1、Designation: C 1336 96 (Reapproved 2002)Standard Practice forFabricating Non-Oxide Ceramic Reference SpecimensContaining Seeded Inclusions1This standard is issued under the fixed designation C 1336; the number immediately following the designation indicates the year oforiginal adoption or, in the ca
2、se of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice covers a procedure for fabricating bothgreen and sintered test samples of s
3、ilicon carbide and siliconnitride containing inclusions. These samples can be used todetermine the sensitivity and detection capability of a nonde-structive examination (NDE) method.1.2 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informati
4、ononly.1.3 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. Refer
5、enced Documents2.1 ASTM Standards:B 331 Test Method for Compressibility of Metal PowdersUniaxial Compaction2C 373 Test Method for Water Absorption, Bulk Density,Apparent Porosity, and Apparent Specific Gravity of FiredWhiteware Products33. Terminology3.1 Definitions of Terms Specific to This Standar
6、d:3.1.1 green specimenformed ceramic specimens as origi-nally compacted prior to high-temperature densification.3.1.2 inclusiona solid discontinuity in a specimen, with acomposition not that of the specimen.3.1.3 seeded inclusionsdiscontinuities intentionallyplaced at prescribed locations in referen
7、ce specimens.3.1.4 sintered specimenformed ceramic specimen afterfiring to densify and remove solvents or binders.4. Significance and Use4.1 This practice describes a method of fabrication ofknown discontinuities in a ceramic specimen. Such specimensare needed and used in nondestructive examination
8、to demon-strate sensitivity and resolution and to assist in establishingproper examination parameters.5. Apparatus5.1 Aerosol Duster, moisture-free.5.2 Die, capable of exerting pressure up to 120 MPa andwill not contaminate the compacted material.5.3 Optical Magnifier, capable of providing 10 to 303
9、magnification.5.4 Tubing, latex, thin-wall, for encapsulating compact dur-ing isopressing.5.5 Carver Press, or similar type of apparatus capable ofexerting the necessary pressure to consolidate the sample.5.6 Cold Isostatic Press, capable of maintaining 500 MPa.5.7 Oven or Furnace, which can maintai
10、n a temperature of500C.5.8 Imaging Equipment, with the capability of producing ahard copy output of the image (that is, 35 mm camera, chargecoupled device (CCD) camera outputted to a video printer, astereo microscope with 4 by 5 instamatic film, etc.).5.9 Sintering Furnaces, capable of reaching temp
11、eratures of1400 to 2200C. Depending on the ceramic system chosen, thefurnace may be required to operate in a vacuum or under inertgas atmospheres, or both, at pressures as high as 200 MPa.5.10 Mettler Scale, or similar device capable of measuringwithin 0.01 mg. Measuring densities according to Archi
12、medesprinciple requires the use of a sample holder suspended inwater attached to the scale.6. Materials6.1 Silicon Carbide or Silicon Nitride Powders, of appro-priate purity and particle size, prepared with sintering aids andbinder representative of the product to be inspected and in amanner appropr
13、iate for dry pressing with granule size less than100 mesh.6.2 Inclusion Spheres, diameters as needed. Inclusion ma-terials selected based on applicable green and sintered inclu-sion that is desired to be investigated for a specific siliconnitride or silicon carbide application.6.2.1 The size, shape,
14、 and composition of the inclusionsshall be determined a priori before seeding. The inclusion1This practice is under the jurisdiction of ASTM Committee C28 on AdvancedCeramics and is the direct responsibility of Subcommittee C28.02 on Design andEvaluation.Current edition approved June 10, 1996. Publi
15、shed August 1996. Originallypublished as C 1336 96. Last previous edition C 1336 96.2Annual Book of ASTM Standards, Vol 02.05.3Annual Book of ASTM Standards, Vol 15.02.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.particles must be
16、 carefully selected based on the ceramicsystem of interest and the purpose of the test samples.6.2.1.1 Samples fabricated to determine the sensitivity andresolution of the NDE test method should have inclusions thatrepresent the type that would be encountered in actual appli-cations. The selection o
17、f the inclusion type should reflect thepossible impurities that are commonly seen after processingand that are present in the raw material.6.2.1.2 Test samples being fabricated for NDE calibrationstandards may require the use of inclusion particles withwell-defined properties (that is, geometry, den
18、sity, modulus,composition, etc.). Such particles may be chosen to be excep-tionally stable during sample fabrication.7. Fabrication of Internal Seeded Inclusions7.1 For Green Specimens:7.1.1 The test piece geometry must be appropriate for thesize and geometry limits of the NDE test method. If thepur
19、pose of the test is to determine if the NDE method issuitable for the detection of inclusions in a particular part/sample, ideally the test sample should be identical to thepart/sample. If this is not feasible due to fabrication or testinglimitations, the test sample should be similar to the part/sa
20、mplein chemical composition, density, and thickness (the thicknessof the test sample should be the same as the thickness in thearea of the part/sample being examined).7.1.2 Procedure:7.1.2.1 Prepare test specimen bars by pouring powder into adie in an amount to position the inclusions at the desired
21、distance from the specimen surfaces. If the inclusions to beseeded are less than 200 m in diameter, level the surface andpress at 60 MPa to facilitate positioning of the inclusions.Pressing is not necessary if the diameter will be greater.7.1.2.2 Remove the ram to expose the specimen. Clean thespeci
22、men of all particles that are not flush with the top surface;this can generally be done with a moisture-free aerosol duster.7.1.2.3 Place large inclusions in the desired location on thespecimen surface. Small inclusions may be moved to thedesired position with a single human hair taped to a stiff pl
23、asticrod with the assistance of an optical magnifier.7.1.2.4 Press the inclusions into the surface at a pressure of60 MPa to hold them in position.7.1.2.5 Record the positions of the inclusions photographi-cally using a CCD camera attached to a stereo microscope orother suitable imaging equipment de
24、pending on the size of theinclusions used.7.1.2.6 Add ceramic powder of a sufficient amount toseparate the adjacent layers of inclusions. If this is the finallayer of powder, press to provide handling strength to the greencompact (nominally 120 MPa); otherwise press at 60 MPa andrepeat 7.1.2.2-7.1.2
25、.5 through until the desired number ofinclusion layers are obtained.7.1.2.7 After final pressing, remove the specimen from thedie and place into thin-wall latex tubing, evacuate the air, andseal the end. Cold isopress at 420 MPa or a pressure mostsuitable for specific material.7.1.2.8 Remove the spe
26、cimen from the tubing and heat to asufficient temperature to decompose the binder if it has beenadded for powder compaction assistance.7.1.2.9 Mark the specimen orientation with a scribe mark orby beveling a corner or edge. Remove extraneous particlesfrom all surfaces with an aerosol duster or brush
27、 (adherentparticles may require light sanding).7.1.2.10 Measure bulk density of the specimen from directvolume and weight measurements.7.2 For Sintered Specimens:7.2.1 Procedure:7.2.1.1 Follow steps in 7.1.2 to produce green specimens.7.2.1.2 Sinter green samples under suitable conditions toachieve
28、full densification. Nominal sintering conditions forsilicon nitride are: 1700 to 1900C for1hinaninertatmosphere at 0 to 200 MPa; for silicon carbide, sinteringtemperatures of 2000 to 2200C for 0.5 h under vacuum arecommonly used. The sintering aids used will dictate the firingconditions. Measure bul
29、k density using a method referenced in2.1 (Test Methods B 331 and C 373) or from volume andweight measurements.7.3 Sintered Inclusion Characteristics:7.3.1 For Silicon Nitride Test BarsMany inclusions reactwith silicon nitride powder and sintering aid powders duringdensification, potentially resulti
30、ng in chemical and structuralchanges to the inclusion and possibly resulting in a reactionzone different in size from the size of the original inclusionbefore densification. For example, iron inclusions can reactwith free silica in the silicon nitride powder during densifica-tion to form iron silici
31、de, with a larger resulting reaction zonethan the original iron inclusion size. The dimensions of theinclusion may increase by 50 %. The final dimensions of theinclusion are affected by the environmental conditions withinthe furnace, cooling rates, soak times, etc. Thus, the effectdensification has
32、on inclusions in silicon nitride should beknown a priori to ensure correct interpretation of results.7.3.2 For Silicon Carbide Test BarsMany inclusions mayalso react with the SiC powder and some of the sintering aidpowders during densification. This reaction may result instructural and chemical chan
33、ges to the inclusion causing thedimensions of the inclusion to be different than that of theoriginal. The reactivity of the inclusion with the SiC powdersor additives should be understood for proper interpretation ofthe results.8. Fabrication of Surface Seeded Inclusions8.1 For Green Specimens:8.1.1
34、 Procedure:8.1.1.1 Prepare test specimen bars by pouring powder into adie in an amount sufficient to make a specimen of the desiredthickness. Level the surface and press at a nominal pressure of60 MPa.8.1.1.2 Remove the ram to expose the specimen. Clean thespecimen of all particles that are not flus
35、h with the top surface;this can generally be done with a moisture-free aerosol duster.8.1.1.3 Place large inclusions in the desired location on thespecimen surface. Small inclusions may be moved to thedesired position with a single human hair taped to a stiff plasticrod with the assistance of an opt
36、ical magnifier.8.1.1.4 Press the inclusions into the surface at a suitablepressure to obtain desired strength for handling of the greencompact (typically 120 MPa).C 133628.1.1.5 Record the position of the inclusions with the use ofimaging equipment or other suitable means.8.1.1.6 Remove the bar from
37、 the die and clear surfaces ofextraneous particles. An aerosol duster or brush should beadequate.8.1.1.7 Remove the specimen from the die and place intothin-wall latex tubing, evacuate the air, and seal the end. Coldisopress at 420 MPa or a pressure most suitable for specificmaterial.8.1.1.8 Remove
38、the specimen from the tubing and heat to asufficient temperature to decompose the binder if it has beenadded for powder compaction assistance.8.1.1.9 Mark the specimen orientation with a scribe mark orby beveling a corner or edge. Remove extraneous particlesfrom all surfaces with an aerosol duster o
39、r brush (adherentparticles may require light sanding).8.1.1.10 Measure bulk density of the specimen from directvolume and weight measurements.8.2 For Sintered Specimens:8.2.1 Procedure:8.2.1.1 Follow steps in 8.1.1 to produce green specimens.8.2.1.2 Sinter green samples under suitable conditions toa
40、chieve full densification. Nominal sintering conditions forsilicon nitride are: 1700 to 1900C for1hinaninertatmosphere at 0 to 200 MPa; for silicon carbide, 2000 to2200C for 0.5 h under vacuum is commonly used. Thesintering aids used will dictate the firing conditions. Measurebulk density using a me
41、thod referenced in 2.1 or from volumeand weight measurements.9. Report9.1 Report the location and measured size of the inclusion.Depending on the size of the inclusion and the precisionrequired, the inclusion can be measured directly or by indirectmethods using suitable imaging equipment.10. Keyword
42、s10.1 advanced ceramics; non-oxide ceramicsASTM 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 of any such patent rights, and
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45、ldmake 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 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).C 13363
