Three-dimensional characterization of powder particles using X-ray computed tomography

Abstract

A method for particle morphology characterization using X-ray computed tomography (XCT) is explored. Firstly, the voxel data of a metal powder is obtained using XCT and an optimized method using erosion and watershed algorithms is proposed for particle separation. Results from the XCT are compared to those from scanning electron microscopy (SEM) to validate the method; examining the number of particles, mean diameter, diameter variance and maximum diameter for each case. The results acquired using 3D XCT voxel data and two-dimensional (2D) XCT slice data are compared. It shows that the 3D XCT measurement more closely matches the SEM results, when compared to the 2D slice results. In the 3D XCT case, to characterize particles, the particle diameter, sphericity and aspect ratio are computed, and the k-means algorithm is used for cluster analysis. Finally, the morphologies of two different powder batches using 3D XCT are performed. The results show that the cluster analysis provides a comprehensive method of evaluation for metal powders, and that 3D morphology measurement provides a better understanding of powder particles than 2D methods.