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

Despite the recent extensive examination of electroless coatings, the effect of the preplating processes on the formation of electroless coatings has remained unresolved. The ability of different preplating processes, degreasing and pickling, to clean the contaminated copper surface before deposition was studied by contact angle determinations, residual oil measurements, and potentiostatic polarization cycles. The influence of preplating processes on the buildup of electroless tin coatings and subsequent deposit structure was studied by scanning electron microscopy. Alkaline degreasers were found to effectively eliminate the organic soil from the surface, thus facilitating uniform coating nucleation and good adhesion properties. Pickling gave rise to a regular coating appearance throughout the structure. In addition, the applicability of contact angle measurements for studying the efficiency of cleaning treatments was demonstrated. [ABSTRACT FROM AUTHOR]