1、 FORD LABORATORY TEST METHOD AQ 106-02 Date Action Revisions 2001 01 31 Revised Editorial no technical change A. Cockman 2000 04 25 Editorial no technical change A. Cockman 1989 04 24 Printed copies are uncontrolled Page 1 of 2 Copyright 2001, Ford Global Technologies, Inc. CONTROL TEST - CHROMATE P
2、ASSIVATION Application This test method is used to determine whether zinc or cadmium-plated and chromate passivated components have been adequately rinsed after processing by checking the level of chromate present. Note: This test method is used to monitor chromate as part of the program to minimize
3、 the risk of chromate dermatitis. Apparatus and Materials Required Kessler Tubes 25 mm diameter x 150 mm long Beaker 500 mL Graduated Cylinder 100 mL Dephenylcarbazide Reagent grade Ethyl Alcohol Reagent grade; CAUTION: Low flash point Phosphoric Acid Concentrated: Reagent grade Potassium Dichromate
4、 Reagent grade Distilled or Deionized Water 10 ppm max total dissolved solids (ASTM D1888) Solutions Required Diphenylcarbazide Solution 1 % of solution in ethyl alcohol FORD LABORATORY TEST METHOD AQ 106-02 Page 2 of 2 Copyright 2001, Ford Global Technologies, Inc. Phosphoric Acid Solution 4 % by v
5、olume Standard Chromate Solution Preparation: Dissolve 0.136 g of potassium dichromate in distilled water and make up to 1 liter. Take a 10 mL sample of this solution and dilute to 1 liter. This solution represents the equivalent of 1 part per million of chromate. Procedure 1. Take a sufficient numb
6、er of parts in the as used condition to give a test surface area of 5000 +/- 1000 mm2. 2. Suspend the parts in 100 mL of distilled or deionized water at 40 +/- 2 C for a minimum time of three (3) minutes. Agitate gently by swirling. 3. Remove the parts from the water, then fill a Kessler tube to thr
7、ee-quarters full with this solution, add 5 mL of the 4 % phosphoric acid followed by 2 mL of the 1 % diphenylcarbazide solution - shake and allow to stand for 5 minutes. 4. Fill a Kessler tube to three-quarters full with the standard chromate solution, add 5 mL of the 4 % phosphoric acid followed by
8、 2 mL of the diphenylcarbazide solution - shake and allow to stand for 5 minutes (min). 5. After allowing the solution to stand for five (5) min to allow a stable color complex to develop, compare the colors developed in the solution against a white background. Evaluation The test solution is compar
9、ed to the blank solution: No color change - Chromate absent. When a color change is observed, compare with the standard 1 ppm Chromate Solution. Color less intense than Standard Solution - less than 1 ppm Chromate present. Color equivalent to Standard Solution - equivalent to 1 ppm Chromate present. Color more intense than Standard Solution - Chromate present in excess of 1 ppm. 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.
