1、 FORD LABORATORY TEST METHOD BI 020-06 Date Action Revisions 2001 03 13 Revised Editorial no technical change A. Cockman 1992 06 29 Printed copies are uncontrolled Page 1 of 2 Copyright 2001, Ford Global Technologies, Inc. DETERMINATION OF pH AND ALKALINITY OF ELECTROCOATING BATHS Application This p
2、rocedure is used for the determination of the alkali or organic amine content of electrocoating baths, containing approximately 7 g of non-volatile paint materials per 100 mL bath. Apparatus Required pH Meter Accuracy 0.1 pH unit. Laboratory Stirrer 0 to 500 rpm with glass shaft approximately 7 mm O
3、.D. by 457 mm long with an approximately 19 mm propeller at one end. Beaker Griffin, low form with spout, 250 mL size. Buret Geissler, 50 mL, 0.1 mL subdivisions. Hydrochloric Acid Standardized solution, approximately 0.05 N. Conditioning and Test Conditions All test values indicated herein are base
4、d 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. Procedure 1. Stir 50 mL of a representative sample in a 250 mL beaker until thoroughly mixed. 2
5、. Place electrodes into sample while agitating. 3. Record initial pH reading. Agitator may be shut off while reading is taken. FORD LABORATORY TEST METHOD BI 020-06 Page 2 of 2 Copyright 2001, Ford Global Technologies, Inc. 4. Gradually add hydrochloric acid standard solution from the buret until th
6、e predetermined end point pH is reached (pH 3.50). 5. Check for unchanged pH reading after 2 minutes and record the applied volume of HCl. 6. Compute the grams of amine or alkali per 100 g of paint solids. mL of acid x N acid x E base = g base/100 g paint solids 5 x g paint solids/100 mL bath or com
7、pute the milli equivalents of base/100 g of paint solids mL acid x N acid x 200 = m E base/100 g paint solids g paint solids/100 mL bath or compute the milli equivalents of base/100 mL of bath mL acid x N acid x 200 = m E base/100 mL bath. 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.
