ASTM_E_2040_-_08_2014.pdf

Designation:E204008(Reapproved 2014)Standard Test Method forMass Scale Calibration of Thermogravimetric Analyzers1This standard is issued under the fixed designation E2040;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method describes the calibration or perfor-mance confirmation of the mass(or weight)scale of thermo-gravimetric analyzers and is applicable to commercial andcustom-built apparatus.1.2 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.3 There is no ISO standard equivalent to this test method.1.4 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.Referenced Documents2.1 ASTM Standards:2E473 Terminology Relating to Thermal Analysis and Rhe-ologyE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test MethodE1142 Terminology Relating to Thermophysical Properties3.Terminology3.1 DefinitionsSpecific technical terms used in this testmethod are defined in Terminologies E473 and E1142.4.Summary of Test Method4.1 The mass signal generated by a thermogravimetricanalyzer is compared to the mass of a reference materialtraceable to a national reference laboratory.Alinear correlationusing two calibration points is used to relate the mass(orweight)signal generated by the thermogravimetric analyzerand that of the reference material.5.Significance and Use5.1 This test method calibrates or demonstrates conformityof thermogravimetric apparatus at ambient conditions.Mostthermogravimetry analysis experiments are carried out undertemperature ramp conditions or at isothermal temperaturesdistant from ambient conditions.This test method does notaddress the temperature effects on mass calibration.5.2 In most thermogravimetry experiments,the masschange is reported as weight percent in which the observedmass at any time during the course of the experiment is dividedby the original mass of the test specimen.This method ofreporting results assumes that the mass scale of the apparatusis linear with increasing mass.In such cases,it may benecessary only to confirm the performance of the instrument bycomparison to a suitable reference.5.3 When the actual mass of the test specimen is recorded,the use of a calibration factor to correct the calibration of theapparatus may be required,on rare occasions.6.Apparatus6.1 The essential equipment required to provide the mini-mum thermogravimetric analytical capability for this testmethod includes the following:6.1.1 Thermobalance,composed of a furnace;a tempera-ture sensor;a balance to measure the specimen mass with aminimum capacity within the range to be calibrated and asensitivity of 61 g;and a means of maintaining the specimen/container under atmospheric control of the gas to be used at apurge rate between 10 to 100 6 5 mL/min.NOTE1Excessive purge rates should be avoided as this may introducenoise due to buoyancy effects and temperature gradients.6.1.2 Temperature Controller,capable of maintaining ambi-ent temperature to 61K.6.1.3 A Data Collection Device,to provide a means ofacquiring,storing,and displaying measured or calculatedsignals,or both.The minimum output signals required forthermogravimetric analysis are mass,temperature,and time.6.1.4 Containers(pans,crucibles,etc.),which are inert tothe specimen and which will remain gravimetrically stable.1This test method is under the jurisdiction ofASTM Committee E37 on ThermalMeasurements and is the direct responsibility of Subcommittee E37.01 on Calo-rimetry and Mass Loss.Current edition approved March 15,2014.Published April 2014.Originallyapproved in 1999.Last previous edition approved in 2008 as E2040 08.DOI:10.1520/E2040-08R14.2For referenced ASTM standards,visit the website www.astm.org,or contactASTM Customer service at serviceastm.org.For Annual Book of ASTM Standardsvolume information,refer to the standards Document Summary page on theASTMwebsite.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 7.Reagents and Materials7.1 A reference material of known mass,which is traceableto a national standards laboratory,such as the National Instituteof Standards and Technology(NIST).Such mass referencematerials are available from most general laboratory equipmentsuppliers.7.2 The mass of the reference material should correspond tothe working range of the analysis.For most work,the massmaximum should be 25 to 50%greater than the material beingexamined.8.Calibration and Standardization8.1 P