As the trend toward multi-materialization continues, the use of aluminum-plastic composite materials are expanding to include structural components such as instrument panel beams, radiator supports, and pedals.Resin on its own has lower strength than metal materials and is subject to greater deformation under load, so it is necessary to prevent elongation and fracture. Therefore, by compositing with aluminum material, these concerns can be eliminated, and weight reduction and reliability can be improved. On the other hand, since the thermal expansion coefficient of each material to be combined differs, repeated cold and heat cycles from high to low temperatures will affect the bonding surface. The key technology to solve this problem is the surface treatment technology for aluminum components that improves the adhesion between different materials. 　UACJ's KO treatment, a highly adhesive surface treatment, forms a porous oxide film on the metal surface by alternating electrolysis of aluminum materials in an alkaline electrolytic solution. Since this is a very thin film treatment, only a few tenths of the thickness of ordinary anode oxide film, it strongly adheres to resins, adhesives, and coating films, resulting in superior strength, thermal conductivity, and heat resistance.  The technology has been established for high performance printed circuit boards, and can contribute to weight reduction of automobiles. 
At the development site, preparations for the test, in which aluminum parts are set in the injection molding machine and resin brackets are joined by injection, were in full swing.

KO treatment sheet

PROFILE

Osamu Kato

Chief Engineer
Processing Technology Development
Research Department No. 6
R&D Devision
UACJ Corporation

PROFILE

Yutaro Chikano

Tomoya Yokota
Processing Technology Development
Research Department No. 6
R&D Devision
UACJ Corporation