Formation of ductile amorphous & nanocrystalline Ni-W alloys by electrodeposition

Amorphous and nanocrystalline Ni-W alloys having both high hardness and hig h ductility were prepared by electrodeposition. The plating bath for the el ectrodeposition contained nickel sulfate, trisodium citrate, sodium tungsta te and ammonium chloride, and was operated at various bath concentrations a nd conditions of electrolysis. The tungsten content of the NI-W electrodepo sits is influenced by the plating bath temperature and the applied current density. An amorphous phase appeared at a tungsten content of more than abo ut 20 atomic pet. The ductility of the electrodeposited alloys is strongly influenced by the plating bath temperature, especially the highly ductile a morphous and nanocrystalline Ni-W alloys containing between 17.7 and 22.5 a t pet W. They have been obtained at a plating bath temperature of 75 degree s C: bending through an angle of 180 degrees is possible without breaking. It is suggested that the ductility of the Ni-W electrodeposited alloys may be strongly influenced by inclusion of the codeposited hydrogen during the electrodeposition process.