PRE-TREATMENT OF CFRP FOR ADHESIVE BONDING USING LOW-PRESSURE BLASTING

摘要

In the automotive industry the application of composite materials is steadily increasing, due to regulations with regard to the reduction of CO_2 emission and the need to compensate the additional weight of batteries in electric cars. One major challenge limiting the utilization of the full lightweight potential is the joining technology, especially in hybrid structures where composites are bonded to metallic parts. A joining technology with a high potential of taking full advantage of the material is adhesive bonding since it allows for an even stress distribution and does not require holes and thus local reinforcements as conventional joints with fasteners do. However, to achieve a strong and durable bond, surface pre-treatment is often necessary to remove surface contaminations such as residues of release agents. With the use of FRP in larger quantities it therefore becomes necessary to develop procedures which allow for automated bonding pre-treatment with a high reliability and low process times. As one possible approach to the aforementioned challenge this paper presents low-pressure blasting, a novel blasting process where the grit is not accelerated by positive but by negative pressure inside a closed jet cap and provides results from surface analyses and mechanical testing which have been performed on CFRP surfaces pre-treated by this process.