Effect of Co and Fe contents on the microstructure and corrosion behaviour of heat-treated Ni-Fe-Co superalloys in 3.5 wt% NaCl aqueous solution

Itshepeng Mogaleadi Christinah Bopape, Enoch Nifise Ogunmuyiwa, Mxolisi Brendon Shongwe, Nthape Percyval Mphasha, Nthabiseng Ntholeng

Research output: Contribution to journalArticlepeer-review

Abstract

The effect of chemical composition on the corrosion behaviour of heat-treated Ni-Fe-Co superalloys has been investigated in aerated 3.5 wt% NaCl aqueous solution. Nickel-base alloys with varying amounts of Fe (5–20 wt%) and Co (30–45 wt%) were fabricated via spark plasma sintering. The alloys were heat-treated at 1000 C in a muffle furnace for 1 hour, and then quenched in distilled water for 5 minutes. Corrosion resistance of the alloys was analysed by measuring potentiodynamic polarization. Corrosion parameters, i.e. Ecorr, icorr, Epass and ipass, were compared for different Co and Fe contents to establish a relationship between the alloy composition and corrosion properties. The results showed that the corrosion resistance of the alloys improved with increasing Co and decreasing Fe content. Accordingly, corrosion rate and corrosion current density (icorr) decreased with increasing Co content and the imposition of heat treatment. Ni-5Fe-45Co (wt%) showed the highest resistance to corrosion with corrosion rates of 0.0145 and 0.00294 mm/year in as-sintered and heat-treated conditions, respectively. Generally, heat treatment improved the grain homogeneity of the microstructures. Characterisation of surface morphologies of as-sintered and heat-treated corroded alloys was conducted using X-ray diffraction (XRD) and scanning electron microscopy (SEM) equipped with energy-dispersive spectroscopy (EDS). [Figure not available: see fulltext.]

Original languageEnglish
JournalInternational Journal of Advanced Manufacturing Technology
DOIs
Publication statusPublished - Oct 29 2021

All Science Journal Classification (ASJC) codes

  • Control and Systems Engineering
  • Software
  • Mechanical Engineering
  • Computer Science Applications
  • Industrial and Manufacturing Engineering

Fingerprint

Dive into the research topics of 'Effect of Co and Fe contents on the microstructure and corrosion behaviour of heat-treated Ni-Fe-Co superalloys in 3.5 wt% NaCl aqueous solution'. Together they form a unique fingerprint.

Cite this