1、 FORD LABORATORY TEST METHOD BI 017-03 Date Action Revisions 2001 03 13 Revised Editorial no technical change A. Cockman 1992 06 19 Printed copies are uncontrolled Page 1 of 6 Copyright 2001, Ford Global Technologies, Inc. DETERMINATION OF COATING WEIGHT - CHROMATE/ZINC DUST COMPLEX PORTASPEC X-RAY
2、ANALYSIS METHOD Application This procedure is used to determine the Cr concentration (in mg/sq ft or surface) of Dacromet coatings on steel substrates by use of the Portaspec X-Ray Spectrophotometer. Equipment Required Portable X-Ray Spectrograph “Portaspec“ Source: Pitchford Industries, Inc. 1901 P
3、ainters Run Road Pittsburgh, PA 15241 Digital Scaler and Timer Model #20 Source: Pitchford Industries, Inc. 1901 Painters Run Road Pittsburgh, PA 15241 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. Procedure Instrument Setup 1. Inspect wiring to see that connections are proper. (Refer to “Schematic for Instrument Setup.“) FORD LABORATORY TEST METHOD BI 017-03 Page
5、2 of 6 Copyright 2001, Ford Global Technologies, Inc. 2. Plug in the power supply unit to a grounded 117 volt line. The GROUND light on the power supply unit must be “on“. 3. Turn the LINE switch to the “on“ position. Turn the FILAMENT switch to the “on“ position. 4. When the READY light goes on, th
6、e X-Ray tube is now capable of being activated. 5. Turn the dial on the Model 20 Scaler (Digital Scaler) to the LINE position. 6. All units of the apparatus are now set for standardization and testing. 7. If the instrument is to be used continuously, the water cooling hoses must be attached to the f
7、ront of the Portaspec Head. Even for intermittent use at higher milliamperage setting, water cooling should be used. (No danger is involved, since the X-Ray automatically shuts off if the unit overheats.) 1This setting of 69.0 does not coincide exactly with the literature value for the K line for ch
8、romium. This is due to the calibration of the goniometer. This correctness of using 69.0 is established by noting that the maximum counting rate (as read on the meter on the Portaspec Head) is achieved at this angle. The meter is activated by setting the switch on the top of the Portaspec Head at ME
9、TER and depressing the thumb switch on the handle at the Portaspec Head. Note: If the X-Ray tube is being activated by means of the thumb switch, the meter is simultaneously activated. Only when the extension cable (On-Off switch) is plugged in the side of the Portaspec head is the thumb switch requ
10、ired to activate the meter. Cr Coating Weight Determinations 1. Place the Portaspec Head directly on the sample to be measured. Make certain that the gonimeter dial and the milliamperage dial have not been changed. 2. Set the timer on the digital scaler to count for 0.6 minutes by setting the multip
11、lier switch in the X 0.1 position and the counter to 06. 3. Turn on the X-Ray tube. CAUTION! 4. Take a scaler count for 0.6 minutes. 5. Turn off the X-Ray tube. 6. Refer to Graph #1 showing DIGITAL SCALER COUNT FOR 0.6 MINUTES VS Cr COATING WEIGHT (in mg/sq ft). Read off the Cr coating weight of the
12、 sample and report as such. FORD LABORATORY TEST METHOD BI 017-03 Page 3 of 6 Copyright 2001, Ford Global Technologies, Inc. Instrument Standardization 1. On the Portaspec Head, set SCALE at X100 and RESPONSE should be at MED. 2. Place the Portaspec Head on the Sample Holder and make certain it is p
13、roperly in place. 3. Insert a CHROMIUM STANDARD Specimen in the Sample Holder and position it under the X-Ray port. 4. Set the goniometer on the Portaspec Head for 69.0. This is accomplished by means of the knob on the left side of the Portaspec Head. (See Footnote 1) 5. Set the timer on the Digital
14、 Scaler to count for 0.2 minutes by setting the multiplier switch in the X 0.1 position and the counter to 02. 6. Turn on the X-Ray tube using either the Thumb Switch on the Portaspec Head or the toggle switch. The toggle switch may be attached to the Portaspec Head via a lead wire plugged into the
15、jack on the left side. This lead wire permits remote operation. Thumb switch, if used, must be kept depressed during entire reading operation. CAUTION: Be certain to follow safety precautions when X-Ray tube is on. See attached safety sheet. 7. Adjust the milliamperage control (using MA CONTROL dial
16、) on the Portaspec Head until the milliameter reading on the Power Supply Unit is about 3.65 milliamperes. CAUTION! Do not exceed 4.0 milliamperes. 8. Make the final adjustment of the milliamperage/setting until a Digital Scaler count of 8,100 - 8,500 - 0.2 minutes is achieved. This is accomplished
17、by alternately taking a reading on the Digital Sealer and adjusting the milliamperage setting. (Clear the Digital Scaler by pressing the RESET button. Take a reading by pressing the COUNT button.) 9. Turn off X-Ray tube by toggle switch or releasing the Thumb Switch. 10. The instrument is now standa
18、rdized for Cr determination and/or z. c. Standard Safety Procedures for Working with the Portaspec X-Ray Spectrophotometer There are three basic positions in which the Portaspec Head may be used. Each one requires its own safety precautions. FORD LABORATORY TEST METHOD BI 017-03 Page 4 of 6 Copyrigh
19、t 2001, Ford Global Technologies, Inc. 1. Portaspec Head attached to the sample holder The test sample holder tray must be inserted completely in the side door to activate the microswitch. The door must be interlocked with the x-ray tube so that the x-ray beam cannot be turned on if the door is open
20、. No other shielding is required. 2. Portaspec Head placed directly on flat sample (a) If the panel is on the floor or a heavy -topped bench, the only shielding required is the placing of three small strips of lead foil around the base of the unit as shown: (b) If the test panel is in such a locatio
21、n that there is no shielding behind it, a flat sheet of lead must be placed behind or under the test sample. 3. Portaspec Head mounted for continuous monitoring When the Portaspec Head is mounted on the pilot line for continuous reading, shielding must be placed on all sides and above and below the
22、unit. Since the exact method of mounting is not established, the positions of the shielding are not firmly fixed. Note 1: In all cases, it is good procedure to occasionally take readings with the portable Geiger counter to assure that there is no stray radiation. Note 2: Film badges are available. T
23、hese should be used by those people operating the x-ray unit or those always in the immediate area. Notes 1 and 2 are especially pertinent when the x-ray unit is mounted on the pilot line. Chemicals, materials, parts, and equipment referenced in this document must be used and handled properly. Each
24、party is responsible for determining proper use and handling in its facilities. FORD LABORATORY TEST METHOD BI 017-03 Page 5 of 6 Copyright 2001, Ford Global Technologies, Inc. DETERMINATION OF COATING WEIGHT - CHROMATE/ZINC COMPLEX SCHEMATIC FOR INSTRUMENT SET - UP FORD LABORATORY TEST METHOD BI 017-03 Page 6 of 6 Copyright 2001, Ford Global Technologies, Inc. DETERMINATION OF COATING WEIGHT - CHROMATE/ZINC COMPLEX
