Electrodeposition and properties of an iron-tungsten alloy

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.