ASTM_B_490_-_09_2014.pdf

Designation:B49009(Reapproved 2014)Standard Practice forMicrometer Bend Test for Ductility of Electrodeposits1This standard is issued under the fixed designation B490;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,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.Scope1.1 This practice describes a procedure for measuring theductility of electrodeposited foils.21.2 This practice is suitable only for the evaluation ofelectrodeposits having low ductility.1.3 The obtained ductility values must only be consideredsemi-quantitative because this test has a significant operatordependence.1.4 This practice is best used for in-house process controlwhere measurements are always made by the same operator.Achange in ductility value can be used as an indication ofpossible changes in the electroplating solution.1.5 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.6 This standard does not purport to address the safetyproblems,if any,associated with its use.It is the responsibilityof the user of this standard to establish appropriate safety andhealth practices and determine the applicability of regulatorylimitations prior to use.2.Referenced Documents2.1 ASTM Standards:3B456 Specification for Electrodeposited Coatings of CopperPlus Nickel Plus Chromium and Nickel Plus Chromium3.Summary of Practice3.1 This practice consists of measuring the bend of a foilheld between the jaws of a micrometer;these are closed untilfracture or cracks appear.4.Significance and Use4.1 This practice is useful as one method of controllingsome electroplating solutions.It serves to indicate the presenceof contamination or some other adverse condition.4.2 Ductility measurements are of particular value whenelectroplated parts are to be subjected to moderate stress suchas that involved in bolting an electroplated bumper to anautomobile or when exposed to a wide range of fluctuatingtemperatures(thermal shock).5.Apparatus5.1 Micrometer,25-mm with flat jaws to measure thethickness and to compress the foil.5.2 Tools such as a hand or power shear,grinding wheel,fileor hack saw,to initiate separation of the foil from the basismetal.5.3 Pair of Sharp Scissors to cut the test specimens.6.Test Specimens6.1 An electrodeposit shall be prepared using a basis metalwith a smooth surface from which the electrodeposit can bereadily separated.Proper preparation of the surface from whichthe foil must be separated undamaged is critical.The depositshall be electroplated at an average current density and underconditions(agitation,temperature,etc.)approximating thoseused on parts electroplated in the solution being tested.Thedeposit thickness shall be 25-30 m.The panels are prepared asin 6.2.6.2 The test panel must be properly passivated beforeplating to allow for separation of the subsequent deposit.Stainless steel,brass or nickel dipped in a chromic acidsolution(see Note 1)for approximately 1 minute can be usedas the basis metal.The panel should be properly rinsed beforeplating.Entering the solution with current on is recommendedto prevent activation of the basis metal.When testing nickeldeposits,other than rinsing,no post treatments shall be used.An alternative method is described in Note 2.NOTE1For convenience,an ordinary hexavalent chromium electro-plating solution can be used for preparing the basis metal.NOTE2As an alternative basis metal,a piece of cold-rolled steel ofany convenient size,such as 100 by 150 mm,shall be properly cleaned,rinsed,acid dipped,rinsed and electroplated with approximately 7.5 m ofnickel.After rinsing,the specimen shall be cleaned anodically for1This practice is under the jurisdiction of ASTM Committee B08 on Metallicand Inorganic Coatings and is the direct responsibility of Subcommittee B08.10 onTest Methods.Current edition approved May 1,2014.Published May 2014.Originallyapproved in 1968.Last previous edition approved in 2009 as B490 09.DOI:10.1520/B0490-09R14.2For a discussion of this test see Mohrnheim,A.F.,“The Bend Test forMeasuring the Strain Limit of Surfaces,”Plating,Vol 50,1963,pp.10941099.3For 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 Document Summary page onthe ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 approximately 15 seconds in a hot alkaline cleaner,rinsed,acid dipped inapproximately 1 N sulfuric acid(approximately 27 mL of concentratedsulfuric acid added to approximately 900 mL of cold water,mixed,anddiluted with cold water to 1 L),rinsed,and immediately placed in theelectroplating solution of the metal to be tested.6.3 The panel size shoul