新型高锰奥氏体合金耐液锌的腐蚀机理

Corrosion mechanisms of a new-type high-manganese austenitic alloy in a molten zinc bath

对自制的一种新型高锰奥氏体耐液锌腐蚀合金在490℃的熔融纯锌液中的腐蚀行为进行了系统的研究,并探讨了其耐液锌腐蚀机理.结果表明,与316L不锈钢相比,新型高锰奥氏体合金具有更好的耐液锌蚀能力,其腐蚀速率为6.42×10-4g.cm-2.h-1,而316L不锈钢的腐蚀速率为1.54×10-3g.cm-2.h-1.新型高锰奥氏体合金在锌液中的最终腐蚀产物为Γ相+δ相+ζ相,而316L不锈钢的腐蚀产物几乎全是ζ相.新型高锰奥氏体合金的腐蚀产物中δ相固溶了质量分数在8.5%左右的Cr,Cr的存在使得δ相稳定性增加,致密的富含Cr的δ相的存在减缓了铁、锌反应速率,提高了新型高锰奥氏体合金的耐液锌腐蚀能力.因此,以锰代镍来制取低成本的新型高锰奥氏体耐液锌腐蚀合金具有可行性.

A new-type high-manganese austenitic alloy for immersed rolls in continuous hot-dip coating lines was developed.The corrosion behaviors of the high-manganese austenitic alloy in molten zinc at 490 ℃ were systematically studied in order to better understand the reaction mechanism.The results indicated that the high-manganese austenitic alloy showed a better corrosion resistance than 316 L stainless steel.Its corrosion rate in molten zinc was calculated to be approximately 6.42×10^-4 g·cm^-2·h^-1,but 1.54×10^-3 g·cm^-2·h^-1 for 316 L stainless steel.The ultimate corrosive products of the high-manganese austenitic alloy were Γ,δ and ζ phases,while that of 316 L stainless steel was almost ζ phase.δ phase in the high-manganese austenitic alloy contains about 8.5% Cr,and the existence of Cr improves the stabilization of δ phase.This δ phase with enrichment of Cr acts as a barrier slowing down the reaction of Fe and Zn,and improves the corrosion resistance of the high-manganese austenitic alloy.Substituting manganese for nickel to manufacture a high-manganese austenitic alloy of low cost is feasible.