1、Designation: F14 80 (Reapproved 2015)Standard Practice forMaking and Testing Reference Glass-Metal Bead-Seal1This standard is issued under the fixed designation F14; the number immediately following the designation indicates the year of originaladoption or, in the case of revision, the year of last
2、revision. A number in parentheses indicates the year of last reapproval. A superscriptepsilon () 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 themagnitude
3、 of thermal expansion (or contraction) mismatchbetween the glass and metal. Tests are in accordance with TestMethod F218 (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 practic
5、es 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 Nickel-Chromium-Iron Sealing AlloysF79 Specification for T
6、ype 101 Sealing Glass2F105 Specification for Type 58 Borosilicate Sealing GlassF218 Test Method for Measuring Optical Retardation andAnalyzing Stress in GlassF256 Specification for Chromium-Iron Sealing Alloys with18 or 28 Percent ChromiumF257 Specification for Twenty-eight Percent (28 %)Chromium-Ir
7、on Alloy for Sealing to Glass (Withdrawn1973)33. Summary of Practice3.1 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 fo
8、roptical retardation from which the axial stress and expansionmismatch 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-
9、metalseal will be a standard reference material such as thosesupplied 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 Publicat
10、ion260).4Until standard reference materials for seals are estab-lished by the NIST, secondary reference materials may beagreed upon between producer and user.55. Apparatus5.1 Polarimeter, as specified in Test Method F218 formeasuring optical retardation and analyzing stress in glass.5.2 Heat-Treatin
11、g and Oxidizing Furnaces, with suitablecontrols and with provisions for 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 Annea
12、ling Furnace, with capability of controlled cool-ing.5.5 Ultrasonic Cleaner, 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 C1
13、4.04 on Physicaland Mechanical Properties.Current edition approved May 1, 2015. Published May 2015. Originallyapproved in 1961. Last previous edition approved in 2010 as F14 80 (2010). DOI:10.1520/F0014-80R15.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Custom
14、er 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 historical standard is referenced onwww.astm.org.4Available from National Institute of Standards and Technology (NIST
15、), 100Bureau Dr., Stop 1070, Gaithersburg, MD 20899-1070, http:/www.nist.gov. C145Gulati, S. T., and Hagy, H. E., “Expansion Measurement Using ShortCylindrical Seal: Theory and Measurement,” Thermal Expansion 6, edited by Ian D.Peggs, Plenum, New York, N. Y., 1978, pp. 113130.Copyright ASTM Internat
16、ional, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States16. Materials6.1 MetalRepresentative rod stock with out-of-round notexceeding 1 % shall be selected, preferably with a diameter inthe range 0.5 to 4 mm. Smaller diameters result in a loss ofsensitivity and larg
17、er diameters tend to be cumbersome andimpractical. Surfaces shall be relatively free of scratches,machine marks, pits, or inclusions that would induce localizedstresses. Length requirements are discussed in 6.2.6.2 GlassRepresentative glass tubing of suitable opticaltransmission with an inside diame
18、ter 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. The length of the tubing shallexceed four times the finished glass diameter. The length of themetal rod must exceed the
19、 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 be made either by flame-working tech-niques or by heating the tubing-rod assembly in a furnace. Ineither case, rotati
20、on of the assembly is strongly recommendedto maintain geometrical symmetry. For furnace sealing, 5 to10 min at a temperature 100C above the softening point of theglass will generally produce a satisfactory seal.7.2 When used as an acceptance test by producer and user,the number of test seals represe
21、nting 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 roddiameter, glass bead diameter and length, and record thesedata.8. Annealing8.1 Once a symmetrical, bubble-free se
22、al 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 in thermal contrac-tion of the two materials from annealing temperature levels.This process involves heating the seal
23、 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 cooled slowlypreferably at a constant rate to below the strain point of theglass. As an alternative, annealing can pro
24、ceed 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 the test is used as an acceptance specification, itis strongly recommended that producer and user mutuallydefine the an
25、nealing 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 glass-metal interface parallel to the sealaxis in accordance with Test Method F218.9.1.1 Place the seal in an index-
26、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 Determine the retardation along the light path throughthe glass in terms of degrees of rotation of the analyzer. Ro
27、tatein 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 coincident withthe glass-metal interface. This condition is termed the point ofextinction.NOTE 1Sealing combinations may
28、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 refraction liquid (or the seal) at the time the retardation is measured.9.1.3 Repeat the above for a total of four mea
29、surements 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 effective wavelength of thelight used in the polarimeter.10. Calculations10.1 Calculate the retardation per unit length,
30、 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.10.2 Calculate the average, R, of the values of R for the testlot.10.3 For each test lot, calculate the average
31、axial seal stressusing the relationship:S 5 R/K (2)where:S = axial stress, Pa,R= average retardation per unit length of the testspecimens, nm/cm, andK = stress-optical coefficient of the glass, nm/cmPa.NOTE 2The stress-optical coefficient K of any reference glass shall besupplied by the producer. Va
32、lues for typical sealing glasses are found inTable A1 of Specifications F79 and F105. See Section 2 for Method ofTest.10.4 Calculate the thermal expansion mismatch (the differ-ential thermal contraction between the glass and the metal fromapproximately the strain point of the glass to room tempera-t
33、ure) using the equation: 5S 1 2 g!CEgFEgDg2EmDm22EgEm11G (3)F14 80 (2015)2where:g= Poissons ratio for glass,Egand Em= elastic moduli of glass and metal, respectively,Pa, andC = shape factor6(see Fig. 1).11. Report11.1 Report shall include the following information:11.1.1 Type of metal and identifica
34、tion,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 coefficient of the glass,11.1.7 Type of light source and effective wavelength,11.1.8 Nominal index of refraction of immer
35、sion 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. DIRECTIONS FOR CLEANING AND HEAT-TREATING SPECIMENS OF GLASS AND METAL FOR MAKING SEALSA1.1 Clean the glass with ultraso
36、nic agitation in 0.5 60.01 % nonionic wetting agent solution at 50 6 5C for 5 61 min. If necessary, precede this by an immersion in a 15 %aqueous hydrofluoric acid solution of 0.15 to 1 min; this isrecommended particularly for aged or weathered glass. Rinsesuccessively in distilled or deionized wate
37、r 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 Mcm.A1.2 Commonly used ASTM sealing alloys are Fe-Ni-Co,Fe-Ni, Ni-Cr-Fe, and Cr-Fe (Note A1.1). Degrease these alloysin trichl
38、oroethylene vapor or liquid, and follow this with theultrasonic cleaning procedure in A1.1. Rinse in water. Immersein 10 6 1 % hydrochloric acid solution at 100 6 5C for 2 60.5 min and follow this with the final rinsing and dryingprocedure in A1.1.NOTE A1.1These sealing alloys are covered by the fol
39、lowing ASTMspecifications:Alloy SpecificationFe-Ni-Co F15Fe-Ni F30Ni-Cr-Fe F31Cr-Fe F256, F257A1.3 Heat treat Fe-Ni-Co and Fe-Ni alloys in wet (satu-rated) hydrogen at 1100 6 20C 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/
40、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 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
41、 (Em/Eg) Relationshipsfor Three Glass/Metal Diameter RatiosF14 80 (2015)3ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity o
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