冲蚀角度对Fe-2.5B耐锌液腐蚀性能的影响

将试样装夹在自制的预设一定冲蚀角度的转盘上进行锌液冲蚀试验,实现流动锌液对试样冲蚀表面0°、30°、60°和90°冲蚀角下的冲刷腐蚀。结果表明:在圆盘转速为70r/min,冲蚀时间为24h的条件下,Fe-2.5B合金(质量分数,%)的冲蚀率随冲蚀角度的增加而逐渐降低,并在高角度下呈现急剧降低的趋势;而316L不锈钢的冲蚀率在冲蚀角为30°时最大,冲蚀角为90°时最小,表现出典型韧性材料的冲蚀率特性。Fe-2.5B合金在流动锌液中的冲蚀率仅为316L不锈钢的33%~38%,其优异耐锌液冲蚀性能依赖于Fe-B合金中网状Fe2B相对流动锌液的阻挡效应。同时,一定韧性相基体的存在对Fe2B在冲蚀过程中起到支撑作用,进而表现出该合金中两相结构在锌液冲蚀中的"腐蚀协同效应"。此外,冲蚀角度的增加造成锌液流速在试样表面的切向冲刷分量弱化而法向冲击分量强化,这使得冲刷对最外层疏松ζ-FeZn13相的移除作用减弱。强的传质过程随冲蚀角度的增加不断弱化,从而使网络状组织结构的Fe-B合金在锌液中的冲蚀率明显降低。

Effects of erosion angle on erosion-corrosion performance of Fe-2.5B alloy in flowingliquid zinc

In order to explore flowing liquid zinc erosion-corrosion on the surface of tested samples under 0°,30°,60°,and 90°erosion angles,all tested samples were fixed on a rotating disk immersed into liquid zinc pot.The experimental results showed that the erosion rate of Fe-2.5B alloy slowly decreases firstly,and then decreases sharply with the increase of erosion angles under testing conditions of liquid zinc erosion speed of 70 r/min and erosion time of 24 h,while the erosion rate of 316L stainless steel reaches a maximum at an erosion angle of 30°and a minimum at erosion angle of 90°erosion angle,displaying typical erosive characteristics of a ductile material in liquid zinc pot.In liquid zinc,the erosion rate of Fe-2.5B alloy is only 33%-38% of that of 316L stainless steel,which is attributed to the favorable barrier effect of netlike Fe2 B to resist liquid zinc erosion.Meanwhile,a little iron matrix in this alloy can provide certain toughness which can support borides during liquid zinc erosion and show a synergistic corrosion behavior.Moreover,the increase of erosion angles leads to the changes of erosive component,such as weakening of tangential scour component and strengthening of normal impact component of liquid zinc velocity on tested sample surface,which results in the decrease of removing effect from liquid zinc scour component on looseζ-FeZn13 corrosion product lain at the outer layers.Therefore,the strong mass transfer process created by flowing liquid zinc can be further weakened with the increasing erosion angles,thus leading to the obvious declined erosion rates of netlike structured Fe-B alloy during liquid zinc erosion.