Formation and Breakdown of Oxide Films in High-Rate Anodic Dissolution of Chromium–Nickel Steels in Electrolytes for Electrochemical Machining

Autor: Dikusar, A. I., Silkin, S. A.
Rok vydání: 2022
Předmět:
ISSN: 1068-3755
DOI: 10.5281/zenodo.7037323
Popis: It is shown that, in high-rate pulsed galvanostatic anodic dissolution of type CSN17335 and AISI 304 chromium–nickel steels in electrolytes for electrochemical machining (ECM) (chloride, nitrate, and mixed chloride–nitrate solutions with a conductivity of 0.15 S/cm) using microsecond pulses with a duration of 20–2000 μs and current densities in the range of 1–100 A/cm2, a substantial fraction of charge (up to ~40%) is spent on the formation of a passivating oxide film with a semiconducting behavior. The electrochemical treatment therefore directly involves the oxide film, not the alloy. As a consequence, the current efficiency of ECM of these materials is ~60–70%, depending on the alloy composition. When using direct current, the rate of machining increases as a result of the oxide film breakdown due to its thermokinetic instability (“thermal explosion”) caused by a rise in the surface temperature.
This is a post-peer-review version of an article published in Surface Engineering and Applied Electrochemistry. The final authenticated version is available online at: DOI: 10.3103/S1068375522040056
Databáze: OpenAIRE
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