Effect of Al Content on Corrosion Resistance of Iron-Based Alloy in Zinc Liquid

Effect of Al content on corrosion resistance of iron-boron alloys substrate in zinc-liquid was investigated.The scanning electron microscopy (SEM) was used to analyze the microstructures of interface between alloy substrate and corrosion spots,and the energy dispersive X-ray spectroscopy (EDS) was used to analyze the chemical composition of the phases involved in Fe-B-Al alloys.A test of examination of mechanical properties and corrosion rate of the alloys was also carried out by use of the micro-indentation method and weight-loss method respectively.The results show that the Al content is more than 18wt% in iron-boron alloys,the intermetallic Fe-Al are formed mostly,which are no wettable in the zinc-liquid,and their corrosion resistance to zinc liquid is enhanced correspondently.Meanwhile,the segregation of B at grains boundary playing as cleaner role is beneficial to improve the toughness of iron-boron alloy.The Fe-24Al-4.2B and Fe-27Al-2.8B alloys both with the excellent corrosion resistance to zinc-liquid and good toughness can be used prolongedly in zinc-plating industry.