1、Designation: C 1494 01 (Reapproved 2007)Standard Test Methods forDetermination of Mass Fraction of Carbon, Nitrogen, andOxygen in Silicon Nitride Powder1This standard is issued under the fixed designation C 1494; the number immediately following the designation indicates the year oforiginal adoption
2、 or, in the case 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 These test methods cover the determination of massfraction % of carbon, nit
3、rogen and oxygen in silicon nitridepowder having chemical compositions within the followinglimits:Element Mass Fraction % RangeCarbon 0.05 to 5.0Nitrogen 30 to 45Oxygen 0.1 to 1.51.2 Two test methods appear in this standard.1.2.1 Total Carbon by the Direct Combustion-Infrared Mea-surement Method.1.2
4、.2 Nitrogen and oxygen by the Inert Gas Fusion-ThermalConductivity Measurement Method.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 a
5、nd determine the applica-bility of regulatory limitations prior to use. Specific hazardstatements are given in Section 6.2. Referenced Documents2.1 ASTM Standards:2E29 Practice for Using Significant Digits in Test Data toDetermine Conformance with SpecificationsE50 Practices for Apparatus, Reagents,
6、 and Safety Consid-erations for Chemical Analysis of Metals, Ores, andRelated MaterialsE 1019 Test Methods for Determination of Carbon, Sulfur,Nitrogen, and Oxygen in Steel and in Iron, Nickel, andCobalt AlloysE 1409 Test Method for Determination of Oxygen andNitrogen in Titanium and Titanium Alloys
7、 by the Inert GasFusion TechniqueE 1569 Test Method for Determination of Oxygen in Tan-talum PowderE 1806 Practice for Sampling Steel and Iron for Determi-nation of Chemical CompositionE 1941 Test Method for Determination of Carbon in Refrac-tory and Reactive Metals and Their Alloys3. Significance a
8、nd Use3.1 These test methods are for the chemical analysis of massfraction of carbon, nitrogen and oxygen in silicon nitridepowder. It is assumed that all who use these test methods willbe trained analysts, capable of performing common laboratoryprocedures skillfully and safely. It is expected that
9、work will beperformed in a properly equipped laboratory.4. Apparatus and Reagents4.1 The procedure was written with commercial carbon andnitrogen/oxygen analyzers in mind. For any other analyzer, theinstrument manual specific to that analyzer shall be consultedfor instrument set-up.4.2 Specific appa
10、ratus and reagents required for each deter-mination are listed in separate sections preceding the procedure.5. Sampling5.1 Procedures for sampling the materials refer to thoseparts of Practice E 1806 pertaining to solid form samples of thetype used for instrumental analysis.6. Hazards6.1 For hazards
11、 to be observed in the use of certain reagentsin this test method, refer to Practice E50.1These test methods are under the jurisdiction of ASTM Committee C28 onAdvanced Ceramics and are the direct responsibility of Subcommittee C28.03 onPhysical Properties and Performance.Current edition approved No
12、v. 1, 2007. Published December 2007. Originallyapproved in 2001. Last previous edition approved in 2001 as C 1494 01.2For 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
13、 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.6.2 Use care when handling hot crucibles and operatingfurnaces to avoid personal injury by either burn or electricalshock.7. Tota
14、l Carbon in Silicon Nitride Powder by DirectCombustionInfrared Detection Method7.1 ScopeThis test method covers the determination ofcarbon in concentrations from 0.05 to 5.0 % mass fraction.7.2 Summary of Test Method3The carbon is converted tocarbon dioxide by combustion in a stream of oxygen. Theam
15、ount of carbon dioxide is measured by infrared (IR)absorption.7.3 ApparatusThis test method is written for use withcommercial carbon analyzers, equipped to carry out the analy-ses operations automatically and calibrated using steel stan-dards with known concentrations of carbon. The operatingprincip
16、les, specifications and descriptions of commercial car-bon analyzers are given in the Practice of E 1019.7.4 Reagents and Materials:7.4.1 CruciblesExpendable ceramic (alumina) or similarrefractory crucibles as specified by commercial carbon analyz-ers manufacturers. Both the crucible and cover, if u
17、sed, mustbe prebaked for a sufficient time to produce constant blankvalues. Use the prebake schedule recommended by the instru-ment manufacturer.7.4.2 Crucible TongsCapable of handling recommendedcrucibles with respect to their sizes, shape and temperature.7.4.3 AcceleratorsCarbon free (or containin
18、g a knownamount of carbon) granular tungsten/tin and iron chip accel-erators shall be used.7.4.4 Carbon Standard MaterialNIST SRM 8j(0.081 %C), SRM 1 lh (0.2 %C), SRM 12h (0.407 %C), andNIST RM 8983 (0.107 %C).7.4.5 OxygenUltra High Purity (99.95 % minimum pu-rity) or Regular grade (99.5 %) purified
19、 by passing over heatedCuO and through CO2/H20 absorbents. (When the instrumenthas a built in purifier, regular grade oxygen can be used.)7.5 Preparation of ApparatusFollow the operating in-structions for the specific equipment used. After having prop-erly set the operating controls of the instrumen
20、t system,condition the apparatus by combustion of several blanksprepared with sample crucible and accelerator in the amountsto be used with the test specimen analyses. Successive blanksshould achieve a steady state value.7.6 Blank Determination:7.6.1 Prebake ceramic crucibles in a muffle or tube fur
21、naceat 1350 C for not less than 15 min or at 1000 C for not lessthan 40 minutes. The crucibles shall be removed from thefurnace, allowed to cool for 1-2 min and placed in a desiccatorfor storage. If the crucibles are not used within four hours, theymust be prebaked again. This prebaking procedure is
22、 to burnoff any organic contaminates.7.6.2 Prepare instrument as outlined in the operators in-struction manual.7.6.3 Determine the instrument blank.(a) Enter 1.000 g weight into weight stack.(b) Add 1.000 g (6 0.005 g) of tungsten/tin accelerator and1.000 g (6 0.005 g) of iron chip accelerator.(c) P
23、lace crucible on furnace pedestal and analyze.(d) Repeat steps 7.6.3a through 7.6.3c a minimum of threetimes.(e) Enter blank value following routine outlined in opera-tors instruction manual.7.7 Instrument Calibration Procedure:7.7.1 This procedure was written specially for a carbonanalyzer. The typ
24、e and amounts of accelerator to be added shallbe adjusted according to the manufacturers recommendationsfor the other instrumentation.7.7.2 Weigh 0.1 to 0.5 g of calibration standard to thenearest mg into a prebaked ceramic or similar refractorycrucible and enter appropriate weight into weight stack
25、.7.7.3 Add approx. 1.0 6 0.005 g of tungsten/tin acceleratorand approx. 1.0 6 0.005 g of iron chips accelerator.7.7.4 Place crucible on pedestal and analyze.7.7.5 Repeat the above steps 7.7.2-7.7.4 a minimum of threetimes for each standard, and calibrate the instrument followingthe auto calibration
26、procedure as outlined in the operatorsinstruction manual.7.7.6 Check calibration by analyzing the calibration stan-dard again if it is not within the reported range. If it is not,repeat steps 7.7.2-7.7.4.7.8 Sample Analysis Procedure:7.8.1 Weigh 0.1 to 0.5 g of sample to the nearest mg into aprebake
27、d expendable ceramic or a similar refractory crucibleand add appropriate weight to the weight stack.47.8.2 Repeat steps 7.7.3 and 7.7.4 in the calibration proce-dure.7.8.3 Each sample shall be analyzed in triplicate and recordthe integral values of the sample.7.9 CalculationMost commercially availab
28、le instrumentscalculate percent concentration directly. If the instrument doesnot give percent concentration, please follow the manufactur-ers directions to ensure all the essential variables in thecalculation of analysis results have been included.Or perform the following calculation to determine p
29、ercentconcentration (% mass):a. Calibration Constant:K 5G 3 P/100Ac Ab(1)where:K = calibration constant (g/integral value),G = mass of calibration sample (g),P = total carbon content of the calibration sample (%mass),Ac= integral value of the calibration sample (7.7.6), andAb= integral value of the
30、blank (7.6.3e).b. Total Carbon Content:3The test method procedure was adapted from (a) ASTM E 1019-94 , “StandardTest Methods for Determination of C, S, N, and O in Iron, Nickel and CobaltAlloys” and ( b) Application Bulletin: “Carbon and Sulfur in Ceramic and SimilarMaterials,” LECO Corp., St. Jose
31、ph, MI.4The weight of sample is chosen based on the expected amount of carbonpresent and so the CO2produced will fall within the detection range of the IRdetector.C 1494 01 (2007)2C 5As Ab! 3 K 3 100m(2)where:C = carbon content (mass %),As= integral value of the sample (7.8.3),Ab= integral value of
32、the blank (7.6.3e),K = calibration constant (g/integral value), andm = mass of the sample (g).7.10 ReportReport carbon concentration as mass fractionpercentage to the desired decimal places as directed in PracticeE29, as well as times of replication of analysis and anydeviations from the standard an
33、alysis procedure.7.11 Precision and Bias:7.11.1 Precision:7.11.1.1 ReproducibilityThree laboratories cooperated intesting this method and obtained reproducibility data for SRM8j, 1 lh, and 12h which are summarized in Table 1. Since thereference value with uncertainty of RM 8983 is determinedduring t
34、his round robin study, no reproducibility is reported.7.11.1.2 RepeatabilityThree laboratories cooperated intesting this method and obtained repeatability data for SRM 8j,1 lh and 12h which are summarized in Table 1. Since thereference value with uncertainty of RM 8983 is determinedduring this round
35、 robin study, no repeatability is reported.7.11.2 BiasNo bias of this test method is established,since insufficient number of laboratories have participated thisround robin study. The accuracy of a reading may be judged bycomparing values obtained with NIST reference standards suchas listed in Table
36、 1 to their reference values and uncertainty.8. Determination of Total Nitrogen and Oxygen in SiliconNitride Powder by Direct Inert Gas Fusion-ThermalConductivity Method8.1 ScopeThis test method covers the determination ofnitrogen (N) in concentrations from 30 to 45 % mass fraction.This test method
37、also covers the determination of oxygen (O)in concentrations from 0.1 to 1.5 % mass fraction.8.2 Summary of Test Method5The specimen, contained ina small single-use graphite crucible, is fused under a flowinghelium atmosphere at a minimum temperature of 1900 Cwhich is sufficient to release oxygen, n
38、itrogen and hydrogenfrom the sample. The oxygen combines with carbon from thecrucible to form carbon monoxide (CO) which is carried by thehelium inert gas stream to a thermal conductivity (TC) detec-tor. Nitrogen present in the sample is released as molecularnitrogen into the flowing helium stream.
39、The nitrogen isseparated from other liberated gases such as hydrogen andcarbon monoxide and is finally measured in a thermal conduc-tivity cell.8.3 ApparatusThis test method is written for use withcommercial nitrogen/oxygen analyzers, equipped to carry outthe analyses operation automatically and cal
40、ibrated usingstandards with known mass fraction % of nitrogen/oxygen. Theoperating principles, specifications and descriptions of com-mercial nitrogen/oxygen analyzers are given in the Practice ofE 1019.8.4 Reagents and Materials:8.4.1 High Temperature Graphite Crucible (resistanceheated) as recomme
41、nded by the manufacturer of the instru-ment.8.4.2 Graphite Crucible (sacrificial heated) as recom-mended by the instrument manufacturer.8.4.3 Crucible Tongs capable of handling recommendedcrucibles and capsules with respect to their sizes, shape andtemperature.8.4.4 Tin Capsules as recommended by th
42、e manufacturer ofthe instrument.8.4.5 Nickel Baskets (Flux) as recommended by the instru-ment manufacturer.8.4.6 Inert Gases (Helium, Compressed Air, Nitrogen orArgon)Use type and purity specified by the instrumentmanufacturer.8.4.7 Calibration Standards:8.4.7.1 OxygenSelect standards with appropria
43、te concen-trations.8.4.7.2 NitrogenSelect standards with appropriate con-centrations.8.4.7.3 Oxygen and NitrogenNIST RM 8983, SiliconNitride Powder.8.5 Preparation of Apparatus and Samples:8.5.1 Follow the operating instructions for the specificequipment used. After having properly set the operating
44、controls of the instrument system, condition the apparatus byanalysis of several blanks prepared with sample crucibles andflux in the amount to be used with the test specimen analyses.Successive blanks should approach a constant value, allowingfor normal statistical fluctuations.8.5.2 The powder sam
45、ple to be analyzed shall be dry anduniform with a particle size distribution of 100 mesh or finer.5Adapted from (a)ASTM E l019-94, “Standard Test Methods for Determinationof C, S, N, and O in Iron, Nickel and Cobalt Alloys” and (b) Application Bulletin,“Oxygen and Nitrogen in Nitride Powders,” LECO
46、Corp., St. Joseph, MI.TABLE 1 Statistical Information for Carbon Analysis (MassFraction %)TestSpecimenCarbonReferenceValueFoundRepeatabilityLimitAReproducibilityLimitBBessemer Steel(NIST SRM 8j)0.081 6 0.001C0.0796 0.0089 0.0066Open-Hearth Steel(NIST SRM 11h)0.200 6 0.001D0.2038 0.0022 0.0126Open-He
47、arth Steel(NIST SRM 12h)0.407 6 0.003E0.4211 0.0055 0.0383Silicon Nitride(NIST RM 8983)0.107 6 0.015F. . .AThe 95 % repeatability limit is defined as 1.96* Urepeatabilitywhich is theuncertainty of a difference of two averages, each based on 3 repeated measure-ments at one laboratory. This Urepeatabi
48、lityis also called repeatability standarddeviation.BThe 95 % reproducibility limit is defined as 1.96* Ureproducibilitywhich is theuncertainty of a difference of two averages, each of which is based on 3 repeatedmeasurements from two different laboratories. This Ureproducibilityis also calledreprodu
49、cibility standard deviation.CThe SRM 8j Certificate reports 4 determinations which have a standarddeviation of 0.001.DThe SRM 11h Certificate reports no deviation from the reference value bymore than 61 in the last significant figure.EThe SRM 12h Certificate reports 5 determinations which have a standarddeviation of 0.003.FThe RM 8983 Certificate reports the uncertainty in the reference value whichis expressed as expanded uncertainty U, at the 95 % level of confidence.C 1494 01 (2007)3If the sample is in bulk form, the sample crushing shall be donew
