1、Designation: C346 87 (Reapproved 2014)Standard Test Method for45-deg Specular Gloss of Ceramic Materials1This standard is issued under the fixed designation C346; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last rev
2、ision. 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 test method covers the determination of the specu-lar gloss of porcelain enameled specimens, but may be appli-cable to ot
3、her specimens having similar reflection characteris-tics. This test method may be used to compare the gloss ofporcelain enameled specimens or to provide an index of acid orabrasion resistance by measurement of gloss loss.NOTE 1Specular gloss is one of several related appearance attributesthat produc
4、e the sensation of glossiness. For this reason, specular glossmeasurements may not always correlate well with visual rankings ofglossiness.NOTE 2Improved correlations with visual judgments can sometimesbe achieved by the use of instruments with different geometries than thosespecified herein. Refer
5、to Test Method D523 for 20, 60, and 85-deggeometries. Values generally cannot be predicated for one geometry frommeasurements made with another.1.2 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 standa
6、rd to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D523 Test Method for Specular GlossE97 Method of Test for Directional Reflectance Factor,45-Deg 0-Deg, of Opaque Specimens by Br
7、oad-BandFilter Reflectometry (Withdrawn 1991)33. Terminology3.1 Definitions:3.1.1 specular glossratio of reflected to incident light,times 1000, for specified apertures of illumination and recep-tion when the axis of reception coincides with the mirror imageof the axis of illumination.NOTE 3In this
8、operational definition, the quantity defined as speculargloss is composed of surface-reflected and body-reflected components.For some low-gloss measurements, an approximate evaluation of thesurface-reflected component of specular gloss may be required (seeSection 9).3.1.2 45-deg specular glossfracti
9、on of visible light inci-dent upon the specimens at 45 to the normal that is reflectedin the direction of mirror reflection.NOTE 4Under ideal conditions, the incident beam should consist ofparallel light, and only light reflected in the true direction of mirrorreflection should be accepted for measu
10、rement.3.1.3 source apertureangular size (solid angle) of the lightsource (lamp filament, if an incandescent source is used)measured from the center of the incident beam lens.3.1.4 receptor apertureangular size (solid angle) of thereceptor window, measured from the center of the receptorlens.4. Sign
11、ificance and Use4.1 This test method may be used to compare the gloss ofporcelain enamel, ceramic, and other finishes or to provide acomparison of their resistance to attack from acid, alkali, orother environmental factors by measurement of gloss loss.5. Apparatus5.1 Instrumental ComponentsThe appar
12、atus shall consistof an incandescent light source and lens furnishing an incidentbeam of rays of required aperture, means for locating thesurface of the specimen, and a receptor located to receive therequired pyramid of rays reflected from the specimen. Thereceptor shall be a photosensitive device h
13、aving maximumresponse near the middle of the visible region of the spectrum.5.2 Geometric ConditionsThe axis of the incident beamshall be 45 from the perpendicular to the specimen surface.The axis of the receptor beam shall be coincident with themirror image of the axis of the incident beam. A flat
14、piece ofpolished black glass in the specimen position shall form animage of the source in the center of the receptor window. Theangular dimensions of the source and receptor shall be asspecified below:1This test method is under the jurisdiction ofASTM Committee B08 on Metallicand Inorganic Coatings
15、and is the direct responsibility of Subcommittee B08.12 onMaterials for Porcelain Enamel and Ceramic-Metal Systems. 19th St., Suite 200,Arlington, VA 22209.Current edition approved May 1, 2014. Published May 2014. Originallyapproved in 1954. Last previous edition approved in 2009 as C346 87 (2009).D
16、OI: 10.1520/C0346-87R14.2For 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.3The last approved version of this hi
17、storical standard is referenced onwww.astm.org.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1AperturesIn Plane ofMeasurement,AdegPerpendicular to Planeof Measurement,AdegSource 1.4 0.4 3.0 1.0Receiver 8.0 0.1 10.0 0.2A“Plane of meas
18、urement” is the plane containing axes of illuminating and viewingbeams.6. Specular Gloss Standards6.1 Specular Gloss Standards Primary working standardsshall be highly polished, plane, black-glass surfaces, or sur-faces of liquids for which the gloss is calculated from the angleof incidence and the
19、refractive index of the material by usingFresnels equation. Polished black glass of refractive index1.540 shall be assigned a 45-deg specular gloss value of 55.9.For the usual variation of refractive index of black glass, achange in index of 0.001 changes the gloss reading by 0.14.6.2 Secondary Work
20、ing Standards Secondary workingstandards of ceramic tile, glass, porcelain enamel, or othermaterials having hard and uniform surfaces may be calibratedfrom the primary standards on a glossmeter determined to be instrict conformance with the requirements prescribed in 5.2.6.3 For greatest accuracy, a
21、lways orient the standards to theposition in which they were originally calibrated.6.4 The importance of the cleanliness of glass standardscannot be overemphasized. They must always be handledcarefully to avoid abrading the surfaces. One or two deepscratches will not reduce the gloss as much as a la
22、rge numberof almost imperceptible abrasions.6.4.1 Never use abrasive cleaners or scouring powders onstandards.6.4.2 When standards are washed in soap and water, a thinfilm of soap or oil may remain on the tile surface, thus resultingin a spurious gloss value. This effect has been found to be mostnot
23、iceable for metal tiles and for higher angle and low glossvalues.6.4.3 The use of a mild detergent is recommended. Repro-ducible cleaning of standards can be accomplished by brushingthem in a solution of detergent and water, 3 g/L (1 tbsp/gal)with a nylon brush followed by a forced rinse in hot wate
24、r(temperature near 66C (150F), with the tile immediatelyblotted dry with a clean paper towel. The tile must not berubbed with the hand or paper towel, either during washing ordrying.7. Test Specimens7.1 Only surfaces of good planarity shall be tested, ifpossible, since surface warpage, waviness, or
25、curvature willaffect test results seriously.8. Procedure8.1 Operate the glossmeter according to the instructions ofthe manufacturer.8.2 Set the instrument to read the assigned gloss value of ahighly polished working standard; then read the gloss of lowerglass standards having poorer image-forming ch
26、aracteristics. Ifthe instrument readings for the latter standards do not agreewith the assigned values to within two gloss units, theinstrument optics may require readjustment; preferably, thisshould be done by the manufacturer.8.3 Measure the gloss of at least three portions of eachspecimen surface
27、. This will give an indication of gloss unifor-mity.8.4 For evaluation of change of gloss of a single specimen,which may be used as a measurement of surface deteriorationof porcelain enameled or ceramic specimens, exercise particu-lar care to see that the glossmeter is in exactly the sameposition on
28、 the specimen for measurements before and aftertreatment and that the illuminating beam is oriented the sameon the specimen. For best results, make several measurementson each specimen in different reproducible positions.NOTE 5For small square or rectangular specimens, such as thosefrequently used f
29、or laboratory tests, a specimen stop attached to theglossmeter head will permit exact duplication of specimen position andorientation.9. Evaluation of Components of Specular Gloss9.1 When required (Note 6), an approximate evaluation ofthe two components of specular gloss may be made as follows:9.1.1
30、 Body-Reflected ComponentObtain an approximateevaluation of the body-reflected component (formerly called“diffuse correction”) of specular gloss by one of the followingtwo procedures:9.1.1.1 Adjust a goniophotometer to read 45-deg speculargloss; then illuminate the specimen perpendicularly and view
31、itat 45 deg with the same receptor aperture as specified in 5.2.Read the magnitude of the body-reflected component.9.1.1.2 Alternatively, measure the 45-deg, 0-deg luminousdirectional reflectance in accordance with Method E97; expresstheir reflectance as a decimal fraction and multiply by 5.5 toobta
32、in an approximate value for the body-reflected componentof specular gloss.9.1.2 Surface-Reflected Component Subtract the body-reflected component from the measured specular gloss toobtain the surface-reflected component.NOTE 6Evaluation of surface-reflected and body-reflected compo-nents of specular
33、 gloss will ordinarily be required only when comparinglow-gloss specimens having quite different diffuse (body) reflectance.10. Calculation10.1 In computing the percent of gloss retained or lost,make a separate computation for each location measured andaverage results after computation.10.2 Calculat
34、e percent change in gloss as follows:Gloss loss, % 5Gi2 GfGi3100Gloss retained, % 5GfGi3100C346 87 (2014)2where:Gi= initial gloss (before treatment), andGf= final gloss (after treatment).11. Report11.1 Report the average specular gloss reading of eachspecimen. When required, report the surface-refle
35、cted andbody-reflected components separately.11.2 Report the presence of any specimen for which por-tions of the test surface differ in gloss from the average bymore than 10 % of the average.11.3 Identify the glossmeter by the name of the manufac-turer and model designation.11.4 Identify the standar
36、ds used, if desired.12. Precision and Bias12.1 The precision and bias of this test method is beingestablished.13. Keywords13.1 ceramic materials-glazed; glass coating; porcelainenamel; specular glossASTM International takes no position respecting the validity of any patent rights asserted in connect
37、ion with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsibl
38、e technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful cons
39、ideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 B
40、arr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).C346 87 (2014)3
