30CrMnSiNi2A钢与TC18钛合金表面处理前后的接触腐蚀性能

Contact Corrosion Behavior of a Super High Strength Steel Coupled with TC18 Titanium Alloy

为了弄清30CrMnSiNi2A钢与TC18钛合金表面处理前后的接触腐蚀性能,对2种材料作了不同的表面处理,研究了其偶接电偶腐蚀的敏感性和表面防护效果;对低腐蚀敏感性的偶对不同的连接状态作了模拟海洋大气的盐雾加速腐蚀,测量了30CrMnSiNi2A钢的疲劳寿命,总结了优良的防护措施。结果表明:30CrMnSiNi2A钢与TC18钛合金直接接触腐蚀严重,电偶腐蚀敏感性为D级;30CrMnSiNi2A钢磷化与TC18钛合金阳极氧化后的偶对腐蚀敏感性降低至B级;30CrMnSiNi2A钢磷化涂漆后与TC18阳极氧化偶对的腐蚀敏感性仍为B级,但其电偶电流进一步降低,30CrMnSiNi2A钢(磷化后涂漆)与TC18(阳极化)之间无论是否胶结连接形成偶对时,盐雾腐蚀对30CrMnSiNi2A钢的疲劳寿命没有显著影响。30CrMnSiNi2A钢表面磷化后涂漆是防止接触腐蚀的有效措施。

Super high strength steel 30CrMnSiNi2A and TC18 Ti alloy were surface-modified by different methods.The contact corrosion behavior and corrosion sensitivity of the surface-modified and unmodified super high strength steels coupled with surface-modified and unmodified Ti alloys as well as the surface protective effectiveness were investigated.The electric couple with low galvanic corrosion sensitivity was then coupled in different manners and tested by salt-spray in simulated and accelerated marine atmosphere,with which the fatigue life of 30CrMnSiNi2A steel was measured and the proper surface protective measures were established.Results indicate that 30CrMnSiNi2A steel is liable to severe coutact corrosion when it is directly contacted with TC18 alloy,and the galvanic corrosion sensitivity of this electric couple is ranked as grade D.When 30CrMnSiNi2A is phosphated and coupled with anodized TC18 alloy,the galvanic corrosion sensitivity is reduced to grade B.Besides,when 30CrMnSiNi2A steel after phosphating and painting treatments is coupled with anodized TC18 alloy,the galvanic corrosion sensitivity is retained as grade B,but the current of the electric couple is reduced.Moreover,whether the phosphated and painted 30CrMnSiNi2A steel is couple with anodized TC18 alloy or not,salt-spray has little effect on the fatigue life of 30CrMnSiNi2A steel.This means that phosphating plus painting of 30CrMnSiNi2A steel can effectively prevent it from contact corrosion.