1、Designation: F 14 80 (Reapproved 2005)Standard Practice forMaking and Testing Reference Glass-Metal Bead-Seal1This standard is issued under the fixed designation F 14; the number immediately following the designation indicates the year of originaladoption or, in the case of revision, the year of las
2、t revision. A number in parentheses indicates the year of last reapproval. A superscriptepsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice covers procedures for preparing and test-ing reference glass-to-metal bead-seals for determining themagnit
3、ude of thermal expansion (or contraction) mismatchbetween the glass and metal. Tests are in accordance withmethod F 218 (2).1.2 This practice applies to all glass-metal combinations,established or experimental, particularly those intended forelectronic components.1.3 The practical limit of the test
4、in devising mismatch isapproximately 300 ppm, above which the glass is likely tofracture.1.4 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 standard to establish appro-priate safety and health practice
5、s and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2F15 Specification for Iron-Nickel-Cobalt Sealing AlloyF30 Specification for Iron-Nickel Sealing AlloysF31 Specification for 42 % Nickel-6 % Chromium-IronSealing AlloyF79 Specification
6、 for Type 101 Sealing GlassF 105 Specifications for Type 58 Borosilicate SealingGlass2F 218 Test Method for Analyzing Stress in GlassF 256 Specification for Chromium-Iron Sealing Alloys with18 or 28 % ChromiumF 257 Specifications for 28 % Chromium-Iron Alloy forSealing to Glass33. Summary of Practic
7、e3.1 Seals of a standard configuration are prepared from arepresentative sample of each metal and glass to be tested.Each material is prepared by an approved method and sized asspecified. The seal is formed, annealed, and measured foroptical retardation from which the axial stress and expansionmisma
8、tch are calculated. At least two specimens are requiredfrom which average values are obtained.4. Significance and Use4.1 The term reference as employed in this practice impliesthat both the glass and the metal of the reference glass-metalseal will be a standard reference material such as thosesuppli
9、ed for other physical tests by the National Institute ofStandards and Technology, or a secondary reference materialwhose sealing characteristics have been determined by seals toa standard reference material (see NIST Special Publication260).4Until standard reference materials for seals are estab-lis
10、hed by the NIST, secondary reference materials may beagreed upon between producer and user.55. Apparatus5.1 Polarimeter, as specified in Method F 218 for measur-ing optical retardation and analyzing stress in glass.5.2 Heat-Treating and Oxidizing Furnaces, with suitablecontrols and with provisions f
11、or appropriate atmospheres(Annex A1) for preconditioning metal, if required.5.3 Glassworking Lamp or Sealing Furnace, radiant tube,muffle, or r-f induction with suitable controls and provision foruse with inert atmosphere.5.4 Annealing Furnace, with capability of controlled cool-ing.5.5 Ultrasonic C
12、leaner, optional.5.6 Micrometer Caliper, with index permitting direct read-ing of 0.02 cm.1This practice is under the jurisdiction of ASTM Committee C14 on Glass andGlass Products and is the direct responsibility of Subcommittee C14.04 on Physicaland Mechanical Properties.Current edition approved Se
13、pt. 1, 2005. Published October 2005. Originallyapproved in 1961. Last previous edition approved in 2000 as F 14 80 (2000).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, ref
14、er to the standards Document Summary page onthe ASTM website.3Withdrawn.4Available from National Institute of Standards and Technology (NIST), 100Bureau Dr., Stop 3460, Gaithersburg, MD 20899-3460.5Gulati, S. T., and Hagy, H. E., “Expansion Measurement Using ShortCylindrical Seal: Theory and Measure
15、ment,” Thermal Expansion 6, edited by Ian D.Peggs, Plenum, New York, N. Y., 1978, pp. 113130.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.6. Materials6.1 MetalRepresentative rod stock with out-of-round notexceeding 1 % shall be se
16、lected, preferably with a diameter inthe range 0.5 to 4 mm. Smaller diameters result in a loss ofsensitivity and larger diameters tend to be cumbersome andimpractical. Surfaces shall be relatively free of scratches,machine marks, pits, or inclusions that would induce localizedstresses. Length requir
17、ements are discussed in 6.2.6.2 GlassRepresentative glass tubing of suitable opticaltransmission with an inside diameter 0.15 to 0.25 mm largerthan the metal rod diameter. The outside diameter of the tubingshall preferably be such that it produces a glass-to-metaldiameter ratio between 1.5 and 2. Th
18、e length of the tubing shallexceed four times the finished glass diameter. The length of themetal rod must exceed the length of the tubing. Surfacecontaminants shall be removed to reduce the risk of makingbubbly seals. An ultrasonic water mark is recommended.7. Seal-Making Procedure7.1 The seal may
19、be made either by flame-working tech-niques or by heating the tubing-rod assembly in a furnace. Ineither case, rotation of the assembly is strongly recommendedto maintain geometrical symmetry. For furnace sealing, 5 to 10min at a temperature 100C above the softening point of theglass will generally
20、produce a satisfactory seal.7.2 When used as an acceptance test by producer and user,the number of test seals representing one determination shall beestablished by mutual agreement. However two seals are aminimum requirement for one determination.7.3 Upon completion of the seal making, determine the
21、 roddiameter, glass bead diameter and length, and record thesedata.8. Annealing8.1 Once a symmetrical, bubble-free seal has been made,proper annealing of the seal becomes the most critical part ofthe procedure. It is by this operation that all stresses arerelieved except those due to the difference
22、in thermal contrac-tion of the two materials from annealing temperature levels.This process involves heating the seal to a temperaturesomewhat higher than the annealing point of the glass andmaintaining this temperature for a time sufficient to relieve theexisting strain. The test specimen is then c
23、ooled slowlypreferably at a constant rate to below the strain point of theglass. As an alternative, annealing can proceed directly oncooling during the making of a seal.8.2 Seal stress and associated expansion mismatch can bevaried markedly by annealing schedule modification. For thisreason, when th
24、e test is used as an acceptance specification, itis strongly recommended that producer and user mutuallydefine the annealing schedule and establish rigid controls for itsmaintenance.9. Procedure for Measuring Optical Retardation9.1 For each specimen measure the retardation in theannealed seal at the
25、 glass-metal interface parallel to the sealaxis in accordance with Method F 218.9.1.1 Place the seal in an index-matching liquid and positionits axis in a direction 45 from the direction of vibration of thepolarizer and analyzer, so that the line of sight is at themidpoint of the glass bead.9.1.2 De
26、termine the retardation along the light path throughthe glass in terms of degrees of rotation of the analyzer. Rotatein a direction that causes the black fringe seen within the glassto move toward the glass-metal interface. Stop rotation of theanalyzer when the center of the black fringe is coincide
27、nt withthe glass-metal interface. This condition is termed the point ofextinction.NOTE 1Sealing combinations may exist in which the thermal expan-sion coefficients of glass and metal at room temperature may differsignificantly. In these cases it may be important to record the temperatureof the refra
28、ction liquid (or the seal) at the time the retardation is measured.9.1.3 Repeat the above for a total of four measurements perseal equally spaced around the interface. Calculate averagerotation, A.9.1.4 Record the optical retardations in degrees, the index ofrefraction of the liquid, and the effecti
29、ve wavelength of thelight used in the polarimeter.10. Calculations10.1 Calculate the retardation per unit length, R, for eachseal as follows:R 5LA180= Dg22 Dm2(1)where:L = effective wavelength of light, nm,A = average analyzer rotation, deg,Dg= glass outside diameter, cm, and,Dm= metal diameter, cm.
30、10.2 Calculate the average, R, of the values of R for the testlot.10.3 For each test lot, calculate the average axial seal stressusing the relationship:S 5 R/K (2)where:S = axial stress, Pa,R= average retardation per unit length of the test speci-mens, nm/cm, andK = stress-optical coefficient of the
31、 glass, nm/cmPa.NOTE 2The stress-optical coefficient K of any reference glass shall besupplied by the producer. Values for typical sealing glasses are found inTable A1 of Specifications F 79 and F 105. See Section 2 for Method ofTest.F 14 80 (2005)210.4 Calculate the thermal expansion mismatch (the
32、differ-ential thermal contraction between the glass and the metal fromapproximately the strain point of the glass to room tempera-ture) using the equation:d5S 1 2ng!CEgFEgDg2EmDm22EgEm1 1G(3)where:ng= Poissons ratio for glass,Egand Em= elastic moduli of glass and metal, respec-tively, Pa, andC = sha
33、pe factor6(see Fig. 1).11. Report11.1 Report shall include the following information:11.1.1 Type of metal and identification,11.1.2 Type of glass and identification,11.1.3 Metal and glass diameters, glass bead length,11.1.4 Number of specimens tested,11.1.5 Annealing schedule,11.1.6 Stress-optical c
34、oefficient of the glass,11.1.7 Type of light source and effective wavelength,11.1.8 Nominal index of refraction of immersion liquid andits temperature at the time of retardation measurements, and11.1.9 Average value, range, and sense of stress and expan-sion mismatch.ANNEX(Mandatory Information)A1.
35、DIRECTIONS FOR CLEANING AND HEAT-TREATING SPECIMENS OF GLASS AND METAL FOR MAKING SEALSA1.1 Clean the glass with ultrasonic agitation in 0.5 60.01 % nonionic wetting agent solution at 50 6 5C for 5 6 1min. If necessary, precede this by an immersion in a 15 %aqueous hydrofluoric acid solution of 0.15
36、 to 1 min; this isrecommended particularly for aged or weathered glass. Rinsesuccessively in distilled or deionized water and alcohol. Blowdry with nitrogen or filtered air, and then oven dry at 1106 5Cfor 15 6 2 min. Rinse water (distilled or deionized) shall havea resistivity greater than 2 MVcm.A
37、1.2 Commonly used ASTM sealing alloys are Fe-Ni-Co,Fe-Ni, Ni-Cr-Fe, and Cr-Fe (Note A1.1). Degrease these alloysin trichloroethylene vapor or liquid, and follow this with theultrasonic cleaning procedure inA1.1. Rinse in water. Immersein 10 6 1 % hydrochloric acid solution at 100 6 5C for 2 60.5 min
38、 and follow this with the final rinsing and dryingprocedure in A1.1.NOTE A1.1These sealing alloys are covered by the following ASTMspecifications:Alloy SpecificationFe-Ni-Co F15Fe-Ni F30Ni-Cr-Fe F31Cr-Fe F 256, F 257A1.3 Heat treat Fe-Ni-Co and Fe-Ni alloys in wet (satu-rated) hydrogen at 1100 6 20C
39、 for 30 6 2 min. Then oxidizein air at 8006 10C for 8 6 2 min. As a result of oxidationFe-Ni-Co should gain 0.2 to 0.4 mg/cm2in weight. Fe-Nishould gain 0.1 to 0.3 mg/cm2in weight.A1.4 Cr-Fe and Ni-Cr-Fe alloys require no prior heattreatment. Oxidize them in wet (saturated) hydrogen at 1200 610C and
40、 1290 6 10C, respectively, for 406 5 min to give again in weight of 0.2 to 0.4 mg/cm2.FIG. 1 Shape Factor, C Modulus Ratio (Em/Eg) Relationships forThree Glass/Metal Diameter RatiosF 14 80 (2005)3ASTM International takes no position respecting the validity of any patent rights asserted in connection
41、 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 responsible t
42、echnical 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 conside
43、ration 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 Barr
44、 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).F 14 80 (2005)4
