Metals (Apr 2021)

Frequency Analysis of Transients in Electrochemical Noise of Superalloys Waspaloy and Ultimet

  • Jesús Manuel Jáquez-Muñoz,
  • Citlalli Gaona-Tiburcio,
  • Jose Cabral-Miramontes,
  • Demetrio Nieves-Mendoza,
  • Erick Maldonado-Bandala,
  • Javier Olguín-Coca,
  • Francisco Estupinán-López,
  • Luis Daimir López-León,
  • José Chacón-Nava,
  • Facundo Almeraya-Calderón

DOI
https://doi.org/10.3390/met11050702
Journal volume & issue
Vol. 11, no. 5
p. 702

Abstract

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Nickel or Cobalt-based superalloys represent an important class of engineering materials, finding widespread application in critical components within the gas turbine engines used for jet propulsion and electricity generation. This research aimed at the frequency analysis of transients in electrochemical noise of Waspaloy and Ultimet superalloys, immersed in 3.5 wt.% in H2SO4 and NaCl solutions at two different temperatures, 25 and 60 °C. Localized corrosion behavior of superalloys was assessed using the electrochemical noise technique (EN) according to ASTM-G199 standard. Three different statistical methods filtered the EN signal, and the polynomial method was employed to obtain the noise resistance (Rn), the localization index (LI), skew and kurtosis, and the power spectral density analysis (PSD). Results indicate that the current and potential noise transients have a better behavior with better clarity when a polynomial is used to show a localized corrosion kurtosis for both superalloys.

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