Ceramic coatings were prepared on AZ91 D Mg alloy by micro-arc oxidation （MAO） in aluminate electrolytes, with Al2O3 nano-additive suspending at different concentrations. Effects of nano-additive concentration on th...Ceramic coatings were prepared on AZ91 D Mg alloy by micro-arc oxidation （MAO） in aluminate electrolytes, with Al2O3 nano-additive suspending at different concentrations. Effects of nano-additive concentration on the structure, phase composition, hardness and anti-corrosion property of the MAO coatings were analyzed by scanning electron microscopy, X-ray diffraction, micro-hardness test and electrochemical method, respectively. The results revealed that Al2O3 nano-particles were mostly incorporated into ceramic coating chemically, transferred into MgAl2O4, rather than being trapped mechanically during MAO process. With the increase of Al2O3 concentration, the voltage-time response, content of MgAl2O4, hardness and anti-corrosion property increased. However, when the concentration varied from 10 g/L to 15 g/L, these behaviors and properties changed only a little. This result indicated that, after the concentration of Al2O3 nano-additive reaching 10 g/L, the incorporation of Al2O3 nano-particles turned into a saturation state, due to the complex process during MAO treatment. Therefore, 10 g/L might be a proper concentration for MAO coating to incorporate Al2O3 nano-particles,展开更多
Ceramic coatings were fabricated on aluminum doped with different concentrations of TiO2 nano-additive. alloy substrates by micro-arc oxidation （MAO） in silicate electrolytes Effects of nano-additive concentration o...Ceramic coatings were fabricated on aluminum doped with different concentrations of TiO2 nano-additive. alloy substrates by micro-arc oxidation （MAO） in silicate electrolytes Effects of nano-additive concentration on the structural and mechanical properties of the MAO coatings were analyzed. The results revealed that some nano-particle were incorporated into the resulting coating during the MAO process, while there was a reasonable concentration for the TiO2 nano-additive. With increasing the nano-additive concentration to 3.2 g/L, the adhesion value increased, while mean friction coefficient and mass loss decreased. A further increase of nano-additive deteriorated the adhesion and mean friction coefficient values, which was consistent with the micro-hardness tests.展开更多
Surface of TiO2 nanoparticles was modified with the in situ chemical oxidative polymerization of aniline. Polyaniline modified TiO2 nanoparticles （PANI-TiO2） were characterized with the FT-IR, XRD, SEM and TEM techn...Surface of TiO2 nanoparticles was modified with the in situ chemical oxidative polymerization of aniline. Polyaniline modified TiO2 nanoparticles （PANI-TiO2） were characterized with the FT-IR, XRD, SEM and TEM techniques. Results confirmed that PANI was grafted successfully on the surface of TiO2 nanoparticles, therefore agglomeration of nanoparticles decreased dramatically. Polyvinyl chloride nanocomposites filled with 1 wt%-5 wt% of PANI-TiO2 and TiO2 nanoparticles were prepared via the solution blending method. PVC nanocomposites were analyzed with FT-IR, XRD, SEM, TG/DTA, DSC and tensile test techniques. Effect of PANI as surface modifier of nanoparticles was discussed according to the final properties of PVC nanocomposites. Results demonstrated that deposition of PANI on the surface of TiO2 nanoparticles improved the interfacial adhesion between the constituents of nanocomposites, which resulted in better dispersion of nanoparticles in the PVC matrix. Also PVC/PANI-TiO2 nanocomposites showed higher thennal resistance, tensile strength and Young＇s modulus compared to those of unfilled PVC and PVC/TiO2 nanocomposites.展开更多
The paper presents the results of a systematic study of the influence of nano-additives of various concentrations,average sizes and composition on the temperature dependence of the viscosity and rheological behavior o...The paper presents the results of a systematic study of the influence of nano-additives of various concentrations,average sizes and composition on the temperature dependence of the viscosity and rheological behavior of water-based drilling fluids.Typical compositions of drilling fluids,such as water suspensions of various clay solutions and gammaxan-based polymer solutions,were considered.Hydrophilic nanoparticles of silicon and aluminum oxides were used as nano-additives at concentrations ranging from 0.25 to 3 wt%.The average nanoparticle size varied from 10 to 151 nm.The temperature of drilling fluids varied from 25℃ to 80℃.It is shown that the addition of nanoparticles to drilling fluids leads to a significant change in their rheological properties depending on the temperature.It was found that with increasing temperature,the yield stress and consistency index of drilling fluids with nanoparticles increase,while the behavior index,on the contrary,decreases.This behavior depends on the size of the nanoparticles.As the particle size increases,their influence on the temperature dependence of the drilling fluids’viscosity increases.In general,it is shown that the addition of nanoparticles makes the viscosity of drilling fluid more stable with regard to the temperature.This is an essential fact for practical application.展开更多
文摘Ceramic coatings were prepared on AZ91 D Mg alloy by micro-arc oxidation （MAO） in aluminate electrolytes, with Al2O3 nano-additive suspending at different concentrations. Effects of nano-additive concentration on the structure, phase composition, hardness and anti-corrosion property of the MAO coatings were analyzed by scanning electron microscopy, X-ray diffraction, micro-hardness test and electrochemical method, respectively. The results revealed that Al2O3 nano-particles were mostly incorporated into ceramic coating chemically, transferred into MgAl2O4, rather than being trapped mechanically during MAO process. With the increase of Al2O3 concentration, the voltage-time response, content of MgAl2O4, hardness and anti-corrosion property increased. However, when the concentration varied from 10 g/L to 15 g/L, these behaviors and properties changed only a little. This result indicated that, after the concentration of Al2O3 nano-additive reaching 10 g/L, the incorporation of Al2O3 nano-particles turned into a saturation state, due to the complex process during MAO treatment. Therefore, 10 g/L might be a proper concentration for MAO coating to incorporate Al2O3 nano-particles,
文摘Ceramic coatings were fabricated on aluminum doped with different concentrations of TiO2 nano-additive. alloy substrates by micro-arc oxidation （MAO） in silicate electrolytes Effects of nano-additive concentration on the structural and mechanical properties of the MAO coatings were analyzed. The results revealed that some nano-particle were incorporated into the resulting coating during the MAO process, while there was a reasonable concentration for the TiO2 nano-additive. With increasing the nano-additive concentration to 3.2 g/L, the adhesion value increased, while mean friction coefficient and mass loss decreased. A further increase of nano-additive deteriorated the adhesion and mean friction coefficient values, which was consistent with the micro-hardness tests.
基金financially supported by the University of Tabriz
文摘Surface of TiO2 nanoparticles was modified with the in situ chemical oxidative polymerization of aniline. Polyaniline modified TiO2 nanoparticles （PANI-TiO2） were characterized with the FT-IR, XRD, SEM and TEM techniques. Results confirmed that PANI was grafted successfully on the surface of TiO2 nanoparticles, therefore agglomeration of nanoparticles decreased dramatically. Polyvinyl chloride nanocomposites filled with 1 wt%-5 wt% of PANI-TiO2 and TiO2 nanoparticles were prepared via the solution blending method. PVC nanocomposites were analyzed with FT-IR, XRD, SEM, TG/DTA, DSC and tensile test techniques. Effect of PANI as surface modifier of nanoparticles was discussed according to the final properties of PVC nanocomposites. Results demonstrated that deposition of PANI on the surface of TiO2 nanoparticles improved the interfacial adhesion between the constituents of nanocomposites, which resulted in better dispersion of nanoparticles in the PVC matrix. Also PVC/PANI-TiO2 nanocomposites showed higher thennal resistance, tensile strength and Young＇s modulus compared to those of unfilled PVC and PVC/TiO2 nanocomposites.
基金supported by the Russian Science Foundation(grant No.17-79-20218-P).
文摘The paper presents the results of a systematic study of the influence of nano-additives of various concentrations,average sizes and composition on the temperature dependence of the viscosity and rheological behavior of water-based drilling fluids.Typical compositions of drilling fluids,such as water suspensions of various clay solutions and gammaxan-based polymer solutions,were considered.Hydrophilic nanoparticles of silicon and aluminum oxides were used as nano-additives at concentrations ranging from 0.25 to 3 wt%.The average nanoparticle size varied from 10 to 151 nm.The temperature of drilling fluids varied from 25℃ to 80℃.It is shown that the addition of nanoparticles to drilling fluids leads to a significant change in their rheological properties depending on the temperature.It was found that with increasing temperature,the yield stress and consistency index of drilling fluids with nanoparticles increase,while the behavior index,on the contrary,decreases.This behavior depends on the size of the nanoparticles.As the particle size increases,their influence on the temperature dependence of the drilling fluids’viscosity increases.In general,it is shown that the addition of nanoparticles makes the viscosity of drilling fluid more stable with regard to the temperature.This is an essential fact for practical application.
