Induction period for nucleation

Experimental results are in general conformity with the Avrami equation, but the interpretation of various observations is still complicated in many instances. One intriguing observation is that the induction period for nucleation is inversely proportional to the length of time the liquid is held in the liquid state after previous melting. This dependence on prior history may be qualitatively understood... 

The induction period for nucleation that takes the reciprocal of nucleation rate is often used. For single-crystal growth, a longer induction period indicates a more stable solution which makes the growth easier. 

Another approach for inhibition of carbon formation is to retard the full dissociation of the hydrocarbon into adsorbed carbon atoms. The presence of potassium on a nickel catalyst results in a significant increase in the induction period for nucleation of carbon whiskers (refer to Figure 5.6). It means that potassium works as promoter also without the presence of water. 

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