Throwing power defined

Yet another, more precise, way to define this important property is as follows. The ability of a bath to produce deposits of more or less uniform thickness on cathodes having macroscopic irregularities is termed macro throwing power. 

The throwing power of a bath is a measure of its ability to produce electroplated coatings of uniform thickness on samples having complex geometries. A quantitative measure of this property can be defined in terms of the so-called Haring and Blum cell, which is used to determine it. In this cell, two cathodes are positioned at unequal distances from two sides of an anode, as shown in Fig. 24M. The throwing power (T.P.) is defined as ... 

Having defined the throwing power quantitatively, we can now proceed to discuss the physical reasons for the dependence of the throwing power on geometry and the methods available to increase the value of the T.P. to acceptable levels. This discussion refers to the so-called macro throwing power. In Section 30.3 we shall discuss the micro throwing power, which controls the smoothness of the deposit and depends on quite different factors. 

Fig. 13. The throwing power of various organoaluminum electrolytes, as defined by the Wagner index.

In this cell, two cathodes connected electronically are positioned at unequal distances from two sides of an anode. The throwing power (TP) is defined as ... 

Having defined the throwing power quantitatively, we can now proceed to discuss the physical reasons for the dependence of the throwing power on geometry and the methods available to increase the value of the TP to acceptable levels. 

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