Peeling mechanism of interlocked interface between etched acrylonitrile-butadiene-styrene and electroplated metal layer

Electroplating of metals on polymer materials is one of the best decorative processes for achieving low cost and light weight. However, low interfacial adhesion often limits practical utilization due to the potential peel-off behavior of metal layers. The interface between the metal layers and acrylonitrile-butadiene-styrene (ABS) substrate and its peeling mechanism are investigated as a function of etching time. Sa, the arithmetic average roughness of the unit area, and Sdr, the interfacial area ratio, are adopted instead of linear roughness, Ra, to quantify the surface profile. As the etching time increases, both Sa and Sdr for the etched ABS and corresponding metal side increase. The failure mode changes from adhesive to cohesive as the etching time increases, and the peel-off strength of the electroplated ABS exhibits a dependence on the tensile strength of the substrate. The peel-off strength of the electroplated ABS specimens increases to 8.46 N/cm after 30 min of etching time, but the interface degrades, forming inner voids. The Sdr ratio (Sdr, polymer / Sdr, plating) is proposed as a surface parameter to predict the peel-off strength of electroplated ABS and represents a new attempt to quantitatively correlate the interfacial morphology with the adhesion strength.