Abstract
The electroless plating method has a particular advantage in that it accepts non-conductive substrates as its substrate materials. The catalyzation pretreatment process is essential for initiating electroless deposition. The most common two-step pretreatment process prior to electroless nickel plating was studied here, which includes the sensitizing step and the activating step. The objective of this study is to investigate the morphological changes of the adsorbate produced on the non-conductive substrates during the period before and after the deposition is initiated. The results obtained are as follows :
By using an ICP for the nickel precipitate weight gain measurement when the glass substrate which conducted the catalyzation process was immersed in an electroless Ni-P plating bath, the results show that deposition is already initiated with a low deposition rate even before the deposition can be confirmed with a visual inspection.
The observations of the catalyzed surfaces using SEM detect the aggregates of adparticles with sizes grown to reach several microns. The incidence of the grown aggregates has a tendency to be higher as the solubility of Sn in the activating solution is increases. Comparing the results of the morphological observation before and after the initiation of the deposition, it should be concluded that the aggregates produced during the activation step play the starting point of the massive nodular grains that exist on the surface of deposits.
