ASTM_F_14_-_80_2015.pdf

Designation:F1480(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 revision.Anumber in parentheses indicates the year of last reapproval.Asuperscriptepsilon()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 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 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 practices 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 Type 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-Iron 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 foroptical 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-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 Publication260).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-Treating 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 Annealing 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 C14.04 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 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 historical standard is referenced onwww.astm.org.4Available from National Institute of Standards and Technology(NIST),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 International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 6.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 larger 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 insi