Abstract:The effects of scandium, zirconium and strontium on the hardness, microstructures, corrosion resistance and friction-wear properties of nickel-aluminium bronze ingot were investigated by means of hardness measurement, optical microscopy (OM), scanning electron microscopy (SEM), energy spectrum analysis and corrosion and friction experiments. The results show that, compared with the un-micro-alloying nickel-aluminium bronze ingot (Cu-8.57Al- 5.3Fe-4.6Ni-1.07Mn-0.63Zn), the micro-alloying nickel-aluminium bronze ingot (Cu-9.97Al-5.4Fe-4.52Ni-1.05Mn- 0.62Zn-0.045Zr-0.03Sr- 0.057Sc) has no significant change in the phase composition, which is composed of α-phase, β-phase (high-temperature phase) and κ-phase, and each phase is remarkably refined. The alloy hardness increases from 212.1HV to 240.7HV. The corrosion occurs preferentially in eutectoid region (α-phase+κ_III-phase), but the refinement of the eutectoid microstructure reduces the probability of generating the corrosion channel. So, in 3.5%NaCl water solution, the micro-alloying nickel-aluminium bronze ingot presents better corrosion and tribological properties, the uniform corrosion rate and the electrochemical corrosion rate decrease by 5.2% and 17.8%, the corrosion rates of micro-alloying nickel-aluminium bronze are 0.023 mm/a and 0.231 mm/a, and the friction coefficient decreases by 23.4% (friction coefficient is 0.019 3), respectively.

Key words: nickel-aluminium bronze; micro-alloying; microstructure; corrosion resistance; friction-wear properties