1、Designation: C1351M 96 (Reapproved 2017)Standard Test Method forMeasurement of Viscosity of Glass Between 104Pas and108Pas by Viscous Compression of a Solid Right CylinderMetric1This standard is issued under the fixed designation C1351M; the number immediately following the designation indicates the
2、 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 test method covers the determination of the vi
3、scos-ity of glass from 104Pas to 108Pas by measuring the rate ofviscous compression of a small, solid cylinder.21.2 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 therespo
4、nsibility 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-iza
5、tion 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:3C338 Test Method for Softening Point of GlassC965 Pra
6、ctice for Measuring Viscosity of Glass Above theSoftening PointC1350M Test Method for Measurement of Viscosity ofGlass Between Softening Point and Annealing Range(Approximately 108Pas to Approximately 1013Pas) byBeam Bending (Metric)3. Terminology3.1 parallel plate viscometera device used to determi
7、nethe viscosity of glass from approximately 104Pas to 108Pasby measuring the rate of change in thickness of a cylindricalspecimen between parallel plates moving perpendicular to theircommon central axis. The equation for calculating viscosity bythe parallel plate method is: 5 2Mgh530V dh/dt!2h31V!11
8、T!(1)where: = viscosity, Pas,M = applied load, g,g = acceleration due to gravity, 980 cm/s2,t = time, s,V = specimen volume, cm3,h = specimen thickness at time t, cm,dh/dt = compression rate, cm/s, and = glass mean coefficient of thermal expansion, 25C tothe measurement temperature, T, m/m/C. See No
9、te1.NOTE 1The term (1 + T) corrects for the specimen dimensionalchanges due to thermal expansion. For low thermal expansion glasses, itcan be ignored. However, for a glass with an of 20 10-6/C at ameasurement temperature of 1000C, this term produces a correction of2 %. Only an estimate of is necessa
10、ry since the correction is small. Usetwice the room temperature coefficient if data are unavailable.4. Significance and Use4.1 This test method is well suited for measuring theviscosity of glasses between the range within which rotationalviscometry (see Practice C965) is useful and the range withinw
11、hich beam bending viscometry is useful (see Test MethodC1350M). It can be used to determine the viscosity/temperature curve in the region near the softening point (seeTest Method C338). This test method is useful for providinginformation related to the behavior of glass as it is formed intoan object
12、 of commerce, and in research and development.5. Apparatus5.1 The apparatus shall consist of a furnace, a means ofcontrolling and measuring its temperature and heating rate,1This test method is under the jurisdiction of ASTM Committee C14 on Glassand Glass Products and is the direct responsibility o
13、f Subcommittee C14.04 onPhysical and Mechanical Properties.Current edition approved Nov. 1, 2017. Published November 2017. Originallyapproved in 1996. Last previous edition approved in 2012 as C1351M 96 (2012).DOI: 10.1520/C1351M-96R17.2Fontana, E. H., “A Versatile Parallel-Plate Viscometer For Glas
14、s ViscosityMeasurements to 1000C,” Bulletin of the American Ceramic Society, Vol 49, No.6, 1970, pp. 594597.3For 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 stan
15、dards 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 Dec
16、ision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1specimen holders and loading rod, and a means of measuringthe rate of viscous compression of the glass specimen.5.2 Furnac
17、e:5.2.1 The furnace shall be electrically heated by resistanceelements. The dimensions and details of the furnace construc-tion are not critical; its cross-section can be circular of 75 mm(3 in.) diameter or square of sides of 75 mm. The furnaceshould have a constant temperature zone that covers the
18、specimen geometry, including the compression range. Differ-ences in temperature greater than 2C within the constanttemperature zone are unacceptable.5.3 Temperature Measuring and Indicating Instruments:5.3.1 For the measurement of temperature, there shall beprovided a calibrated Type K, R, or S ther
19、mocouple. Thethermocouple shall be housed in a double-bore alumina tubewith its junction placed within 5 mm of the specimen near theaxis of the furnace. The thermocouple shall be referenced to0C by means of an ice bath, and its emf measured with acalibrated potentiometer that can be read with a sens
20、itivityequivalent to 60.1C and an accuracy of 60.5C. Precautionsshall be taken to ensure that the ice bath is maintained at 0Cthroughout the test.Alternately, the output of the thermocouplecan be measured on a calibrated, direct reading meter (elec-tronic thermometer) that can be read with a sensiti
21、vity of60.1C and an accuracy of 60.5C. See Note 3 for tempera-ture lag-lead corrections.5.4 Furnace Control:5.4.1 Suitable means shall be provided for maintaining thefurnace at a fixed control point and for controlling the heatingand cooling rates. Commercially available programmingequipment provide
22、s excellent control. A variable transformerwith manual control is an inexpensive, but less adequate meansof accomplishing the required control.5.5 Specimen Holder and Loading Rod:5.5.1 A typical configuration is presented in Fig. 1. Posi-tioned horizontally on top of the support stand is a stationar
23、yplate (see Note 2),6mm(;14 in.) thick by diameter of thesupport stand. A movable plate, 6 mm thick by 44 mmminimum diameter is placed parallel and concentrically abovethe fixed plate. (See parallel plates in Fig. 1.) Attached to thetop center of the movable plate in a shrink fit configuration isa 9
24、-mm (;38-in.) diameter centerless-ground alumina rod oflength sufficient to reach approximately 150 mm (6 in.) beyondthe top of the furnace or its supporting structure, or both. Thisassembly provides a means for loading the specimen duringmeasurement. Bushings attached to the external frame guidethe
25、 shaft with a minimum amount of friction.NOTE 2Alumina and vitreous silica are suitable materials for theassembly components, as are noble or low expansion metals used in pairs.The user must observe temperature limitations for these alternate materi-als.5.6 Extensometer for Measuring Thickness Chang
26、e:5.6.1 The means of observing the rate of thickness changeof the specimen should allow reliable reading of total change ofat least 6 mm. The extensometer shall permit direct reading of0.010 mm and estimates of 0.001 mm. Its accuracy shall besuch that the error of indication will not exceed 62 % for
27、 anymeasured translation. This will limit the minimum translationthat may be used in calculation. A linearly variable differentialtransformer (LVDT) is suitable for this purpose, as is any otherdevice (for example, optical or capacitative), provided thatlength changes are reliably measured as specif
28、ied.5.7 Micrometer Calipers:5.7.1 Micrometer calipers, which can be read to an accuracyof at least 0.01 mm are required for measuring specimendimensions.6. Preparation of Test Specimen6.1 Specimens required for this test method are small, right,circular cylinders. Nominal dimensions are 6 mm (;14 in
29、.) to12 mm (;12 in.) diameter and 3 to 6 mm thick. Specimens canbe either core-drilled from flat stock or sliced from a rod. Inboth cases, the flat surfaces must be ground and polished to beplane-parallel to 60.001 mm. Cylinders made by dry pressingof frit at high pressure can provide meaningful dat
30、a.7. Calibration7.1 Direct calibration of the apparatus is accomplished byusing standard glasses, such as those supplied and certified bythe National Institute of Standards and Technology (NIST),FIG. 1 A Typical Parallel Plate ViscometerC1351M 96 (2017)2having known viscosity/temperature values.4Bia
31、s should becorrected by overall instrument calibration.7.1.1 Determine the viscosity using test cylinders of cali-brating glasses which cover a range of cross-sections expectedto be used for routine testing. Determine the viscosity byfollowing the standard procedure described in Sections 8 and 7.7.1
32、.2 Mathematically fit resulting data to a convenient form(for example, polynomial or Fulcher5equation). Fit the datasupplied for the glass SRM to a Fulcher equation.7.1.3 Calculate the viscosities from both equations deter-mined in 7.1.2 at 20C minimum intervals over the measuredrange. Determine the
33、 viscosity ratio, SRM fit/ measured fit=fractional correction, and construct a calibration curve offractional correction versus log viscosity (measured fit). This isused to correct experimental viscosity data. (See Note 3.)Corrections greater than 20 % are cause for concern and shouldinitiate appara
34、tus troubleshooting.NOTE 3If analyses are performed under some heating or cooling ratetime-temperature function, the thermocouple temperature may lag or leadthe actual sample temperature. If thermocouple lag or lead does occur, thecalibration curve described in 7.1.3 would incorporate this temperatu
35、rebias as well as any viscosity bias. To assess whether thermocouple lag orlead exists, viscosities for a glass SRM may be measured under isothermalconditions at several temperatures. Compare temperatures at equivalentviscosity levels from the analysis of the same glass SRM measured underthe heating
36、 or cooling rate condition. Temperature differences indicatethermocouple lag or lead. The difference should be applied as a tempera-ture correction to measured temperatures prior to generating the calibra-tion curve (7.1.3) or applying the calibration correction to test data(Section 9).8. Procedure8
37、.1 Deflection data may be taken either under isothermalconditions or heating at a controlled rate not to exceed5C/min.8.2 Identify the time-temperature function (for example,5C/min heating rate) to be used in the test. Generate a curveof background deflection against temperature by performing ameasu
38、rement with the upper loading plate in contact with thelower support plate (pieces of platinum foil may be used forseparation) while operating the furnace under the chosentime-temperature function. The thickness change of the testspecimen is determined by algebraic subtraction of this back-ground cu
39、rve from the measured curve.8.3 Measure the specimen diameter and thickness with amicrometer to within 0.01 mm and record the results.8.4 To protect the parallel plates from reaction with thespecimen, sandwich the specimen between two platinum foilpieces and place the sandwich concentrically between
40、 theparallel plates. All platinum foil must be the same thicknessand suitably thin (preferably 25 m thick) so as to allow seatingof the components in their required position.8.5 Adjust the position of the extensometer to the lower endof its measuring range. Place the furnace in position and startthe
41、 chosen time-temperature function.8.6 When a usable deflection rate is reached, begin record-ing extensometer, time and temperature data to be used in datareduction. The collection interval should not exceed 1 min.Suitable means of accumulating data include computer-controlled data acquisition or pl
42、otting the thickness change andtemperature of the specimen with a two pen recorder operatingon a convenient time base. (If such a recording device is notavailable and data must be taken manually, the thicknesschange and temperature may be recorded by taking readings ofboth the extensometer and tempe
43、rature alternately at 30-sintervals so that each will be read at 1-min. intervals. Becauseit is less accurate than the other methods, the user is discour-aged from using this method to acquire data.) If the extensom-eter goes off range during the test, reset it. Compression of thesample to a thickne
44、ss less than 1 mm is excessive.9. Calculation9.1 Use the corrected change in extensometer readings, dh,during a given time interval, dt, as the rate of thickness change,dh/dt, at the temperature corresponding to the middle of thatinterval. Also record the specimen thickness change, d,atthemidpoint o
45、f the time interval; use it to calculate the specimenthickness:h 5 h02 d (2)where:h0= the initial specimen thickness.Substitute those data into Eq 1 to calculate the viscosity, .Correct the viscosity using the calibration curve (see Section 7)by multiplying the viscosity by the fractional correction
46、 factorcorresponding to that viscosity.10. Report10.1 At a minimum, report the following information:10.1.1 Identification of the glass tested,10.1.2 Manufacturing source and date,10.1.3 Calibration reference,10.1.4 Temperature and viscosity points,10.1.5 Date of test and name of operator, and10.1.6
47、 Other observations (for example, sample crystallizedduring measurement).11. Precision and Bias11.1 PrecisionIn the absence of round robin testing, aspecific precision statement cannot be made. However, Fonta-nas paper2describing the parallel plate method can be used toprovide insight into the preci
48、sion and bias of the test method.Precision can be estimated from the data scatter in mathemati-cal curve fitting of data.11.2 BiasIn general, this procedure should yield valuesfor viscosity points to 610 % of referenced SRM values.Systematic departures may occur for values obtained near thebeginning
49、 and end of the determination where the thicknesschange rates are small. A rigid test of the apparatus is tocalibrate with one NIST SRM glass and then measure otherNIST SRM glasses based on this calibration. If the otherstandard glass values are within 4C of certification, satisfac-tory performance has been established. If errors arise that4Table 2, Annual Book of ASTM Standards, Vol 15.01, NIST Special PublicationNo. 260.5Fulcher, G. S., Journal of the American Ceramic Society , Vol 8, 1925, pp.339355.C1351M 96 (2017)3i
