The Effect of Non-Nitric and Non-Cyanide Pretreatment On the Corrosion Resistance of Electroless Nickel on Aluminum Alloys

摘要

Currently, the most common pretreatment processes for aluminum alloys utilize nitric acid and cyanide-based chemistries to produce a zincate surface compatible with electroplating. There has always been some concern over the risk associated with improper use of nitric acid or cyanide in these processes. This has lead to the recent development of pretreatment cycles based on less hazardous chemicals. This paper discusses these new processes and compares them to the more accepted cycles. The discussion will include a comparison of operating parameters of the cycles, resultant zincate morphology, and a direct comparison of resultant properties after EN deposition. In addition the corrosion resistance of various electroless nickel deposits using the new pretreatment chemistries will be compared to such using conventional pretreatment cycles.