铝合金表面锆钛硅烷复合转化膜的研究

Study on Zirconium-titanium Silane Composite Conversion Film of Aluminum Alloy Surface

为了提高铝合金表面耐腐蚀性能,本文通过六氟锆酸、六氟钛酸、偏钒酸钠、单宁酸组成的转化浴在铝表面制备了TVMC转化膜,并在此基础上,进一步研究了复合硅烷转化膜材BTSEPT(双-[3-(三乙氧基硅)丙基]-四硫化物)/GPTMS(3-[2,3-环氧丙氧]丙基三甲氧基硅烷)对涂层性能的改善。采用扫描电子显微镜(SEM)、X射线能谱(EDS)、X射线衍射谱(XRD)、傅里叶红外光谱(FT-IR)、X射线光电子能谱(XPS)观察转化膜的微观形貌和分析转化膜的结构组成,采用电化学阻抗谱(EIS)和极化曲线(Tafel)评价转化膜的耐腐蚀性能。结果表明,制备的TVMC/BG复合转化膜均匀完整,改善了TVMC涂层表面的裂纹与不平整情况,复合膜主要由C、O、Si、S、V元素组成且在表面分布均匀,膜层主要由Si-O-Si以及Si-O-C的交联结构组成,对基材的保护性能良好,使自腐蚀电位降低130 mV,腐蚀电流密度为1.092×10^(-8)A·cm^(-2),相对于基材降低约4个数量级。结果表明BTSEPT/GPTMS硅烷的复合膜层成功附着在TVMC涂层表面,进一步提高了对A5052铝合金的保护性能。

In order to improye the corrosion resistancc of aluminurn alloy,the TVMC conversion film wa-s prepared on the surface of aluminum hy the conversion bath cmposed of hexafluorezirconic acid,he-xaflurotitanium acid,soium partial vandate and tannic acid,und en this busis,the composite silune cx-nversion film(BTSEPT(Bis[3-(triethosysilyl)propyl]tetrasulfide))/GPTMS(3-Gly-cidosypropyltrimethosysilane)was funther etudied in enhancing the costing perfermance.The mierelructure and composition of the con-version coating were scrutinized by employing scanning electron mierscору(SEM),energy-dispersive X-ray spertucoру(EDS),X-ray diffraction(XRD),Fourier-transferm infrared spectroscopy(FT-IR),and X-ray phøtocdectron spectrsспру(XPS)The corrosion resislance of the comerin coating was asssadl th-rugh eletrochenical impedace spextropy(EIS)and polari-zation curves(Tafel).Results indicated thut the prepared TVMС/BG composite conversión coating exhibited a uniform und intaet structure,ameliorat-ing cracks and irregularities on the TVMC coating surface.The composite coating predominantly compris-ed C,O,Si,S and V elements,evenly distributed on the surface.The film primarily consisted of cross-linked structures,such as Si-O-Si and Si-0-C,displaying excellent protective properties on the substrate.The self-corrosion potential decreased by 130mV,and the corrosion current density was 1.092×10^(-8)A·cm^(-2),denoting a reduction of approximately four orders of magnitude compared to the substrate.In conclusion,the TVMC coating surface was successfully adhered to the composite film of BTSEPT/GPTMS silan-e,thereby further enhancing the protective performance on A5052 aluminum alloy.