from the conferences organized by TANGER Ltd.
In this work, the microstructural changes of nickel coated aluminium and hydronalium substrates were investigated after the heat treatment above the melting point of pure aluminium. The 99.0Ni powder was used to produce the coating using high velocity oxyfuel spraying on 5 mm thick 99.5Al and AlMg3 sheets surface. As-sprayed samples were annealed in the temperature range of 660 - 800°C in ambient atmosphere. The dwell time for isothermal exposure was set from several minutes up to several hours depending on used temperature. Resulting microstructures were investigated by means of metallography and light and scanning electron microscopy techniques. Employed heat treatment allowed to form two different (binary and ternary) hypereutectic alloys. The main differences resulted from different initial substrate microstructures and chemical composition. Compare to pure aluminium substrate microstructure, hydronalium alloy contained a number of nucleation sites in the form of eutectic and/or intermetallic phases and also, probably due to the higher diffusion mobility of aluminium, exhibited the faster dissolution of as-sprayed nickel coating region.
Keywords: aluminium, hydronalium, thermal spraying, heat treatment, electron microscopy - scanning© This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.