汽车用MB15镁合金的表面改性与耐腐蚀性能

Surface modification and corrosion resistance of MB15 magnesium alloy for automobile

采用电化学辅助沉积技术在汽车用MB15镁合金表面制备了超疏水有机硅烷膜,研究了沉积电位、沉积时间和添加剂对膜层显微形貌、膜厚、疏水性和耐腐蚀性能的影响。结果表明,MB15镁合金表面膜层的疏水角和膜厚都会随着沉积电位增加而逐渐增大,在沉积电位为1.4 V时,MB15镁合金表面膜层的疏水角和厚度分别为152.9°和4.7μm,疏水角达到MB15镁合金基材的2.84倍。经过电沉积制备的表面硅烷膜的疏水角都明显高于MB15镁合金基材,电沉积硅烷膜的耐腐蚀性能也都优于MB15镁合金基材,且当沉积时间为200 s时,MB15镁合金表面膜层具有最佳的耐腐蚀性能。添加十六烷基三甲基溴化铵(CTAB)有助于提高MB15镁合金表面有机硅烷膜的厚度和疏水角,且添加CTAB的硅烷膜在沉积时间为120 s时就已经实现了超疏水特性。添加CTAB的MB15镁合金表面膜层的耐腐蚀性明显高于MB15镁合金基材,且高于未添加CTAB的MB15镁合金表面膜层。

Super hydrophobic organosilane films were prepared on the surface of MB15 magnesium alloy by electrochemical assisted deposition.The effects of deposition potential,deposition time and additives on the morphology,thickness,hydrophobicity and corrosion resistance of the films were studied.The results show that the hydrophobic angle and film thickness of the surface film of MB15 magnesium alloy increase gradually with the increase of deposition potential.When the deposition potential is 1.4 V,the hydrophobic angle and thickness of the surface film are 152.9°and 4.7μm,respectively,and the hydrophobic angle reaches 2.84 times of the MB15 magnesium alloy substrate.The hydrophobic angle of the surface silane film prepared by electrodeposition is obviously higher than that of the alloy substrate,and the corrosion resistance of the deposited silane film is also better than that of the alloy substrate.When the deposition time is 200 s,the surface film has the best corrosion resistance.Adding cetyl trimethyl ammonium bromide(CTAB)can help to improve the thickness and hydrophobic angle of the organic silane film,and the superhydrophobic properties of the silane film adding CTAB can be implemented at the deposition time of 120 s.The corrosion resistance of the surface layer added with CTAB is significantly higher than that of the MB15 magnesium alloy substrate,and is higher than that of the surface film without CTAB addition.