Advanced Characterisation Techniques
Members of Staff
There are a large number of macroscopic physical properties associated with the different ceramic forms that are used for making microwave dielectrics, heat resistant coatings, superconductors, transformer cores and thermistors. In many cases subtle variations in the atomic structure of these materials leads to significant changes in physical properties. In order to study these atomic structural changes and to correlate them with the physical macroscopic properties we need to use a number of advanced characterisation tools including:
- Synchrotron X-ray powder diffraction - X-ray powder diffraction is one of the most commonly used tools in the study of crystalline phases; residual stresses and quantitative analysis. The use of synchrotron X-rays can extend the range and complexity of the materials under study. The data can be used in conjunction with other measurement such as resistivity or temperature in order to directly correlate a atomic structural change with the macroscopic properties.
- Energy dispersive X-ray diffraction - We use this method to scan over a fabricated ceramic component to build up a 3D density contrast map (like a tomograph) that also contains structural and chemical information. This technique (called TEDDI) is being developed in the Manchester Materials Science Centre and gives a valuable (and non destructive) insight into ceramic manufacture.
- Small crystal crystallography - If ceramic grains are separable from the bulk they can be studied using synchrotron X-ray small molecule crystallography. Currently the record for a structure solved in this way is from a grain with an average dimension of 4 micron. The advantage if this method is that it gives unambiguous information about the atomic arrangement in the material but the disadvantage is that it may not be representative of the bulk.
- Time resolved crystallography - A new detector called RAPID2 (Refined ADC Per Input Detector version 2) is still a world leader in the field of rapid, high resolution powder diffraction. The new station at the SRS can collect data at millisec rates or better and with no loss in peak resolution. We have a capability that can deliver fast high resolution (refinable) diffraction data from operational materials. This is opening up completely new insights into the way functional materials respond to their imposed environment.
Current Research Projects
- The development of Tomographic Energy Dispersive Diffraction Imaging (TEDDI) for non-destructive 3D images of materials including engineering components, biological systems, ceramics and cementitious materials
- Functional electroceramics research using synchrotron based techniques to evaluate materials structure as a function of processing.
- The development of station 6.2 at Daresbury Laboratory. The collection of ultra-rapid medium-high resolution in situ diffraction data from materials during in-service performance
- The construction of Diffex, a solid-state silicon strip detector for the study of dynamic reactions that will be compatible with the very high X-ray fluxes produced from 21st century light sources