Abstract: The specific surface area of a powder sample measured by gas adsorption (the so-called BET method) is a well-established method within conventional powder metallurgy, ceramics, pharmaceuticals and geology. As a true measurement (based on gas pressure), within a given particle size range, the specific surface area provides quantitative information on particle morphology. When applied to lower surface area materials, the use of krypton gas a probe molecule improves resolution of the BET method by approximately 300× over nitrogen gas. The relationship between BET surface area, particle size and particle morphology has been established for a wide range of materials using techniques such as x-ray diffractometry and electron microscopy. When applied to powders used in additive manufacturing processes, the bulk morphology information obtained can be connected to powder characteristics such defect content, retained fines and contamination.
Authors: Dave van der Wiel
Keywords: powder characterization, surface area, BET, adsorption, morphology