聚四氟乙烯/Al_3O_2-TiO_2复合涂层的制备及其疏水性能研究

Preparation of PTFE/Al_3O_2-TiO_2 Composite Coating and Its Hydrophobic Property

目的在铝合金表面制备耐磨、耐蚀、高结合强度的疏水涂层。方法采用大气等离子喷涂(APS)在铝合金基体上制备AT(Al3O2-Ti O2)涂层,在AT涂层上采用溶胶-凝胶法制备聚四氟乙烯(PTFE)面层,借助扫描电子显微镜、X射线衍射仪、3D形貌仪、接触角测试仪等仪器对涂层的显微结构、成分、粗糙度、接触角进行表征。结果喷距为120 mm、电流为680 A、送粉量为18 g/min的条件下,实心AT涂层和空心AT涂层表面粗糙度为6.99μm、6.13μm,孔隙率为5.88%、15.18%,硬度为945.82HV0.3、768.1HV0.3,与基体的结合强度为32 MPa、28 MPa,实心AT涂层与PTFE涂层的结合强度为19 MPa。实心PTFE/AT复合涂层与水的静态接触角最大可达130.9°,PTFE涂层表面含有氟化物和硅化物。结论实心粉末AT涂层表面粗糙度较大,综合性能优于空心粉末AT涂层,因此,将实心AT涂层作为复合涂层的底层。实心PTFE/AT复合涂层具有与荷叶表面相仿的微纳米二元粗糙结构,具有良好的疏水性能,疏水性能与表面含氟物质的疏水基团以及低表面能的二元粗糙结构相关。

The work aims to prepare hydrophobic coating of wear resistance,corrosion resistance and high bonding strength on the aluminum alloy surface.The AT（Al3O2-Ti O2） coatings were prepared on the substrate of the aluminum alloy by using atmospheric plasma spraying（APS）.The PTFE coatings were prepared on the surface of AT coating by virtue of sol-gel method.The microstructure,composition,roughness and static contact angle were characterized by scanning electron microscope,X-ray diffraction,3D topography tester and contact angle tester,respectively.Provided with following process parameters：spray distance of 120 mm,current of 680 A and powder feeding rate of 18 g/min,the roughness of solid powder AT coating and hollow powder AT coating is 6.99 μm,6.13 μm,respectively; porosity 5.88%,15.18%; hardness 945.82HV0.3,768.1HV0.3; adhesion force with matrix 32 MPa,28 MPa; and adhesion force between the solid AT coating and PTFE coating 19 MPa.The static contact angle of the solid PTFE/AT composite coating with water was up to 130.9°.The surface of PTFE coating contained fluoride and silicide.The overall performance of AT coating prepared by solid irregular AT powder is significantly superior to that of AT coating prepared by hollow spherical AT powder,and the roughness of solid AT coating is higher than that of the hollow AT coating.Therefore the solid AT coating is chosen as the substrate of composite coating.The solid PTFE/AT composite coatings have a nanostructure dual rough structure similar with lotus leaf surface.The composite coating is of good hydrophobic properties,the hydrophobic property related to the hydrophobic groups of the fluorine-containing substance on the coating surface and the dual rough structure with low surface energy.