1、Designation: E1860 13Standard Test Method forElapsed Time Calibration of Thermal Analyzers1This standard is issued under the fixed designation E1860; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A numb
2、er 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 elapsed-time signal from thermalanalyzers.1.2 The values sta
3、ted 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 t
4、he 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:2D3350 Specification for Polyethylene Plastics Pipe and Fit-tings MaterialsD3895 Test Method for Oxidative-
5、Induction Time of Poly-olefins by Differential Scanning CalorimetryD4565 Test Methods for Physical and Environmental Per-formance Properties of Insulations and Jackets for Tele-communications Wire and CableD5483 Test Method for Oxidation Induction Time of Lubri-cating Greases by Pressure Differentia
6、l Scanning Calorim-etryE473 Terminology Relating to Thermal Analysis and Rhe-ologyE487 Test Method for Constant-Temperature Stability ofChemical MaterialsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test MethodE1142 Terminology Relating to Thermophysical Prope
7、rtiesE1858 Test Method for Determining Oxidation InductionTime of Hydrocarbons by Differential Scanning Calorim-etryE1868 Test Method for Loss-On-Drying by Thermogravim-etryE2161 Terminology Relating to Performance Validation inThermal Analysis3. Terminology3.1 Definitions:3.1.1 The technical terms
8、used in this test method aredefined in Terminologies E473, E1142, and E2161, includingcalibration, conformance, relative standard deviation, and ther-mal analysis.4. Summary of Test Method4.1 The elapsed time signal generated by a thermal analyzeris compared to a clock (or timer) whose performance i
9、s knownand traceable to a national metrology institute. The thermalanalyzer may be said to be in conformance, if the performanceof the thermal analyzer is within established limits.Alternatively, the elapsed time signal may be calibrated usinga two point calibration method.5. Significance and Use5.1
10、 Most thermal analysis experiments are carried out underincreasing temperature conditions where temperature is theindependent parameter. Some experiments, however, are car-ried out under isothermal temperature conditions where theelapsed time to an event is measured as the independentparameter. Isot
11、hermal Kinetics (Test Methods E2070), ThermalStability (Test Method E487), Oxidative Induction Time (OIT)(Test Methods D3895, D4565, D5483, E1858, and Specifica-tion D3350 and Loss-on-Drying (Test Method E1868) arecommon examples of these kinds of experiments.5.2 Modern scientific instruments, inclu
12、ding thermalanalyzers, usually measure elapsed time with excellent preci-sion and accuracy. In such cases, it may only be necessary toconfirm the performance of the instrument by comparison to asuitable reference. Only rarely will it may be required tocorrect the calibration of an instruments elapse
13、d time signalthrough the use of a calibration factor.5.3 It is necessary to obtain elapsed time signal conformityonly to 0.1 times the repeatability relative standard deviation1This test method is under the jurisdiction ofASTM Committee E37 on ThermalMeasurements and is the direct responsibility of
14、Subcommittee E37.10 onFundamental, Statistical and Mechanical Properties.Current edition approved Sept. 15, 2013. Published September 2013. Originallyapproved in 1997. Last previous edition approved in 2007 as E1860 07. DOI:10.1520/E1860-13.2For referenced ASTM standards, visit the ASTM website, www
15、.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.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1(stand
16、ard deviation divided by the mean value) expressed as apercent for the test method in which the thermal analyzer is tobe used. For those test methods listed in Section 2 thisconformity is 0.1 %.6. Apparatus6.1 Timer or Stopwatch, with timing capacity of at least 3 h(10 800 s), a resolution of 0.1 s
17、or better and an accuracy of 1.5s per day which performance has been verified using standardsand procedures traceable to a national metrology institute (suchas the National Institute of Standards and Technology (NIST).Such timers are available from most laboratory equipmentsuppliers.7. Calibration7.
18、1 Perform any elapsed time signal calibration proceduresrecommended by the manufacturer of the thermal analyzer asdescribed in the Operators Manual.8. Procedure8.1 Obtain the instrument reaction time (I).8.1.1 Reset the timer and the elapsed time signal for thethermal analyzer to zero elapsed time.8
19、.1.2 Simultaneously start the timer and the elapsed timesignal for the thermal analyzer. Allow them to run for 6 to 10s. Simultaneously stop the timer and the elapsed time signal forthe thermal analyzer. Record the elapsed time from the timer ast1. Record the elapsed time from the thermal analyzer a
20、s t2.NOTE 1The elapsed time of the timer (t1) is equal to the elapsed timeof the thermal analyzer (t2) plus the instrument reaction time (I). Theinstrument reaction time is that required for the thermal analyzer toinitialize and terminate the thermal analysis experiment and may be up toseveral secon
21、ds. The instrument start up time does not affect the elapsedtime of the thermal analysis experiment since the experiment is exclusiveof this time.NOTE 2Data acquisition rate shall be set to the maximum available.NOTE 3Time measurements shall be recorded in seconds retaining allavailable digits.8.1.3
22、 Calculate the instrument reaction time I by Eq 2 (9.2).8.2 Obtain the calibration constant (S).8.2.1 Reset the timer and the elapsed time signal for thethermal analyzer to zero elapsed time.8.2.2 Simultaneously start the timer and the elapsed timesignal for the thermal analyzer. Allow them to run f
23、or aminimum of 10 000 s ( = 167 min = 2.8 h = 2 h, 47 min).Simultaneously stop the timer and the elapsed time signal forthe thermal analyzer (see Note 2, Note 3, and Note 4). Recordthe elapsed time from the timer as tt. Record the elapsed timefrom the thermal analyzer as to.8.2.3 Calculate the value
24、 for S using Eq 3 (see 9.3).8.3 Using the values for I and S from 8.1.3 and 8.2.3,calculate the percent conformity (C) using Eq 4 or table ofpercent conformity values (see 9.4).9. Calculation9.1 For the purpose of these procedures, it is assumed thatthe relationship between observed elapsed time (to
25、) and theactual elapsed time (t) is linear and is governed by Eq 1:t 5 toS (1)where:t = true experimental elapsed time (s),to= thermal analyzer observed elapsed time (s), andS = slope (nominal value = 1.00000).9.2 Using the values for t1and t2from 8.1, the instrumentreaction time (I) may be calculat
26、ed by:I 5 t12 t2(2)9.3 Using the values for ttand tofrom 8.2, the calibrationconstant S may be calculated by:S 5 tt2 I!/to(3)where:tt= observed time of reference timer.9.3.1 When performing this calculation, retain all availabledecimal places in the measured value and in the value of S.9.4 Using the
27、 value for S from 9.3, the percent conformityof the instrument elapsed time indicator may be calculated asfollows:C 5 1.00000 2 S! 3100% (4)NOTE 4The percent conformity is usually a very small number andexpressing it as a percent value may be inconsistent with SI metricnotation. Because of its effec
28、t on the experiment and because of commonuse, it is expressed as a percent is this procedure.9.4.1 Conformity may be estimated to one significant figureusing the following criteria:9.4.1.1 If S lies:Between 0.9999 and 1.0001, then conformity is better than 0.01 %,Between 0.9990 and 0.9999 or between
29、 1.0001 and 1.0010, then conformity isbetter than 0.1 %, andBetween 0.9900 and 0.9990 or between 1.0010 and 1.0100, then conformity isbetter than 1 %.9.5 Using the determined value for S, Eq 1 may be used tocalculate the true elapsed time (t) from an observed elapsedtime (to).10. Report10.1 Report t
30、he following information:10.1.1 Model number and description of the Thermal Ana-lyzer used,10.1.2 The value of S as determined in 8.2.3 reported to atleast five places to the right of the decimal point, and10.1.3 Conformity as determined in 9.4.11. Precision and Bias11.1 An interlaboratory study of
31、elapsed time calibrationwas conducted in 1996 that included participation by ninelaboratories using instruments from four manufacturers. Theresults were treated by Practice E691.311.2 Precision:11.2.1 The mean value for the calibration constant wasS = 0.999853.3Supporting data have been filed at AST
32、M International Headquarters and maybe obtained by requesting Research Report RR:E37-1019. ContactASTM CustomerService at serviceastm.org.E1860 13211.2.2 The repeatability (within laboratory) standard devia-tion for S was 0.000034.11.2.2.1 Two values, each the mean of duplicate determina-tions withi
33、n a single laboratory should be considered suspect ifthey differ by more than the 95 % repeatability limit r= 0.000095.11.2.3 The reproducibility (between laboratory) standarddeviation for S was 0.00024.11.2.3.1 Two values, each the mean of duplicate determina-tions in differing laboratories, should
34、 be considered suspect, ifthey differ by more than the 95 % reproducibility limitR = 0.00069.11.3 Bias:11.3.1 The measurement of conformity in this test method isa comparison of the calibration constant S with the theoreticalvalue of 1.000000 and provides an indication of bias.11.3.2 The mean value
35、for conformity was C = 0.015 %.11.3.3 Conformity was found to vary widely among instru-ment models but in no case exceeded C = 0.05 %. This value isfar better than the nominal conformity of 1 % required for mostthermal analysis experiments.12. Keywords12.1 calibration; elapsed time; thermal analysis
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39、ommittee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).E1860 133
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