【astm標(biāo)準(zhǔn)】d 1400 - 94 (2000)

1、Designation: D 1400 – 9400Standard Test Method for Nondestructive Measurement of Dry Film Thickness of Nonconductive Coatings Applied to a Nonferrous Metal Base1This standard is issued under the fixed designation D 1400;

2、 the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscri

3、pt epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the nondestructive measurement of the dry film thickness of electrically nonconductive coatings appli

4、ed over a nonferrous metal base using commercially available eddy current instruments. This test method is intended to supplement manufacturers’ instructions for the manual operation of the gages, and is not intended to

5、replace them.1.2 This test method is not applicable to coatings that are will be readily deformable under the load of the measuringinstruments, as the instrument probe must be placed directly on the coating surface to ta

6、ke a reading. 1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only. 1.4 This standard does not purport to address all of the safety concerns, if a

7、ny, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.2. Referenced

8、Documents2.1 ASTM Standards:1 This test method is under the jurisdiction of ASTM Committee D-1 D01 on Paint and Related Coatings, Materials, and Applications and is the direct responsibility ofSubcommittee D01.23 on Phys

9、ical Properties of Applied Paint Films. Current edition approved Aug. 15, 1994. Nov. 10, 2000. Published October 1994. January 2001. Originally published as D 1400 – 56. Last previous edition D 1400 – 8794.1This document

10、 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 the previous version. Because it may not be technically possible to adequately depict

11、all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version of the standard as published by ASTM is to be considered the official document.Copyright

12、69; ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.nonconductive coatings that are set at the points where the gage no longer registers the shim thicknesses within

13、 the manufacturer’s stated accuracy (for example, 610 %). traceable to a suitable national standard.7.4 Follow the manufacturer’s instructions for the specific adjustment of the instrument.7.5 Measure the thickness of a

14、series of calibration standards covering the expected range of coating thickness. To guard againstmeasuring with an inaccurate gage, recheck the gage at regular intervals. That interval should be set and maintained throu

15、ghout the control process.7.6 If the substrate material to be tested changes in roughness, shape, thickness or composition, re-verify calibration and adjustas necessary.8. Procedure8.1 Use the instrument only after it ha

16、s been calibrated in accordance with Section 7.8.2 Ensure that the coating is dry prior to use of the instrument.8.3 Inspect the probe tip and surface to be measured to assure ensure that they are clean, o. Otherwise err

17、oneous readings canresult.8.4 Take readings in areas free of vibration, electrical, electrical or magnetic fields.8.5 If thickness readings are found to be outside the8.5 Verify calibration range established in 7.3, repe

18、at the calibration procedure in the appropriate range. Check the calibrationbefore, during, and after each use periodically to ensure that the instrument continues to read properly. If the instrument is found to be out o

19、f adjustment, remeasure the thicknesses taken since the last satisfactory calibration check was made.8.6 Take a sufficient number of readings to characterize the surface.8.6.1 For laboratory measurements a recommended mi

20、nimum is of three—for a 3 75 by 6 in. (75 150-mm (3 by 150 mm) panel6-in.) panel, and more in proportion to size.8.6.2 For field measurements a recommended minimum is five determinations at random for every 100 ft2 (10 m

21、2) of the surface area. Each of the five determinations should be the mean of three separate gage readings within the area of a 1?2 in. (12 mm) 4-cm (1.5-in. ) diameter circle.8.7 Take measurements no closer than 1 in. (

22、25 mm) to an at least 13 mm (1?2 in.) away from any edge or 3 in. (75 mm) toanother mass corner of metal. the specimen. If such measurements are necessary, it is necessary to measure closer than 1?2-in., recheck the cali

23、bration base metal reading in the specific areas to determine the extent of the effect (if any) the edge or mass of metal has on the instrument reading. measurement.9. Report9.1 Report the following information: the9.1.1

24、 instrument used, serial numbers,9.1.2 range, and mean of the thickness readings fou, and9. D1.3 depending upon the application, it may be useful to record the individual readings as well.10. Precision and Bias10.1 Preci

25、sion—On the basis of an interlaboratory—A new round-robin study of this test method, conducted to determine wasperformed recently. Data are being analyzed statistically. When completed, the precision of several types of

26、instrument in measuring a moderate range of coating thicknesses, the intralaboratory required repeatability and interlaboratory coefficients reproducibility sections of variation, calculated using procedures described in

27、 Practice D 3980, were found to this test method will be those shown in Table 1 for written and the instrument evaluated. Based upon these coefficients the following criteria should be used for judging, at the 95 % confi

28、dence level the acceptability of results:10.1.1 Repeatability—Two results, each the mean of four measurements, obtained by the same operator using instruments fromthe same category should be considered suspect if they di

29、ffer by more than the maximum allowable difference values given round-robin study documented in Table 1 for the appropriate film thickness.10.1.2 Reproducibility—Two results, each the mean of four measurements, obtained

30、by operators in different laboratories usinginstruments from the same category should be considered suspect if they differ by more than the maximum allowable difference values given in Table 1 for the appropriate film th

31、ickness. an ASTM research report.10.2 Bias—The bias for this test method for measuring dry film thickness cannot be measured at this time, because each instrument has its own bias.11. Keywords11.1 coating thickness; dry