Effects of Er addition and cooling rate on the corrosion resistance of Zn-5Al alloys

Abstract

Galfan (Zn-5Al-RE) coating is widely used in high-strength steel wires. The effects of cooling rate and the adulteration of erbium (Er) on the microstructure and corrosion resistance of Zn-5Al alloys were investigated in this study. The results show that the Zn-5Al alloy is made up of the primary η-Zn phase and eutectic structure at a high cooling rate. As the cooling rate decreases, the corrosion current firstly increased and then decreased due to decrease of the primary η-Zn content, the appearance and grew of α-Al phase. Moreover, the addition of Er leads to the formation of Er-containing intermetallic compounds in the Zn-5Al alloy, reducing the size of the primary η-Zn and α-Al phase, decreasing the corrosion current density, and improving the density and compactness of the corrosion product.

Effect of Al Content on the Microstructure and Properties of Zn-Al Solder Alloys

“…Zn-5Al is composed entirely of a coarse eutectic structure [24]. When the total content of Al is 15 wt.%, the alloy consists of both eutectoid (α+η) and eutectic (η+β) structures [25][26][27][28][29]. Furthermore, Zn-15Al can be found to have the finest eutectoid structures compared to the other three alloys [30].…”

The Effects of B on the Microstructure and Corrosion Resistance of Zn–6Al–3Mg Alloy Coating

“…The integration of RE and Si elements into the ZAM alloy can enhance the homogeneity of the coating surface structure and stabilize corrosion products. [20] Moreover, Ge et al [21] observed that Er addition to Zn-5Al alloy generated Er-containing intermetallic compounds within the coating, refining the primary η-Zn and α-Al phases and substantially increasing corrosion resistance by densifying the corrosion products. Research indicates that the precipitated phase is enriched at the grain boundary when 0.02wt%B is added, and the electrical conductivity and mechanical properties of Al-Mg-Si alloy are significantly improved.…”