Synthesis And Applications Of Field's Alloy Nanoparticles

Field's Alloy nanoparticles not only can improve the wear resistance of the lubricating oil as good lubricant additive,but they are also potential tempering mediums through being made into composite films.In this study,both the preparation of Field's Alloy nanoparticles and the friction,mechanics and thermal properties of their composites were studied.The main contents of this study were as follows:1)One-step method of nanoemulsification technique and ultrasonic mulsification method were used to prepare nanoparticles.The nanoparticles with particle sizes of 20 nm and 120 nm were prepared respectively by adjusting the experimental temperature,reaction time,ultrasonic power and other parameters.Atomic force microscopy was used to observe the morphology of particles and the differential scanning calorimeter were used to analysis thermal performance separately.2)The oil of mass fraction of 0.02%,0.04%,0.06%,0.08% and 0.1% respectively were obtained by dispersing a certain mass of nanoparticles into PAO oil using the method of ultrasonic.We used the method of sedimentation to test the dispersion stability.In order to evaluate the tribological properties of the nanofluid,the lubricating oil with different mass fraction were tested on the ball-to-disk friction and wear tester.The experimental results showed that the friction coefficient decreases with the increase of the mass fraction of nanoparticles at first.When the mass fraction increases to 0.08%,the lubrication effect reached the optimum state.At this time,the friction coefficient which was the minimum was44.4% lower than that of pure lubricating oil.If we continued to increase the mass fraction,the friction coefficient increased which meant that the lubrication effect became worse.3)Mixed solutions of mass fractions of 1%,2%,3%,4% and 5% were prepared by dispersing nanoparticles into the PVA solution using ultrasonic method.The solution were made into films using the method of tape casting.The composite films with nanoparticles showed that there was a heat absorption and exothermic phenomenon in the process of temperature rise and reduction,which was due to the phase transition process of the melting and condensation of nanoparticles.It was proved that nanoparticles could be doped in the films to play the role of phase transition normally.The young's modulus of the composite films suddenly dropped and rose at the phase transition temperature of the nanoparticles through testing the quantitative nanoscale mechanics at different temperatures of the pure polyvinyl alcohol and composite films of 5%mass fraction.Meanwhile,the young's module of the composite film was higher than that of the pure polyvinyl alcohol film,and the adhesion force to the needle tip was smaller than that of the pure polyvinyl alcohol film.