documents
2.1 ASTM Standards:
D 1129 Terminology Relating to Water
E 109 Method for Dry Powder Magnetic Particle Inspection
E 180Practice for Determining the Precision of ASTM Methods for Analysis and Testing of Industrial Chemicals
F109Terminology Relating to Surface Imperfections on Ceramics Practice for Determining the Precision of ASTM Methods
for Analysis and Testing of Industrial and Specialty Chemicals
F 465 Recommended Practice for Developing Precision and Accuracy Data on ASTM MethodsMethod for the Analysis of
Meat and Meat Products
2.2 British Standard:
BS 2955 Glossary of Terms Relating to Powders
3. Terminology
absolute or true density—See absolute or true density under density.
absorbance—the logarithm of that fraction of an incident light beam that is dissipated in the sample, being neither transmitted nor
reflected.
absorbed moisture—water held mechanically in the material and having physical properties not substantially different from
ordinary water at the same temperature and pressure.
absorption—(1) the relationship of the weight of the water absorbed by a ceramic specimen, subjected to prescribed immersion
procedure, to the weight of the dry specimen.
(2) the capacity of a substance to take up a substance, usually a liquid or gas, with the formation of an apparently
homogeneous mixture.
adsorption—the capacity of a substance to accept and retain on its surface a layer of another substance, usually a gas or a liquid.
agglomerate—a jumbled mass or collection of two or more particles or aggregates, or a combination thereof, held together by
relatively weak cohesive forces caused by weak chemical bonding or an electrostatic surface charge generated by handling or
processing.
DISCUSSION—Common usage in powder technology (and British Standard BS 2955) has the terms “aggregate” and “agglomerate” interchanged in
meaning from the definitions presented here, and care must be taken to determine in context which definition is in use.
This terminology is under the jurisdiction of ASTM Committee C-21 on Ceramic Whitewares and Related Products and is the direct responsibility of Subcommittee
C21.01 on Nomenclature.
Current edition approved June 10, 2000. Published August 2000. Originally published as C242–50T. Last previous edition C242–99a.
This terminology is under the jurisdiction of ASTM Committee C21 on Ceramic Whitewares and Related Products and is the direct responsibility of Subcommittee
C21.01 on Editorial and Teminology.
Current edition approved Nov. 1, 2007. Published January 2008. Originally approved in 1950. Last previous edition approved in 2001 as C 242 – 01.
For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
, Vol 11.01.volume information, refer to the standard’s Document Summary page on the ASTM website.
Annual Book of ASTM Standards, Vol 15.05.
Withdrawn.
Annual Book of ASTM Standards, Vol 15.02.
Available from British Standards Institute, 2 Park St., London, England W1A 2B5.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
C242–01 (2007)
aggregate—a dense mass of particles held together by strong intermolecular or atomic cohesive forces that is stable to normal
mixing techniques, including high-speed stirring and ultrasonics.
alumina porcelain— See alumina porcelain under porcelain.
alumina whiteware— See alumina whiteware under ceramic whiteware.
andalusite—a polymorph, along with sillimanite and kyanite, of composition Al O ·SiO which on firing dissociates to yield
2 3 2
principally mullite.
apparent or pycnometric density—See apparent or pycnometric density under density.
apparent porosity— See apparent porosity under porosity.
average particle size—a single value representing the entire particle-size distribution.
DISCUSSION—It is essential to specify the basis under which the average is obtained.
ball clay—a secondary clay, commonly characterized by the presence of organic matter, high plasticity, high dry strength, long
vitrification range, and a light color when fired.
ball milling—amethodofgrindingandmixingmaterial,withorwithoutliquid,inarotatingcylinderorconicalmillpartiallyfilled
with grinding media such as balls or pebbles.
basalt ware—a black unglazed vitreous ceramic ware having the appearance of basalt rock.
Belleek china—a highly translucent whiteware composed of a body containing a significant amount of frit and normally having
a luster glaze.
bentonite—a distinct type of fine-grained clay containing not less than 85 % montmorillionite clay having the formula
(OH) Si Al O nH O and composed of units made up of two silica tetrahedral sheets with a central alumina octahedral sheet.
8 4 20 2
beryllium oxide (beryllia) (BeO)—an inorganic material of exceptionally high thermal conductivity which is toxic in the powder
form.
bias—a constant or systematic error, as opposed to a random error, manifesting itself as a persistent positive or negative deviation
of the method average from the accepted reference value. E 180; F 465
binder—acementingmedium;eitheramaterialaddedtothemixturetoincreasethegreenordrystrengthascompacted,andwhich
may be expelled during sintering or calcining, or a material added to a mixture for the purpose of cementing together particles.
DISCUSSION—A binder may be either a permanent addition, or a temporary additive to a ceramic product.
bisque fire—See bisque fire under firing.
blackbody—the ideal, perfect emitter and absorber of thermal radiation which emits radiant energy at the maximum rate possible,
as a consequence of its temperature, and absorbs all incident radiation.
blistering—the development during firing of enclosed or broken macroscopic vesicles or bubbles in a body, or in a glaze or other
coating.
bloating—substantial swelling produced by a heat treatment that causes the formation of a vesicular structure.
blunging—the wet process of blending, or suspending ceramic material in liquid by agitation.
body—the structural portion of a ceramic article, or the material or mixture from which it is made.
bone ash—calcined bone consisting essentially of calcium phosphate.
bone china—a translucent china made from a ceramic whiteware body composition containing a minimum of 25 % bone ash.
bright glaze—See bright glaze under glaze.
calcine—a ceramic material or mixture fired to less than fusion for use as a constituent in a ceramic composition.
capillary action—thephenomenonofintrusionofaliquidintointerconnectedsmallvoids,pores,andchannelsinasolid,resulting
from surface tension.
cassiterite (SnO )—an inorganic mineral of the tetragonal form used as a source of tin and tin oxide.
casting—aprocessforformingceramicwarebyintroducingabodyslipintoaporousmoldwhichabsorbssufficientwater(orother
liquid) from the slip to produce a semirigid article.
drain casting (hollow casting)—forming ceramic ware by introducing a body slip into an open porous mold, and then draining
off the remaining slip when the case has reached the desired thickness.
solid casting— forming ceramic ware by introducing a body slip into a porous mold which usually consists of two major
sections, one section forming the contour of the outside and the other forming the contour of the inside of the ware and allowing
a solid cast to form between the two mold faces.
ceramic article—an article having a glazed or unglazed body of crystalline or partly crystalline structure, or of glass, which body
is produced from essentially inorganic, nonmetallic substances and either is formed from a molten mass which solidifies on
cooling, or is formed and simultaneously or subsequently matured by the action of the heat.
1 3
⁄4 to ⁄8 in. (6.4 to 9.5 mm)
ceramic mosaic tile—an unglazed tile formed by either the dust-pressed or plastic method, usually
2 2
thick, and having a facial area of less than 6 in. (39 cm ) and which is usually mounted on sheets approximately 1 by 2 ft (0.3
by 0.6 m) to facilitate setting.
DISCUSSION—Ceramic mosaic tile may be of either porcelain or natural clay composition and may be either plain or with an abrasive mixture
throughout.
C242–01 (2007)
ceramic paste—a French term synonymous with “ceramic body.”
ceramic process—the production of articles or coatings from essentially inorganic, nonmetallic materials, the article or coating
being made permanent and suitable for utilitarian and decorative purposes by the action of heat at temperatures sufficient to
cause sintering, solid-state reactions, bonding, or conversion partially or wholly to the glassy state.
ceramics—a general term applied to the art or technique of producing articles by a ceramic process, or to the articles so produced.
ceramic whiteware—a fired ware consisting of a glazed or unglazed ceramic body which is commonly white and of fine texture,
designating such product classifications as tile, china, porcelain, semivitreous ware and earthenware.
alumina whiteware— any ceramic whiteware in which alumina (Al O ) is an essential crystalline phase.
2 3
cordierite whiteware—any ceramic whiteware in which cordierite (2MgO·2Al O ·5SiO ) is the essential crystalline phase.
2 3 2
forsterite whiteware—any ceramic whiteware in which forsterite (2MgO·SiO ) is the essential crystalline phase.
steatite whiteware—any ceramic whiteware in which magnesium metasilicate (MgO·SiO ) is the essential crystalline phase.
titania whiteware— any ceramic whiteware in which titania (TiO ) is the essential crystalline phase.
zircon whiteware— any ceramic whiteware in which zircon (ZrO ·SiO ) is the essential crystalline phase.
2 2
chemical porcelain— See chemical porcelain under porcelain.
china—a glazed or unglazed vitreous ceramic whiteware made by the china process and used for nontechnical purposes,
designating such products as dinnerware, sanitary ware, and artware when they are vitreous. (See also bone china.)
china clay—See kaolin.
china process—the method of producing glazed ware by which the ceramic body is fired to maturity, following which the glaze
is applied and matured by firing at a lower temperature.
china sanitary ware (sanitary plumbing fixtures)—glazed, vitrified whiteware fixtures having a sanitary service function.
clay—a natural mineral agglomerate, consisting essentially of hydrous aluminum silicates; plastic when sufficiently wetted, rigid
when dried en masse, and vitrified when fired to a sufficiently high temperature.
clear glaze—See clear glaze under glaze.
closed porosity—See closed porosity under porosity.
coefficient of friction—the ratio of the parallel component of force required to overcome or have a tendancy to overcome the
resistance to relative motion of two surfaces in physical contact one with another, but otherwise unconstrained, to the normal
component of the force—usually the force as a result of gravity—applied through the object which tends to cause the friction.
color difference—(1) the magnitude and character of the difference between two colors, described by such terms as redder, bluer,
lighter, darker, grayer, or cleaner. (2) the magnitude and direction of the difference between a sample and a standard, computed
from tristimulus values, or chromaticity coordinates and luminance factor, by means of a specified set of color difference
equations.
color space—a three dimensional arrangement for representing all possible colors; for example, in the color space defined by the
color scales L, a, and b used to describe the color of opaque specimens, scale L is a measure of lightness, a is a measure of
redness (plus) or greenness (minus), and b is a measure of yellowness (plus) or blueness (minus).
color standard—a plaque or other physical standard of established color value, against which standardization of an instrument
is made.
DISCUSSION—It may be a reference standard at a calibration laboratory, a transfer standard used to calibrate a particular instrument, or a working
standard for routine use.
comminution—the act or process of reduction of particle size with attendant increase in surface area and population of particles,
usually but not necessarily by grinding, milling, or pulverizing.
conductive ceramic tile—tile made from special body compositions or by methods that result in specific properties of electrical
conductivity while retaining other normal physical properties of ceramic tile.
connected porosity— See connected porosity under porosity.
cordierite porcelain— See cordierite porcelain under porcelain.
cordierite whiteware— See cordierite whiteware under ceramic whiteware.
corundum—a naturally occurring hexagonal mineral of the compositionAl O , which can also be prepared synthetically to high
2 3
purity; noted for its hardness (9 on Mohs scale) and refractoriness (M.P. = 2045°C).
DISCUSSION—Itformsthegemvarietiesrubyandsapphirewithappropriateimpurities.Itmaycontainassociatedmineralssuchasdiasporeorvarious
silicates, or both. Commonly coarsely crystalline, sometimes microcrystalline.
covering power—the ability of a glaze to cover the surface of the fired ware uniformly and completely.
crawling—apartingandcontractionoftheglazeonthesurfaceofceramicwareduringdryingorfiring,resultinginunglazedareas
bordered by coalesced glaze.
crazing—the cracking that occurs in fired glazes or other ceramic coatings as a result of tensile stresses. May also occur in the
surface portion of uncoated (unglazed) whiteware bodies.
crystalline glaze— See cry
...
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