ASTM E2918-2018a Standard Test Method for Performance Validation of Thermomechanical Analyzers.pdf

1、Designation: E2918 18aStandard Test Method forPerformance Validation of Thermomechanical Analyzers1This standard is issued under the fixed designation E2918; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision

2、. 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 provides procedures for validatingtemperature and length change measurements of thermome-chanical analyzers (TMA)

3、and analytical methods based uponthe measurement of temperature and length change. Perfor-mance parameters include temperature repeatability, linearity,and bias; and dimension change repeatability, detection limit,quantitation limit, linearity, and bias.1.2 Validation of apparatus performance and an

4、alyticalmethods is a necessary requirement for quality initiatives.Results may also be used for legal purposes.1.3 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.4 This standard does not purport to address all of thesafety co

5、ncerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety, health, and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.5 This international standard was developed in accor-dance wit

6、h internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards

7、:2E473 Terminology Relating to Thermal Analysis and Rhe-ologyE1142 Terminology Relating to Thermophysical PropertiesE1363 Test Method for Temperature Calibration of Thermo-mechanical AnalyzersE1970 Practice for Statistical Treatment of ThermoanalyticalDataE2113 Test Method for Length Change Calibrat

8、ion of Ther-momechanical AnalyzersE2161 Terminology Relating to Performance Validation inThermal Analysis and Rheology3. Terminology3.1 Technical terms used in this test method are defined inTerminologies E473, E1142, and E2161, including termsanalyte, bow, Celsius, coeffcient of linear thermal expa

9、nsion,detection limit, linearity, quantification limit, relative standarddeviation, repeatability, standard deviation,thermodilatometry, thermomechanical analysis, and valida-tion.4. Summary of Test Method4.1 Temperature and time are the primary independentparameters and length change is the primary

10、 dependent experi-mental parameters provided by thermomechanical analysis.4.2 Temperature, a measured value, is validated by perform-ing a measurement of the penetration in sharply meltingmaterials at three (or more) different known melting tempera-tures.4.3 Length change, a measured value, is valid

11、ated byperforming a measurement of the linear thermal expansion forthree (or more) test materials.4.4 Validation of a thermomechanical test method basedupon length change may be performed using the test specimenas the analyte.4.5 The length change of three (or more) specimens (nomi-nally representin

12、g the maximum, midpoint and minimum ofthe range of the test method) are measured in triplicate (ormore). A fourth blank specimen, containing no analyte, ismeasured in triplicate (or more).NOTE 1Repeatability is determined by performing a sufficient numberof determinations to calculate valid estimate

13、s of the standard deviation orrelative standard deviation of the measurement.4.5.1 Temperature and length change measurement linearityand bias are determined from the linear regression correlationof the results from measurements of the three (or more)specimens.1This test method is under the jurisdic

14、tion ofASTM Committee E37 on ThermalMeasurements and is the direct responsibility of Subcommittee E37.10 onFundamental, Statistical and Mechanical Properties.Current edition approved Dec. 1, 2018. Published January 2019. Originallyapproved in 2013. Last previous edition approved in 2018 as E2918 18.

15、 DOI:10.1520/E2918-18A.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 the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr

16、 Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recomme

17、ndations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.14.5.2 Length change detection limit and quantitation limitare determined from the standard deviation of the blankdetermination with no analyte present.4.5.3 Temperature and length change repeatability are de

18、-termined from the repeatability measurements of three (ormore) specimens.4.5.4 Length change validation is independent of the tem-perature validation. The respective validations need not in-volve consistent ranges.5. Significance and Use5.1 This test method may be used to determine and validatethe

19、performance of a particular thermomechanical analyzerapparatus.5.2 This test method may be used to determine and validatethe performance of a particular method based upon thermome-chanical analyzer temperature or length change measurements.5.3 This test method may be used to determine the repeat-abi

20、lity of a particular apparatus, operator, or laboratory.5.4 This test method may be used for specification andregulatory compliance purposes.6. Apparatus6.1 Thermomechanical Analyzer (TMA)The essential in-strumentation required to provide the minimum thermome-chanical analytical or thermodilatometri

21、c capability for this testmethod include:6.1.1 A rigid specimen holder of an inert, low expansivitymaterial ( 0.6 m/m C) to center the specimen in a furnaceand to fix the specimen to mechanical ground.NOTE 2Apparatus capable of higher temperature operation may beconstructed of materials with greater

22、 expansivity. Additionally, a correc-tion for expansion of the material of construction is included in dimen-sional change measurements.6.1.2 A rigid expansion probe of inert low expansivitymaterial (0.6 m/m K) that contacts the specimen with anapplied compressive force (see Note 2). The circular ar

23、ea incontact with the test specimen shall have a diameter between0.5 mm and 1.1 mm.NOTE 3Expansion probes of other diameters may be used but shall bereported.6.1.3 A sensing element, linear over a minimum range of 2mm, to measure the displacement of the rigid expansion probewith a minimum resolution

24、 of 650 nm due to resultant changesin length of the specimen.6.1.4 A force transducer or weight to generate a constantforce of 1.0 mN to 100 mN (0.1 g to 10 g) 6 2.5 % that isapplied through the rigid expansion probe to the specimen.6.1.5 A furnace to provide uniform and controlled heatingor cooling

25、 of a specimen to a constant temperature or at aconstant rate within the applicable temperature range of thismethod.6.1.6 A temperature controller capable of executing a spe-cific temperature program by operating the furnace betweenselected temperature limits at a constant rate of temperaturechange

26、between 2 C/min and 10 C/min (or greater) to within60.1 C/min or at an isothermal temperature constant to 60.1C.6.1.7 A temperature sensor to provide an indication of thespecimen/furnace temperature over the range from 20 C to300 C (or greater) readable to 60.1 C.NOTE 4This temperature range is the

27、minimum required to performthis validation. Many thermomechanical analyzers are applicable to abroader temperature range.6.1.8 A means of sustaining an environment around thespecimen of a dry, inert gas at a purge rate of 10 mL/min to 50mL/min 6 5 mL/min.NOTE 5Typically 99+ % pure nitrogen, argon or

28、 helium is employedwhen oxidation in air is a concern. Unless effects of moisture are to bestudied, use of dry purge gas is recommended and is essential foroperation at subambient temperatures.6.1.9 A data collection device, to provide a mean ofacquiring, storing and displaying measured or calculate

29、d sig-nals or both. The minimum output signals required for ther-momechanical analysis are change in linear dimension(length), temperature, and time.NOTE 6A data acquisition rate of equal to or greater than 1 data pointper second is required to achieve the desired measurement precision.6.1.10 Auxili

30、ary instrumentation considered useful (but notessential) in conducting this method includes:6.1.10.1 Cooling capability to hasten furnace cool downfrom elevated temperatures, to provide constant cooling ratesor to sustain an isothermal subambient temperature.6.1.10.2 Specimen containers, stable and

31、inert to the tem-perature of interest to protect the specimen holder from the testspecimen melt. Such containers are typically constructed of thesame material as the specimen holder and expansion probe.6.2 A micrometer or other length measuring device todetermine specimen dimension of up to 10 mm wi

32、th anaccuracy of 625 m.7. Reagents and Materials7.1 Indium (In), 99.99+ % purity, preferably a certifiedreference material for which the melting temperature is known.7.2 Bismuth (Bi), 99.99+ % purity, preferably a certifiedreference material for which the melting temperature is known.7.3 Zinc (Zn),

33、99.99+ % purity, preferably a certified refer-ence material for which the melting temperature is known.7.4 Tungsten (W), 99.9+ % pure, a right circular cylinder,6.0 mm to 6.5 mm in diameter, 7 mm to 9 mm in length havingflat and parallel ends to within 625 m.7.5 Lead (Pb), 99.9 + pure, a right circu

34、lar cylinder, 6.0 mmto 6.5 mm in diameter and 7 mm to 9 mm in length having flatand parallel ends to within 625 m.7.6 Copper (Cu), 99.9+ % pure, a right circular cylinder, 6.0mm to 6.5 mm in diameter and 7 mm to 9 mm in length havingflat and parallel ends to within 625 m.8. Calibration and Standardi

35、zation8.1 Turn on the power and allow the instrument to equili-brate for at least one hour prior to any measurements.E2918 18a28.2 Perform any cleaning and calibration procedures de-scribed by the manufacturer in the apparatus operatorsmanual.8.3 Perform temperature and length change calibration ac-

36、cording to Test Methods E1363 and E2113, respectively, usingthe same purge gas, purge gas flow rate, and heating rate (here5 C/min) to be used for validation experiments.NOTE 7The position of the temperature sensor is critical and shall notbe changed during the course of this procedure.9. Procedure

37、for Determining Temperature Repeatability,Linearity, and Bias9.1 This process involves characterizing, three (or more)test specimens taken to represent the high, medium and lowportions of the temperature range over which performance is tobe validated (see Table 1).NOTE 8The details of this procedure

38、 are written using zinc, bismuthand indium as analytes with their nominal melting temperatures at 420 C(high), 271 C (medium), and 157 C (low). Other materials, such as thoseindicated in Table 1, with melting temperatures approximately equidistanton the temperature scale may be used but shall be rep

39、orted.9.2 Prepare three (or more) high melting (zinc), minimummelting (bismuth), and low melting (indium) test specimensweighing between 10 mg and 15 mg.NOTE 9The specimen should have a smooth surface on both top andbottom. Avoid the use of specimens with sharp ridges and irregularsurfaces. These ma

40、y lead to false values for the onset temperature.9.3 Place the largest zinc specimen on the specimen holder.NOTE 10The test specimen may be placed in a specimen container onthe specimen holder to protect the specimen holder from the melted testspecimen.9.4 Move the furnace to enclose the specimen ho

41、lder so thatthe specimen is centered in the uniform temperature zone.9.5 Place the expansion probe in contact with the testspecimen and apply a load of 50 mN (5 g) 6 2.5 %.9.6 Purge the sample chamber with inert purge gas at a rateof 10 mL/min to 50 mL/min constant to within 65 mL/min.NOTE 11Use the

42、 same temperature sensor position, purge gas, andpurge gas flow rate throughout all calibration and specimen testingexperiments.9.7 Heat (or cool) the test specimen to a temperature about50 C below the calibration melting temperature of the testspecimen (see Table 1) and allow the apparatus to equil

43、ibratefor at least 1 min.9.8 Heat the specimen at 5.0 C/min through the meltingtransition until the probe reaches a point of maximum penetra-tion after the transition. Record the thermal curve (see Fig. 1).NOTE 12Other heating rates may be used but shall be reported.Analytical performance may be aff

44、ected by heating rate, purge gas andpurge gas flow rate. Slower heating rates increase precision.NOTE 13Validation is limited to the heating rate, purge gas, purge gasflow rate, temperature range, and length change examined.9.9 Cool the test specimen to ambient temperature. Thethermal curve need not

45、 be recorded.9.10 Prepare a thermal curve with dimension on the Y-axisand temperature on the X-axis (see Fig. 1). Determine theextrapolated onset temperature and report as T(Zn)1.9.10.1 Extrapolate the baseline before the transition into thetransition region.9.10.2 Construct a tangent to the curve a

46、t the steepest slopeof the penetration region.9.10.3 Determine the temperature corresponding to theintersection of the lines constructed in steps 9.10.1 and 9.10.2.NOTE 14Retain all available digits.9.11 Repeat steps 9.3 9.10 for the largest medium meltingtemperature (bismuth) specimen. Record the t

47、emperature asT(Bi)1.NOTE 15Loading and unloading of the specimen is required todetermine analytical repeatability.9.12 Repeat steps 9.3 9.10 for the largest low meltingtemperature (indium) specimen. Record the temperature asT(In)1.9.13 Repeat steps 9.3 9.10 for each of the two remaininghigh melting

48、temperature (zinc) specimens (see Note 10 andNote 15). Record these values as T(Zn)2 and T(Zn)3.9.14 Repeat steps 9.3 9.10 for each of the two remainingmedium melting temperature (bismuth) specimens (see Note10 and Note 15). Record these values as T(Bi)2 and T(Bi)3.9.15 Repeat steps 9.3 9.10 for eac

49、h of the remaining lowmelting temperature specimens (see Note 10 and Note 15).Record these values as T(In)2 and T(In)3.9.16 Using the three (or more) values from steps 9.10 and9.13, calculate the mean high melting temperature (T(Zn) andstandard deviation (s(Zn) for the highest melting temperaturemeasurements.NOTE 16See Practice E1970 for the determination of mean andstandard deviation.9.17 Using the three (or more) values from steps 9.11 and9.14, calculate the mean melting temperature (T(Bi), andstandard deviation (s(Bi) for the m