Pulse electrodeposited nickel molybdenum

Abstract

Electrodeposition allows the surface properties of a material to differ from the bulk. The use of binary alloys can greatly increase the range of applications that can be achieved with the deposition of pure metals. In this study the deposition of nickel molybdenum alloys is investigated. The presence of Ni in the solution allows the Mo to be deposited. NiXMo1−X (x=0·85 to 0·82) alloys were electrodeposited using pulsed deposition techniques from sulphate and sulphamate based electrolytes. Similar atomic compositions are reported to those found in films deposited using conventional Direct Current (DC) techniques. However an improvement in the physical properties of the films is produced using the pulsed deposition technique. It is found that the stress levels in the film are reduced, leading to reduced cracking. Good tribological properties and a nanostructured grain size are also found. During heat treatment at >550°C progressive grain growth occurs. A number of techniques have been used to establish deposit structure, including energy dispersive X-ray analysis, scanning electron microscopy and hot stage transmission electron microscopy. The good corrosion resistance of the films was revealed using potentiodynamic techniques.The mechanisms by which the films deposit are discussed briefly.