1、Designation: E967 08 (Reapproved 2014)Standard Test Method forTemperature Calibration of Differential ScanningCalorimeters and Differential Thermal Analyzers1This standard is issued under the fixed designation E967; the number immediately following the designation indicates the year oforiginal adopt
2、ion 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 temperature calibrationof differential the
3、rmal analyzers and differential scanningcalorimeters over the temperature range from 40 to +2500C.1.2 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.3 This test method is similar to ISO standard 113571.1.4 This standard does
4、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-tionary statements ar
5、e given in Section 7.2. Referenced Documents2.1 ASTM Standards:2E473 Terminology Relating to Thermal Analysis and Rhe-ologyE1142 Terminology Relating to Thermophysical Properties2.2 ISO Standards:3113571 Plastics-Differential Scanning Calorimetry (DSC)-Part 1: General Principles3. Terminology3.1 Def
6、initionsSpecific technical terms used in this testmethod are defined in Terminologies E473 and E1142.4. Summary of Test Method4.1 This test method consists of heating the calibrationmaterials at a controlled rate in a controlled atmospherethrough a region of known thermal transition. The heat flowin
7、to the calibration material or the difference of temperaturebetween the calibration material and a reference sample and areference material is monitored and continuously recorded. Atransition is marked by the absorption of energy by thespecimen resulting in a corresponding endothermic peak in thehea
8、ting curve.NOTE 1Heat flow calibrations are sometimes determined in conjunc-tion with temperature calibration. Some differential scanning calorimeterspermit both heat flow and temperature calibrations to be obtained from thesame experimental procedure.5. Significance and Use5.1 Differential scanning
9、 calorimeters and differential ther-mal analyzers are used to determine the transition temperaturesof materials. For this information to be meaningful in anabsolute sense, temperature calibration of the apparatus orcomparison of the resulting data to that of known standardmaterials is required.5.2 T
10、his test method is useful in calibrating the temperatureaxis of differential scanning calorimeters and differential ther-mal analyzers.6. Apparatus6.1 Apparatus shall be of either type listed below:6.1.1 Differential Scanning Calorimeter (DSC), capable ofheating a test specimen and a reference mater
11、ial at a controlledrate and of automatically recording the differential heat flowbetween the sample and the reference material to the requiredsensitivity and precision.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
12、 constant rate within the applicable temperaturerange of this test method.6.1.1.2 A Temperature Sensor, to provide an indication ofthe specimen temperature.6.1.1.3 Differential sensors, to detect a heat flow (power)difference between the specimen and reference.6.1.1.4 Test Chamber Environment, a mea
13、ns of sustaining atest chamber environment of nitrogen or other inert purge gasat a purge rate of 10 to 50 mL/min.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 edit
14、ion approved March 15, 2014. Published April 2014. Originallyapproved in 1983. Last previous edition approved in 2008 as E967 08. DOI:10.1520/E0967-08R14.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMS
15、tandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from International Organization for Standardization (ISO), 1, ch. dela Voie-Creuse, CP 56, CH-1211 Geneva 20, Switzerland, http:/www.iso.org.Copyright ASTM International, 100 Barr Harbor Drive, PO
16、 Box C700, West Conshohocken, PA 19428-2959. United States16.1.1.5 A Temperature Controller, capable of executing aspecific temperature program by operating the furnace(s)between selected temperature limits at a rate of temperaturechange of 10K/min.6.1.1.6 Data Collection Device, to provide a means
17、ofacquiring, storing, and displaying measured or calculatedsignals, or both. The minimum output signals required for DSCare heat flow, temperature, and time.6.1.2 Differential Thermal Analyzer (DTA), capable of heat-ing a test specimen and reference material at a controlled rateand of automatically
18、recording the differential temperaturebetween sample and reference material both to the 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
19、 to contain thespecimen and reference in accordance with the specific require-ments of this test method.6.3 Nitrogen, or other inert purge gas supply.6.4 A Balance, to weigh specimens or containers (pans,crucibles, vials, etc.), or both to 60.1 mg. The balance shouldhave a capacity greater than 20 m
20、g.7. Precautions7.1 Toxic or corrosive effluents, or both, may be releasedwhen heating some 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
21、 are taken sufficiently closetogether so that linear temperature indication may be approxi-mated. Linear temperature indications means that there exists alinear, or first order, dependence on the temperature determinedby the instruments temperature sensor on the true temperatureof the sample materia
22、l in its container and that this relation isadequately expressed by Eq 1.8. Calibration Materials8.1 For the temperature range covered by manyapplications, the melting transition of 99.99 % pure materialsin Table 1 may be used for calibration.9. Procedure9.1 Two Point Calibration:9.1.1 Select two ca
23、libration materials from Table 1, withmelting temperatures one above and one below the 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
24、Into a clean specimen holder, placea5to15-mgweighed amount of calibration material. Other 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 th
25、roughout the experiment.9.1.2.3 Heat (or cool) the calibration material rapidly to30C below 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
26、 but must be noted in thereport. Record the resulting thermal curve.NOTE 2Temperature scale 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
27、the resultant curve, measure the temperaturesfor the desired points on the curve, Te, Tp(see Fig. 1) retainingall available decimal places.where:Te= extrapolated onset temperature for fusion, C, andTp= melting peak temperature, C.NOTE 3The actual temperature displayed on the temperature axisdiffers
28、depending upon the instrument type; for example, sampletemperature, program temperature, sample program temperature average.Follow the instructions of the particular instrument manufacturer to obtainsample temperature at the point of interest.NOTE 4The available precision of the temperature measurem
29、entsdepends upon instrument capabilities and the temperature range of thetest. 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 temperature when measured by differential s
30、can-ning calorimeters and other instruments where the test specimen is not inintimate contact with the temperature sensor. For instruments in which theTABLE 1 Melting Temperature of Calibration MaterialNOTE 1The values in Table 1 were determined under special, highlyaccurate steady state conditions
31、that are not attainable or applicable tothermal analysis techniques. The actual precision of this test method isgiven in Section 12 of this test method.Calibration MaterialMelting TemperatureA(C) (K)Mercury 38.834 234.316Water 0.01B273.16BPhenoxybenzene 26.87 300.02Gallium 29.765B302.915BBenzoic Aci
32、d 122.37 395.52Indium 156.598B429.748BTinC231.928B505.078BBismuth 271.442 544.592Lead 327.502 600.652Zinc 419.527B692.677BAntimony 630.74 903.89Aluminum 660.32B933.47BSilver 961.78B1234.93BGold 1064.18B1337.33BCopper 1084.62B1357.77BNickel 1455 1728Cobalt 1494 1767Palladium 1554 1827Platinum 1772 20
33、45Rhodium 1963 2236ARossini, F. D., Pure Applied Chemistry, Vol 22, 1970, p. 557.BThe melting temperatures of these materials have been selected as primary fixedpoints for the International Practical Temperature Scale of 1990. See Mangum, B.W., and Furukawa, G. T., Guidelines for Realizing the Inter
34、national PracticalTemperature Scale of 1990 (ITS-90), NIST Technical Note 1265.CSome materials have different crystalline forms (for example, tin) or may reactwith the container. These calibration materials should be discarded after their initialmelt.E967 08 (2014)2temperature sensor is in intimate
35、contact with the sample, (such as somedifferential thermal analyzers), Tpis taken as the transition temperature.9.1.3 Using the apparent transition temperatures thusobtained, calculate the slope (S) and intercept (I)ofthecalibration Eq 1 (see Section 10). The slope and interceptvalues reported shoul
36、d be mean values from duplicate deter-minations based on separate specimens.9.2 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)tobesufficiently close to 1.0000, a one-point calibration proceduremay be used.
37、NOTE 6If the slope value differs by only 1 % from unity (that is, S 1.0100), a 1C 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 practicalwith
38、in the temperature range of interest.9.2.3 Determine the apparent transition temperatures of thecalibration material using steps 9.1.2.1 9.1.2.5.9.2.4 Using the apparent transition temperature thusobtained, calculate the intercept (I) of the calibration equationusing all available decimal places. Th
39、e value reported shouldbe a mean value based upon duplicate determinations 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 a
40、ssumed thatthe relationship between observed temperature (TO) and actualspecimen temperature (T) is a linear one governed by thefollowing equation:T 5 TO 3 S!1I (1)where:S and I = the slope and intercept, respectively. (See 10.2 forthe values for S and I, used in Eq 1.)NOTE 7For some instruments, th
41、e assumption of a linear relationbetween observed and actual specimen temperature 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 Us
42、ing the standard temperature values taken fromTable 1 and the corresponding 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 TS2! 2 TS13 TO2!#/TO12 TO2! (3)where:S = slope (nominal value = 1.00),I
43、 = intercept,TS1= reference transition temperature for standard 1 takenfrom Table 1,TS2= reference transition temperature for standard 2 takenfrom Table 1,TO1= observed transition temperature for standard 1 deter-mined in Section 9, andTO2= observed transition temperature for standard 2 ob-served in
44、 Section 9.NOTE 8I has 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 sign
45、ificant figures andI should be calculated retaining all available decimal places.FIG. 1 Reference Material Melting EndothermE967 08 (2014)310.3 One-Point CalibrationIf the slope value determinedabove is sufficiently close to 1.000, only the intercept need bedetermined through a one-point calibration
46、 procedure.I 5 TS12 TO1(4)10.4 Using the determined values for S and I, Eq 1 may 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
47、Complete identification and description of the refer-ence materials used including 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 Iden
48、tification of the sample atmosphere by gas flowrate, purity, and composition, and11.1.5 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 Bias1
49、2.1 The precision of this test method was determined in aninterlaboratory test in which 14 laboratories participated usingfour instrument models.4In 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 informa
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