1、Designation: E2918 13Standard 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) a
3、nd analytical methods based uponthe measurement of temperature and length change. Perfor-mance parameters include temperature repeatability, linearityand bias; and dimension change repeatability, detection limit,quantitation limit, linearity and bias.1.2 Validation of apparatus performance and analy
4、ticalmethods 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 conce
5、rns, 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.2. Referenced Documents2.1 ASTM Standards:2E473 Terminology Relating to Thermal Ana
6、lysis 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 Calibration of Ther-momechanical AnalyzersE2161 Te
7、rminology Relating to Performance Validation inThermal Analysis3. Terminology3.1 Technical terms used in this test method are defined inTerminologies E473, E1142, and E2161, including termsanalyte, bow, Celsius, coeffcient of linear thermal expansion,detection limit, linearity, quantification limit,
8、 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 dependent experi-mental parameters provided by thermom
9、echanical 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 validated byperforming a measurement of the linear thermal e
10、xpansion 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 representing the maximum, midpoint and minimum ofthe range of the
11、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 estimates of the standard deviation orrelative standard deviati
12、on 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.4.5.2 Length change detection limit and quantitation limitare determined from the standard dev
13、iation of the blankdetermination with no analyte present.4.5.3 Temperature and length change repeatability are de-termined from the repeatability measurements of three (ormore) specimens.1This test method is under the jurisdiction ofASTM Committee E37 on ThermalMeasurements and is the direct respons
14、ibility of Subcommittee E37.10 onFundamental, Statistical and Mechanical Properties.Current edition approved April 1, 2013. Published May 2013. DOI: 10.1520/E2918-13.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual B
15、ook 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 States14.5.4 Length change validation is independent of the tem-perature validation. The
16、 respective validations need not in-volve consistent ranges.5. Significance and Use5.1 This test method may be used to determine and validatethe performance of a particular thermomechanical analyzerapparatus.5.2 This test method may be used to determine and validatethe performance of a particular me
17、thod based upon thermome-chanical analyzer temperature or length change measurements.5.3 This test method may be used to determine the repeat-ability of a particular apparatus, operator, or laboratory.5.4 This test method may be used for specification andregulatory compliance purposes.6. Apparatus6.
18、1 Thermomechanical Analyzer (TMA)The essential in-strumentation required to provide the minimum thermome-chanical analytical or thermodilatometric 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 furnac
19、eand to fix the specimen to mechanical ground.NOTE 2Apparatus capable of higher temperature operation may beconstructed of materials with greater expansivity. Additionally, a correc-tion for expansion of the material of construction is included in dimen-sional change measurements.6.1.2 A rigid expan
20、sion probe of inert low expansivitymaterial (0.6 m/m K) that contacts the specimen with anapplied compressive force (see Note 2). The circular area incontact with the test specimen shall have a diameter between0.5 and 1.1 mm.NOTE 3Expansion probes of other diameters may be used but shall bereported.
21、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 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 to 100 mN (0.1 to 10 g) 6 2
22、.5 % that is appliedthrough the rigid expansion probe to the specimen.6.1.5 A furnace to provide uniform and controlled heatingor cooling 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 execu
23、ting a spe-cific temperature program by operating the furnace betweenselected temperature limits at a constant rate of temperaturechange between 2 and 10C/min (or greater) to within 60.1C/min or at an isothermal temperature constant to 60.1C.6.1.7 A temperature sensor to provide an indication of the
24、specimen/furnace temperature over the range from 20 to 300C(or greater) readable to 60.1C.NOTE 4This temperature range is the minimum required to performthis validation. Many thermomechanical analyzers are applicable to abroader temperature range.6.1.8 A means of sustaining an environment around the
25、specimen of a dry, inert gas at a purge rate of 10 to 50 mL/min6 5 mL/min.NOTE 5Typically 99+ % pure nitrogen, argon or 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 t
26、emperatures.6.1.9 A data collection device, to provide a mean ofacquiring, storing and displaying measured or calculated 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
27、 equal to or greater than 1 data pointper second is required to achieve the desired measurement precision.6.1.10 Auxiliary instrumentation considered useful (but notessential) in conducting this method includes:6.1.10.1 Cooling capability to hasten furnace cool downfrom elevated temperatures, to pro
28、vide constant cooling ratesor to sustain an isothermal subambient temperature.6.1.10.2 Specimen containers, stable and 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
29、 and expansion probe.6.2 A micrometer or other length measuring device todetermine specimen dimension of up to 10 mm with 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
30、), 99.99+ % purity, preferably a certifiedreference material for which the melting temperature is known.7.3 Zinc (Zn), 99.99 + % purity, preferably a certifiedreference material for which the melting temperature is known.7.4 Tungsten (W), 99.9+ % pure, a right circular cylinder,6.0 to 6.5 mm in diam
31、eter, 7 to 9 mm in length having flat andparallel ends to within 625 m.7.5 Lead (Pb), 99.9 + pure, a right circular cylinder, 6.0 to6.5 mm in diameter and 7 to 9 mm in length having flat andparallel ends to within 625 m.7.6 Copper (Cu), 99.9+ % pure, a right circular cylinder, 6.0to 6.5 mm in diamet
32、er and 7 to 9 mm in length having flat andparallel ends to within 625 m.8. Calibration and Standardization8.1 Turn on the power and allow the instrument to equili-brate for at least one hour prior to any measurements.8.2 Perform any cleaning and calibration procedures de-scribed by the manufacturer
33、in the apparatus operatorsmanual.8.3 Perform temperature and length change calibration ac-cording to Practices E1363 and E2113, respectively, using thesame purge gas, purge gas flow rate, and heating rate (here5C/min) to be used for validation experiments.NOTE 7The position of the temperature sensor
34、 is critical and shall notE2918 132be changed during the course of this procedure.9. Procedure 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 r
35、ange over which performance is tobe validated (see Table 1).NOTE 8The details of this procedure are written using zinc, bismuthand indium as analytes with their nominal melting temperatures at 420(high), 271 (medium), and 157 (low) C. Other materials, such as thoseindicated in Table 1, with melting
36、temperatures approximately equidistanton the temperature scale may be used but shall be reported.9.2 Prepare three (or more) high melting (zinc), minimummelting (bismuth), and low melting (indium) test specimensweighing between 10 and 15 mg.NOTE 9The specimen should have a smooth surface on both top
37、 andbottom. Avoid the use of specimens with sharp ridges and irregularsurfaces. These may 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 spec
38、imen holder from the melted testspecimen.9.4 Move the furnace to enclose the specimen holder 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
39、purge gas at a rateof 10 to 50 mL/min constant to within 6 5 mL/min.NOTE 11Use the 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 about50C below the calibration melti
40、ng temperature of the testspecimen (see Table 1) and allow the apparatus to equilibratefor 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
41、heating rates may be used but shall be reported.Analytical performance may be affected 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 exami
42、ned.9.9 Cool the test specimen to ambient temperature. Thethermal curve need not 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 th
43、e transition into thetransition region.9.10.2 Construct a tangent to the curve at 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
44、 9.10 for the largest medium meltingtemperature (bismuth) specimen. Record the temperature 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 temperatur
45、e asT(In)1.9.13 Repeat steps 9.3 9.10 for each of the two remaininghigh melting 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
46、15). Record these values as T(Bi)2 and T(Bi)3.9.15 Repeat steps 9.3 9.10 for each 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 temper
47、ature (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
48、(s(Bi) for the medium melting temperaturemeasurements.9.18 Using the three (or more) values from steps 9.12 and9.15, calculate the mean low melting temperature (T(In) andstandard deviation (s(In) for the low melting temperaturemeasurements.9.19 Calculate the repeatability value (r(T) for the melting
49、temperature values s(n), s(Bi) and s(Zn) using Eq 6. Report thisvalue as the temperature repeatability value.TABLE 1 Recommended Melting Temperature Metals Used inThermoanalytical MethodsAMaterialMelting Temperature(C)GalliumB29.7666IndiumB156.5936TinC231.928BismuthB271.402LeadB327.462ZincC419.527AluminumC660.323SilverC961.78GoldC1064.18AThe values in Table 1 were determined using special very high purity materials,and highly accurate steady state conditions that are not attainable or applicable tothermal analysis techniques.BBedfor
