ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Electrochemical and statistical assessment of corrosion behavior of sintered Ni–Cr alloys in acidic media

Ghalia A. Gaber and Lamiaa Z. Mohamed

Department of Chemistry, Faculty of Science (Girls), Al-Azhar University, Nasr City, Egypt

E-mail: ghaliaasaid@azhar.edu.eg

Received: 13 February 2026  Accepted: 3 June 2026

Abstract:

This study examines the corrosion characteristics of sintered nickel-chromium (Ni-xCr) alloys (x equal to 0.0, 0.5, 1.0, 4.0, 8.0, and 12.0 wt.%Cr) in three acidic environments: 1 M HNO₃, 1 M H₂SO₄, and 1 M H₃PO₄, employing a scientific methodology. The chromium composition of the alloys varies from 0 to 12 wt%. Corrosion performance was assessed using statistical modeling, surface analysis, electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PDP), and weight loss measurements. Although the effect of chromium concentration, based on weight-loss data, was not statistically significant at the 95% confidence level (p = 0.103), two-way analysis of variance (ANOVA) indicated that the corrosive medium significantly influences the corrosion rate (CR) (p = 0.001). The electrochemical findings indicate that the incorporation of chromium markedly enhances performance: pure nickel displayed elevated corrosion current density (I_corr) values of 3.138 µA/cm² in HNO₃, 0.378 µA/cm² in H₂SO₄, and 0.544 µA/cm² in H₃PO₄, whereas the introduction of 1.0 wt% Cr substantially reduced I_corr to 0.481, 0.036, and 0.205 µA/cm² in the respective solutions. EIS investigations confirmed that low- to moderate-Cr additions significantly enhanced polarization resistance, indicating improved stability of the passive film. The corrosive medium was identified as the principal factor affecting corrosion behavior in response surface regression, yielding a statistically significant model (p = 0.001) with an R² of 80.69%. The results indicate that although chromium improves electrochemical resistance and aids passivation, the corrosive nature of the acidic environment remains the primary determinant of corrosion performance in sintered Ni–xCr alloys.

Keywords: Nickel–chromium alloys; Corrosion resistance; Acidic media; Electrochemical analysis; Analysis of variance; Post Hoc Tukey’s honestly significant difference test

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-026-05163-z

Chemical Papers 80 (11) 13031–13054 (2026)