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The role of Bi 3+ ‐complex ion as the stabilizer in electroless nickel plating process
Author(s) -
Wang K.,
Hong L.,
Liu ZL.
Publication year - 2009
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.11807
Subject(s) - stabilizer (aeronautics) , nickel , ion , electroless nickel plating , plating (geology) , chemistry , electroless plating , deposition (geology) , percolation (cognitive psychology) , layer (electronics) , chemical engineering , inorganic chemistry , polymer chemistry , organic chemistry , electroplating , mechanical engineering , geophysics , engineering , neuroscience , paleontology , sediment , biology , geology
Bi 3+ ‐complex ion is presented here as a less toxic stabilizer for use in electroless nickel plating (ENP) to replace the existing Pb 2+ ion stabilizer. The asymmetric derivatives of EDTA are identified to be a type of coordination ligands that can combine with Bi 3+ ions to form soluble complexes in the acidic ENP solution. In the ENP system studied the Bi 3+ ‐complex ion displays a critical stabilizer concentration of about 10 −5 mol/L, that is, the percolation concentration over which the ENP rate drops sharply. Besides the experimental measurement, deposition rates of both Ni and P are also simulated by using a kinetic model that has been derived from the double electric layer theory. The Bi 3+ ‐complex ion, behaving like conventional Pb 2+ ion, stabilizes ENP bath through the chemical replacement reaction at the surface of Ni deposition layer and results in a passive plating surface. This investigation also verifies the properties of the EN deposit, which are insignificantly affected by the length of service time of the plating solution by employing Bi 3+ ‐complex ion stabilizer. © 2009 American Institute of Chemical Engineers AIChE J, 2009