Structure and Properties of Deposits

In considering the structure of metals, we distinguish three basic structures  

From atomistic aspects, a metal can be considered as a fixed lattice of positive ions permeated by a gas of free electrons [1], Positive ions are the atomic cores, while the electrons are the valence electrons. Since there are about 1022 atoms in 1 cm3 of a metal, one can expect that some atoms are not exactly in their right place. Thus, one can expect that a real lattice will contain defects (imperfections). The most common defects are point defects (e.g. a vacancy, an interstitial) and dislocations (e.g. the edge dislocation, screw dislocation) [2]. 

The electronic structure of metals and metallic surfaces are interpreted by the free-electron theory of metals [1, 2]. 

Since there is a strong interrelationship between the structure and the properties of deposits, this section discusses both these subjects. 

In Sect. 3.7.1, we give an example of how structure parameters determine the 

All deposits of metals are made of grains whose structural-physical nature (1) can be divided into four types (1) columnar, (2) fine-grained, (3) fibrous, and (4) banded. In terms of their practical macroscopic physical properties, their main characteristics may be summarized as follows  

Those types that are of low strength and hardness but possess high degree of ductility. Examples are metals deposited under low-current-density conditions. 

Those types are characterized by typical grain sizes of 10 to 100 mn. The deposits are relatively hard and brittle, whereas some are rather ductile. Examples are metals deposited under high-current-density conditions containing hydrated oxides as a consequence. 

Those types that are intermediate in nature between types 1 and 2. 

Those types that contain grains of extremely small dimensions (less than 10 nm). Typically, bright deposits (as a result of additives, for instance) such as Ni-P 

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Structure and properties of deposits. These can be understood and interpreted on the basis of a variety of surface and bulk analytic techniques and methods that reveal electrical, magnetic, and physical properties of metals and alloys. 

Mass transport plays an important role in pulsed metal deposition. On the one hand it limits the maximum rate of deposition and influences the structure and properties of deposits. On the other hand it effects the macrothrowing and microthrowing power. Under dc conditions, the maximum deposition rate is given by the limiting current density, fg, where the metal ion concentration... 

Many books have been dedicated over the years to the topic of electrodeposition (see, for example, Refs. 1-6). These books deal with a variety of sub-topics such as surface preparation of the substrate prior to deposition, thermodynamics and kinetics of electrodeposition, the reactions that take place on an atomistic level, the mechanisms of growth, the effect of bath chemistry and operating conditions, the deposition of specific metals and alloys, the structure and properties of deposits, etc. 

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