γ and α-(Fe, Ni) phase characterization using image processing and effect of phase formation on the P/M Fe(100-x)Ni(x) alloys properties

Abstract

The present investigation aims to study the quantitative phase analysis using image processing technique and the effect of phases on the wear and corrosion behavior of Fe(100-x)Ni(x) alloys (where x = 10 to 50 wt%). Specimens were fabricated by powder metallurgy (P/M) and sintered at 1250 °C for 1 h. γ-(Fe,Ni) and α-(Fe,Ni) phase formation in sintered specimens were confirmed from X-ray diffraction (XRD) analysis. The increase in γ phase fraction with the addition of Ni content was evident in the samples. The quantitative analysis of phase formation was done with the help of Image Processing technique, using the two-dimensional images, collected from Scanning Electron Microscope (SEM). A Pin on disc wear test revealed the minimum wear loss in Fe70Ni30 samples. Corrosion test of specimens has been examined in saline medium (3.5 wt% NaCl) using potentiodynamic and electrochemical impedance spectroscopy techniques. Samples containing more γ phase have shown high corrosion resistance in saline medium. Maximum protection efficiency against corrosion (~76%) was achieved in Fe50Ni50 specimens. © 2020 Elsevier B.V.