1、Designation: C 1494 01Standard 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 or, in the case o
2、f 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, nitrogen and oxygen i
3、n 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.1.2.2 Nitrogen and ox
4、ygen 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 and determine the a
5、pplica-bility of regulatory limitations prior to use. Specific hazardstatements are given in Section 6.2. Referenced Documents2.1 ASTM Standards:2E 29 Practice for Using Significant Digits in Test Data toDetermine Conformance with SpecificationsE 50 Practices for Apparatus, Reagents, and Safety Prec
6、au-tions for Chemical Analysis of MetalsE 1019 Standard Test Methods for Determination of Car-bon, Sulfur, Nitrogen, and Oxygen in Steel and in Iron,Nickel, and Cobalt AlloysE 1409 Standard Test Method for Determination of Oxygenin Titanium and Titanium Alloys by the Inert Gas FusionTechniqueE 1569
7、Standard Test Method for Determination of Oxygenin Tantalum PowderE 1806 Practice for Sampling Steel and Iron for Determi-nation of Chemical CompositionE 1941 Determination of Carbon in Refractory and Reac-tive Metals and Alloys3. Significance and Use3.1 These test methods are for the chemical analy
8、sis 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 work will beperformed in a properly equipped laboratory
9、.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 apparatus and reagents required for each deter-mination are
10、 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 to be observed in the use of certain reagentsin this t
11、est method, refer to Practice E 50.6.2 Use care when handling hot crucibles and operatingfurnaces to avoid personal injury by either burn or electricalshock.7. Total Carbon in Silicon Nitride Powder by DirectCombustionInfrared Detection Method7.1 ScopeThis test method covers the determination ofcarb
12、on in concentrations from 0.05 to 5.0 % mass fraction.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 April 10, 2001. Published May 2001.2F
13、or 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.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C7
14、00, West Conshohocken, PA 19428-2959, United States.7.2 Summary of Test Method3The carbon is converted tocarbon dioxide by combustion in a stream of oxygen. Theamount of carbon dioxide is measured by infrared (IR)absorption.7.3 ApparatusThis test method is written for use withcommercial carbon analy
15、zers, equipped to carry out the analy-ses operations automatically and calibrated using steel stan-dards with known concentrations of carbon. The operatingprinciples, specifications and descriptions of commercial car-bon analyzers are given in the Practice of E 1019.7.4 Reagents and Materials:7.4.1
16、CruciblesExpendable ceramic (alumina) or similarrefractory crucibles as specified by commercial carbon analyz-ers manufacturers. Both the crucible and cover, if used, mustbe prebaked for a sufficient time to produce constant blankvalues. Use the prebake schedule recommended by the instru-ment manufa
17、cturer.7.4.2 Crucible TongsCapable of handling recommendedcrucibles with respect to their sizes, shape and temperature.7.4.3 AcceleratorsCarbon free (or containing 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
18、 %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 by passing over heatedCuO and through CO2/H20 absorbents. (When the instrumenthas a built in purifier, regular grade oxygen can be used.)
19、7.5 Preparation of ApparatusFollow the operating in-structions for the specific equipment used. After having prop-erly set the operating controls of the instrument system,condition the apparatus by combustion of several blanksprepared with sample crucible and accelerator in the amountsto be used wit
20、h 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 furnaceat 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 t
21、o 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 to burnoff any organic contaminates.7.6.2 Prepare instrument as outlined in the operators in-struction manual.7.6.3 Determine the instrum
22、ent 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) Place crucible on furnace pedestal and analyze.(d) Repeat steps 7.6.3a through 7.6.3c a minimum of threetimes.(e) Enter blank value followi
23、ng routine outlined in opera-tors instruction manual.7.7 Instrument Calibration Procedure:7.7.1 This procedure was written specially for a carbonanalyzer. The type and amounts of accelerator to be added shallbe adjusted according to the manufacturers recommendationsfor the other instrumentation.7.7.
24、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.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 pe
25、destal 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 procedure as outlined in the operatorsinstruction manual.7.7.6 Check calibration by analyzing the calibration stan-dard again if it is not
26、 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 aprebaked 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
27、 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 available instrumentscalculate percent concentration directly. If the instrument doesnot give percent concentration, please follow the manufactur
28、-ers directions to ensure all the essential variables in thecalculation of analysis results have been included.Or perform the following calculation to determine percentconcentration (% mass):a. Calibration Constant:K 5G 3 P/100Ac Ab(1)where:K = calibration constant (g/integral value),G = mass of cal
29、ibration 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 blank (7.6.3e).b. Total Carbon Content:C 5As Ab! 3 K 3 100m(2)where:C = carbon content (mass %),As= integral value of the sample (7.8.3),A
30、b= integral value of the blank (7.6.3e),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.C1494012K = calibration constant (g/integral value), andm = mass of the sample (g).7.10 ReportReport carbon concentration as mass fractio
32、npercentage to the desired decimal places as directed in PracticeE 29, as well as times of replication of analysis and anydeviations from the standard analysis procedure.7.11 Precision and Bias:7.11.1 Precision:7.11.1.1 ReproducibilityThree laboratories cooperated intesting this method and obtained
33、reproducibility data for SRM8j, 1 lh, and 12h which are summarized in Table 1. Since thereference value with uncertainty of RM 8983 is determinedduring this round robin study, no reproducibility is reported.7.11.1.2 RepeatabilityThree laboratories cooperated intesting this method and obtained repeat
34、ability 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 robin study, no repeatability is reported.7.11.2 BiasNo bias of this test method is established,since insufficient number of laboratories have par
35、ticipated thisround robin study. The accuracy of a reading may be judged bycomparing values obtained with NIST reference standards suchas listed in Table 1 to their reference values and uncertainty.8. Determination of Total Nitrogen and Oxygen in SiliconNitride Powder by Direct Inert Gas Fusion-Ther
36、malConductivity Method8.1 ScopeThis test method covers the determination ofnitrogen (N) in concentrations from 30 to 45 % mass fraction.This test method 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
37、 small single-use graphite crucible, is fused under a flowinghelium atmosphere at a minimum temperature of 1900 Cwhich is sufficient to release oxygen, nitrogen and hydrogenfrom the sample. The oxygen combines with carbon from thecrucible to form carbon monoxide (CO) which is carried by thehelium in
38、ert gas stream to a thermal conductivity (TC) detec-tor. Nitrogen present in the sample is released as molecularnitrogen into the flowing helium stream. The nitrogen isseparated from other liberated gases such as hydrogen andcarbon monoxide and is finally measured in a thermal conduc-tivity cell.8.3
39、 ApparatusThis test method is written for use withcommercial nitrogen/oxygen analyzers, equipped to carry outthe analyses operation automatically and calibrated usingstandards with known mass fraction % of nitrogen/oxygen. Theoperating principles, specifications and descriptions of com-mercial nitro
40、gen/oxygen analyzers are given in the Practice ofE 1019.8.4 Reagents and Materials:8.4.1 High Temperature Graphite Crucible (resistanceheated) as recommended by the manufacturer of the instru-ment.8.4.2 Graphite Crucible (sacrificial heated) as recom-mended by the instrument manufacturer.8.4.3 Cruci
41、ble Tongs capable of handling recommendedcrucibles and capsules with respect to their sizes, shape andtemperature.8.4.4 Tin Capsules as recommended by the manufacturer ofthe instrument.8.4.5 Nickel Baskets (Flux) as recommended by the instru-ment manufacturer.8.4.6 Inert Gases (Helium, Compressed Ai
42、r, Nitrogen orArgon)Use type and purity specified by the instrumentmanufacturer.8.4.7 Calibration Standards:8.4.7.1 OxygenSelect standards with appropriate concen-trations.8.4.7.2 NitrogenSelect standards with appropriate con-centrations.8.4.7.3 Oxygen and NitrogenNIST RM 8983, SiliconNitride Powder
43、.8.5 Preparation of Apparatus and Samples:8.5.1 Follow the operating instructions for the specificequipment used. After having properly set the operatingcontrols of the instrument system, condition the apparatus byanalysis of several blanks prepared with sample crucibles andflux in the amount to be
44、used with the test specimen analyses.Successive blanks should approach a constant value, allowingfor normal statistical fluctuations.8.5.2 The powder sample to be analyzed shall be dry anduniform with a particle size distribution of 100 mesh or finer.If the sample is in bulk form, the sample crushin
45、g shall be donewithout adding oxygen to the sample. Avoid using an Agate5Adapted 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 Corp., St. Joseph, MI.TAB
46、LE 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-Hearth Steel(NIST SRM 12h)0
47、.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 Urepeatabilityis also called repeat
48、ability 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 calledreproducibility standard deviati
49、on.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.C1494013apparatus which will add oxygen in the form of Silicon Oxide.The sample and calibration standards shall
