Diffusion in Al-Ni and Al-NiCr Interfaces at Moderated Temperatures

abstrakt

angličtina

The diffusion couples for experimental study were prepared by HVOF spraying of nickel and nickel with 20wt.% of chromium powders onto the aluminium steet s surface. The interfaces with sharp gradient of chemical concentration of these elements were prepared. Annealing at the temperatures 600oC and 630oC, close to the Al+Al3Ni eutectic melting point (639,9oC), with different dwell times were realized. The reactants during the annealing diffuse and create layers of Al3Ni2 and Al3Ni intermediate phase compositions. Moreover, nickel without assistance of chromium diffuses preferably by using grain boundaries into aluminium substrate and produces the strengthening of the substrate by stable Al3Ni and metastable Al9Ni2 particles. The microstructures were obtained by scanning electron microscope. Layer theckness measurements were realized by means of image analyses. Chemical composition was estimated by energy dispersive microanalysis measurements. According to the results of these analyses performed the average chemical interdiffusion coefficients and Wagner s integral interdiffusion coefficients were calculated.

diffusion, Al-Ni, Al-NiCr, aluminides

ČELKO, L.; KLAKURKOVÁ, L.; ŠVEJCAR, J.

24. 6. 2009

Ironix conferences management

Rome, Italy

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