Open AccessCHARACTERISTICS OF AISI 420 STAINLESS STEEL MODIFIED BY COMBINING GAS NITRIDING AND CrN COATING
Author(s) -
Thanh V. Q. Nguyen,
Thanh Van Doan,
Trung Van Trinh,
Huy Van Vu
Publication year - 2021
Publication title -
acta metallurgica slovaca
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.277
H-Index - 13
eISSN - 1338-1156
pISSN - 1335-1532
DOI - 10.36547/ams.27.3.1035
Subject(s) - nitriding , materials science , coating , corrosion , tafel equation , metallurgy , microstructure , layer (electronics) , porosity , composite material , electrochemistry , electrode , chemistry
AISI 420 stainless steel is widely used in applications where wear and corrosion resistance are required. However, the heat treatment and nitriding process can drastically reduce the corrosion resistance of this stainless steel. This article focuses on investigating the influence of steel substrate and gas nitriding efficiency at two temperatures of 520 oC and 550 oC on some properties of CrN coating. The experiments were carried out to evaluate the surface hardness, microstructure and phase composition of nitrided layers. The coating adhesion and load capacity of the coating were performed according to VDI 3198 standard. Electrochemical testing was performed in a solution of 3.5% NaCl and then using the Tafel method to determine the corrosion current and corrosion potential. The thickness of CrN and CrN/CrN coating was 1.6 μm and 3 μm, respectively. The study showed that the corrosion resistance of coatings fabricated through duplex technology was affected not only by the normal defects but also by the porosity on the nitrided surface. The corrosion resistance of multilayer duplex coating was improved compare with mono-layer duplex coating due to its ability to cover and reduce pores and pitting defects.