1、Designation: E 967 08Standard 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 () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method describes the temperature calibrationof differential thermal analyzers a
3、nd differential scanningcalorimeters over the temperature range from 40 to +2500 C.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 not purport to
4、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 are given in Sect
5、ion 7.2. Referenced Documents2.1 ASTM Standards:2E 473 Terminology Relating to Thermal Analysis and Rhe-ologyE 1142 Terminology Relating to Thermophysical Properties2.2 ISO Standard:113571 Plastics-Differential Scanning Calorimetry (DSC)-Part 1: General Principles3. Terminology3.1 Specific technical
6、 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 heating the calibrationmaterials at a controlled rate in a controlled atmospherethrough a region of known thermal transition. The heat flowinto the calibration mater
7、ial 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 theheating curve.NOTE 1Heat fl
8、ow 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 calorimeters and differ
9、ential 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 This test method is usefu
10、l 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 material at a controlledrate
11、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 constant rate within th
12、e 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 means of sustaining atest c
13、hamber 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 ThermalTest Methods and Practices.Current edition approved Sept
14、. 1, 2008. Published October 2008. Originallyapproved in 1983. Last previous edition approved in 2003 as E 967 03.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to th
15、e standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.6.1.1.5 A Temperature Controller, capable of executing aspecific temperature program by operating the furnace(s)between selected tem
16、perature limits at a rate of temperaturechange of 10K/min.6.1.1.6 Data Collection Device, to provide a means 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 Analyze
17、r (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 requiredsensitivity and precision.6.2 Containers (pans, crucibles, vials, lids, closures, seals,etc.),
18、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 this test method.6.3 Nitrogen, or other inert purge gas supply.6.4 A Balance, to weigh specimens or cont
19、ainers (pans,crucibles, vials, etc.), or both to 6 0.1 mg. The balance shouldhave a capacity greater than 20 mg.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 tem
20、perature 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 approxi-mated. Linear temperature indications means that there exists alinear, or first order, dependence o
21、n 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 Materials8.1 For the temperature range covered by many applica-tions, the melting transition of 99.99
22、% 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 temperaturerange of interest. The calibration materials should be as closeto the temperature range of
23、 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. Other specimenmasses may be used but must be indicated in the report.9.1.2.2 Load the specimen into the
24、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 to 30C below the calibration temperature and allow to stabilize.9.1.2.4 Heat the calibration material at 10
25、C/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 scale calibration may be affected by temperaturescan rate, specimen holder, purge gas and purge gas
26、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, Tp(see Fig. 1) retainingall available decimal places.where:Te= extrapolated onset temperature for fu
27、sion, 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, sample program temperature average. Followthe instructions of the particular instrument manufacturer
28、to obtain sampletemperature at the point of interest.NOTE 4The available precision of the temperature measurementsdepends upon instrument capabilities and the temperature range of thetest. Below 300 C, measurements to 60.5 C are common while atgreater than 700 C 6 2 C is reasonable.NOTE 5For high-pu
29、rity crystalline materials (not polymers), Teistaken as the transition temperature 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 c
30、ontact with the sample, (such as someTABLE 1 Melting Temperature 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 isgi
31、ven in Section 12 of this test method.Melting TemperatureACalibration 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 419.527B
32、692.677BAntimony 630.74 903.89Aluminum 660.32B933.47BSilver 961.78B1234.93BGold 1064.18B1337.33BCopper 1084.62B1357.77BNickel 1455 1728Cobalt 1494 1767Palladium 1554 1827Platinum 1772 2045Rhodium 1963 2236AF. D. Rossini, Pure Applied Chemistry, Vol 22, 1970, pg. 557.BThe melting temperatures of thes
33、e materials have been selected as primaryfixed 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 crys
34、talline forms (for example, tin) or may reactwith the container. These calibration materials should be discarded after their initialmelt.E967082differential thermal analyzers), Tpis taken as the transition temperature.9.1.3 Using the apparent transition temperatures thus ob-tained, calculate the slo
35、pe (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.9.2 One-Point Calibration:9.2.1 If the slope value (S) previously has been determinedin 9.1 (using the two-point c
36、alibration calculation in 10.2)tobesufficiently 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), a 1 C error will be produced if the test temperaturediffers by 100 C from the calibration temperature.9.2.2 Selec
37、t 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 transition temperatures of thecalibration material using steps 9.1.2.1-9.1.2.5.9.2.4 Using the apparent transition tempera
38、ture 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 determinations onseparate specimens.9.3 If practical, adjustment to the temperature scale of theinstrument should be made so t
39、hat temperatures are accuratelyindicated directly.10. Calculations10.1 For the purposes of this procedure, it is assumed thatthe relationship between observed temperature (TO) and actualspecimen temperature (T) is a linear one governed by thefollowing equation:T 5 TO 3 S! 1 I (1)where:S and I = the
40、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 temperature may not hold. Undersuch conditions, calibration temperatures sufficiently close together shallbe used
41、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 corresponding observed temperatures takenfrom experimental 9.1.2.5, calculate the slope and interceptusing the following e
42、quations: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 = intercept,TS1= reference transition temperature for standard 1 takenfrom Table 1,TS2= reference transition temperature for standard 2 takenfrom Table 1,TO1= observed transition temp
43、erature for standard 1 de-termined in Section 9, andTO2= observed transition temperature for standard 2 ob-served in 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
44、 a dimensionless number whose valueis independent of the units of I and T.FIG. 1 Reference Material Melting EndothermE96708310.2.2 S should be calculated to four significant figures andI should be calculated retaining all available decimal places.10.3 One-Point CalibrationIf the slope value determin
45、edabove 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 beused to calculate the actual specimen transition temperature (T)from an observed transition temperature (TO).
46、 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 including source and purity,11.1.2 Description of the instrument used for tests,11.1.3 Statement of the mass, dimension
47、s, 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, and11.1.5 Results of the calibration procedure including valuesfor slope and intercept. Values of S and I shall be
48、 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 in which 14 laboratories participated usingfour instrument models3. In this test, two highly pure metallicmelting
49、 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 Repeatability (Single Analyst) The standard deviationof results (each the average of duplicates), obtained by t
