Environment-friendly and chromium-free passivation of copper and its alloys

Tao Yang, Wenge Chen*, Xin Li, Jiulong Song, Longlong Dong, Yongqing (Richard) Fu*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

11 Citations (Scopus)
28 Downloads (Pure)


Benzotriazole (BTA) and tolyltriazole (TTA) were used to passivate pure copper and chromium bronze alloys for environmental protection. Using the chemical immersion treatment, a dense film of chromium-free passivation layer was formed on surfaces of both the pure copper and chromium bronze alloys. Microstructure, crystalline phases and chemical bonds of the passivation layers were systematically characterized, and the passivation mechanisms were studied. The passivation layer was mainly consisted of CuO, Cu2O, polymers of Cu-BTA-TTA and Cu(I)BTA-TTA. The formation mechanism of the chromium-free passivation layer was identified as combined oxidation and adsorption, and the main passivation processes included oxidation and dissolution of the matrix, adsorption of BTA and its derivatives, self-stabilization process of the adsorbed film, and filling of passivation film’s voids by oxide particles.
Original languageEnglish
Article number102826
Number of pages8
JournalMaterials Today Communications
Early online date22 Sept 2021
Publication statusPublished - 1 Dec 2021


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