1、Designation: D5682 08 (Reapproved 2012)D5682 18Standard Test Methods forElectrical Resistivity of Liquid Paint and Related Materials1This standard is issued under the fixed designation D5682; the number immediately following the designation indicates the year oforiginal adoption or, in the case of r
2、evision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*Scope1.1 These test methods cover the determination of specific resistance (resistivity) of liquid p
3、aints, solvents, and other fluids inthe range of 0.6 to 2640 M-cm.1.2 Test MethodAdescribes a procedure for making resistance tests with a commonly used paint application test assembly (Fig.1 and Fig. 2).1.3 Test Method B describes a procedure for making resistance tests with a conductivity meter (F
4、ig. 3).1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.5 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 esta
5、blish appropriate safety safety, health, and healthenvironmental practices and determine theapplicability of regulatory limitations prior to use.1.6 This international standard was developed in accordance with internationally recognized principles on standardizationestablished in the Decision on Pri
6、nciples for the Development of International Standards, Guides and Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Terminology2.1 Definitions:2.1.1 specific resistance (resistivity), nthe ratio of the d-c potential gradient in volts per centimetre
7、 paralleling the current flowwithin the specimen to the current density in amperes per square centimetre at a given instant of time and under prescribedconditions.2.1.1.1 DiscussionThis is numerically equal to the resistance between opposite faces of a centimetre cube of the liquid. The units are oh
8、m centimetres(or megohm centimetres).2.2 Definitions of Terms Specific to This Standard:2.2.1 kilohm (K), nresistance value equal to 1000 (103).2.2.2 megohm (M), nresistance value equal to 1 000 000 (106).2.2.3 ohm-centimetre (or megohm-centimetre), nunit of specific resistance (resistivity).3. Summ
9、ary of Test Methods3.1 Test Methods A and B measure direct current through concentric cylinder electrodes immersed in a liquid paint specimen.4. Significance and Use4.1 These tests are suitable for testing paints adjusted for compatibility with various electrostatic spray coating applications, andby
10、 their use, spray performance can be optimized.1 These test methods are under the jurisdiction of ASTM Committee D01 on Paint and Related Coatings, Materials, and Applications and are the direct responsibility ofSubcommittee D01.24 on Physical Properties of Liquid Paints and electrical resistance; e
11、lectrical resistivity; electrostatic spray applicationcompatibility; paintapplication test assembly; specific resistanceAPPENDIX(Nonmandatory Information)X1. TESTING THE PROBE (CELL CONSTANT DETERMINATION)X1.1 These cells depend on concentricity of the inner and outer section for accuracy and repeat
12、ability. The cell constant may betested by the following method. Both cells have identical cell constants by design, so may be tested in same manner. The mainreason for doing this is to determine whether the cell is in good condition, clean, and operating properly. If the cell is dirty ordamaged, it
13、 will not give the correct cell constant.X1.2 Obtain a standard solution of approximately 1000 /cm.X1.3 Measure the resistance of the standard solution (in ohms) using the probe and an ohmmeter with full scale reading of about25 , since the test meters normally used in these methods are not suitable
14、 for measuring this low value of resistance.X1.4 The cell constant may be found by substituting in the following equation:K 5P/R (X1.1)where:K = the cell constant in cm,P = the resistance in M-cm, andR = the resistance in M.X1.5 This value is typically 132, but may vary slightly because of manufactu
15、ring tolerances, or slight damage while in use. If thecell constant is 133, reclean the cell and recheck the constant. If it is still outside the range 128 to 133, then the outersleeve probably has been damaged and must be replaced.D5682 185SUMMARY OF CHANGESCommittee D01 has identified the location
16、 of selected changes to this standard since the last issue (D5682 - 95(2002) that may impact the use of this standard. (Approved June 1, 2008.)(1) Information on specific suppliers of instruments has been removed in keeping with ASTM policy.(2) The section on Apparatus has been split in two and move
17、d to the two different test methods.(3) The section on Reagents and Materials has been renumbered.(4) Asentence has been added to theApparatus section for MethodAindicating that the meter that is currently available is digital.(5) A diagram of the digital apparatus for Method A has been added (Figur
18、e 2) and the previous Figure 2 has been renumber toFigure 3.(6) Several typographical errors have been corrected.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advi
19、sed that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either
20、reapproved or withdrawn.Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If
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