Electrodeposition of Fe–W Coatings from a Citric Bath with Use of Divided Electrolytic Cell

Enhanced Tribological Properties of Electrodeposited Fe–W Alloy Coatings through Carburization

“…The electrolytic solution was prepared by dissolving iron sulfate in the aqueous solution of sodium citrate following the addition of sodium tungstate; finally, ammonium chloride and sodium bromide were added. It has been reported that solution prepared through this way contains 80–90% ferric ions of total iron concentration. − The pH of the solution was maintained in the range of 7.5–8.0 by adding aqueous ammonia solution (10%), and it was dropped to about 7.0–7.5 by the end of the experiment. The current density was varied from 100 to 1000 A/m 2 , while the temperature of bath (55 °C), composition and time for electrodeposition (i.e., an hour) were kept constant for each experiment.…”

“…The bath with a lower concentration of Fe 3+ ions produces Fe-rich Fe–W alloys . However, it is also reported that the solutions containing bivalent iron (Fe 2+ ) can also produce 80–90% ferric ions of total iron, if Fe 2+ ions were dissolved first in the aqueous solution of sodium citrate prior to the addition of sodium tungstate. − The composition of Fe–W alloy coatings also depends on the ratio between Fe and W, bath temperature, pH, and applied current density . The higher concentration of W in the solution resulted in a higher fraction of W in the alloy coatings and increased the hardness from 250 to 437 kg/mm 2 .…”