Chemical surface treatment and metallization of ABS, PVC and PVC/ABS blends

To replace ABS in plated objects, samples of PVC and blends of PVC/ABS, in mass ratio of 20/80, 40/60 and 60/40, were subjected to step-conditioning (etching) in sulfochromic solution, under different conditions of concentration, time and temperature, being plated in sequence. Modifications of the surface of the samples after conditioning were analyzed by scanning electron microscopy, atomic force microscopy and roughness. The quality of metal deposition was evaluated by visual inspection and adhesion tests. Results show that increasing the amount of PVC in the blend required more aggressive operational conditions to promote metallic adhesion; higher temperature, immersion time and sulfochromic solution concentration. From all tested conditions with the sulfochromic solution for the treatment of PVC, and 20/80 and 40/60 PVC/ABS blend samples, the concentration of 350 g L^–1 of chromic acid and 400 g L^–1 of sulfuric acid at 70 ^oC and immersion time of 15 minutes, resulted in the deposition of metal layers in all evaluated specimens. These were approved in adhesion and corrosion tests.

plating; ABS; PVC; PVC/ABS blends