Durability of Adhesively Bonded Structure.

摘要

Two adhesives were exposed to marine atmosphere for a 10-year period. The specimens compared durability of phosphoric acid anodize to sodium dichromate/sulfuric acid (OFPL) surface preparations, each primed with a chromated epoxy primer. Double lap shear specimens were exposed with no load and spring loaded to two stress levels to compare combined corrosion/stress effects. Nondestructive tests were conducted to determine their capability to show delaminations or the presence of corrosion in the adhesive bond line. Specimens were tested for residual mechanical properties after 5 and 10 years. Both room and elevated temperature testing were accomplished. Elevated temperature testing of exposed specimens showed reduced strength significantly below unexposed elevated temperature strengths. Phosphoric acid anodized specimens with the chromated epoxy primer showed markedly superior strength retention to the chromic/sulfuric (OFPL) etch in static stressed specimen in the marine atmosphere. Wedge opened crack extension tests also differentiated between the less and more durable adhesive bonding processes. Adhesive joining, Bonding, Glass transition temperature, Filiform corrosion, Phosphoric acid anodize, Forest product laboratory etch, Lap shear, Crack extension.