Study On Phase Equilibrium Of Zn-Al-Ni-Sb Quaternary System

In the use history of steel material,corrosion has always been one of the main reasons for the destruction of steel material.Therefore,the protection of steel is the direction of many people's research and efforts.Hot dip galvanizing is an effective and simple steel corrosion protection technology,which is widely used in modern life products.It is found that the content of Si in the hot-dip galvanizing steel will make the coating too thick and the quality of the coating poor.The researchers found that not only the Si content of the steel itself affects the hot-dip galvanizing of silicon steel,but also the trace elements added in the molten pool will affect the thickness and quality of the coating.Therefore,in order to obtain the coating with excellent performance in the protection of iron and steel,Al,Ni,Ti,V and other elements are usually added into the zinc bath,so as to achieve the purpose of restraining the Sandelin effect when the workpiece is dipped.With the improvement of modern life quality,not only the coating quality has higher requirements,the appearance of beautiful coating is also increasingly loved by people.It is worth noting that if Sn,Pb,Sb and other elements are added to the molten pool,the"zinc flower"will appear on the surface of the plated piece,so the ornamental performance of the piece can be improved.At present,there are many researches on the influence of Al and Ni elements on the coating,but the influence of the addition of sb elements,i.e.Al,Ni and Sb elements on the structure and properties of the coating has not been reported yet.In order to study the interaction of Al,Ni and Sb elements in the galvanizing process,it is necessary to study the phase equilibrium of Zn Al Ni sb quaternary system.To study the mechanism of Zn-Al-Ni-Sb quaternary system when galvanizing,this work uses the research method of balanced alloy.SEM-EDS and XRD are used to study the isothermal cross-section of Zn-Al-Ni ternary system with zinc-rich corner at450? and the isothermal cross-section of Zn-Al-Ni-Sb quaternary system with zinc-rich corner?93at.%Zn?at 450 and 600?.The results show that there are two three-phase equilibrium regions in 450? isothermal section:L+?+?and L+Al₃Ni₂+?,three two-phase equilibrium regions:L+??L+??L+Al₃Ni₂.There are two four-phase equilibrium regions in the Zn-Al-Ni-Sb quaternary system 450? isothermal section:L+Al₃Ni₂+Al Sb+Sb₂Zn₃and L+Al₃Ni₂+Sb₂Zn₃+?,six three-phase equilibrium regions:L+Al₃Ni₂+Al Sb?L+Al Sb+Sb₂Zn₃?L+Sb₂Zn₃+??L+Al₃Ni₂+Sb₂Zn₃?L+?+?and L+Al₃Ni₂+?.One four-phase equilibrium region in 600? isothermal section of the Zn-Al-Ni-Sb quaternary system:L+Al Ni+Al Sb+?,three three-phase equilibrium regions:L+Al Ni+Al Sb,L+Al Ni+?and L+?+Al Sb.No new binary,ternary and quaternary compounds were found in the ternary and quaternary systems in this study.This work also investigated the effect of adding different contents of Al?Ni?Sb elements and different immersion time on the appearance of the coating,the thickness of the alloy layer,the hardness of the coating and the corrosion resistance of the Q235steel in hot dip galvanizing.The experimental results show that the addition of appropriate amount of Al?Ni elements can inhibit the Zn-Fe reaction,and the addition of Sb elements will weaken the coating thickness.The ideal coating with excellent comprehensive performance can be obtained by adding 0.04 wt.%Al?0.1wt.%Ni and0.08 wt.%Sb in the designed molten pool at the same time.