Electrodeposited alloys

Electrodeposition is more flexible than electroless deposition, in that it is not limited by the requirement of having a catalytically active surface. Electrodeposition allows a wider variation in the alloy composition and in the deposit properties than does electroless deposition. This flexibility has not been widely exploited, however, and most of the electrodeposited alloys have had compositions similar to those obtained by electroless deposition (i.e. CoP or CoNiP). 

The first structural examination of Mn-Al electrodeposits was made by Read and Shores [144] in 1966. Since then, several structural studies of both as-deposited and thermally annealed films have been reported [126-129, 133, 134, 145-151], As is often the case with electrodeposited alloys, several phases with varying degrees of deviation... 

Using specific metal combinations, electrodeposited alloys can be made to exhibit hardening as a result of heat treatment subsequent to deposition. This, it should be noted, causes solid precipitation. When alloys such as Cu-Ag, Cu-Pb, and Cu-Ni are coelectrodeposited within the limits of diffusion currents, equilibrium solutions or supersaturated solid solutions are in evidence, as observed by x-rays. The actual type of deposit can, for instance, be determined by the work value of nucleus formation under the overpotential conditions of the more electronegative metal. When the metals are codeposited at low polarization values, formation of solid solutions or of supersaturated solid solutions results. This is so even when the metals are not mutually soluble in the solid state according to the phase diagram. Codeposition at high polarization values, on the other hand, results, as a rule, in two-phase alloys even with systems capable of forming a continuous series of solid solutions. 

The electrodeposited alloys are alloys in the true metallurgical sense, showing a phase structure indicated by the appropriate phase diagram to be stable at the temperature of electrodeposition sometimes some interesting differences in behaviour are noted. Thus, for example, cast alloys of... 

This chapter is arranged as follows experimental strategies for direct determination of surface structure are discussed. Experimental findings are then presented in the areas of ionic adsorption, electrodeposition, alloy surface oxidation, and organic molecular adsorption. 

An early comprehensive review on electrodeposition of Mo alloys with iron-group metals was presented by Brenner. The development of different baths, as well as the effect of operating conditions on the Mo content of the alloy is described in detail in that work. Electrodeposited alloys of Mo were claimed to be of limited practical value, because of their poor physical characteristics compared to the corresponding alloys of W. 

Cha] Magnetic properties measurements, magnetostriction measurements, XRD Co based alloys with 4 to 15 mass% Cu and 9 to 13 mass% Fe, structural and magnetic properties of electrodeposited alloys... 

It is general experience in materials science that alloy can exhibit qualities that are unobtainable with parent metals. This is particularly true for electrodeposited alloys, mainly due to formation of metastable phases and intermediate layers. Some important properties of materials, such as hardness, ductility, tensile strength. Young s modulus, corrosion resistance, solderability, wear resistance, antifriction service, etc., may be enhanced. At the same time, some properties that are not characteristic for parent metals, such as high magnetic permeability, other magnetic and electrical properties, amorphous structure, etc., can also be obtained. In some cases, alloy coatings may be more suitable for subsequent electroplate overlayers and conversion chemical treatments [1],... 

Concerning scientific approach of the electrodeposition of alloys, all the results obtained until 1995, mainly connected with the thermodynamics and kinetics of alloy electrodeposition, are summarized in the chapter by Despic and Jovic [1] and Jovic et al. [5]. In the present chapter, the morphology of electrodeposited alloys will be the main subject. 

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