1、Designation: E2918 13E2918 18Standard 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 r
2、evision. 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 validating temperature and length change measurements of thermomechanicalanalyzers
3、(TMA) and analytical methods based upon the measurement of temperature and length change. Performance parametersinclude temperature repeatability, linearity and bias; and dimension change repeatability, detection limit, quantitation limit,linearity and bias.1.2 Validation of apparatus performance an
4、d analytical methods is a necessary requirement for quality initiatives. Results mayalso be used for legal purposes.1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.4 This standard does not purport to address all of the s
5、afety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety safety, health, and healthenvironmental practices and determine theapplicability of regulatory limitations prior to use.1.5 This international standard was developed
6、in accordance with internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1
7、 ASTM Standards:2E473 Terminology Relating to Thermal Analysis and RheologyE1142 Terminology Relating to Thermophysical PropertiesE1363 Test Method for Temperature Calibration of Thermomechanical AnalyzersE1970 Practice for Statistical Treatment of Thermoanalytical DataE2113 Test Method for Length C
8、hange Calibration of Thermomechanical AnalyzersE2161 Terminology Relating to Performance Validation in Thermal Analysis and Rheology3. Terminology3.1 Technical terms used in this test method are defined in Terminologies E473, E1142, and E2161, including terms analyte,bow, Celsius, coeffcient of line
9、ar thermal expansion, detection limit, linearity, quantification limit, relative standard deviation,repeatability, standard deviation, thermodilatometry, thermomechanical analysis, and validation.4. Summary of Test Method4.1 Temperature and time are the primary independent parameters and length chan
10、ge is the primary dependent experimentalparameters provided by thermomechanical analysis.4.2 Temperature, a measured value, is validated by performing a measurement of the penetration in sharply melting materialsat three (or more) different known melting temperatures.4.3 Length change, a measured va
11、lue, is validated by performing a measurement of the linear thermal expansion for three (ormore) test materials.1 This test method is under the jurisdiction ofASTM Committee E37 on Thermal Measurements and is the direct responsibility of Subcommittee E37.10 on Fundamental,Statistical and Mechanical
12、Properties.Current edition approved April 1, 2013Aug. 1, 2018. Published May 2013August 2018. Originally approved in 2013. Last previous edition approved in 2013 as E2918 13. DOI: 10.1520/E2918-13.10.1520/E2918-18.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Cu
13、stomer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to
14、the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright
15、 ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States14.4 Validation of a thermomechanical test method based upon length change may be performed using the test specimen as theanalyte.4.5 The length change of three (or more) specimens (nominally repr
16、esenting the maximum, midpoint and minimum of the rangeof the test method) are measured in triplicate (or more). A fourth blank specimen, containing no analyte, is measured in triplicate(or more).NOTE 1Repeatability is determined by performing a sufficient number of determinations to calculate valid
17、 estimates of the standard deviation orrelative standard deviation of the measurement.4.5.1 Temperature and length change measurement linearity and bias are determined from the linear regression correlation ofthe results from measurements of the three (or more) specimens.4.5.2 Length change detectio
18、n limit and quantitation limit are determined from the standard deviation of the blank determinationwith no analyte present.4.5.3 Temperature and length change repeatability are determined from the repeatability measurements of three (or more)specimens.4.5.4 Length change validation is independent o
19、f the temperature validation. The respective validations need not involveconsistent ranges.5. Significance and Use5.1 This test method may be used to determine and validate the performance of a particular thermomechanical analyzerapparatus.5.2 This test method may be used to determine and validate t
20、he performance of a particular method based uponthermomechanical analyzer temperature or length change measurements.5.3 This test method may be used to determine the repeatability of a particular apparatus, operator, or laboratory.5.4 This test method may be used for specification and regulatory com
21、pliance purposes.6. Apparatus6.1 Thermomechanical Analyzer (TMA)The essential instrumentation required to provide the minimum thermomechanicalanalytical or thermodilatometric capability for this test method include:6.1.1 A rigid specimen holder of an inert, low expansivity material ( 0.6 m/m C) to c
22、enter the specimen in a furnace andto fix the specimen to mechanical ground.NOTE 2Apparatus capable of higher temperature operation may be constructed of materials with greater expansivity. Additionally, a correction forexpansion of the material of construction is included in dimensional change meas
23、urements.6.1.2 A rigid expansion probe of inert low expansivity material (0.6 m/m K) that contacts the specimen with an appliedcompressive force (see Note 2). The circular area in contact with the test specimen shall have a diameter between 0.5 mm and 1.1mm.NOTE 3Expansion probes of other diameters
24、may be used but shall be reported.6.1.3 A sensing element, linear over a minimum range of 2 mm, to measure the displacement of the rigid expansion probe witha minimum resolution of 650 nm due to resultant changes in length of the specimen.6.1.4 A force transducer or weight to generate a constant for
25、ce of 1.0 mN to 100 mN (0.1 g to 10 g) 6 2.5 % that is appliedthrough the rigid expansion probe to the specimen.6.1.5 A furnace to provide uniform and controlled heating or cooling of a specimen to a constant temperature or at a constantrate within the applicable temperature range of this method.6.1
26、.6 A temperature controller capable of executing a specific temperature program by operating the furnace between selectedtemperature limits at a constant rate of temperature change between 2 C/min and 10C/min 10 C/min (or greater) to within60.1C/min 60.1 C/min or at an isothermal temperature constan
27、t to 60.1C.60.1 C.6.1.7 A temperature sensor to provide an indication of the specimen/furnace temperature over the range from 20 C to 300C300 C (or greater) readable to 60.1C.60.1 C.NOTE 4This temperature range is the minimum required to perform this validation. Many thermomechanical analyzers are a
28、pplicable to a broadertemperature range.6.1.8 Ameans of sustaining an environment around the specimen of a dry, inert gas at a purge rate of 10 mL/min to 50 mL/min6 5 mL/min.NOTE 5Typically 99+ % pure nitrogen, argon or helium is employed when oxidation in air is a concern. Unless effects of moistur
29、e are to be studied,use of dry purge gas is recommended and is essential for operation at subambient temperatures.E2918 1826.1.9 A data collection device, to provide a mean of acquiring, storing and displaying measured or calculated signals or both.The minimum output signals required for thermomecha
30、nical analysis are change in linear dimension (length), temperature, andtime.NOTE 6A data acquisition rate of equal to or greater than 1 data point per second is required to achieve the desired measurement precision.6.1.10 Auxiliary instrumentation considered useful (but not essential) in conducting
31、 this method includes:6.1.10.1 Cooling capability to hasten furnace cool down from elevated temperatures, to provide constant cooling rates or tosustain an isothermal subambient temperature.6.1.10.2 Specimen containers, stable and inert to the temperature of interest to protect the specimen holder f
32、rom the testspecimen melt. Such containers are typically constructed of the same material as the specimen holder and expansion probe.6.2 A micrometer or other length measuring device to determine specimen dimension of up to 10 mm with an accuracy of 625m.7. Reagents and Materials7.1 Indium (In), 99.
33、99+ % purity, preferably a certified reference material for which the melting temperature is known.7.2 Bismuth (Bi), 99.99+ % purity, preferably a certified reference material for which the melting temperature is known.7.3 Zinc (Zn), 99.99 + 99.99+ % purity, preferably a certified reference material
34、 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 having flatand parallel ends to within 625 m.7.5 Lead (Pb), 99.9 + pure, a right circular cylinder, 6.0 mm to 6.5 mm in diameter and 7 mm to 9 m
35、m in length having flatand parallel ends to within 625 m.7.6 Copper (Cu), 99.9+ % pure, a right circular cylinder, 6.0 mm 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 Standardization8.1 Turn on the power and allow the instrument to
36、equilibrate for at least one hour prior to any measurements.8.2 Perform any cleaning and calibration procedures described by the manufacturer in the apparatus operators manual.8.3 Perform temperature and length change calibration according to Practices Test Methods E1363 and E2113, respectively,usin
37、g the same purge gas, purge gas flow rate, and heating rate (here 5C/min) 5 C/min) to be used for validation experiments.NOTE 7The position of the temperature sensor is critical and shall not be changed during the course of this procedure.9. Procedure for Determining Temperature Repeatability, Linea
38、rity, and Bias9.1 This process involves characterizing, three (or more) test specimens taken to represent the high, medium and low portionsof the temperature range over which performance is to be validated (see Table 1).NOTE 8The details of this procedure are written using zinc, bismuth and indium a
39、s analytes with their nominal melting temperatures at 420 C (high),271 C (medium), and 157 (low) C.C (low). Other materials, such as those indicated in Table 1, with melting temperatures approximately equidistantTABLE 1 Recommended Melting Temperature Metals Used inThermoanalytical MethodsAMaterial
40、Melting Temperature(C)GalliumB 29.7666IndiumB 156.5936TinC 231.928BismuthB 271.402LeadB 327.462ZincC 419.527AluminumC 660.323SilverC 961.78GoldC 1064.18A The values in Table 1 were determined using special very high purity materials,and highly accurate steady state conditions that are not attainable
41、 or applicable tothermal analysis techniques.B Bedford, R.E., Bonnier, G., Maas, H., and Pavese, F., “Recommended Values ofTemperature on the International Temperature Scale of 1990 for a Selected Set ofSecondary Reference Points,” Metrologia, Vol 33, 1996, pp. 133154.C Mangum, B. W., “Special Repor
42、t on the International Temperature Scale of1990,” Journal of Research of the National Institute of Standards and Technology,Vol 95, 1990, pp. 6977.E2918 183on the temperature scale may be used but shall be reported.9.2 Prepare three (or more) high melting (zinc), minimum melting (bismuth), and low m
43、elting (indium) test specimens weighingbetween 10 mg and 15 mg.NOTE 9The specimen should have a smooth surface on both top and bottom. Avoid the use of specimens with sharp ridges and irregular surfaces.These may lead to false values for the onset temperature.9.3 Place the largest zinc specimen on t
44、he specimen holder.NOTE 10The test specimen may be placed in a specimen container on the specimen holder to protect the specimen holder from the melted testspecimen.9.4 Move the furnace to enclose the specimen holder so that the specimen is centered in the uniform temperature zone.9.5 Place the expa
45、nsion probe in contact with the test specimen and apply a load of 50 mN (5 g) 6 2.5 %.9.6 Purge the sample chamber with inert purge gas at a rate of 10 mL/min to 50 mL/min constant to within 6 5 65 mL/min.NOTE 11Use the same temperature sensor position, purge gas, and purge gas flow rate throughout
46、all calibration and specimen testing experiments.9.7 Heat (or cool) the test specimen to a temperature about 50C 50 C below the calibration melting temperature of the testspecimen (see Table 1) and allow the apparatus to equilibrate for at least 1 min.9.8 Heat the specimen at 5.0 C/min through the m
47、elting transition until the probe reaches a point of maximum penetration afterthe transition. Record the thermal curve (see Fig. 1).NOTE 12Other heating rates may be used but shall be reported.Analytical performance may be affected by heating rate, purge gas and purge gas flowrate. Slower heating ra
48、tes increase precision.NOTE 13Validation is limited to the heating rate, purge gas, purge gas flow rate, temperature range, and length change examined.9.9 Cool the test specimen to ambient temperature. The thermal curve need not be recorded.FIG. 1 Penetration for Temperature ValidationE2918 1849.10
49、Prepare a thermal curve with dimension on the Y-axis and 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 the transition region.9.10.2 Construct a tangent to the curve at the steepest slope of the penetration region.9.10.3 Determine the temperature corresponding to the intersection 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
