Kinetic control reversibility tests

There are a number of ways to test for the reversibility of an electrode reaction. Any deviation is an indication of partial (or total) kinetic control. 

In Section 13.1, it was noted that implicit in the theory of kinetic and thermodynamic control is the fact that the kinetic product (Z in Fig. 13.1 and Y in Fig. 13.2), which is produced more rapidly, is also reconverted to starting material more rapidly. The thermodynamic product, on the other hand, being more stable, is not so readily reconverted to starting material. Experimental Procedure E provides tests of the relative stabilities of the two semicarbazone products toward the reverse reaction. The results of these experiments should provide additional evidence as to which of the semicarbazones is the product of kinetic control and which is the product of thermodynamic control. 

Cyclic voltammetry (CV), a widely used potential-dynamic electrochemical technique, can be employed to obtain qualitative and quantitative data about surface and solution electrochemical reactions including electrochemical kinetics, reaction reversibility, reaction mechanisms, electrocatalytical processes, and effects of electrode structures on these parameters. A potentio-stat instrument such as the Solatron 1287 is normally used to control the electrode potential. The CV measurement is normally conducted in a three-electrode configuration or electrochemical cell containing a working electrode, counter electrode, and reference electrode, as illustrated in Figure 7.1. However, with alternative configurations, CV measurements can also be performed using a two-electrode test cell. The electrolyte in the three-electrode cell is normally an aqueous or non-aqueous liquid solution. 

The sensitivity of intergranular corrosion to heat treatment and the complexity of kinetics involved with segregation and precipitation that induce intergranular corrosion have made accelerated test of intergranular corrosion almost impossible. However, a proper selection of alloy in reverse engineering and careful control of the heat treatment process will help eliminate this type of corrosion. 

---