Preparation And Corrosion Behavior Of Bulk Zirconium-based Amorphous Alloys In NaCl Solution

Amorphous alloys atoms are arranged in a special structure of short-range order and long-range disorder,and there are no grain boundaries,dislocations and other microscopic defects inside,which make this kind of materials have some excellent mechanical,physical and chemical properties.With the development of marine resources,people will put forward higher requirements for corrosion resistance of equipment in service in marine environment,so it is necessary to find and explore some new corrosion resistance substitute materials.Amorphous alloys with high strength,hardness and corrosion resistance have broad application prospects in marine engineering.In this paper,the corrosion behavior of Zr-based amorphous alloys with high fracture toughness and large glass forming capacity in simulated seawater was studied.In this paper,the preparation and corrosion behavior of Zr-based amorphous alloys such as Zr-Cu-Al,Zr-Ni-Al and Zr-Cu-Ni-Al in 3.5wt.%Na Cl solution are studied.The influence of the constituent elements in the Zr-based amorphous alloy on the formation and corrosion properties of glass,the influence of the different structural relaxation states on the corrosion properties of the amorphous alloy,the formation and destruction of the passivation film and other corrosion behaviors were studied.The main research results are as follows:（1）The decrease of Zr/Cu in the Zr-Cu-Al amorphous alloys is beneficial to the improvement of glass forming ability,while the decrease of Zr/Al in the Zr-Ni-Al amorphous alloys is beneficial to the improvement of glass forming ability.The corrosion resistance of Zr-Ni-Al amorphous alloys is higher than that of Zr-Cu-Al amorphous alloys.The corrosion resistance of Zr-Cu-Al amorphous alloys increases with the increase of Zr/Cu,and the corrosion resistance of Zr-Ni-Al amorphous alloys increases with the increase of Zr/Al.The passivation film composition of amorphous alloy is mainly the corresponding oxides of alloying elements.（2）The increase of Ni content in Zr-Cu-Ni-Al amorphous alloys can improve the corrosion resistance of the amorphous alloy.The corrosion resistance of Zr-Cu-Ni-Al amorphous alloys is better than that of Zr-Cu-Al amorphous alloys.The Zr-Cu-Ni-Al amorphous alloys also has pitting corrosion,and the Zr₆₅Cu₁₅Ni₁₀Al₁₀ amorphous alloy with more Ni elements and more Zr/Al has better corrosion resistance than the Zr₅₅Cu₃₀Ni₅Al₁₀ amorphous alloy with less Ni.The passivation films formed on the surface of Zr-Cu-Ni-Al amorphous alloys are mainly composed of ZrO₂,Al₂O₃ and NiO.（3）Annealing treatment of amorphous alloy reduces the free volume content of amorphous alloy and has better structural stability.The annealed amorphous alloy has higher corrosion resistance than the crystalline alloy and the as-cast amorphous alloy,and the annealed amorphous alloy for 2 h and 4 h has the best corrosion resistance.The structural relaxation can improve the corrosion resistance of the amorphous alloy,which may be related to the structural stability of the amorphous alloy.（4）Pitting corrosion occurs in Zr-based amorphous alloys,and the passivated film is destroyed by Cl^-adsorption,resulting in metal dissolution.In the Zr-based amorphous alloy containing Cu element,the selective dissolution of Cu element occurs,that is,Cu element accumulates and other elements dissolve.The galvanic reaction is formed in the corrosion pit of Zr-based amorphous alloy containing Cu element,which accelerates the corrosion rate.