ASTM_F_144_-_80_2015.pdf

Designation:F14480(Reapproved 2015)Standard Practice forMaking Reference Glass-Metal Sandwich Seal and Testingfor Expansion Characteristics by Polarimetric Methods1This standard is issued under the fixed designation F144;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 the preparation and testing of areference glass-metal sandwich seal for determining stress inthe glass or for determining the degree of thermal expansion(or contraction)mismatch between the glass and metal.Testsare in accordance with Test Method F218(Section 2).1.2 This practice applies to all glass and metal(or alloy)combinations normally sealed together in the production ofelectronic components.1.3 The practical limit of the test in deriving mismatch isapproximately 300 ppm,above which the glass is likely tofracture.1.4 This standard does not purport to address all of thesafety problems,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Sealing AlloysF47 Test Method for Crystallographic Perfection of Siliconby Preferential Etch Techniques(Withdrawn 1998)3F79 Specification for Type 101 Sealing GlassF105 Specification for Type 58 Borosilicate Sealing GlassF218 Test Method for Measuring Optical Retardation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 Chromium3.Summary of Practice3.1 Seals of a standard configuration are prepared fromrepresentative specimens of the glass and metal to be tested.The glass and metal are cleaned,treated,and sized to specifiedproportions.Plane-interfaced seals are formed,annealed,andmeasured for residual optical retardation.The stress parallel tothe interface in each seal is calculated from the opticalretardation,and the average stress and thermal expansionmismatch are computed for the sample.4.Significance and Use4.1 The term“reference”as employed in this practiceimplies that either the glass or the metal of the referenceglass-metal seal will be a“standard reference material”such asthose supplied for other physical tests by the National Instituteof Standards and Technology,or a secondary reference materialwhose sealing characteristics have been determined by seals toa standard reference material(see NBS Special Publication260).Until standard reference materials for seals are estab-lished by the NIST,secondary reference materials may beagreed upon between manufacturer and purchaser.5.Apparatus5.1 Polarimeter,as specified in Test Method F218 formeasuring optical retardation and analyzing stress in glass.5.2 Cut-Off Saw,with diamond-impregnated wheel and No.180 grit abrasive blade under flowing coolant for cutting andfine-grinding glass rod.5.3 Glass Polisher,buffing wheel with cerium oxide polish-ing powder or laboratory-type equipment with fine-grindingand polishing laps.5.4 Heat-Treating and Oxidizing Furnaces,with suitablecontrols and with provisions for appropriate atmospheres(Annex A1)for preconditioning metal,if required.5.5 Sealing Furnace,radiant tube,muffle or r-f inductionwith suitable controls and provision for use with inert atmo-sphere.5.6 Annealing Furnace,with capability of controlled cool-ing.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 1971.Last previous edition approved in 2010 as F144 80(2010).DOI:10.1520/F0144-80R15.2For 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.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 5.7 Ultrasonic Cleaner,optional.5.8 Fixture for Furnace Sealing,design as suggested inAnnex A2.5.9 Micrometer Caliper,with index permitting direct read-ing of 0.02 cm.5.10 Immersion Mercury Thermometer.6.Materials6.1 MetalFive representative specimen pairs of the metalfrom either rod or plate stock with dimensions satisfying therequirements of 7.1.The surfaces to be sealed should berelatively free of scratches,machine marks,pits,or inclusionsthat would induce localized stresses.The sealing su