ASTM E967-2003 Standard Practice for Temperature Calibration of Differential Scanning Calorimeters and Differential Thermal Analyzers《差示扫描量热仪与差热分析仪温度校准的标准实施规范》.pdf

1、Designation: E 967 03Standard Test Method forTemperature Calibration of Differential ScanningCalorimeters and Differential Thermal Analyzers1This standard is issued under the fixed designation E 967; the number immediately following the designation indicates the year oforiginal adoption or, in the c

2、ase of 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 This test method describes the temperature calibrationof differential thermal analyzers

3、and differential scanningcalorimeters over the temperature range from 40 to +2500C.1.2 Computer or electronic based instruments, techniques,or data manipulation equivalent to this test method may also beused.1.3 SI units are the standard.1.4 This test method is similar to ISO standard 113571.1.5 Thi

4、s 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. Specific precau-tiona

5、ry statements are given in Section 7.2. Referenced Documents2.1 ASTM Standards:E 473 Terminology Relating to Thermal Analysis2E 968 Practice for Heat Flow Calibration of DifferentialScanning Calorimeters2E 1142 Terminology Relating to Thermophysical Proper-ties2E 1953 Practice for Description of The

6、rmal Analysis Appa-ratus32.2 ISO Standard:113571 Plastics-Differential Scanning Calorimetry (DSC)-Part 1: General Principles3. Terminology3.1 Specific technical terms used in this test method aredefined in Terminologies E 473 and E 1142.4. Summary of Test Method4.1 This test method consists of heati

7、ng the calibrationmaterials at a controlled rate in a controlled atmospherethrough a region of known thermal transition. The heat flowinto the calibration material or the difference of temperaturebetween the calibration material and a reference sample and areference material is monitored and continu

8、ously recorded. Atransition is marked by the absorption of energy by thespecimen resulting in a corresponding endothermic peak in theheating curve.NOTE 1Heat flow calibrations are sometimes determined in conjunc-tion with temperature calibration. Some differential scanning calorimeterspermit both he

9、at flow and temperature calibrations to be obtained from thesame experimental procedure.5. Significance and Use5.1 Differential scanning calorimeters and differential ther-mal analyzers are used to determine the transition temperaturesof materials. For this information to be meaningful in anabsolute

10、 sense, temperature calibration of the apparatus orcomparison of the resulting data to that of known standardmaterials is required.5.2 This test method is useful in calibrating the temperatureaxis of differential scanning calorimeters and differential ther-mal analyzers.6. Apparatus6.1 Apparatus sha

11、ll be of either type listed below:6.1.1 Differential Scanning Calorimeter (DSC), capable ofheating a test specimen and a reference material at a controlledrate and of automatically recording the differential heat flowbetween the sample and the reference material to the requiredsensitivity and precis

12、ion.6.1.1.1 A Furnace(s), to provide uniform controlled heatingor cooling of a specimen and reference to a constant tempera-ture or at a constant rate within the applicable temperaturerange of this test method.6.1.1.2 A Temperature Sensor, to provide an indication ofthe specimen temperature.1This te

13、st method is under the jurisdiction of ASTM Committee E37 on ThermalMeasurements and is the direct responsibility of Subcommittee E 37.01 on TestMethods and Practices.Current edition approved March 10, 2003. Published April 20038. Originallyap-proved in 1983. Last previous edition approved in 1997 a

14、s E 967 97.2Annual Book of ASTM Standards, Vol 14.02.3Available form American National Standards Institute, 11 W. 42nd St., 13thFloor, New York, NY 100361Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.6.1.1.3 Differential sensors, to

15、 detect a heat flow (power)difference between the specimen and reference.6.1.1.4 Test Chamber Environmenta means of sustaininga test chamber environment of nitrogen or other inert purge gasat a purge rate of 10 to 50 mL/min.6.1.1.5 A Temperature Controllercapable of executing aspecific temperature p

16、rogram by operating the furnace(s)between selected temperature limits at a rate of temperaturechange of 10K/min.6.1.1.6 A Recording Devicecapable of recording and dis-playing on the Y-axis and fraction of the heat flow signal (DSCcurve) including the signal noise as a function of any fractionof the

17、temperature (or time) signal on the X-axis including thesignal noise.6.1.2 Differential Thermal Analyzer (DTA), capable of heat-ing a test specimen and reference material at a controlled rateand of automatically recording the differential temperaturebetween sample and reference material both to the

18、requiredsensitivity and precision.6.2 Containers (pans, crucibles, vials, lids, closures, seals,etc.), that are inert to the specimen and reference materials andthat are of suitable structural shape and integrity to contain thespecimen and reference in accordance with the specific require-ments of t

19、his test methd.6.3 Nitrogen, or other inert purge gas supply.6.4 A Balance, to wiegh specimens or containers (pans,crucibles, vials, etc.), or both to 6 0.1 mg. The blance shouldhave a capacity greater than 20 mg.7. Precautions7.1 Toxic or corrosive effluents, or both, may be releasedwhen heating so

20、me material and could be harmful to personneland to apparatus.7.2 This test method assumes linear temperature indication.Care must be taken in the application of this test method toensure that calibration points are taken sufficiently closetogether so that linear temperature indication may be approx

21、i-mated. Linear temperature inications means that there exists alinear, or first order, dependence on the temperature determinedby the instruments temperature sensor on the true temperatureof the sample material in its container and that this relation isadequately expressed by Eq. 1.8. Calibration M

22、aterials8.1 For the temperature range covered by many applica-tions, the melting transition of 99.99 % pure materials inTable 1 may be used for calibration.9. Procedure9.1 Two Point Calibration:9.1.1 Select two calibration materials from Table 1, withmelting temperatures one above and one below the

23、temperaturerange of interest. The calibration materials should be as closeto the temperature range of interest as practical.9.1.2 Determine the apparent transition temperature foreach calibration material.9.1.2.1 Into a clean specimen holder, placea5to15-mgweighed amount of calibration material. Oth

24、er specimenmasses may be used but must be indicated in the report.9.1.2.2 Load the specimen into the instrument chamber,purge the chamber with dry nitrogen (or other inert gas) at aflow rate of 10 to 50 cm3/min throughout the experiment.9.1.2.3 Heat (or cool) the calibration material rapidly to30C b

25、elow the calibration temperature and allow to stabilize.9.1.2.4 Heat the calibration material at 10C/min throughthe transition until baseline is reestablished above the transi-tion. Other heating rates may be used but must be noted in thereport. Record the resulting thermal curve.NOTE 2Temperature s

26、cale calibration may be affected by temperaturescan rate, specimen holder, purge gas and purge gas flow rate. Thetemperature calibration shall be made under the same conditions used fortest specimens.9.1.2.5 From the resultant curve, measure the temperaturesfor the desired points on the curve, Te, T

27、p(see Fig. 1) retainingall available decimal places.where:Te= extrapolated onset temperature for fusion, CTp= melting peak temperature, CNOTE 3The actual temperature displayed on the temperature axisdiffers depending upon the instrument type; for example, sample tempera-ture, program temperature, sa

28、mple program temperature average. Followthe instructions of the particular instrument manufacturer to obtain sampletemperature at the point of interest.NOTE 4The available precision of the temperature measurementsdepends upon instrument capabilities and the temperature range of theTABLE 1 Melting Te

29、mperature of Calibration MaterialNOTE 1The values in Table 1 were determined under special, highlyaccurate steady state conditions that are not attainable or applicable tothermal analysis techniques. The actual precision of this test method isgiven in Section 12 of this test method.Melting Temperatu

30、reACalibration Material(C) (K)Mercury 38.834 234.316Water 0.01B273.16BPhenoxybenzene 26.87 300.02Gallium 29.765B302.915BBenzoic Acid 122.37 395.52Indium 156.598B429.748BTinC231.928B505.078BBismuth 271.442 544.592Lead 327.502 600.652Zinc 419.527B692.677BAntimony 630.74 903.89Aluminum 660.32B933.47BSi

31、lver 961.78B1234.93BGold 1064.18B1337.33BCopper 1084.62B1357.77BNickel 1455 1728Cobalt 1494 1767Palladium 1554 1827Platinum 1772 2045Rhodium 1963 2236Iridium 2447 2720AF. D. Rossini, Pure Applied Chemistry, Vol 22, 1970, pg. 557.BThe melting temperatures of these materials have been selected as prim

32、aryfixed points for the International Practical Temperature Scale of 1990. SeeGuidelines for Realizing the International Practical Temperature Scale of 1990(ITS-90), by B. W. Mangum and G. T. Furukawa, NIST Technical Note 1265.CSome materials have different crystalline forms (for example, tin) or ma

33、y reactwith the container. These calibration materials should be discarded after their initialmelt.E967032test. Below 300C, measurements to 60.5C are common while at greaterthan 700C,6 2C is reasonable.NOTE 5For high-purity crystalline materials (not polymers), Teistaken as the transition temperatur

34、e when measured by differential scan-ning calorimeters and other instruments where the test specimen is not inintimate contact with the temperature sensor. For instruments in which thetemperature sensor is in intimate contact with the sample, (such as somedifferential thermal analyzers), Tpis taken

35、as the transition temperature.9.1.3 Using the apparent transition temperatures thus ob-tained, calculate the slope (S) and intercept (I) of the calibra-tion Eq 1 (see Section 10). The slope and intercept valuesreported should be mean values from duplicate determinationsbased on separate specimens.9.

36、2 One-Point Calibration:9.2.1 If the slope value (S) previously has been determinedin 9.1 (using the two-point calibration calculation in 10.2) to besufficiently close to 1.0000, a one-point calibration proceduremay be used.NOTE 6If the slope value differs by only 1 % from unity (that is, S 1.0100),

37、 a 1 C error will be produced if the test temperaturediffers by 100C from the calibration temperature.9.2.2 Select a calibration material from Table 1. The cali-bration temperature should be centered as close as practicalwithin the temperature range of interest.9.2.3 Determine the apparent transitio

38、n temperatures of thecalibration material using steps 9.1.2.1-9.1.2.5.9.2.4 Using the apparent transition temperature thus ob-tained, calculate the intercept (I) of the calibration equationusing all available decimal places. The value reported shouldbe a mean value based upon duplicate determination

39、s onseparate specimens.9.3 If practical, adjustment to the temperature scale of theinstrument should be made so that temperatures are accuratelyindicated directly.10. Calculations10.1 For the purposes of this procedure, it is assumed thatthe relationship between observed temperature (TO) and actuals

40、pecimen temperature (T) is a linear one governed by thefollowing equation:T 5 TO 3 S! 1 I (1)where:S and I = the slope and intercept, respectively. (See 10.2for the values for S and I, used in Eq 1.)NOTE 7For some instruments, the assumption of a linear relationbetween observed and actual specimen t

41、emperature may not hold. Undersuch conditions, calibration temperatures sufficiently close together shallbe used so that the instrument calibration is achieved with a series of linearrelations.10.2 Two-Point Calibration:10.2.1 Using the standard temperature values taken fromTable 1 and the correspon

42、ding observed temperatures takenfrom experimental 9.1.2.5, calculate the slope and interceptusing the following equations:S 5 TS12 TS2!/TO12 TO2! (2)I 5 TO13 TS! 2 TS13 TO2!#/TO12 TO2! (3)where:S = slope (nominal value = 1.00),I = intercept,TS1= reference transition temperature for standard 1 takenf

43、rom Table 1,TS2= reference transition temperature for standard 2 takenfrom Table 1,TO1= observed transition temperature for standard 1 de-termined in Section 9, andFIG. 1 Reference Material Melting EndothermE967033TO2= observed transition temperature for standard 2 ob-served in Section 9.NOTE 8I has

44、 the same units (that is, C or K) as TS1, TS2, TO1andTO2which are consistent with each other. The value for I will be differentdepending upon the units used. S is a dimensionless number whose valueis independent of the units of I and T.10.2.2 S should be calculated to four significant figures andI s

45、hould be calculated retaining all available decimal places.10.3 One-Point CalibrationIf the slope value determinedabove is sufficiently close to 1.000, only the intercept need bedetermined through a one-point calibration procedure.I 5 TS12 TO1(4)10.4 Using the determined values for S and I, Eq 1 may

46、 beused to calculate the actual specimen transition temperature (T)from an observed transition temperature (TO). Values of T maybe rounded to the nearest 0.1C.11. Report11.1 The report shall include the following:11.1.1 Complete identification and description of the refer-ence materials used includi

47、ng source and purity,11.1.2 Description of the instrument used for tests,11.1.3 Statement of the mass, dimensions, geometry, andmaterial of the specimen, material of the specimen holder andtemperature program,11.1.4 Identification of the sample atmosphere by gas flowrate, purity, and composition, an

48、d11.1.5 Results of the calibration procedure including valuesfor slope and intercept. Values of S and I shall be reported tothe nearest 0.0001.11.1.6 The specific dated version of this test method.12. Precision and Bias12.1 The precision of this test method was determined in aninterlaboratory test i

49、n which 14 laboratories participated usingfour instrument models. In this test, two highly pure metallicmelting point calibration materials (indium and zinc) were usedto obtain values for the calibration constants S and I. Usingthese constants, the melting point of a third highly purematerial (lead), intermediate to these two calibration materials,was determined.12.2 The following criteria may be used to judge theacceptability of actual sample temperature information deter-mined using the two-point calibration procedure of this testmethod.12.2.1 R