Electrochemical corrosion and product formation mechanism of M42 high-speed steel in NaH2PO4-Na2SO4 passivating electrolyte

Bibliographic Details
Title: Electrochemical corrosion and product formation mechanism of M42 high-speed steel in NaH2PO4-Na2SO4 passivating electrolyte
Authors: Gang Cao, Huaichao Wu, Guangqin Wang, Long Nie, Kui Yuan, Bin Ji
Source: Arabian Journal of Chemistry, Vol 17, Iss 9, Pp 105940- (2024)
Publisher Information: Elsevier, 2024.
Publication Year: 2024
Collection: LCC:Chemistry
Subject Terms: High-speed steel, Electrochemical corrosion, Thermodynamic analysis, Characterization technique, Surface condition, Product formation, Chemistry, QD1-999
More Details: High-speed steel (HSS) rolls operate in harsh conditions, making them vulnerable to surface degradation. Material removal technology for repairing defective HSS roll surfaces is the most effective way to maintain their integrity and reduce production costs. Electrochemical corrosion machining, with its excellent machining capabilities, offers a promising method for repairing HSS roll surfaces. However, the outer working layer of these rolls is made of premium HSS containing passivating metallic elements, complicating its corrosion behavior, particularly in passivating electrolytes. To elucidate the corrosion behavior and uncover the underlying mechanisms of corrosion and product formation of HSS during electrochemical corrosion machining, this study investigates the electrochemical corrosion process and behavior of M42 HSS used in rolls within a NaH2PO4-Na2SO4 passivating electrolyte. Metallographic etching experiments indicated that M42 HSS comprises a tempered martensitic matrix along with M2C and M6C eutectic carbides. Characteristics of oxidative reactions for M42 HSS in the electrolyte were observed in cyclic voltammetry. By conducting anodic polarization tests, along with thermodynamic analysis and characterization techniques, the entire electrode system was thoroughly examined, including corrosion phenomena, varying processes, and underlying mechanisms of corrosion and product formation. Notably, this study is the first to construct a Pourbaix diagram for the M42 HSS-H2PO4−-SO42−–H2O system. The thermodynamic analysis revealed that the applied potential variation significantly influences corrosion behavior of M42 HSS, confirming by the characterization results. The adsorption phenomenon on the cathodic surface requires a higher potential (such as 6 V) to occur. Electrochemical reactions primarily occur on the anodic surface, while the cathodic surface (or in the electrolyte) mainly engages in chemical reactions with no electronic participation. Furthermore, the electrochemical corrosion process of HSS is driven by one or more corrosion mechanisms, such as galvanic corrosion, pitting, or intergranular corrosion. Therefore, these findings from this study contribute to the development of repairing HSS roll surfaces based on electrochemical corrosion machining in future engineering applications.
Document Type: article
File Description: electronic resource
Language: English
ISSN: 1878-5352
Relation: http://www.sciencedirect.com/science/article/pii/S1878535224003423; https://doaj.org/toc/1878-5352
DOI: 10.1016/j.arabjc.2024.105940
Access URL: https://doaj.org/article/fbdede3b47e54257ae98f5e3aad7e1a7
Accession Number: edsdoj.fbdede3b47e54257ae98f5e3aad7e1a7
Database: Directory of Open Access Journals
More Details
ISSN:18785352
DOI:10.1016/j.arabjc.2024.105940
Published in:Arabian Journal of Chemistry
Language:English