1、Designation: D 4399 05Standard Test Method forMeasuring Electrical Conductivity of Electrocoat Baths1This standard is issued under the fixed designation D 4399; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revis
2、ion. 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 determination of the elec-trical conductivity of electrocoat baths or ultrafiltrate samplesusing co
3、mmercially available equipment.1.2 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of
4、 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:2D 1125 Test Methods for Electrical Conductivity and Re-sistivity of WaterD 1193 Specification for Reagent Water3. Su
5、mmary of Test Method3.1 A specimen is placed in a conductivity cell, or con-versely a conductivity cell is placed in an electrocoat material,and the cell is connected to a conductivity bridge. Theelectrical conductivity is read directly off the meter of thebridge as the instantaneous peak reading.4.
6、 Significance and Use4.1 The conductivity of electrocoat baths results from thepresence of ionic species in the bath, which come from thevehicle and from the presence of impurities present as ioniz-able acids, bases, salts, or combinations of these. The presenceof excessive amounts of ionic impuriti
7、es is detrimental to theapplication and performance properties of electrocoatingpaints. The test is suitable for use in research, production,quality control and electrocoat bath process control.4.2 Other related methods for determining the electricalconductivity of water are described in Test Method
8、s D 1125.5. Apparatus5.1 Conductivity BridgeBattery, or AC/DC line-operated,capable of providing a conductivity reading almost instanta-neously.5.2 Conductivity CellDip or fill type, cell constant of 1.0.5.3 ThermometerAny type capable of 0.5C accuracywith a 2 to 32C range.5.4 Measuring VesselAny su
9、itable cylindrical containercapable of holding sufficient electrocoat sample to cover theelectrodes of the conductivity cell, and allowing at least 25 mmbetween the conductivity cell and the sides of the vessel.6. Reagents and Materials6.1 Purity of WaterReferences to water shall be under-stood to m
10、ean water conforming to Type II of SpecificationD 1193.6.2 Cleaning SolventAn appropriate solvent for the elec-trocoat material under measurement.7. Sampling and Sample Preparation7.1 The sample should be obtained while the electrocoatbath is under proper circulation so that a uniform sample isobtai
11、ned. In the case of an ultrafiltrate, the material should bethoroughly mixed or stirred prior to sampling to ensureuniformity.7.2 After sampling and prior to removing a test specimen, itis mandatory that the samples be shaken or stirred until they arehomogeneous and free of any settled material. Thi
12、s is particu-larly important if there is a delay between sampling the bathand performing the test on the bath materials. The absence ofsettled material can be ascertained visually (in a transparentcontainer) or by inserting a spatula, scraping the bottom of thecontainer and making sure that there is
13、 no settled matter. Shakeor stir the sample until specimens are taken for measurement;THIS POINT IS VERY IMPORTANT.8. Procedure8.1 Calibrate the conductivity cell prior to use following themanufacturers instructions.8.2 Rinse the measuring container several times with por-tions of the electrocoat ma
14、terial under test.1This test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings, Materials, andApplications and is the direct responsibility ofSubcommittee D01.21 on Chemical Analysis of Paints and Paint Materials.Current edition approved Jan. 1, 2005. Published Febr
15、uary 2005. Originallyapproved in 1984. Last previous edition approved in 1999 as D 4399 90 (1999).2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Docu
16、ment Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.8.3 Take a representative portion of the electrocoat bath orpermeate sample and place it in the measuring container. Stirthe specimen thoroughly to
17、keep it from settling.8.4 Adjust the temperature of the specimen to 25 6 0.5C.This is very important, since temperature differences causedisagreements in results and are a major source of error in thesemeasurements.8.5 Immerse the cell in the specimen, and move the cell upand down several times to d
18、isplace any air bubbles from insidethe cell. Hold the cell in a slightly inclined position in thecenter of the container with the vents at the top of the cellhousing beneath the surface of the liquid. If a fill-type cell isused, pour the specimen into the conductivity cell.8.6 Read and record the co
19、nductivity as described in themanufacturers instructions regarding the use of the instru-ment. Avoid measuring times longer than 15 s to preventelectrocoat sample deposition on the cell electrodes. Perform asecond measurement on another specimen, repeating steps in8.3 and 8.6. Calculate the mean of
20、both measurements.8.7 Take extreme care to prevent contamination of thesample and equipment. Rinse the cell with deionized water andan appropriate solvent immediately after use. Keep cell cleanand do not allow the dry electrocoat sample to accumulate onthe interior of the cell.9. Report9.1 Report th
21、e conductivity in terms of microsiemens (ormicroohms per centimetre) to the nearest 1 % of the deter-mined conductivity.10. Precision and Bias10.1 PrecisionIn an interlaboratory study of this testmethod, with five laboratories measuring five electrocoat bathsamples with conductivities ranging from 7
22、20 to 1750 S/cm(microohms/cm), the intralaboratory coefficient of variationwas found to be 2.6 % relative at 25 df, and the interlaboratorycoefficient of variation 4.2 % relative at 20 df. Based on thesecoefficients, the following criteria should be used for judgingthe acceptability of results at th
23、e 95 % confidence level:10.1.1 RepeatabilityTwo results, each the mean of dupli-cate determinations, obtained by the same operator on differentdays should be considered suspect if they differ by more than7.6 % relative.10.1.2 ReproducibilityTwo results, each the mean of du-plicate determinations, ob
24、tained by operators in different labo-ratories should be considered suspect if they differ by morethan 16.5 % relative.10.2 BiasBias cannot be determined for this methodbecause there are no accepted standards for the electricalconductivity of electrocoat baths or ultrafiltrate samples.11. Keywords11
25、.1 electrocoat bath; electroconductivityASTM 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 advised that determination of the validity of any such patent rights, and the
26、 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 reapproved or withdrawn. Your comments are invited either for revision of
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28、ake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).D4399052
