1、Designation:D754221Standard Test Method forAir Oxidation of Carbon and Graphite in the Kinetic Regime1This standard is issued under the fixed designation D7542;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision
2、.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope*1.1 This test method recommends a standard procedure formeasuring oxidation rates in air of various grades of nucleargraphite and/or manufa
3、ctured carbon.Following the standardprocedure recommended here,one can obtain kinetic param-eters that characterize the oxidation resistance in standardconditions of tested materials and that can be used to formaterials selection and qualification,and for quality controlpurposes in the fabrication p
4、rocess.1.2 This test method covers the rate of oxidative weight lossper exposed nominal geometric surface area,or per initialweight of machined test specimens of standard size and shape,or both.The test is valid in the temperature range where therate of air oxidation of graphite and manufactured car
5、bon islimited by reaction kinetics.1.3 This test method also provides a standard oxidationtemperature(as defined in 3.1.7),and the kinetic parameters ofthe oxidation reaction,namely the apparent activation energyand the logarithm of pre-exponential factor in Arrheniusequation.The kinetic parameters
6、of Arrhenius equation arecalculated from the temperature dependence of oxidation ratesmeasured over the temperature range whereArrhenius plots(asdefined in 3.1.8)are linear,which is defined as the“kinetic”or“chemical control”oxidation regime.For typical nuclear gradegraphite materials it was found t
7、hat the practical range oftesting temperatures is from about 500 C to 550 C up toabout 700 C to 750 C.1.4 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.5 This standard does not purport to address all of thesafety concerns,if
8、any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.6 This international standard was developed in accor-dance with international
9、ly recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Referenced Documents2.1 ASTM Standards:2C559 Test Method
10、for Bulk Density by Physical Measure-ments of Manufactured Carbon and Graphite ArticlesE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test MethodE898 Practice for Calibration of Non-Automatic WeighingInstrumentsE1582 Test Method for Temperature Calibration of Th
11、ermo-gravimetric AnalyzersE1970 Practice for Statistical Treatment of ThermoanalyticalData3.Terminology3.1 Definitions:3.1.1 Definitions are ordered by oxidation rates first,fol-lowed by activation energy as calculated from oxidation rates.3.1.2 area-normalized oxidation rate(ORa),nrate ofweight los
12、s due to oxidation of a machined test specimen at agiven temperature,divided by the nominal geometric surfacearea of the specimen.3.1.2.1 DiscussionThe rate of weight loss is determinedby a linear fit of the weight loss plotted against time in therange from 5%to 10%loss of original specimen weight.T
13、heunits of area-normalized oxidation rate,ORa,are g h-1m-2.3.1.3 weight-normalized oxidation rate(ORw),nrate ofweight loss due to oxidation of a machined specimen at a giventemperature,divided by the initial weight of the specimen.3.1.3.1 DiscussionThe rate of weight loss is determinedby a linear fi
14、t of the weight loss plotted against time in therange from 5%to 10%loss of original specimen weight.Theunits of weight-normalized oxidation rate,ORware:1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products,Liquid Fuels,and Lubricants and is the direct responsibility
15、ofSubcommittee D02.F0 on Manufactured Carbon and Graphite Products.Current edition approved Nov.1,2021.Published November 2021.Originallyapproved in 2009.Last previous edition approved in 2015 as D7542 15.DOI:10.1520/D7542-21.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orconta
16、ct ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.*A Summary of Changes section appears at the end of this standardCopyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
