Titania films with nano-sized pores were prepared on the NaOH？HCl pretreated NiTi alloy substrate by sol？gel method.A crack-free film is obtained for the sample with a dense inner layer and a porous outside layer（s...Titania films with nano-sized pores were prepared on the NaOH？HCl pretreated NiTi alloy substrate by sol？gel method.A crack-free film is obtained for the sample with a dense inner layer and a porous outside layer（sample TC1＋1）.The X-ray diffraction shows that the titania films are composed of anatase,and a little Ni4Ti3 phase in the heat treated substrate is also detected.The X-ray photoelectron spectroscopy results indicate that the titania film completely covered the NiTi substrate for sample TC1＋1.The sample TC1＋1 is hydrophilic with a contact angle about 20°,and UV illumination treatment for 15 min further decreases the contact angle to（9.2±3.2）°.The potentiodynamic polarization test in 0.9% NaCl solution reveals a better corrosion resistance of sample TC1＋1 than the polished NiTi sample.展开更多
Single Ni-P and Ni-Mo-P coatings as well as duplex Ni-P/Ni-Mo-P coatings with the same compositions were prepared by electroless plating.The residual stresses of the coatings on the surface and cross sections were mea...Single Ni-P and Ni-Mo-P coatings as well as duplex Ni-P/Ni-Mo-P coatings with the same compositions were prepared by electroless plating.The residual stresses of the coatings on the surface and cross sections were measured by nanoindentation and AFM analysis,and the corrosion behaviour of the coatings in10%HCl solution was evaluated by electrochemical methods,to establish the correlation between the residual stresses and corrosion behaviour of the coatings.The results showed that the single Ni-P and duplex Ni-P/Ni-Mo-P coatings presented residual compressive stresses of241and206MPa respectively,while the single Ni-Mo-P coating exhibited a residual tensile stress of257MPa.The residual compressive stress impeded the growth of the pre-existing porosity in the coatings,protecting the integrity of the coating.The duplex Ni-P/Ni-Mo-P coatings had better corrosion resistance than their respective single coating.In addition,the stress states affect the corrosive form of coatings.展开更多
Composite coatings consisting of carbon and polytetrafluoroethylene(PTFE) were prepared on Ti alloy substrate by a simple two-step process of hydrothermal and impregnation. The morphology, composition, hydrophobic and...Composite coatings consisting of carbon and polytetrafluoroethylene(PTFE) were prepared on Ti alloy substrate by a simple two-step process of hydrothermal and impregnation. The morphology, composition, hydrophobic and corrosion properties of the composite coatings were characterized by scanning electron microscopy(SEM), Fourier transform infrared spectroscopy(FTIR), water contact angle method, X-ray photoelectron spectroscopy(XPS) and electrochemical technique, respectively. The effect of PTFE content on the corrosion properties of the composite coatings was studied. It is found that the composite coating film exhibits a full coverage with uniformly distributed PTFE when 0.1 mol/L of glucose is used as carbon source and 20 wt.% PTFE suspension as impregnating solution. The coating with 20 wt.% PTFE has a good bonding strength with Ti plate and exhibits excellent hydrophobic property with a water contact angle of 142.3° as well as superior corrosion resistance with corrosion current density as low as 0.0045 μA/cm^2. With regard to its excellent hydrophobicity and corrosion resistance, the carbon-PTFE composite coating may find potential application in automobiles and metal corrosion industries.展开更多
基金Project(xjj2011096)supported by the Fundamental Research Fund for the Central Universities,ChinaProject(201107)supported by the Open Project Program of State Key Laboratory of Metastable Materials Science and Technology,ChinaProject(50901058)supported by the National Natural Science Foundation of China
文摘Titania films with nano-sized pores were prepared on the NaOH？HCl pretreated NiTi alloy substrate by sol？gel method.A crack-free film is obtained for the sample with a dense inner layer and a porous outside layer（sample TC1＋1）.The X-ray diffraction shows that the titania films are composed of anatase,and a little Ni4Ti3 phase in the heat treated substrate is also detected.The X-ray photoelectron spectroscopy results indicate that the titania film completely covered the NiTi substrate for sample TC1＋1.The sample TC1＋1 is hydrophilic with a contact angle about 20°,and UV illumination treatment for 15 min further decreases the contact angle to（9.2±3.2）°.The potentiodynamic polarization test in 0.9% NaCl solution reveals a better corrosion resistance of sample TC1＋1 than the polished NiTi sample.
基金Project(ZR2011EMM014)supported by Shandong Provincial Natural Science Foundation of China
文摘Single Ni-P and Ni-Mo-P coatings as well as duplex Ni-P/Ni-Mo-P coatings with the same compositions were prepared by electroless plating.The residual stresses of the coatings on the surface and cross sections were measured by nanoindentation and AFM analysis,and the corrosion behaviour of the coatings in10%HCl solution was evaluated by electrochemical methods,to establish the correlation between the residual stresses and corrosion behaviour of the coatings.The results showed that the single Ni-P and duplex Ni-P/Ni-Mo-P coatings presented residual compressive stresses of241and206MPa respectively,while the single Ni-Mo-P coating exhibited a residual tensile stress of257MPa.The residual compressive stress impeded the growth of the pre-existing porosity in the coatings,protecting the integrity of the coating.The duplex Ni-P/Ni-Mo-P coatings had better corrosion resistance than their respective single coating.In addition,the stress states affect the corrosive form of coatings.
基金Project(2018YFB1502500) supported by the National Key Research and Development Program of ChinaProject supported by State Key Laboratory of Powder Metallurgy,Central South University,China+1 种基金Projects(21506258,51774127) supported by the National Natural Science Foundation of ChinaProject(2019RS2067) supported by the Science and Technology Planning Project of Hunan Province,China
文摘Composite coatings consisting of carbon and polytetrafluoroethylene(PTFE) were prepared on Ti alloy substrate by a simple two-step process of hydrothermal and impregnation. The morphology, composition, hydrophobic and corrosion properties of the composite coatings were characterized by scanning electron microscopy(SEM), Fourier transform infrared spectroscopy(FTIR), water contact angle method, X-ray photoelectron spectroscopy(XPS) and electrochemical technique, respectively. The effect of PTFE content on the corrosion properties of the composite coatings was studied. It is found that the composite coating film exhibits a full coverage with uniformly distributed PTFE when 0.1 mol/L of glucose is used as carbon source and 20 wt.% PTFE suspension as impregnating solution. The coating with 20 wt.% PTFE has a good bonding strength with Ti plate and exhibits excellent hydrophobic property with a water contact angle of 142.3° as well as superior corrosion resistance with corrosion current density as low as 0.0045 μA/cm^2. With regard to its excellent hydrophobicity and corrosion resistance, the carbon-PTFE composite coating may find potential application in automobiles and metal corrosion industries.
