Effects of ternary metal additions on corrosion of spark plasma sintered Ni-Fe alloys in H2SO4 and NaCl

M B Shongwe,P A Olubambi,I M Makena,O O Ajibola,F V Adams

doi:10.4314/bcse.v32i2.12

Abstract

Effect of ternary additions on electrochemical behavior of Ni-Fe binary alloys developed by Spark Plasma Sintering (SPS) were investigated and reported. All specimens revealed common passivity behavior in H 2 SO 4 . Both binary and ternary alloys did not reveal passivity region under saline conditions. The alloys have lower corrosion rates in NaCl than in H 2 SO 4 . Binary Ni 50 Fe 50 alloy is characterized by large pits in H 2 SO 4 and homogeneous corrosion on surface in NaCl. Ni 50 Fe 40 Ta 10 shows better passivity in 1 M H 2 SO 4 and Ni 50 Fe 40 Al 10 has the lowest corrosion rate in 3.5 wt.% NaCl. KEY WORDS : Spark plasma sintering, Corrosion, Ni-Fe based alloy, Ternary alloys, Powder metallurgy Bull. Chem. Soc. Ethiop. 2018 , 32(2), 337-349. DOI: https://dx.doi.org/10.4314/bcse.v32i2.12

Highlights

Ni-Fe base alloys have wide applications as parts of devices in pumps, pipeline, turbines, ultrasupercritical (USC) boiler applications, and in active chemical reactors
After compaction, bordering metal powder particles are bonded by cold welds, which offer the compressed particles sufficient mechanical strength to be handled while diffusion processes form and grow necks at these contacting surfaces at the working sintering temperature [14]
In the present research, the study of the corrosion behavior of the spark plasma sintering of NiFe alloy enhanced with ternary additions is being considered

Summary

Introduction

Ni-Fe base alloys have wide applications as parts of devices in pumps, pipeline, turbines, ultrasupercritical (USC) boiler applications, and in active chemical reactors. The present work aimed at investigating the influence of ternary metal additives (as anti-oxidants on the Ni-Fe-base austenitic matrix) on the corrosion of sintered Ni-Fe based alloy using potentiodynamic polarization technique.

Results

Conclusion