Characteristic of electrolytic composite layers containing titanium and aluminium in nickel matrix
Iwona Napłoszek-Bilnik, Antoni Budniok, Grzegorz Dercz, Lucjan Pająk, Eugeniusz Łągiewka Uniwersytet Śląski, ul. Bankowa 12, 40-007 Katowice
Annals 3 No. 6, 2003 pages 47-52
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abstract The influence of the presence of Ti and Al powder in the galvanic bath on the chemical composition of Ni+Al, Ni+Ti, Ni+Al+Ti layers was investigated. The layers were obtained on a steel substrate under galvanostatic conditions; for Ni+Al layers j = 450 mA/cm2, for Ni+Ti j = 175 mA/cm2, for Ni+Al+Ti j = 200 mA/cm2. It was stated, that Al and Ti percentages increase with an increase in the amount of Al and Ti powders in the bath and reach the value of 44% for Al (Fig. 2) and 75% for Ti (Fig. 5). Chemical composition of Ni+Al+Ti depends on the ratio of the mass of Ti and Al powders in the bath and varies from 4 to 25% for Al and 12 to 60% for Ti (Fig. 7). The influence of deposition current density on the percentage of incorporated Al, Ti and Al+Ti was ascertained for the layer obtained from the bath of optimal composition. The phase composition of the layers was investigated by the X-ray diffraction method (Figs. 3, 6, 9). Atomic absorption spectroscope was used for chemical characterization of the layers. The thickness of the layers was estimated using microscope method on the base of cross-sectional images of the layers (Figs. 1, 4, 7). The size of the nickel crystallites has been determined from the half-width of the diffraction lines. The mechanism of incorporation of solid particles into to the layers’ structure was explained basing on Ni2+ adsorption/desorption processes on the metal powder. Key words: composite layers, intermetallic phase, aluminium, titanium