1、Designation: F44 95 (Reapproved 2011)F44 16Standard Specification forMetallized Surfaces on Ceramic1This standard is issued under the fixed designation F44; the number immediately following the designation indicates the year of originaladoption or, in the case of revision, the year of last revision.
2、Anumber in parentheses indicates the year of last reapproval.Asuperscriptepsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This specification covers requirements for powdered refractory metal coatings produced with or without additives. Thesecoatings are appl
3、ied to ceramic bodies in order to join ceramic bodies to metals or to other metallized ceramics by means of brazingor soldering. Included in this specification are requirements for a secondary metallic layer which is usually applied over therefractory metal layer.1.2 The values stated in inch-pound
4、units are to be regarded as standard. The values given in parentheses are mathematicalconversions to SI units that are provided for information only and are not considered standard.1.3 The values stated in inch-pound units are to be regarded as the standard. The values given in parentheses are for i
5、nformationonly.2. Referenced Documents2.1 ASTM Standards:2E3 Guide for Preparation of Metallographic SpecimensF19 Test Method for Tension and Vacuum Testing Metallized Ceramic Seals3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 ceramicsas referred to in this specification are
6、 understood to be inorganic, nonmetallic materials, the major phase ofwhich must be crystalline. A glassy intercrystalline matrix may be present as one of the minor phases.3.1.2 metallizing on a ceramic, is a process whereby a sintered matrix of metal particles firmly adheres to the ceramic.3.1.3 re
7、fractory metalsthose metals with melting points equal to or higher than that of chromium. Therefore, this groupincludes chromium, columbium, molybdenum, rhenium, tantalum, and tungsten.4. Ordering Information4.1 The manufacturer and purchaser shall agree upon specific quality levels as outlined in t
8、he 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 Vacuum tightness of brazed metallized ceramic assemblies (dependent on allowab
9、le use of manufacturers product)(Section 11).5. Uniformity of Metallizing5.1 Either of the following two levels of quality may be agreed upon between manufacturer and purchaser, depending upon enduse, seal area, and geometry.5.2 Level ALess Demanding Application:1 This specification is under the jur
10、isdiction of ASTM Committee F01 on Electronics and is the direct responsibility of Subcommittee F01.03 on MetallicMaterialsMaterials, Wire Bonding, and Flip Chip.Current edition approved June 1, 2011May 1, 2016. Published June 2011May 2016. Originally approved in 1968. Last previous edition approved
11、 in 20062011 as F44-95(2006).(2011). DOI: 10.1520/F0044-95R11.10.1520/F0044-16.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on
12、 the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users
13、 consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States15.2.1 Thin areas where the cer
14、amic substrate can usually be seen 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 one coated band, spot, or pattern detail.5.2.1.2 Their extremities are no closer than 10 % of the to
15、tal band length to each other.5.2.1.3 They are no wider than 10 % of the width of the band but not exceeding 1 mm.5.2.1.4 Their cumulative length does not exceed 25 % of the total band length.5.2.2 Defects such as brush marks, screen marks, marks in the metallizing left by foreign matter such as lin
16、t, dust, etc., and pitsor blisters, will be acceptable if they meet the four conditions outlined in 5.2.1.1 through 5.2.1.4. Such defects will also beacceptable if their raised edges do not interfere with proper assembly of the joint.5.2.3 Projections on metallized surfaces, such as oversized partic
17、les or agglomerates will be objectionable if they interfere withassembly.5.2.4 Continuous coatings over sharp edges or corners with a radius less than 132 in. (0.8 mm) will not be required unless byspecific agreement between manufacturer and purchaser.5.3 Level BDemanding Application:5.3.1 Thin area
18、s will be unacceptable where the ceramic substrate can be seen through the metallizing when examined at 40magnification.5.3.2 Defects through which the underlying ceramic can be observed, such as brush or screen marks, marks left by foreignmatter such as lint or dust, and pits or chips, will be acce
19、ptable only if all of the following conditions are met:5.3.2.1 There are no more than two such defects on any coated band, spot, or pattern detail.5.3.2.2 Their extremities are not 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 %
20、of the width of area nor longer than 2 % of the length of area.5.3.3 Continuous coatings over sharp corners with a radius less than 132 in. (0.8 mm) will not be required so long as subsequentplating covers the radius. The specific gap permissible at such a corner shall be agreed upon by manufacturer
21、 and purchaser.5.3.4 Projections on metallized surfaces, such as oversize particles or agglomerates will be objectionable if they interfere withassembly or alignment.6. Thickness of Metalizing6.1 Measure thickness by observation through a calibrated micrometer eyepiece in a metallurgical microscope.
22、 Measure apolished cross section that is perpendicular to the metallized surface. The measurement shall consist of the average of at least threerepresentative readings taken where the upper and lower edges of the layer are parallel. Magnification must be at least 400 toobtain satisfactory accuracy.
23、A suggested method for specimen preparation is shown in Appendix X1.6.2 Thickness of the sinter-fired metallize layer shall range from 0.0004 in. (0.01 mm) to 0.002 in. (0.05 mm) unless otherwisemutually agreed upon between the manufacturer and the purchaser.7. Continuity of Metalizing7.1 The partic
24、les in the metallized layer must be sintered in order to form a dense matrix when viewed in cross section at 400.This cross section will indicate the extent of three-dimensional sintering.8. Discoloration of the Ceramic8.1 Almost invariably some discoloration of the ceramic adjacent to the metallize
25、d layer will exist (Note 1). The manufacturewill not be required to eliminate discoloration completely.NOTE 1The actual color and depth of penetration depend on the metallizing formula and processing cycle. Where a given degree of discolorationis objectionable to the user, the manufacturer may be ab
26、le to substitute a practice which will yield acceptable results. It is recognized that metallizedcoating properties vary with the formula and processing. If the user requires such a change to reduce coloration compromise may be necessary.9. Secondary Metallic Layer on Metallizing9.1 A secondary meta
27、llic layer on the metallizing shall be applied by the manufacturer unless otherwise specified.9.2 All metallized areas must be completely covered unless otherwise specified.9.3 The purchaser shall specify the metal to be applied.9.4 Manufacturer and purchaser shall agree upon the layer thickness, in
28、cluding maximum and minimum thickness limits.Measurement shall be by microscopicalmicroscopic examination as described in 6.1.9.5 Brightness of clean matte deposits may not be specified.9.6 Oxide films on the secondary metallic layer will not be cause for rejection.9.7 Defects such as blisters devel
29、oped in subsequent heating operations will be acceptable only in 5.2 Level A application andonly if all the following conditions are met:F44 1629.7.1 There are no more than two blisters on any one coated band, spot, or pattern detail.9.7.2 No blister is closer than 10 % of the total band length to a
30、nother blister.9.7.3 Maximum dimension of any blister does not exceed 10 % of the width of the band; in any case not to exceed 132 in. (0.8mm).9.8 The secondary metallic layer must adhere to the metallizing underneath to the extent that no separation exists at thisinterference in tension or torque p
31、eel tests after sintering of the layer in a suitable protective atmosphere.9.9 Cleanliness such as absence of fingerprints, dirt, etc., which may interfere with brazing or soldering, is not a requirementfor acceptance unless agreed upon between manufacturer and purchaser.9.10 When the secondary meta
32、llic layer is omitted from the purchaser requirements, the following items shall become a partof this specification:9.10.1 Metallized surfaces shall be reasonably free from dirt, grease, fingerprints, etc., in keeping with normal good handlingpractice, unless this condition is specifically agreed up
33、on between manufacturer and purchaser.9.10.2 The degree of oxidation acceptable on the metallizing shall be agreed upon between the manufacturer and purchaser.10. Bond Strength10.1 The manufacturer and purchaser shall agree on specific values of bond strength of brazed metallized ceramics.10.2 Quant
34、itative measurements of the bond strength may be made by the following, or other methods agreed upon betweenmanufacturer and purchaser.10.2.1 Torque Peel Test A torque peel test may be used where a standardized strip of a strong, ductile metal such as nickelis brazed to the metallized and secondary
35、metal surface. See Appendix X2.10.2.2 A tension test may be made in accordance with Test Method F19. This tension test really measures the combined effectsof all the factors involved in making the joint. It may also measure either the adherence of the metallizing to the ceramic or thecohesive streng
36、th of the sintered metal layer itself, depending on where the fracture occurs.11. Vacuum Tightness11.1 Vacuum tightness, where required by the user, shall be tested in accordance with Test Method F19, or by other methodagreed upon between the manufacturer and the purchaser.12. Keywords12.1 bond stre
37、ngth; metallizing of ceramics; thickness controlAPPENDIXES(Nonmandatory Information)X1. SUGGESTED METHOD FOR PREPARATION OF SPECIMENS FOR MICROSCOPYX1.1 Cut the specimen with a water-cooled diamond cutoff saw.X1.2 If the specimen is too small to handle readily during subsequent polishing, it may be
38、mounted by any of the ordinarymethods. (Approved methods of mounting are given in Methods E3.) It is best to mount a complete seal section in a resin whichcontains fillers so that the relatively soft metal phases adjacent to hard ceramic phases do not become rounded during polishing.X1.3 Rough grind
39、 on 240 and 400-grit diamond laps. This step should remove 0.040 in. and 0.060 in. (1 to 1.5 mm) stock fromthe surface in order to remove completely all surface damage caused by the cutoff operation.X1.4 Fine grind with 15-m diamond grinding compound on a hardwood or napless cloth-covered wheel. Thi
40、s step should imparta polished look to the ceramic and reduce the dark “plucked-out” areas considerably when viewed at 100 to 200 magnificationthrough a metallurgical microscope.X1.5 Polish successively with 6, 3, and 1-m diamond compounds on napless cloth or chemotextile-covered wheels. Anotherpoli
41、sh with submicron diamonds will improve the polish on the metal phases.F44 163X1.6 Perform final polishing with alpha alumina of particle size 0.1 to 0.3 m, on the same type wheels as in preceding steps. Thisstep has two purposes: ( a) to remove scratches from the metal phases, and ( b) to give some
42、 relief and therefore contrast to theglassy phases of the ceramic and the metallizing layer.X1.7 Use heavy pressure with the diamond abrasives. Usually about a minute on each wheel will be sufficient to completelyremove the marks made by the previous step. The final alumina stage should be done with
43、 light but firm touch; time in this stageshould be as short as possible in order to minimize relief of the softer metal phases.X2. TEST FOR METALLIZING QUALITYX2.1 The following test may be used to determine the quality of metallizing on any ceramic surfaces having metallized areas 0.125by 0.125 in.
44、 (3.18 by 3.18 mm) or larger. The ceramic surface should be flat to 0.001 in. (0.02 mm), although curved metallizedsurfaces may also be tested. Curved surfaces tend to yield slightly higher values.X2.2 The ceramic may be metallized by any method. A secondary metallic layer may be deposited as desire
45、d or the surfaceotherwise 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 0.66 0.02 by 25.4 mm) long snugly against the metallized surface so that 0.125 6 0.005 in. (3.18 6 0.01 mm) of its length is heldagainst the metallizing. Braze
46、using silver-copper eutectic solder and good established brazing techniques.X2.3 Hold the ceramic firmly in a suitable fixture and gently bend the metal tab at right angles to the metallized surface at thepoint of contact. Grasp the end of the metal tab by a suitable pressure grip and pull at right
47、angles to the ceramic surface untilfailure occurs. The manufacturer and the purchaser shall agree upon acceptable low limits and maximum range.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of th
48、is 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 technical committee and must be reviewed every five ye
49、ars 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 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 Harbor Drive, PO Box C
