3D MORPHOLOGICAL CHARACTERIZATION OF CARBON-BLACK AGGREGATES USING TRANSMISSION ELECTRON-MICROSCOPY

A three-dimensional modeling technique is used to characterize the str ucture of carbon-black aggregates. The relative positions of individua l particles in aggregates are determined using transmission electron m icroscopy (TEM). Data are acquired from two-dimensional projections ta ken with the aggregates at two different orientations with respect to the electron beam. Computerized aggregate models are generated using d ata from TEM projections in our reconstruction algorithm. Inspection o f these models shows that their projections very closely replicate the TEM micrographs. Quantitative analysis of the aggregate models reveal s that aggregates generally exhibit anisotropy, in the form of a reduc tion of aggregate breadth, or ''flatness,'' in one direction. The flat sides tend to align preferentially, along the plane of the TEM sample grid. The dimensions for each aggregate with respect to its best-fitt ing plane of flatness are determined, and are related through a ''flat ness index.''