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UM E-Theses Collection (澳門大學電子學位論文庫)

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Title

Pitting corrosion and cavitation erosion resistance of friction-surfaced AISI 201 coating

English Abstract

AISI 201 austenitic stainless steel (ASS) coatings were fabricated on AISI 304 ASS substrate via friction surfacing (FS) with different processing parameters. Hardness, cavitation erosion and pitting corrosion characteristics of the FSed 201 coatings were investigated. X-ray diffractometer (XRD), scanning electron microscope (SEM), electron backscatter diffractometer (EBSD) and atomic force microscope (AFM) were used to study the metallurgical properties and cavitation morphology of 304, 201 and FSed 201 coatings. The hardness of the FSed coatings was improved by dynamic recrystallization (DRX). Compared with as-received (AR) 201 (252.72 HV1), the hardness of the FSed coatings was increased up to 270.37 HV1. Severe plastic deformation (SPD) enhanced the pitting resistance of the FSed coating due to breakage of microscale MnS inclusions in the AR 201 into the inapparent size after FS. Compared with the pitting potential (Epit) of AR 201 (−4.9 mVSCE), the Epit of the FSed 201 coatings was increased up to +176.2 mVSCE. Compared with the fragmentation of MnS inclusions, however, the improvement in pitting resistance caused by the crystallographic effect with different spindle speeds was not so obvious. After FS, the average grain size of the FSed 201 coating is larger than AR 201 due to DRX. Compared with AR 201, the cavitation erosion resistance of the FSed 201 coating was enhanced to 1.4 fold due to its higher hardness and martensitic transformability.

Issue date

2021.

Author

Shi, Qing Qing

Faculty

Faculty of Science and Technology

Department

Department of Electromechanical Engineering

Degree

M.Sc.

Subject

Austenitic stainless steel -- Corrosion

Supervisor

Kwok, Chi Tat

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Location
1/F Zone C
Library URL
991010066917506306