1、Designation: F 44 95 (Reapproved 2006)Standard Specification forMetallized Surfaces on Ceramic1This standard is issued under the fixed designation F 44; the number immediately following the designation indicates the year of originaladoption or, in the case of revision, the year of last revision. A n
2、umber 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 specification covers requirements for powderedrefractory metal coatings produced with or without additives.These coatings are appl
3、ied to ceramic bodies in order to joinceramic bodies to metals or to other metallized ceramics bymeans of brazing or soldering. Included in this specification arerequirements for a secondary metallic layer which is usuallyapplied over the refractory metal layer.1.2 The values stated in inch-pound un
4、its are to be regardedas the standard. The values given in parentheses are forinformation only.2. Referenced Documents2.1 ASTM Standards:2E3 Guide for Preparation of Metallographic SpecimensF19 Test Method for Tension and Vacuum Testing Metal-lized Ceramic Seals3. Terminology3.1 Definitions of Terms
5、 Specific to This Standard:3.1.1 ceramicsas referred to in this specification areunderstood to be inorganic, nonmetallic materials, the majorphase of which must be crystalline. A glassy intercrystallinematrix may be present as one of the minor phases.3.1.2 metallizing on a ceramic, is a process wher
6、eby asintered matrix of metal particles firmly adheres to the ceramic.3.1.3 refractory metalsthose metals with melting pointsequal to or higher than that of chromium. Therefore, this groupincludes chromium, columbium, molybdenum, rhenium, tanta-lum, and tungsten.4. Ordering Information4.1 The manufa
7、cturer and purchaser shall agree upon spe-cific quality levels as outlined in the following sections:4.1.1 Uniformity of metallizing (Section 5),4.1.2 Thickness of metallizing (Section 6),4.1.3 Secondary metal layer on the metallizing (Section 9),4.1.4 Values for bond strength (Section 10), and4.1.5
8、 Vacuum tightness of brazed metallized ceramic as-semblies (dependent on allowable use of manufacturers prod-uct) (Section 11).5. Uniformity of Metallizing5.1 Either of the following two levels of quality may beagreed upon between manufacturer and purchaser, dependingupon end use, seal area, and geo
9、metry.5.2 Level ALess Demanding Application:5.2.1 Thin areas where the ceramic substrate can usually beseen without magnification through the metallizing will beacceptable only if all of the following conditions are met:5.2.1.1 There are no more than two such areas on any onecoated band, spot, or pa
10、ttern detail.5.2.1.2 Their extremities are no closer than 10 % of the totalband length to each other.5.2.1.3 They are no wider than 10 % of the width of theband but not exceeding 1 mm.5.2.1.4 Their cumulative length does not exceed 25 % of thetotal band length.5.2.2 Defects such as brush marks, scre
11、en marks, marks inthe metallizing left by foreign matter such as lint, dust, etc., andpits or blisters, will be acceptable if they meet the fourconditions outlined in 5.2.1.1 through 5.2.1.4. Such defectswill also be acceptable if their raised edges do not interferewith proper assembly of the joint.
12、5.2.3 Projections on metallized surfaces, such as oversizedparticles or agglomerates will be objectionable if they interferewith assembly.5.2.4 Continuous coatings over sharp edges or corners witha radius less than132 in. (0.8 mm) will not be required unlessby specific agreement between manufacturer
13、 and purchaser.5.3 Level BDemanding Application:5.3.1 Thin areas will be unacceptable where the ceramicsubstrate can be seen through the metallizing when examinedat 403 magnification.1This specification is under the jurisdiction of ASTM Committee F1 onElectronics and is the direct responsibility of
14、Subcommittee F01.03 on MetallicMaterials.Current edition approved Jan. 1, 2006. Published January 2006. Originallyapproved in 1968. Last previous edition approved in 2000 as F 44-95 (2000).2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at servic
15、eastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5.3.2 Defects through which the underlying ceramic can be
16、observed, such as brush or screen marks, marks left by foreignmatter such as lint or dust, and pits or chips, will be acceptableonly if all of the following conditions are met:5.3.2.1 There are no more than two such defects on anycoated band, spot, or pattern detail.5.3.2.2 Their extremities are not
17、 closer together than 10 %of the length of the metallized area in which they occur.5.3.2.3 They are not wider than 5 % of the width of area norlonger than 2 % of the length of area.5.3.3 Continuous coatings over sharp corners with a radiusless than132 in. (0.8 mm) will not be required so long assubs
18、equent plating covers the radius. The specific gap permis-sible at such a corner shall be agreed upon by manufacturer andpurchaser.5.3.4 Projections on metallized surfaces, such as oversizeparticles or agglomerates will be objectionable if they interferewith assembly or alignment.6. Thickness of Met
19、alizing6.1 Measure thickness by observation through a calibratedmicrometer eyepiece in a metallurgical microscope. Measure apolished cross section that is perpendicular to the metallizedsurface. The measurement shall consist of the average of atleast three representative readings taken where the upp
20、er andlower edges of the layer are parallel. Magnification must be atleast 4003 to obtain satisfactory accuracy.Asuggested methodfor specimen preparation is shown in Appendix X1.6.2 Thickness of the sinter-fired metallize layer shall rangefrom 0.0004 in. (0.01 mm) to 0.002 in. (0.05 mm) unlessotherw
21、ise mutually agreed upon between the manufacturer andthe purchaser.7. Continuity of Metalizing7.1 The particles in the metallized layer must be sintered inorder to form a dense matrix when viewed in cross section at4003. This cross section will indicate the extent of three-dimensional sintering.8. D
22、iscoloration of the Ceramic8.1 Almost invariably some discoloration of the ceramicadjacent to the metallized layer will exist (Note 1). Themanufacture will not be required to eliminate discolorationcompletely.NOTE 1The actual color and depth of penetration depend on themetallizing formula and proces
23、sing cycle. Where a given degree ofdiscoloration is objectionable to the user, the manufacturer may be able tosubstitute a practice which will yield acceptable results. It is recognizedthat metallized coating properties vary with the formula and processing. Ifthe user requires such a change to reduc
24、e coloration compromise may benecessary.9. Secondary Metallic Layer on Metallizing9.1 A secondary metallic layer on the metallizing shall beapplied by the manufacturer unless otherwise specified.9.2 All metallized areas must be completely covered unlessotherwise specified.9.3 The purchaser shall spe
25、cify the metal to be applied.9.4 Manufacturer and purchaser shall agree upon the layerthickness, including maximum and minimum thickness limits.Measurement shall be by microscopical examination as de-scribed in 6.1.9.5 Brightness of clean matte deposits may not be specified.9.6 Oxide films on the se
26、condary metallic layer will not because for rejection.9.7 Defects such as blisters developed in subsequent heatingoperations will be acceptable only in 5.2 Level A applicationand only if all the following conditions are met:9.7.1 There are no more than two blisters on any one coatedband, spot, or pa
27、ttern detail.9.7.2 No blister is closer than 10 % of the total band lengthto another blister.9.7.3 Maximum dimension of any blister does not exceed10 % of the width of the band; in any case not to exceed132 in.(0.8 mm).9.8 The secondary metallic layer must adhere to the metal-lizing underneath to th
28、e extent that no separation exists at thisinterference in tension or torque peel tests after sintering of thelayer in a suitable protective atmosphere.9.9 Cleanliness such as absence of fingerprints, dirt, etc.,which may interfere with brazing or soldering, is not arequirement for acceptance unless
29、agreed upon between manu-facturer and purchaser.9.10 When the secondary metallic layer is omitted from thepurchaser requirements, the following items shall become apart of this specification:9.10.1 Metallized surfaces shall be reasonably free fromdirt, grease, fingerprints, etc., in keeping with nor
30、mal goodhandling practice, unless this condition is specifically agreedupon between manufacturer and purchaser.9.10.2 The degree of oxidation acceptable on the metalliz-ing shall be agreed upon between the manufacturer andpurchaser.10. Bond Strength10.1 The manufacturer and purchaser shall agree on
31、specificvalues of bond strength of brazed metallized ceramics.10.2 Quantitative measurements of the bond strength maybe made by the following, or other methods agreed uponbetween manufacturer and purchaser.10.2.1 Torque Peel Test A torque peel test may be usedwhere a standardized strip of a strong,
32、ductile metal such asnickel is brazed to the metallized and secondary metal surface.See Appendix X2.10.2.2 A tension test may be made in accordance with TestMethod F19. This tension test really measures the combinedeffects of all the factors involved in making the joint. It mayalso measure either th
33、e adherence of the metallizing to theceramic or the cohesive strength of the sintered metal layeritself, depending on where the fracture occurs.11. Vacuum Tightness11.1 Vacuum tightness, where required by the user, shall betested in accordance with Test Method F19, or by othermethod agreed upon betw
34、een the manufacturer and the pur-chaser.F 44 95 (2006)212. Keywords12.1 bond strength; metallizing of ceramics; thicknesscontrolAPPENDIXES(Nonmandatory Information)X1. SUGGESTED METHOD FOR PREPARATION OF SPECIMENS FOR MICROSCOPYX1.1 Cut the specimen with a water-cooled diamond cutoffsaw.X1.2 If the
35、specimen is too small to handle readily duringsubsequent polishing, it may be mounted by any of theordinary methods. (Approved methods of mounting are givenin Methods E3.) It is best to mount a complete seal section ina resin which contains fillers so that the relatively soft metalphases adjacent to
36、 hard ceramic phases do not become roundedduring polishing.X1.3 Rough grind on 240 and 400-grit diamond laps. Thisstep should remove 0.040 in. and 0.060 in. (1 to 1.5 mm) stockfrom the surface in order to remove completely all surfacedamage caused by the cutoff operation.X1.4 Fine grind with 15-m di
37、amond grinding compoundon a hardwood or napless cloth-covered wheel. This stepshould impart a polished look to the ceramic and reduce thedark “plucked-out” areas considerably when viewed at 100 to2003 magnification through a metallurgical microscope.X1.5 Polish successively with 6, 3, and 1-m diamon
38、dcompounds on napless cloth or chemotextile-covered wheels.Another polish with submicron diamonds will improve thepolish on the metal phases.X1.6 Perform final polishing with alpha alumina of particlesize 0.1 to 0.3 m, on the same type wheels as in precedingsteps. This step has two purposes: ( a) to
39、 remove scratchesfrom the metal phases, and ( b) to give some relief andtherefore contrast to the glassy phases of the ceramic and themetallizing layer.X1.7 Use heavy pressure with the diamond abrasives.Usually about a minute on each wheel will be sufficient tocompletely remove the marks made by the
40、 previous step. Thefinal alumina stage should be done with light but firm touch;time in this stage should be as short as possible in order tominimize relief of the softer metal phases.X2. TEST FOR METALLIZING QUALITYX2.1 The following test may be used to determine thequality of metallizing on any ce
41、ramic surfaces having metal-lized areas 0.125 by 0.125 in. (3.18 by 3.18 mm) or larger. Theceramic surface should be flat to 0.001 in. (0.02 mm), althoughcurved metallized surfaces may also be tested. Curved surfacestend to yield slightly higher values.X2.2 The ceramic may be metallized by any metho
42、d. Asecondary metallic layer may be deposited as desired or thesurface otherwise prepared for brazing. Position a clean,ductile metal tab 0.125 6 0.001 by 0.025 6 0.001 by 1 in.(3.18 6 0.02 by 0.6 6 0.02 by 25.4 mm) long snugly againstthe metallized surface so that 0.125 6 0.005 in. (3.18 6 0.01mm)
43、of its length is held against the metallizing. Braze usingsilver-copper eutectic solder and good established brazingtechniques.X2.3 Hold the ceramic firmly in a suitable fixture andgently bend the metal tab at right angles to the metallizedsurface at the point of contact. Grasp the end of the metal
44、tabby a suitable pressure grip and pull at right angles to theceramic surface until failure occurs. The manufacturer and thepurchaser shall agree upon acceptable low limits and maximumrange.ASTM International takes no position respecting the validity of any patent rights asserted in connection with
45、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 technic
46、al 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 consideration
47、 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 Harbo
48、r 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 44 95 (2006)3
