Microthrowing power

Nickel sulfamate is more soluble than the sulfate salt, and baths can be operated using higher nickel concentrations and higher currents. Sulfamate baths have been found to have superior microthrowing power, the abiUty to deposit in small cracks or crevices. Using one nickel salt, only a hydrometer and pH paper are needed to control the bath. A small amount of chloride salt was added as a proprietary. Highly purified nickel sulfamate concentrates are commercially available that can be used to make up new plating baths without further purification. 

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... 

The properties of electrolyte are usually characterized by electrolytic conductance, covering power, macrothrowing power, and microthrowing power. 

Microthrowing power indicates the extent to which metal electrodeposition occurs at the outer plane of the substrate or at the base of valleys or cracks. Microthrowing power can be improved by activating the surfaces at the base of valleys or cracks to promote electrodeposition there, while inhibiting the outer surfaces by using inhibitors preferentially. In many cases, microthrowing power is inversely related to macrothrowing power. 

The poor microthrowing power of the Ag deposit obtained from the nitrate electrolytes at the small current densities can be explained in the following way ... 

The fact that this phenomenon is only observed at microprofiles not exceeding 100 pm in amplitude necessitated the introduction of the concept of microthrowing power as a category different from ordinary throwing power [11]. The latter is used in technical literature to describe the quality of electrolytes in plating on macroprofiles, at which a similar effect is never observed. The difference between a microprofile and a macroprofile can be seen from Fig. 2.27. 

Popov KI, Maksimovic MD, Stevanovic RM, Rrstajic NV (1984) Fundamental aspect of pulsating current metal electrodeposition. VIII the effect pulse to pause ratio on microthrowing power of metal deposits. Surf Technol 22 155-158... 

This phenomenon involves irregularities not larger than 100 nm in amplitude, and the quality of an electrolyte required to produce such an effect was measured by the so-called microthrowing power. ... 

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