1、 FORD LABORATORY TEST METHOD BI 017-02 Date Action Revisions 2001 03 13 Revised Editorial no technical change A. Cockman 1992 06 17 Printed copies are uncontrolled Page 1 of 2 Copyright 2001, Ford Global Technologies, Inc. COATING WEIGHT-CHROMATE/ZINC DUST COMPLEX Application This procedure is desig
2、ned to remove the Dacromet coating without attack of substrate to obtain the coating weight of Dacromet in mg. Equipment Required Analytical Balance Convection Oven Metal Shear Crystallizing Dish 190 x 100 mm Pyrex brand #3140. Flat bottom and straight sides. VWR 25411-162 or equivalent. Small Hair
3、Brush Chemicals Concentrated HCl Inhibitors Activol #15900 Source: Harry S. Miller Company 4th and Bristol Streets Philadelphia, PA 19140 or equivalent. Conditioning and Test Conditions All test values indicated herein are based on material conditioned in a controlled atmosphere of 23 +/- 2 C and 50
4、 +/- 5 % relative humidity for not less than 24 h prior to testing and tested under the same conditions unless otherwise specified. FORD LABORATORY TEST METHOD BI 017-02 Page 2 of 2 Copyright 2001, Ford Global Technologies, Inc. Procedure 1. Prepare the stripping solution by adding concentrated HCl
5、to water to obtain a 25 % (by volume) solution of HCl. Add activol 15900 to obtain solution 1 % inhibitor (by volume) 750 mL of water, 250 mL of HCl acid, and 10 mL of inhibitor. The Activol inhibits the attack of the acid on the substrate. Stir the solution and cool to 23 +/- 2 C. 2. Pour the strip
6、ping solution into the crystallizing dish. 3. Clean panels to be stripped with a spray rinse of reagent trichloroethylene followed by desiccation. Weigh the clean panel to be stripped on an analytical balance. Also determine the panel area in square inches. A size of 4 x 6 is recommended as 50 to 15
7、0 mg of coating will be removed. 4. Immerse the weighed panel into the solution. Make sure the panel is totally beneath the stripping solution. The exposure times will depend on the cure of the Dacromet and have been found to take 1 to 15 minutes. 5. Brush the weighed panel with the hair brush as it
8、 is stripping. 6. After the panel appears stripped, indicated by no further evolution of the H2 and the panel appears bright and metallic color, remove from the bath and rinse with water. The water is added to the bath if analysis of the stripped coating is desired. Spray rinse the panel with methan
9、ol. 7. Dry the panel, preferably by air and heat (100 C) and reweigh. 8. Obtain the loss in weight and calculate the mg/sq ft coating weight. (Original wt of - wt of stripped) x 144 sq in (1 sq ft) x 1000 = mg/sq ft (panel & coating panel) area of panel (sq in) of coating Example: (109.6900 g - 109.
10、5700 g) x 144 sq in x 1000 = 720 mg/sq ft 24 sq in 9. If desired, the bath solution could be analyzed by atomic absorption for chromium and zinc after the proper dilution. Do not reuse acid solution. Chemicals, materials, parts, and equipment referenced in this document must be used and handled properly. Each party is responsible for determining proper use and handling in its facilities.
