Crack initiation transport process

This is the case for magnesium and calcium electrodes whose cations are bivalent. The surface films formed on such metals in a wide variety of polar aprotic systems cannot transport the bivalent cations. Such electrodes are blocked for the metal deposition [28-30], However, anodic processes may occur via the breakdown and repair mechanism. Due to the positive electric field, which is the driving force for the anodic processes, the film may be broken and cracked, allowing metal dissolution. Continuous metal dissolution creates an unstable situation in the metal-film and metal-solution interfaces and prevents the formation of stable passivating films. Thus, once the surface films are broken and a continuous electrical field is applied, continuous metal dissolution may take place at a relatively low overpotential (compared with the high overpotential required for the initial breakdown of the surface films). Typical examples are calcium dissolution processes in several polar aprotic systems [31]. 

Jersey chose not to develop this process further but was likely instrumental in influencing the designers of the first FCC unit. The cracking of hydrocarbon vapors with these clays gave interesting yield selectivities. Furthermore, it was observed that the best yield selectivities were seen in the initial moments of the cracking reaction. This may have led researchers in the direction of a continuous operation. In addition, the transport of fine powders was clearly easier than conveying pellets or beads. 

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