Electrodeposition and properties of an iron-tungsten alloy

Abstract

Iron-tungsten alloys were obtained from citrate electrolytes. The relation between Fe(II) and Fe(III), which permits maintaining the stability of an electrolyte as well as obtaining high-quality deposits for a long time, is revealed. The results of investigations show that the discharge of iron ions takes place from the three valent ions. It is found that the concentration of sodium tungstate in the electrolyte contributes to the codeposition of tungsten, increasing its ratio in the alloy. It is established that the current efficiency and composition of iron-tungsten coatings depend on the current density and the conditions of electrolysis. The microhardness of iron-tungsten deposits increases with an increase in the deposition temperature and depends on the tungsten content in the alloy. Investigations with an electron microscope have shown that, on the alloy surface, superficial inhomogeneous films with the content of tungsten and oxygen different from that in the deposit are formed. The obtained alloys have concentration and structure inhomogeneities.

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

“…The microhardness values of carburized coatings increase linearly with the carburizing temperature for all samples. All carburized Fe-47WC (1000 A/m 2 ) coatings show better HV than Fe-50WC (500 A/m 2 ) and Fe-51WC (100 A/m 2 ); however, Fe-47WC (1000 A/m 2 ) carburized at 850 °C displays a maximum hardness value of 712 HV, which is much better than most of the Fe–W alloys reported in the literature. ,, …”

“…One of the major mechanistic differences between electrodeposition of Fe–W alloys and Ni–W or Co–W alloys is, the former deposits with trivalent iron (Fe 3+ ) ions but the latter two are electrodeposited from bivalent (Ni 2+ , Co 2+ ) ions . The reduction potential of Fe 3+ (−0.036 V) is higher than that of bivalent Ni 2+ (−0.25 V) and Co 2+ (−0.28 V) ions that hinders the electrodeposition of iron alone; therefore, it mostly codeposits with W through citrate-complex formation in contrast to Ni and Co.…”

“…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 .…”

Comparative Analysis of Metal Electrodeposition Rates towards Formation of High-Entropy WFeCoNiCu Alloy

“…The difference in j applied by various authors is the most obvious cause of the inconsistency in the results, but even for the same j, the numbers vary due to the divergency of the other plating conditions, such as bath composition and temperature. Nevertheless, the papers cover some important cases of the influence of those parameters on the v. Plots of at% W and CE against j are quite common [14][15][16][18][19][20], even though some authors stay at a constant value of j, described as optimal [17,21]. Plots of induced metal deposition rates against j tend to increase monotonically due to the apparent increase in current passing through the circuit.…”

Análise comparativa entre o cobre e o ferro como metais indutores na eletrodeposição do tungstênio e na formação das ligas metálicas de Cu-W e Fe-W

“…Observam-se, como características comuns, uma estrutura lisa e contínua, com alguns grãos de contornos bem definidos, conforme destacado na Figura 18. Esse tipo de formação é comum em ligas eletrodepositadas de tungstênio (Alimadadi et al, 2009, Bobanova et al, 2007. A liga obtida no experimento 1 apresentou uma micro falha, conforme apresentado na Figura 17, possivelmente causada por bolhas de hidrogênio que ficaram aderidas à superfície durante o processo de eletrodeposição, impedindo que a liga crescesse naquele ponto (Ghaferi et al, 2015, Donten et al, 2000.…”