ČELKO Ladislav Central European Institute of Technology BUT, Brno University of Technology

Spoluautoři KLAKURKOVÁ Lenka, JECH David, JULIŠ Martin, SLÁMEČKA Karel, ŠVEJCAR Jiří

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, by means of high velocity oxyfuel spraying, onto 5 mm thick 99.5Al and AlMg3 sheets surface. As-sprayed samples were annealed in the range of 660 - 800 °C in ambient atmosphere. Based on temperature height was an isothermal dwell set up from several minutes up to hundred hours. Resulting microstructures were investigated by means of metallography, light and scanning electron microscopy techniques. Provided heat treatment allowed to form two different (binary and ternary) hypereutectic alloys. The main difference resulted from initial substrates microstructures and chemical composition. Compare to pure aluminium substrate microstructure, hydronalium alloy contained a number of nucleation sites in a form of eutectic and/or intermetallic phases and as well probably due to the higher diffusion mobility of aluminium the faster dissolution of as-sprayed nickel coating region occurred.

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