PCI SEMI NICK Semi Bright Nickel process produces very active, ductile highly leveled, sulphur free Nickel deposits. This process is suitable as an undercoat for Multi layer Nickel Plating processes which gives exceptional potential values between semi bright and bright Nickel deposit to achieve high corrosion resistance thereby meeting the latest requirements of all Automotive Majors
Under the effects of moisture and atmospheric contaminants, corrosion initiates in cracks or pores in the chromium topcoat. As the chromium is electrochemically more noble than the nickel, corrosive attack takes place in the bright nickel with the formation of pits. As corrosion continues, the pitting becomes deeper and eventually reaches the substrate, resulting in rusting or other base metal corrosion. At the same time the thin chromium layer may become partly dislodged through undercutting. Because bright nickel is relatively electrochemically active, the rate of attack can be quite rapid under corrosive conditions. With PCI SEMI NIK process the bottom layer of semi-bright nickel is electrochemically noble compared with the bright nickel. Therefore corrosion will take place preferentially in the bright nickel layer. The result is that, when the attack reaches the interface, corrosion will tend to spread laterally in the top layer rather than penetrate into the semi-bright coating. Microscopic examination shows typically flat bottomed pits in the bright nickel. This effectively retards the pitting attack because, before the pit can penetrate further, a considerable portion of the bright nickel layer must be removed.
PCI TRISHEEN Nickel Process surpasses automotive requirements for corossion protection. This is a sandwich intermediate strike nickel layer between semi-bright and bright nickel layers. Thie nickel layer is obtained with TriSheen Process produces more Sulphur in the deposit and hence it becomes more active than bright and semi-bright nickel layer. As a result Tri-nickel layer corrodes preferentially when exposed to corrosive atmosphere and protects the top and bottom layer thereby increases the corrosion protection ability. PCI TRISHEEN Nickel Process Produces extremely ductile deposit and delivers the desired potential difference among the layers.