1、 FORD LABORATORY TEST METHOD EU-BQ 003-04 Date Action Revisions 2000 11 09 Revised Editorial - no technical change A. Cockman 1994 02 28 Printed copies are uncontrolled Page 1 of 2 Copyright 2000, Ford Global Technol ogies, Inc. DETERMINATION OF MICRO CRACK OR MICRO PORE DENSITY IN ELECTROPLATED CHR
2、OMIUM COATINGS Application This method is used to determine the crack or pore density of electroplated chromium coatings by depositing copper in the cracks or pores, with subsequent microscopic examination under reflected light. Apparatus and Chemicals Required Microscope Capable of magnifying to 10
3、0X, with reflected light. Micrometer Eyepiece Graduated in .02 mm divisions. Copper Sulphate c.p. (CuSO 4 .5H 2 O) Sulphuric Acid c.p. ( 1.84 g/cm 3 ) Nitric Acid c.p. (1.42g/cm 3 ) Plating Unit Of suitable size with copper anode, capable of operating at 0.3A/dm 2 , and 3.5 - 5.0 volts. Degreasing A
4、gent Conditioning and Test Conditions All test values indicated herein are based on material conditioned in a controlled atmosphere of 23 +/ - 2 C and 50 +/ - 5 % relative humidity for not less than 24 h prior to testing and tested under the same conditions unless otherwise specified. FORD LABORATOR
5、Y TEST METHOD EU-BQ 003-04 Page 2 of 2 Copyright 2000, Ford Global Technologies, Inc. Procedure Method A - For Checking Parts Immediately After Plating Cycle 1. Prepare plating solution by dissolving 200 g/L of copper sulphate in distilled water, add 20 g/L of the sulphuric acid. 2. Clean the sample
6、s if there is any delay after chromium plating using the degreasing agent. Note: Avoid use of a ny electrolytic treatment. 3. Connect sample and anode to the electrical supply and activate. 4. Immerse anode plus sample in the plating solution. Plate for approximately 1 minute, at 23 +/ - 2 C, at an
7、average current density of approximately 0.3 A/dm 2 between 3.5 and 5.0 volts. 5. Remove sample from plating solution and switch off current. 6. Wash the sample under hot running tap water, rinse with distilled water, and then acetone. Dry by means of warm air. Evaluation 1. Using the micrometer eye
8、piece, examine the sample at 100X magnification under the microscope using reflected light, and determine the length over which a minimum of 40 cracks/pores occur. 2. Calculate cracks/mm for micro cracked chromium. Calculate pores/sq mm for micro poro us chromium. Method B - For Checking Parts That
9、Have Been Plated in Excess of 24 Hours 1. Immerse samples in 15 % nitric acid solution for 4 minutes at approximately 95 C. This assists in revealing cracks or pores. 2. Remove the samples from the nitri c acid and rinse in distilled water. 3. Continue as in Method A, para 3 - 6. Evaluation As outlined under Method A. Chemicals, materials, parts, and equipment referenced in this document must be used and handled properly. Each party is responsible fo r determining proper use and handling in its facilities.
