Scanning electron microscopy study of the diffusion coating structure

The application of a widely-used scanning electron microscopy method for investigation of diffusion layers structure has been studied. The application of this method excludes the necessity of quite a labour-consuming process of replicas preparation. The modern serial scanning electron microscopes have the resolution two orders worse than the transmission ones. However, the magnification of the order of 6000 times is a helpful magnification for instruments of a 300 A resolution. This is exactly the resolution of the MSM-2 model scanning microscope. The grain size of niobium stannide and other niobium-tin system phases, formed in the course of diffusion production of niobium stannide layers have been determined using both scanning and transmission electron microscopy. It is reasonable to use scanning electron microscopy method for grain size investigation in thin diffusion layers. In the presence of relatively rough structure constituents this method gives a more trustworthy picture than the replicas method, but the investigation into the fine intragranular structure should be carried out with the help of transmission electron microscopy. In order to obtain maximum data on the diffusion layer structure, it is advisable to perform a complex investigation using both scanning and transmission electron microscopy