Improving the adhesion of plastic/metal direct bonding by injection moulding using surface modifications

Abstract

In this work, the surface of aluminium alloy A5052 thin plate was treated by chemical etching and atmospheric plasma before applying primer to enhance its adhesion with PC/ABS under insert moulding. The chemical etching was conducted with an ammonia aqueous solution; nanostructures were produced on metal surface, namely to increase the mechanical interlocking effect between polymer and metal. In another experiment, DBD atmospheric plasma treatment was used to clean and activate polar groups on the surface. In general, the chemical change affects bonding strength significantly in the case of A5052/PC + ABS hybrids, the bonding strength improved 2.5 times after the two-step process of chemical etching and plasma treatment.

Keywords:

• Injection moulding
• plasma surface modification
• chemical etching
• primer coating

Acknowledgements

The authors would like to thank the Ministry of Science and Technology, Taiwan, R.O.C. for financially supporting this research and the provision of DBD plasma system by Aerothermal & Plasma Physics Laboratory (APPL).