Investigation on the precipitate morphology and fraction characterization by atomic force microscopy

Precipitate was typically characterized by the transmission electron microscopy (TEM) or scanning electron microscopy (SEM) to analyze the relationship between material property and precipitate fraction. However, these procedures tend to be are always time consuming because of the complicated sample preparation process involved and the observation course. Particularly, sometime the precipitate can't be highlighted solely from the images easily. In this study, atomic force microscopy (ATM) was performed to characterize the morphology and fraction of the precipitate in this paper. Five kinds of materials were selected and prepared by electropolishing or vibration polishing method to display the precipitates on the sample surface. The experiment results prove that different types of precipitates with higher values for height on a sample surface could be clearly observed by AFM, and the images quality is highly relied upon the surface quality. The precipitate fraction can be calculated using the AFM micrographs and image photo post treated software (IPP). It was turned out that AFM is found suitable for observation almost all kinds of precipitates, and the precipitates can be easily separated from the images. Not only vibration polishing but also electrolytic polishing could offer a smooth surface for observing nanosized precipitates by AFM. A comparison of the fraction result obtained by AFM and precise microchemical analysis proves that the fraction measurement result obtained by AFM is acceptable.