University of Manchester

Imaging microsphere composites

William J Parnell
Project Completed

Scientific Case

Advanced composites are key to a multitude of modern technologies. Of importance in sonar applications is the use of microsphere composites, where small micron-diameter sized stiff shells are distributed throughout a polymer substrate. The microspheres provide a number of important properties for the composite material, in particular permitting the user to tune the density and elastic properties carefully. However the materials are frequently under large compression and it is not fully understood how the microstructure of the microsphere material responds to this imposed stress. This initial exploratory study will image the material under atmospheric pressure, at various lengthscales in order to allow a full understanding of the size and distribution of the microspheres. As well as providing an understanding of the visualization of the medium at the micron scale, this study will permit optimization of future imaging techniques.

Experiment Design

Microspheres are typically of the order of 10 microns in diameter, shell thicknesses are approximately 0.1 micron. As such it is unlikely that shell walls can be imaged on first pass.
Sometimes in-service materials also contain barytes of the order of 10-100 microns to modify density.
Imaging over a number of length scales, from the micron up will enable local aspects of the microspheres to be imaged and also distributions over the sample size to be viewed. Sample sizes will be taken as 1-5 mm depending upon the field of view and resolution required
In order to image over these different scales it appears prudent to use the Nikon custom bay for higher resolution scanning and the Xradia microXCT for the lower resolution imaging.
Scanners and Rigs
Nikon Custom 320kV Bay
Not Required
Approximately 4 scans required, perhaps more, depending on discussions with Tristan and other technical staff
Xradia MicroXCT
Not Required
Approximately 8 scans required, perhaps more, depending on discussions with Tristan and other technical staff

Sample & Safety

Microsphere composites, 1mm cubed, no known hazards

Scan Records

Project Report