1、Designation:D 4820 99Standard Test Methods forCarbon BlackSurface Area by Multipoint B.E.T.NitrogenAdsorption1This standard is issued under the fixed designation D 4820;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last
2、 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 thenitrogen surface area of carbon blacks by the conventionalBrunauer,Emmett,and
3、 Teller(B.E.T.)theory of multilayer gasadsorption behavior using multipoint determinations.Thesetest methods specify the sample preparation and treatment,instrument calibrations,required accuracy and precision ofexperimental data,and calculations of the surface area resultsfrom the obtained data.1.2
4、 The values stated in SI units are to be regarded as thestandard.The values given in parentheses are for informationonly.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-pria
5、te safety and health practices and determine the applica-bility of regulatory limitations prior to use.(The minimumsafety equipment should include protective gloves,sturdy eyeand face protection,and means to deal with accidental mercuryspills.)2.Referenced Documents2.1 ASTM Standards:D 1799 Practice
6、 for Carbon BlackSampling PackagedShipments2D 1900 Practice for Carbon BlackSampling Bulk Ship-ments2D 3324 Practice for Carbon BlackImproving Test Repro-ducibility Using ASTM Reference Blacks2D 4483 Practice for Determining Precision for Test MethodStandards in the Rubber and Carbon Black Industrie
7、s23.Significance and Use3.1 These test methods are used to measure the standardnitrogen surface area of carbon blacks by the Multipoint(B.E.T.)Method.4.Sampling4.1 Samples may be taken in accordance with PracticeD 1799 and Practice D 1900.TESTMETHODASURFACEAREA BYCLASSICALGLASSVACUUMAPPARATUS5.Summa
8、ry of Test Method5.1 The nitrogen surface area is measured by evaluating theamount of nitrogen absorbed,at liquid nitrogen temperature,bya carbon black standard(or other carbon black sample)atseveral(at least five)partial pressures of nitrogen.6.Apparatus6.1 Classical Glass Vacuum Apparatus or equiv
9、alent,con-structed as shown in Fig.1,including diffusion pump,manom-eter,and buret similar to the one illustrated in Fig.1.6.1.1 Equivalent apparatus must include:manometer,gasburet,gas storage vessels,diffusion and vacuum pumps,andsample cell(see Note 7).6.2 Oven,vacuum-type,capable of temperature
10、regulationto6 5C at 200C.Pressure should be less than 135 Pa(1mmHg).6.3 Sample cells which,when attached to the vacuumapparatus,will maintain pressure below 1.35 mPa(10 nm Hg).6.4 Dewar Flasks,two each with volumes of 2 dm3.6.5 Mechanical Vacuum Pump.6.6 McCloud Gage,or equivalent means to measure s
11、tatusof the vacuum.6.7 Balance,Analytical,with 0.1 mg sensitivity.6.8 Gas-tight glass stopcock assemblies as required for theapparatus.6.9 Supply of small(30 cm3)glass vials with caps for ovendrying samples.6.10 Heating Mantle or equivalent,capable of maintaininga temperature of 300 6 10C.7.Reagents
12、7.1 Purity of ReagentsReagent grade chemicals shall beused in all tests.Unless otherwise indicated,it is intended thatall reagents shall conform to the specifications of the Commit-tee on Analytical Reagents of the American Chemical Society,1This test method is under the jurisdiction ofASTM Committe
13、e D-24 on CarbonBlackand is the direct responsibility of Subcommittee D24.21 on AdsorptiveProperties of Carbon Black.Current edition approved Aug.10,1999.Published September 1999.Originallypublished as D 4820 89.Last previous edition D 4820 97.2Annual Book of ASTM Standards,Vol 09.01.1Copyright ASTM
14、,100 Barr Harbor Drive,West Conshohocken,PA 19428-2959,United States.NOTICE:This standard has either been superseded and replaced by a new version or discontinued.Contact ASTM International(www.astm.org)for the latest information.where such specifications are available.3Other grades may beused,provi
15、ded it is first ascertained that it is of sufficiently highpurity to permit its use without lessening the accuracy of thedetermination.7.2 Purity of Water Unless otherwise indicated,refer-ences to water shall be understood to mean distilled water orwater of equal purity.7.3 Liquid nitrogen.7.4 Ultra
16、-high purity nitrogen gas,cylinder,or other sourceof prepurified nitrogen gas.7.5 Ultra-high purity helium gas,cylinder,or other source ofprepurified helium gas.7.6 Instrument grade mercury.7.7 High vacuum stopcock grease,Apiezon-type N.8.Preparation of ApparatusNOTE1This procedure only need be performed for the initial cali-bration of the gas buret or when a modification is made to the gas buret.8.1 Zero the manometer by evacuating both arms of themanometer to a pressure below 1.35 mPa(10 nmHg)
