Optimization of the preplating processes in the fabrication of electrolessly tin-coated copper tube

Despite the recent extensive examination of electroless coatings, the effec t of the preplating processes on the formation of electroless coatings has remained unresolved. The ability of different preplating processes, degreas ing and pickling, to clean the contaminated copper surface before depositio n was studied by contact angle determinations, residual oil measurements, a nd potentiostatic polarization cycles. The influence of preplating processe s on the buildup of electroless tin coatings and subsequent deposit structu re was studied by scanning electron microscopy. Alkaline degreasers were fo und to effectively eliminate the organic soil from the surface, thus facili tating uniform coating nucleation and good adhesion properties. Pickling ga ve rise to a regular coating appearance :throughout the structure. In addit ion, the applicability of contact angle measurements for studying the effic iency of cleaning treatments was demonstrated.