1、 FORD LABORATORY TEST METHOD AQ 110-01 Date Action Revisions Rev. 0 2014 12 01 Released L. Click / A. Wedepohl, NA Controlled document at www.MATS Copyright 2014, Ford Global Technologies, LLC Page 1 of 9 ZINC PHOSPHATE COVERAGE EVALUATION FOR PAINTED STEEL CHASSIS COMPONENTS Application This proced
2、ure is designed to evaluate the percentage of zinc phosphate crystal coverage, size, and morphology on a production steel component. Procedure applies to E-coated or powder coated non-galvanized, steel chassis components. Apparatus and Materials Required Band saw Part tag, paper with twistable wire
3、Vapor Corrosion Inhibiting (VCI) paper or VCI plastic bags Water cooled cut-off saw (or, similar low heat cutting method) Ultrasonic cleaner Ethanol or isopropyl alcohol Scanning Electron Microscope (SEM) with Energy Dispersive X-ray capability Paint pen Scribe Digital camera Chemicals, materials, p
4、arts, 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. Procedure Sample selection and identification 1) Obtain a part (e.g. control arm, sub-frame, etc.) after processing through the fina
5、l rinse stages of the phosphate line after post-seal and prior to entering the E-coat tank. 2) When handling zinc phosphate parts use clean gloves (rubber, nitrile, latex, or cloth). Avoid handling at the locations identified on the print for evaluation. 3) Ensure that the part is not collected just
6、 before or after a significant pretreatment system adjustment. 4) Dry the part through the E-coat bake oven or 175 C (350 F) for 10 minutes or until dry. Keep the temperature below 230 C ( 450 F) to avoid decomposition of the phosphate crystals. The use of other FORD LABORATORY TEST METHOD AQ 110-01
7、 Copyright 2014, Ford Global Technologies, LLC Page 2 of 9 clean, fast, drying methods is allowed. Slow air drying of the parts may lead to surface rust and should be avoided. 5) Take a photo of parts on the coating rack to show orientation and include in the final report. A copy of the daily check
8、sheet for each stage of the alkaline cleaner and phosphate bath conditions shall also be included in the final report. If an outside lab will be performing the analysis, then these items should accompany the part shipment. 6) Tag the part with the date, time, part number, plant, and line. Tagging wi
9、ll prevent accidental marking of the locations for evaluation. 7) The coating facility may perform the phosphate evaluation internally or use an outside laboratory. The facility may choose to send the entire part or send cut sections. In either case, parts and cut sections should be stored away from
10、 humidity and moisture in vapor corrosion inhibitor (VCI) paper or bags or a plastic bag with desiccant. 8) Examination Locations: Examine three external locations, three internal locations, and one weld location for a total of 7 specimens. Check the part print to determine if the locations have alr
11、eady been established. Number the locations one through seven with No. 7 as the weld location. Each location will be an area 25 mm x 25 mm. a) If the part is a uniform matte grey in appearance use the locations identified on the part print and mark each 25 mm x 25 mm area with a paint pen. If locati
12、ons are not shown on the part print, then select three external and three internal locations on different components of the assembly. External and internal location evaluation areas should be at least 10 mm away from welds. For the weld location, select a representative weld than can be examined on
13、the front and back side. b) If the part is not uniform in appearance, substitute one 25 mm x 25 mm external location with the worst external non-uniform appearance and/or one internal location with the worst internal non-uniform appearance. The total number of locations remains the same. 9) Once the
14、 locations are determined, use a paint pen to draw a second square for the cut lines approximately 50 mm x 50 mm around the 25 mm x 25 mm evaluation area. Write the location number from the part print between the two squares. 10) Initial sectioning of the part on the outer cut lines should not damag
15、e the evaluation area in any way. Cutting methods that produce excessive heat can potentially damage the phosphate. Band saws have been used successfully. 11) Photograph the locations with the cut lines so both the color and condition of the surface is captured along with the location. For internal
16、locations, photograph after marking the 25 mm x 25 mm examination area. Example photo taken after cutting showing the cut lines and 25 mm x 25 mm examination area in blue. FORD LABORATORY TEST METHOD AQ 110-01 Copyright 2014, Ford Global Technologies, LLC Page 3 of 9 12) Zinc phosphate should have u
17、niform matte grey appearance. Non-ideal phosphate deposits may show blush rust, black discolorations, gold, streaks, white dust, or a bluish surface. A visual guide is shown in Appendix A. Complete the visual description column in Appendix D for each of the locations. 13) Final cutting of the sample
18、 down to the 25 mm x 25 mm evaluation area should be completed with a water cooled abrasive saw or metal shear to avoid damage to the evaluation area. 14) Write the location number on the specimen with a scribe and label the surfaces interior and exterior. Avoid marking with a paint pen as the ID ma
19、y be removed during the cleaning process. 15) Clean the specimens in the ultrasonic cleaner filled with ethanol or isopropanol to remove any contaminants from the surface. Dry with clean compressed air. Handle the specimens by the edges with rubber gloved hands. Phosphate coverage, size, and morphol
20、ogy 16) Mount the specimen onto the SEM stage and evacuate the chamber. 17) Scan the surface and find a location that represents the typical crystal morphology, size, and coverage observed for that location. Note: EDS may be used to differentiate zinc phosphate from iron oxides if needed. i) Capture
21、 an image of the phosphate at each location with 10 micron scale bar at 1000X. ii) If the phosphate coverage or morphology is obviously non-uniform, take a low magnification image at 250X to show the inconsistency and then capture images of each typical region at 1000X. 18) Estimate the percent cove
22、rage (5%, 50%, 100%, etc.) and determine the morphology. Use Appendix B as a reference for coverage levels and morphology (nodule, flake) 19) Determine the average crystal size by measuring 5 crystals at 1000x for each location. For flake or other elongated type crystals measure the longest dimensio
23、n. 20) Complete the table in Appendix D for all locations. 21) The weld location will be evaluated at four different regions. An example weld evaluation is shown in Appendix C. a) On the weld bead. b) Heat affected zone 1 mm away from the toe of the weld. c) Base metal 10 mm away from the weld. d) B
24、ack side in of the weld The following should accompany this report: 11 macroscopic photographs (6 exterior, 3 interior, 2 weld) showing the regions on the marked part, including the location ID. SEM images on 3 exterior regions = 3 images SEM images on 3 interior regions = 3 images SEM images of 4 w
25、eld regions = 4 images 1 photo of the part in the coating rack as processed in the plant, showing orientation Daily check sheet from the plant Table containing the phosphate data for each location (Appendix D). FORD LABORATORY TEST METHOD AQ 110-01 Copyright 2014, Ford Global Technologies, LLC Page
26、4 of 9 Appendix A Visual Examples of Phosphate Surface Appearance Matte gray finish. Ideal Condition Gold and Streaky (right, from poor oxide removal) Bluish and Streaky (right, from poor conditioning) Dark or Shiny (from low temperature) Gold or Blush Rust (from low accelerator) FORD LABORATORY TES
27、T METHOD AQ 110-01 Copyright 2014, Ford Global Technologies, LLC Page 5 of 9 Appendix B Phosphate Coverage Examples: SEM images of decreasing phosphate coverage on hot rolled steel (page 6), phosphate + oxide on hot rolled steel (page 7), and decreasing phosphate coverage levels on cold rolled steel
28、 (page 8). 95-100% coverage Nodule morphology 3 m crystal size on HR steel 90% coverage with oxides present Nodule morphology 4 m crystal size on HR steel 70% coverage Platelet morphology 10 m crystal size on HR steel FORD LABORATORY TEST METHOD AQ 110-01 Copyright 2014, Ford Global Technologies, LL
29、C Page 6 of 9 Appendix B Phosphate Coverage 50% coverage Platelet morphology 11 m crystal size on HR steel 10% coverage Nodule morphology 5 m crystal size on HR steel 5% coverage with oxides present Nodule morphology 8 m crystal size on HR steel FORD LABORATORY TEST METHOD AQ 110-01 Copyright 2014,
30、Ford Global Technologies, LLC Page 7 of 9 Appendix B Phosphate Coverage 100% coverage Platelet morphology 8 m crystal size on CR steel 100% coverage Nodule morphology 3 m crystal size on CR steel 40% coverage Flower-like morphology 50 m crystal size on CR steel FORD LABORATORY TEST METHOD AQ 110-01
31、Copyright 2014, Ford Global Technologies, LLC Page 8 of 9 Appendix CFour Regions of the Weld Evaluation a. At the weld bead. b. Heat affected zone 1 mm away from the toe of the weld. c. Base metal 10 mm away from the weld. d. Back side of the weld. b c1 mm 10 mm daFORD LABORATORY TEST METHOD AQ 110-
32、01 Copyright 2014, Ford Global Technologies, LLC Page 9 of 9 Appendix D Data Table Plant Name and Location: Coating Line No: Part Name: Part Number: Date Coated: Time Coated: Location on Part Surface Location (External/Internal) Visual Description of Surface (gray/gold, etc.) % Coverage Size, microns Morphology SEM Figure Number 1 2 3 4 5 6 7a, weld bead 7b, 1mm away 7c, 10 mm away 7d, backside
