Silicone (RTV) sealant bonded aluminum joints: An experimental study

The performance of adhesively bonded joints in terms of strength, sealing capacity and environmental resistance is of concern to designers in many fields including the marine industry. In the present work floating roller peel tests were utilized to study the bond properties of aluminum-silicone (RTV) joints. An attempt was made to identify the factors that affect the joint strength. Experiments revealed that peel strength increased with sealant thickness and decreased at high peel rates. Organo-silane primer SS4044 was found to improve the weatherability and strength of the joint. Results point out that mechanical interlocking combined with chemical alteration of the substrate surface was responsible for this improved adhesion. Combinations of three different environmental parameters were studied, and it was shown that seawater was the most hostile single type and a combined exposure to seawater and UV radiation (to simulate a marine environment) proved to be the worst overall. Tests showed that relaxation was governed by sealant thickness alone and was not affected by the marine environment.