The fourth WINTEREV meeting was hosted by CEIT, San Sebastian on 22-23 February 2007. Hosted by Dr Jose Manuel Sanchez, the WINTEREV was attended by 17 people from 9 organisations from across industry, academia and RTOs. The subject was "Characterisation of Engineered Surfaces and Coatings in Hard Materials" and included Developments in Microscopical Techniques (optical and electron), Surface Characterisation (Techniques and Methods), Developments in Coatings (Characterisation and Testing) and Performance Issues.
A major part of the world’s production of hardmetals is manufactured with a coating or engineered surface. Coatings and surface layers are generally thin (of the order 10 m) and usually multiphased with microstructural features in the nano range (20-200 nm). Characterisation of these zones, whether it be by phase analysis or through mechanical behaviour, provides significant challenges for the science and engineering community. The purpose of this current one day WINTEREV meeting was to bring together researchers and industrial colleagues to discuss the possibilities and limitations of current characterisation methods and debate emerging new techniques such as acoustic methods and orientation imaging. Coatings are multiphase and can contain carbides, carbonitrides, ceramic phases, transition metals and alloy binders. To assess performance and confirm processing quality and consistency it is necessary to be able to measure the size, shape, composition and distribution of each constituent, as well as characterising the scale dependence of their physical and mechanical properties in combination. Clearly no one technique is sufficient for this purpose and it is necessary to use a range of complementary methods.
For microstructural purposes the science community has used TEM, FEGSEM, Optical, X ray, GDS and other advanced instruments such as SIMS and EELS for examination of these small regions of material. Each instrument provides unique information on a specific attribute; for example TEM for internal defects/dislocations/boundaries, FEGSEM for high resolution measurements of phase size, shape and distribution, X-ray for phase composition and Optical for more macroscopic issues, like reproducibility over large areas and gross defect characterisation. The WINTEREV meeting addressed various aspects of this suite of conventional techniques as well reviewing new opportunities such as electron back scatter diffraction patterns, that can be of potential value by generating orientation information that could be used to automate the process of phase size and distribution measurement.
For mechanical characterisation of coatings there are, again, many options open to the researcher. For example, indentation methods for plastic and fracture behaviour (often on a very fine scale, such as microscratch and nanoindentation testing methods), surface acoustic waves for elastic property measurement, beam bending for joint substrate/coating characterisation and, in principle, micro hot hardness for high temperature studies (although this is not often reported due its challenging nature). Also, knowledge of residual stresses is vital in interpreting the performance of coatings. It was intended that this meeting would informally examine the latter topic and the advantages and disadvantages of various mechanical tests, triggered by some specific presentations.