Electrodeposition of Ni-Fe-W nanocrystalline alloy and its characterization
Tungsten alloys have attracted more and more interest because of their excellent properties and potential application prospect. Many researchers have reported the deposition mechanism, structure and properties of nickel-tungsten alloys, and summarized the effects of bath composition and experimental conditions on the properties and tungsten content of nickel-tungsten alloys. The properties, structure and phase changes of Ni-W alloy coatings were mainly reported in more literatures. In addition, many literatures have reported the electroplating of Fe-W alloy and its process, and the structure and properties of the coating have been studied in detail. Ni-Fe-W alloy has the advantages of both Ni-Fe-W alloy and Fe-W alloy, and has excellent wear resistance and corrosion resistance. The Ni-Fe-W amorphous alloy coating obtained by electroplating transforms into amorphous inclusion nanocrystalline after tempering at a certain temperature, and then completely transforms into nanocrystalline structure after tempering at a higher temperature. The nickel - iron - tungsten alloy coating after tempering treatment has high hardness, wear resistance and corrosion resistance. However, in the process of heat treatment, the workpiece may have the following disadvantages: (1) the microstructure of the matrix material is changed,(2) the workpiece is deformed, and (3) the unplated part is oxidized. The disadvantages of these heat treatment seriously restrict the wide application of amorphous Ni-Fe-W alloy.
Nanocrystalline Ni-Fe-W alloy coatings with bright appearance and compact structure were prepared by direct current electrodeposition. The adhesion of the coating to steel and copper matrix is quite good. Compared with the amorphous Ni-Fe-W alloy, the Ni-Fe-W nanocrystalline alloy has better corrosion resistance and higher hardness, which can replace the traditional chromium plating process and avoid the limitation caused by tempering process.
