1、Designation:D 1400 9400Standard Test Method forNondestructive Measurement of Dry Film Thickness ofNonconductive Coatings Applied to a Nonferrous MetalBase1This standard is issued under the fixed designation D 1400;the number immediately following the designation indicates the year oforiginal adoptio
2、n or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript 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
3、of electrically nonconductive coatingsapplied over a nonferrous metal base using commercially available eddy current instruments.This test method is intended tosupplement manufacturers instructions for the manual operation of the gages,and is not intended to replace them.1.2 This test method is not
4、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 take a reading.1.3 The values stated in SI units are to be regarded as the standard.The values given in parentheses are for
5、information only.1.4 This standard does not purport to address all of the safety concerns,if any,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 regulatorylimitations prior to use.2.R
6、eferenced Documents2.1 ASTM Standards:1This 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 Physical Properties of Applied Paint Films.Current edition approvedAug.15,199
7、4.Nov.10,2000.Published October 1994.January 2001.Originally published as D 1400 56.Last previous edition D 1400 8794.1This 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 the previous version.Becauseit may
8、 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 ASTM International,100 Barr Harbor D
9、rive,PO Box C700,West Conshohocken,PA 19428-2959,United States.D 823 Practices for Producing Films of Uniform Thickness of Paint,Varnish,and Related Products on Test Panels2D 1005 Test Method for Measurement of Dry-Film Thickness of Organic Coatings Using Micrometers2D 1730 Practices for Preparation
10、 of Aluminum and Aluminum-Alloy Surfaces for Painting3D 3980 Practice for Interlaboratory Testing of Paint and Related Materials23.Summary of Test Method3.1 After calibrating the instrument using shims of known thickness and either a bare part of the metal object or metal of thesame kind,the instrum
11、ent probe is placed in contact3.1 Instruments complying with the coated metal.In instruments of this type,electrical characteristics of a coil and the probeare changed test method measure coating thickness by the eddy currents created in substrates by the alternating flux use of the coil.eddy curren
12、ts.The extent of such changes varies with the distance between the probe and the metal,the distance being the thicknessof the dry coating film.3.2 It should instrument must be recognized that placed directly on the accuracy of the measurements can be influenced oraffected when measurements are made
13、closer than 1 in.(25 mm)coating surface to an edge or 3 in.(75 mm)to another mass ofmetal.take a reading.4.Significance and Use4.1 The results of many test methods applicable to coatings are markedly affected instrument probe is energized by alternatingcurrent that induces eddy currents in the metal
14、 substrate.The eddy currents in turn create opposing alternating magnetic fields inthe substrate that modify the electricknal characteristics of the dry film,some examples being adhesion,flexibility,and hardnessto name a few.To be able to compare results obtained by different operators,it probe coil
15、.The extent of such changes is essentialto measure film thickness closely.4.2 Most protective and high performance coatings are applied to meet a requirement or a specification for dependent upon thedry film thickness of each coat,or for distance between the complete system,or both.Coatings must be
16、applied within certainminimum probe and maximum thickness tolerances in order that they can fulfill their intended function.In addition to potentialperformance deficiencies,it is uneconomical to apply more material than necessary when coating large areas such as metalstructures the metal,and coils.This test method is used to measure film the distance being shown on the instrument meter asthickness(mils or microns)of coatings on nonferrous metals.the intervening coating.5.Apparatus5.1 Eddy Curren
