Acta Metallurgica Sinica (English Letters) ›› 2025, Vol. 38 ›› Issue (6): 889-903.DOI: 10.1007/s40195-025-01842-0

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Corrosion Evolution Behavior of Ti/Zr/Oligomeric Epoxy Silane Composite Chemical Conversion Coatings on Multi-metals

Yunhu Ding1,2, Yingpeng Li2, Hongfang Liu1(), Wenhao Wang2, Yijun Wei2, Haitao Duan2, Wen Zhan2()   

  1. 1School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
    2Wuhan Research Institute of Materials Protection, China Academy of Machinery Science and Technology Group Co., Ltd., Wuhan 430030, China
  • Received:2024-10-18 Revised:2024-12-08 Accepted:2025-01-10 Online:2025-06-10 Published:2025-03-22
  • Contact: Hongfang Liu, liuhf@hust.edu.cn; Wen Zhan, zhanwen-0000@163.com

Abstract:

The new energy vehicle body composed of multi-metals requires a synchronous chemical conversion coating to exhibit excellent corrosion resistance. Herein, we prepared a titanium/zirconium/water-based oligomeric epoxy silane composite chemical conversion coating on multi-metals, and conducted an investigation into its electrochemical behavior and micro-zone structural characteristics upon immersion in a 3.5% NaCl solution. The electrochemical results combined with characterization results revealed that the corrosion evolution characteristics of the composite coatings could be categorized into three stages of mild corrosion, synergistic protection, and substrate damage. Besides, Si-OH groups interact with Me-OH at the defect on the multi-metal surface to form an organic monolayer coating. This organic monolayer coating, in conjunction with the synergistic inorganic conversion layer comprising Al2O3, TiO2·2H2O, ZrO2·2H2O, effectively cooperates with the corrosion products to hinder the erosion by the corrosive medium and suppresses the progression of the anodic reaction.

Key words: Composite chemical conversion, Ti/Zr/epoxy silane coatings, Aluminum alloys, Galvanized steel, Corrosion behavior