Determination of the "overall" nucleation density on tungsten: a new treatment of the data

A new treatment of scanning electron microscopy data is presented and has been applied to study the temperature dependence of diamond nucleation on sintered tungsten. The data analysis is performed in the framework of a nucleation and grain growth model that is able to describe both the nucleation kinetics and the evolution in time of the substrate surface coverage by diamond. The nucleation model provides the determination of a new quantity, the ''overall'' nucleation density, which represents the number of surface nuclei that would be obtained if the nucleus growth rate was nil. Comparison between the calculated ''overall'' nucleation density and the measured surface density of diamond crystallites shows that the total number per unit area of nuclei counted by microscopic techniques might not be a representative parameter of the nucleation process.