| Popis: |
Cermet materials are widely used as protective coatings for wear problems; in particular, WCCo and Cr3C2NiCr cermets are well known. However, SiC cermets appear as alternative materials for some applications. In this study an SiCNiCr cermet has been plasma sprayed and its metallurgical structure determined. Despite the fact that SiC is not suitable for plasma spraying, the proper choice of spraying parameters makes it possible to produce coatings with a composite structure of unmodified SiC particles in an Ni20Cr alloy matrix. Such coatings are acceptable from the viewpoint of providing adequate resistance to abrasion, but their microstructure is not stable, particularly in high temperature environments, owing to the tendency of SiC to react with the metal matrix. The metallurgical structure of the coating in the assprayed condition and its degradation at high temperature (up to 1000 °C) have been studied by means of analytical techniques such as optical microscopy, scanning electron microscopy, X-ray diffraction and energy-dispersive spectroscopy microanalysis. |
