1、Designation: C 693 93 (Reapproved 2008)Standard Test Method forDensity of Glass by Buoyancy1This standard is issued under the fixed designation C 693; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A num
2、ber 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 densityof glasses at or near 25C, by buoyancy.1.2 This standard does not purport to addre
3、ss all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard 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:2E12 Terminology
4、 Relating to Density and Specific Gravityof Solids, Liquids, and Gases3. Terminology3.1 Definition:3.1.1 density of solidsthe mass of a unit volume of amaterial at a specified temperature. The units shall be stated asgrams per cubic centimetre (see Terminology E12).4. Significance and Use4.1 Density
5、 as a fundamental property of glass has basicsignificance. It is useful in the physical description of the glassand as essential data for research, development, engineering,and production.5. Apparatus5.1 Analytical Balance, with sensitivity and accuracy of 0.1mg.5.2 Beaker, of convenient capacity (2
6、50 to 750 cm3)tofitinside the balance chamber and allow immersion of the basketor wire loop specimen holder in distilled water.5.3 Thermometers, calibrated (20 to 30C), sensitive to0.1C for determining air and water temperatures.5.4 Nickel-Chromium-Iron or Platinum-Alloy Wire, lessthan 0.2-mm diamet
7、er for suspending the specimen either in abasket or a loop made of the same wire. The suspension wireshall be cleaned by degreasing or heating in a vacuum.3Anacceptable alternative method of cleaning the platinum-alloywire is to heat in an oxidizing gas flame until there is no longerany color emitte
8、d from the gases passing around the wire.5.5 Weights, with accuracy of 0.1 mg.5.6 Barometer, with sensitivity of 1-mm Hg (optional, seeNote 3).6. Reagent6.1 Distilled Water, fresh, boiled, and used within 24 h,allowed to stabilize at balance air temperature for at least 2 hin the beaker.7. Test Spec
9、imen7.1 Specimens weighing about 20 g, with a minimum ofseeds or other inclusions (Note 1), shall be taken or cut fromthe sample object, preferably in cylindrical or rectangular barform with smooth, slightly rounded surfaces having no cracksor sharp edges.NOTE 1For a specimen of 20 g with a density
10、of approximately 2.5g/cm3, a gaseous void of diameter 2 mm will cause an error in measureddensity of 0.05 %.7.2 The specimens shall be cleaned, handling them withtweezers throughout subsequent operations, by immersionpreferably in an ultrasonic bath of hot nitric acid, chromic-sulfuric acid, or orga
11、nic degreasing solvent, followed by arinsing in alcohol and distilled water. For samples only soiledby ordinary handling or exposure, adequate cleaning may be1This test method is under the jurisdiction of ASTM Committee C14 on Glassand Glass Products and is the direct responsibility of Subcommittee
12、C14.04 onPhysical and Mechanical Properties.Current edition approved April 1, 2008. Published December 2008. Originallyapproved in 1971. Last previous edition approved in 2003 as C 693 93 (2003).2Withdrawn. The last approved historical version of this standard is referencedon www.astm.org3Bowman, H.
13、A., and Schoonover, R. M., “Procedure for High Precision DensityDeterminations by Hydrostatic Weighing.” Journal of Research, National Bureau ofStandards, Vol 71C, No. 3, JulyAugust 1967, pp. 179198.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,
14、United States.obtained using a warm 2 % volume MICRO-brand4detergent,followed by a deionized or distilled water rinse.8. Procedure8.1 Hold the specimens and covered beaker of boileddistilled water near the laboratory balance until the water hascooled to ambient temperature before weighing.8.2 Read t
15、he laboratory air temperature to the nearest 1C.Read the barometric pressure to the nearest 1-mm Hg. A fixedlaboratory average barometric pressure estimate is an accept-able alternative to the barometric pressure measurement (seeNote 3). Determine the density, rA, of the air from Table 1.8.3 Weigh t
16、he glass specimen in air to the nearest 0.1 mgand record as WA.8.4 Place the beaker of water with immersed thermometeron a platform supporting it over the balance pan so that the panor balance arm is free to swing.8.5 Place the specimen in the basket or loop holder and hangthis holder from the balan
17、ce arm by means of a suitable hookand the suspension wire. Immerse the basket and specimen byraising the beaker of distilled water until the surface of thewater is at a predetermined reference position on the suspen-sion wire.NOTE 2Before use, the beaker of water should be covered tominimize dust. J
18、ust before the weighing of the basket and specimen, thewater surface near the suspension wire may be cleaned by a vacuumnozzle or pipet technique. The suspended assembly should be agitatedslightly with a vertical motion to wet the suspension wire above themeniscus at the reference position and to en
19、sure that no air bubbles areadhering to the glass or holder.NOTE 3A laboratory average barometric pressure estimate may bedetermined from the elevation of the laboratory estimated to the nearest170 m (500 ft). The national average barometric pressure corrected to sealevel (0 elevation) is 760-mm Hg.
20、 For each 341-m (1000-ft) increase inelevation, barometric pressure decreases by approximately 25-Hg. Forglass densities in the range of 2 to 6 g/cm3, a barometric pressure estimatebased on this relationship will result in density measurement bias of lessthan 0.004 % under normal atmospheric pressur
21、e variations.8.6 Weigh the glass and holder in the distilled water to thenearest 0.1 mg and record as WT.8.7 Remove the glass from the holder. At the referenceposition, weigh the empty holder in the distilled water, to thenearest 0.1 mg and record as WO.8.8 Read the distilled water temperature to th
22、e nearest 0.1Cand determine the water density from Table 2. Record this asrW.9. Calculation9.1 Calculate the weight of the specimen in water, WW,asfollows:WW5 WT2 WO(1)9.2 Calculate the glass density, r, at the average air-waterlaboratory temperature, TL, as follows:r5WArW2 WWrA!WA2 WW!(2)9.3 Calcul
23、ate the glass density, rS, at a standard referencetemperature, TS, as follows:rS5r1 1 3aTS2 TL!(3)where a is the approximate instantaneous coefficient oflinear thermal expansion at TS.NOTE 4For low expansion glasses or small temperature intervals orboth, this correction is not required.10. Report10.
24、1 Report the following information:10.1.1 Identification of test sample, production, manufac-turer, glass type, and so forth as required,10.1.2 Density of glass, r or rS, in grams per cubiccentimetre,10.1.3 Temperature, TSor TL, for which glass density isreported,10.1.4 Thermal history of specimen.
25、If unknown, it shouldbe so stated, and10.1.5 Estimate of the volume of voids and inclusions.11. Precision and Bias11.1 Precision:11.1.1 With proper precautions taken to minimize dissolvedair in the water and adhering air bubbles during immersion ofthe specimen and holder, this procedure will yield g
26、lass densityto a standard deviation within 60.1 %.11.1.2 With precautions taken to minimize air-water tem-perature differences and to correct for temperature, etc., effectson air and water density, this procedure will yield glass densityto a standard deviation close to 60.03 %.4Manufactured by Inter
27、national Products Corporation, PO Box 70, Burlington,NJ 08016.TABLE 1 Density of Dry Air, g/cm3Temperature,CPressure, mm Hg720 730 740 750 760 77020 0.001 141 0.001 157 0.001 173 0.001 189 0.001 205 0.001 22121 137 153 169 185 201 21622 134 149 165 181 197 21223 130 145 161 177 193 20824 126 142 157
28、 173 189 20425 122 138 153 169 185 20026 118 134 149 165 181 19627 115 130 146 161 177 19228 111 126 142 157 173 18829 107 123 138 153 169 18430 104 119 134 150 165 180C 693 93 (2008)211.2 BiasThree glass density standard reference materialsare available from the Standard Reference Materials Program
29、,National Institute of Standards and Technology. Bias can beexperimentally assessed by measurement of density by thisprocedure for these glasses.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of
30、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 responsible technical committee and must be reviewed every five
31、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 consideration at a meeting of theresponsible technical com
32、mittee, 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 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 1
33、9428-2959,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).TABLE 2 Density of Air-Free Water, g
34、/cm3Temperature,C0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.920 0.998 20 818 816 814 812 810 808 806 804 80121 799 797 795 793 791 788 786 784 782 77922 777 775 773 770 768 766 763 761 759 75623 754 752 749 747 744 742 740 737 735 73224 730 727 725 722 720 717 715 712 710 70725 705 702 700 697 694 692 689 687 684 68126 679 676 673 671 668 665 662 660 657 65427 652 649 646 643 640 638 635 632 629 62628 624 621 618 615 612 609 606 603 600 59829 595 592 589 586 583 580 577 574 571 56830 565 562 559 556 553 550 547 543 540 537C 693 93 (2008)3
