Mechanical Properties of Ni-Fe Alloy deposits in Acidic Sulfamate Bath

초록

The mechanical properties of Ni-Fe alloy deposits in acidic sulfamate bath were investigated. Electrodepositions of Ni-Fe alloy were carried out under galvanostatic conditions with various electrolysis variables such as current density, temperature and pH solution. Microstructure of Ni-Fe alloy deposits was also investigated using X-ray diffraction analysis technique. The Fe content in the Ni-Fe deposit was decreased from 12.4wt.% to 5.3wt.% with increasing current density from 5 to 25A/dm2. However, the Fe content was increased from 6.5wt.% to 8wt.% when bath temperature was elevated from 40 to 70℃. The hardness of Ni-Fe deposit was increased with an increment of Fe content, and the hardness reached 550VHN at 12.4wt.%Fe. The internal stress gradually increased with increasing the Fe content in the deposit and obtained the highest value of 21kg/mm2 at the 12.4wt.%Fe. XRD analysis showed that the increase of Fe content in Ni-Fe alloy deposit induced grain size refining. With decreasing grain size, the hardness of deposits increased following the regular Hall-Petch relationship.