Synthesis Of Gemini With Double (Triple) Bond And Its Application In Acid Nickel Electroplating

As a surface treatment, bright nickel-plating has widely been used in metal plating, electroforming, PCB circuit boards and other fields. Brightener is usually added into Watts bath for the acquisition of bright, leveling nickel coating. Brightener can be divided into three categories, including primary, secondary and auxiliary brightener.To begin with,14 quaternary ammonium Geminis with double (triple) bond were synthesized and characterized their structures by H1NMR and C13NMR in this thesis. These Geminis can be used as the secondary brightener. lb (E)-1,1'-(but-2-ene-1,4-diyl) bis(2,4-dimethylpyridinium) and le (E)-1,1'-(but-2-ene-l,4-diyl) bis (triethylammonium) are the representatives of these Geminis.Then, the effects of these Geminis above on the coatings'brightness, morphology, electrodeposition, and the bath's throwing, coverage, leveling power were studied by the Hull cell experiments, color separations, scanning electron microscopy, thickness gauge, profilometer, strain gauge, electrochemical workstation and other methods.lb has better overall performance than the other 7 brighteners.Furthermore, Hull cell test results showed that a flat crystal-surface could be obtained in the solutions with small amount of leveling additives like lb. Results of the polarization curves and cyclic voltammetry curves also supported this conclusion in the electrochemical view. In addition, the brightness and internal stress results gave evidence to the synergies of primary brightener such as saccharin and pyridine Geminis like 1b. Meanwhile, the throwing power results indicated the synergies between sodium allyl(a example of Walking Agent) and alkyl Geminis like le.Moreover, Brighteners'polarization on the cathode not only can be used to research the agents'cathode behaviors, but also can help to select the suitable agent concentrations. There is a coincidence between these concentrations with the orthogonal result.Finally,8 brightener formulas were optimized by orthogonal analysis. Every formula contained one Gemini and 5 other commercial additives. The formula containing lb was the best according to their overall performances.