Effects of reinforced nanofluid with nanoparticles on cutting tool wear morphology

Superalloys are grouped as hard-to-cut materials with relatively poor machinability.Tool wear is considered one of the main machinability attributes in machining superalloys.Although numerous works have been reported on factors governing tool life in machining superalloys,no study was found on the effect of nanoparticles stability on nanofluid performance and consequently resulted tool wear morphologies.In the present work,the nanoparticles were reinforced by means of improving the stability of the base fluid.To that accomplished,the surface active agent (surfactant) was added to the base cutting fluid as a reinforcing element.The effects of new lubricant on the tool wear morphology of A286 works parts were assessed.

Synthesis of newly cationic surfactant based on dimethylaminopropyl amine and their silver nanoparticles:Characterization;surface activity and biological activity

The chemical structure of newly synthesized cationic surfactants based on Schiff base was confirmed using Fourier transform infrared spectroscopy,proton nuclear magnetic resonance spectroscopy,and mass spectroscopy.The synthesized surfactants were used in the synthesis of silver nanoparticles by a simple one-step method.The silver nanoparticle（AgNPs） formation was confirmed using transmission electron microscopy（TEM）,electron diffraction（SAED）,dynamic light scattering（DLS）,and energy dispersive X-ray spectroscopy（EDX）.The structure of the surfactant played an important role in the synthesis process.Increasing the hydrophobic chain length,the stability,and the amount of surfactant increased the quantity of AgNPs formed.The surface activity of the synthesized cationic surfactants was determined using surface tension measurements at three different temperatures.The synthesized surfactants showed a high tendency toward adsorption and micellization.Increasing the hydrophobic chain length of the synthesized surfactant increased its adsorption.Screening the synthesized cationic surfactants and their nano-form against bacteria and fungi showed that they are highly effective.The silver nanoparticles enhanced the biological activity of the synthesized cationic surfactants.

Effect of H_2O_2 and nonionic surfactant in alkaline copper slurry

For improving the polishing performance, in this article, the roles of a nonionic surfactant（Fatty alcohol polyoxyethylene ether） and H2O2 were investigated in the chemical mechanical planarization process, respectively.Firstly, the effects of the nonionic surfactant on the within-wafer non-uniformity（WIWNU） and the surface roughness were mainly analyzed. In addition, the passivation ability of the slurry, which had no addition of BTA, was also discussed from the viewpoint of the static etch rate, electrochemical curve and residual step height under different concentrations of H2O2. The experimental results distinctly revealed that the nonionic surfactant introduced in the slurry improved the WIWNU and surface roughness, and that a 2 vol% was considered as an appropriate concentration relatively. When the concentration of H2O2 surpasses 3 vol%, the slurry will possess a relatively preferable passivation ability, which can effectively decrease the step height and contribute to acquiring a flat and smooth surface. Hence, based on the result of these experiments, the influences of the nonionic surfactant and H2O2 are further understood, which means the properties of slurry can be improved.

Strategies for synthesizing non-bioaccumulable alternatives to PFOA and PFOS

This minireview describes the strategies for synthesis of fluorinated surfactants potentially non- bioaccumulable. Various strategies have been focused on （Ⅰ） reducing the length of the perfluorocarbon chain, （Ⅱ） introducing hereto atoms into the fluorocarbon chain, （Ⅲ） introducing branch （herein and after branch means the fluoro-carbon chain section is not straight）. In most cases, the surface tensions versus the surfactant concentrations have been assessed. These above strategies led to various highly fluorinated （perfluorinated or not perfluorinated） surfactants whose chemical changes enabled to obtain novel alternatives to perfluorooctanoic acid （PFOA） and perfluorooctane sulphonate （PFOS）.