| Popis: |
Electrochemical behaviour of the intermetallic phase in 65% phosphoric acid using potentiostatic method in the potential range from −800 to +100 mV v.s. SSE was investigated. This intermetallic phase of complex chemical composition Cux-Bey-NizZrq forms during solidification of the alloy of above mentioned system. Earlier investigations have shown that the intermetallic phase influences the alloys' properties. Because of its significance, the study of electrochemical behaviour of this intermetallic phase was undertaken. On the basis of preliminary investigations of chemical composition by a microprobe this intermetallic phase was first synthetized and then investigated in different structural states, as cast and homogenized at 950°C and 1000°C. In the active part of the polarization curve, the intermetallic phase has the most negative potential in the as cast state, and most positive after homogenization at 950°C, although the difference in potential values between potentials of the two homogenized states is rather small. At the more positive potentials than −400 mV the highest current densities show the polarization curve in an as cast state. This behaviour is in accordance with the change of microstructure of the intermetallic phase of the mentioned three different states. Namely, heterogeneity is the most pronounced in the as cast state due to the presence of considerable amounts of solid solution rich in copper. Homogenization leads to positive decrease of the phase rich in copper. |
