Search

Only a small amount of the massive quantities of fly ash derived from lignite combustion in power stations is currently utilized, while the largest portion of ash is directly discharged into ponds and landfills. Therefore, alternative applications should be introduced for the valorization of this industrial waste, thus satisfying current environmental demands. Fly ash can be considered for incorporation into upgraded metal-ceramic composites to provide weight reduction for energy savings, better insulation properties, decreased shrinkage and enhanced corrosion resistance, to contribute towards hardness and wear properties as well as to reduce the high production cost of the composites. So far, only limited data are reported regarding the use of fly ash as a dispersoid into nickel-based composite coatings. In the present study, the feasibility of manufacturing innovative nickel fly ash bulk composites was investigated, starting from powder blends of nickel and 0-50 wt. % recycled lignite highly-calcareous fly ash, and applying powder metallurgy techniques. Composite specimens were successfully prepared and examined by means of XRD and 5EM-EDX analyses as well as apparent density and Vickers microhardness measurements. The obtained metal-ceramic microstructures exhibit a satisfactory densification degree indicative of an effective consolidation process. By adding fly ash into nickel matrix, lightweight nickel-based composites with no significant reduction in nickel hardness are produced. [ABSTRACT FROM AUTHOR]