DIGITAL LIBRARY: CAMX 2024 | SAN DIEGO, CA | SEPTEMBER 9-12

Get This Paper

Replacing Water Break Testing for Objective and Quantitative Control of Coating and Bonding Processes

Description

Title: Replacing Water Break Testing for Objective and Quantitative Control of Coating and Bonding Processes

Authors: Joann Hilman, Rose Roberts, Rose Dean, Giles Dillingham

DOI: 10.33599/nasampe/c.24.0251

Abstract: "Coating processes, such as painting, form a bond between the paint and the first few molecular layers of the material being coated. Small amounts of contaminants can cause visual defects and loss of durability or performance in the finished product. It is crucial to understand the condition of the surface that is being coated. The historical qualification method for many coating procedures has been the water break test. In this test a surface is dipped in or sprayed with water, and the behavior of the water on the surface is observed by a technician. If the water remains a smooth sheet over the surface, then the part passes the test. If the water breaks (beads up) on the surface, then the part fails the test. This method of qualification is subjective, depending on the technician to determine if the amount of water break is within scope. Water break also does not have the resolution required for materials that must have very high surface energies for successful coating. The limitations of the water break test can lead to both false positives (bad parts being accepted) and false negatives (good parts being rejected). Many industries would benefit from a replacement for the water break test that is quantifiable, objective, and non-destructive. In this work the water break test is compared to water contact angle analysis on composite and metal samples with various levels of contamination and treatment. Aluminum samples were contaminated via spin coating with varying amounts of silicone. Contamination levels were verified using Fourier transform infrared spectroscopy. Composite samples underwent atmospheric plasma treatment to increase surface energy. Contaminated and treated sample surfaces were qualified with water break test (ASTM F22) and water contact angle analysis. Contact angles that correlated to the transition from a water break free to a water break surface correspond to surfaces that were marginal in terms of cleanliness, surface energy, and bondability. "

References: 1. B. Ellis, ""The water break test,"" Circuit World, vol. 31, no. 4, pp. 47-50, 2005. 2. F. M. Fowkes, ""Attractive Forces at Interfaces,"" Ind. Eng. Chem, vol. 56, no. 12, pp. 40-54, 1964. 3. D. K. Owens and R. C. Wendt, ""Estimation of the Surface Free Energy of Polymers,"" Journal of Applied Polymer Science, vol. 13, pp. 1741-1747, 1969. 4. ASTM Standard F22, ""Standard Test Method for Hydrophobic Surface Films by the Water-Break Test,"" ASTM International, West Conshohocken, PA, 2007. 5. A. Kuhn, ""Determining whether a metal surface is really clean: Two testing methods offer an inexpensive yet accurate means for measuring cleanliness,"" Metal Finishing, vol. 103, no. 9, pp. 16-21, 2005. 6. R. G. Dillingham, B. R. Oakley and L. H. Dillingham, ""Method and device for detecting substances on surfaces,"" US Patent 10380754, April 24, 2017. 7. C. W. Extrand and S. I. Moon, ""When Sessile Drops are No Longer Small: Transitions from Spherical to Fully Flattened,"" Langmuir, vol. 26, no. 14, p. 11815–11822, 2010. 8. ASTM Standard D1002-05, ""Standard Test Method for Apparent Shear Strength of Single-Lap-Joint Adhesively Bonded Metal Specimens by Tension Loading (Metal-to-Metal),"" ASTM International, West Conshohocken, PA, 2005. 9. R. Adams and A. Harris, ""The influence of local geometry on the strength of adhesive joints,"" Int. J. Adhesion and Adhesives, vol. 7, no. 2, pp. 69-80, 1987. 10. S. John, A. Kinloch and F. Matthews, ""Measuring and predicting the durability of bonded carbon fiber/epoxy composite joints,"" Composites, vol. 22, no. 2, pp. 121-127, 1999.

Conference: CAMX 2024 | San Diego CA

Publication Date: 2024/9/9

SKU: TP24-0000000251

Pages: 11

Price: $22.00

Get This Paper