Anti-corrosion Zeolite Membrane For Ti-6Al-4V Against Stress Corrosion And High Temperature Corrosion

Ti-6Al-4V alloy is an important corrosion-resistant titanium alloy that has received much attention and is widely used in the aerospace industry.At present,it has been widely used in the manufacture of aircraft propulsion systems,such as compressor blades and fasteners.In the marine environment,the compressor blades are surrounded by humid air,which is rich in salt(especially NaCl)and water vapor.Since the compressor blades usually work at 200~600?,they are also subject to strong centrifugal force when in service,so it is of great significance to study the anti-corrosion methods of Ti-6Al-4V alloy in high temperature stress corrosion environment and to figure out how to improve its corrosion resistance.For the anticorrosive performance of metal materials,synthesizing an anticorrosive membrane on the metal surface is a cost-effective method.It is found that zeolite membrane has great application potential due to the excellent physical and chemical stability and anticorrosive properties,and has become a new type of environmentally friendly materials.Therefore,it is of great theoretical and application value to synthesize an anticorrosive zeolite membrane on the surface of Ti-6Al-4V alloy.Triethoxysilane(YDH-151)was used as a silane coupling agent to prepare MFI zeolite anticorrosive membrane on the surface of titanium alloy by means of silane hot pressing method.The optimal preparation process was thus determined as: 0.003g/L TS-1 zeolite,hot pressing temperature of 80°C,and hot-pressing pressure of 4MPa.After that the zeolite membrane was modified by GO(Graphene oxide),and then studied for the formation mechanism of the GO/YDH-151/TS-1 composite anticorrosive membrane.Results show that the corrosion resistance rate after GO being introduced was leveled up from 81.3% to 99.8%.The introduction of GO during the self-assembly process of the composite membrane causes the hydrophobicity and binding force of the anticorrosive membrane to be slightly reduced,thus reduce the density and increase the surface roughness.However,due to the excellent corrosion resistance of YDH-151/GO membrane and the good dispersion characteristics of GO,it strongly compensates for the space defects brought by it,which greatly enhances the corrosion resistance.The anticorrosion performance of Ti-6Al-4V alloy composite anticorrosive membrane under high temperature,stress and corrosion was studied by high temperature electrochemical noise method.Through a self-made high-temperature tensile electrochemical test system,the effect of temperature and solid salt corrosion environment on the GO/YDH-151/TS-1 composite anticorrosive membrane during the stretching process were studied by comparing three conditions: 250? solid salt corrosion environment,room temperature solid salt corrosion environment,and solid salt corrosion environment.The results show that the anticorrosive membrane sustains a very good protection performance on the titanium alloy substrate at 250?.Corrosive media and water vapor have not penetrated the membrane layer or even reached the substrate.However,the increase of temperature will cause more GO/YDH-151/TS-1 membranes into cracks,aggravate the degree of corrosion,and reduce the corrosion resistance.