1、Designation:D439905(Reapproved 2011)Standard Test Method forMeasuring Electrical Conductivity of Electrocoat Baths1This standard is issued under the fixed designation D4399;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of
2、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.Scope1.1 This test method covers the determination of the elec-trical conductivity of electrocoat baths or ultrafiltrate samplesusin
3、g commercially available equipment.1.2 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.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:2D1125 Test Methods for Electrical Conductivity and Resis-tivity of WaterD1193 Specification for Reagent Water3.Summary
5、 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.Signifi
6、cance 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 impurities is detrime
7、ntal 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 Methods D1125.5.Appar
8、atus5.1 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 suitable cylindrical
9、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 mean water conforming
10、to Type II of SpecificationD1193.6.2 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 isobtained.In the case of an u
11、ltrafiltrate,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.This is particu-larly importan
12、t 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 no settled matter.Shakeor stir
13、 the sample until specimens are taken for measurement;THIS POINT IS VERY IMPORTANT.1This test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings,Materials,and Applications and is the direct responsibility ofSubcommittee D01.21 on Chemical Analysis of Paints and Paint
14、 Materials.Current edition approved June 1,2011.Published June 2011.Originallyapproved in 1984.Last previous edition approved in 2005 as D4399 051.DOI:10.1520/D4399-05R11.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual
15、Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 8.Procedure8.1 Calibrate the conductivity cell prior to use following themanufacturer
16、s instructions.8.2 Rinse the measuring container several times with por-tions of the electrocoat material under test.8.3 Take a representative portion of the electrocoat bath orpermeate sample and place it in the measuring container.Stirthe specimen thoroughly to 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 i
