Description:
Electroplating Ni-B Alloy has a number of superior properties, but boric acid that an indispensable buffer in electroplating baths are harmful to environment. Sodium citrate and sodium propionate can be an environmentally friendly alternative to boric acid. The aqueous solution of waste electroplating solution containing boron will pollute the environment. Therefore, this study has developed a green electroplating solution with citrate and/or propionate as buffers to replace the original plating solution with boric acid as the buffer. The characteristics of the Ni-B coatings electrodeposited from electroplating solution of different buffers were compared with those coated with conventional boric acid using XRD, SEM and TEM. The analysis results presented that there is a significant difference of microstructures among the Ni-B coatings of different buffers and conventional Ni-B coatings, and will affect their corrosion resistance and mechanical properties. Sodium citrate and sodium propionate influenced the orientation and grain size of nickel deposits. The corrosion resistance and mechanical property of nickel deposits from different buffers is comparable to that of boric acid baths. The best corrosion resistance of Ni-B coatings occurred at electrodeposited form the electroplating solution added sodium citric which the i corr value equal to 2*10 -6 A/cm 2 . This Ni-B alloy coatings also has the lowest wear rate of 26.18x10 -6 mm 3 /Nm and the highest hardness of 971 Hv. The results attributed to the adsorption of citrate complexes effects the Ni deposition sequence and crystallization of the coatings