WANG Li-jun,WEN Guang,LI Ming-kun,WANG Meng-chao,CHEN Hui.Microstructure and Corrosion Resistance Mechanism of TiAlN/CrN Multilayer Coatings[J],49(8):268-274
Microstructure and Corrosion Resistance Mechanism of TiAlN/CrN Multilayer Coatings
Received:January 10, 2020  Revised:August 20, 2020
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DOI:10.16490/j.cnki.issn.1001-3660.2020.08.031
KeyWord:TiAlN/CrN multilayer coating  TiAlN coating  CrN coating  multi-arc ion plating  corrosion resistance  electrochemical property
              
AuthorInstitution
WANG Li-jun 1.Chengdu Industrial Vocational Technical College, Chengdu , China
WEN Guang 1.Chengdu Industrial Vocational Technical College, Chengdu , China
LI Ming-kun 1.Chengdu Industrial Vocational Technical College, Chengdu , China
WANG Meng-chao 2.Southwest Jiaotong University, Chengdu , China
CHEN Hui 2.Southwest Jiaotong University, Chengdu , China
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Abstract:
      The work aims to study the difference in microstructure and electrochemical properties of multilayer coating (TiAlN/CrN) and single coating (TiAlN and CrN) and analyze the corrosion resistance factors of coatings with different structures, to provide theoretical reference for the development of new anti-corrosive coatings based on the characteristics of electrochemical parameters, microstructure and corrosion morphology. 150 nm Cr coating was deposited on 316 stainless steel substrate with multi-arc ion plating as the transition layer. Then, CrN and TiAlN coatings were deposited alternately to prepare the TiAlN/CrN multilayer coatings with a thickness of 10 nm. Finally, CrN and TiAlN coatings were prepared for contrast. The cross-sectional morphology and microstructure of coatings were characterized by SEM and XRD and the corrosion resistance mechanism was analyzed. Combined with polarization curves and impedance spectrum, the electrochemical properties of three coatings were tested and immersion corrosion test was carried out to the coatings. The TiAlN/CrN multilayer coating exhibited a face centered cubic structure and showed co-extensive growth and (200) preferred orientation. Through the comparison of measurement results of potential polarization curves for the multilayer coating, stainless steel substrate and single coating, the corrosion potential of multilayer coating shifted positively to -0.36 V, the corrosion current density decreased to 0.501 μA/cm2 and the polarization resistance was 120 kΩ•cm2. In terms of EIS, TiAlN/CrN multilayer coating possessed the lowest value of CPE (29.83×10-6 Ω-1•cm-2•sn), n of 0.922 and resistance of 1.50×106 Ω•cm2, compared with stainless steel substrate and single coating. Furthermore, the corrosion morphology of multilayer coating was closed to the morphology of as-deposited coating. Therefore, the TiAlN/CrN multilayer coating exhibited superior corrosion resistance. Nano-layered structure changes the original growth mode of single coating, inhibits the growth of coarse columnar crystals, reduces the inherent defects and grain size of the coating, and plays a positive role in the corrosion resistance of the coating.
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