Comparison of TiAIN,AICrN, and AICrN/TiAIN coatings for cutting-tool applications

Monolayer and bilayer coatings of TiAlN, AlCrN, and AlCrN/TiAlN were deposited onto tungsten carbide inserts using the plasma enhanced physical vapor deposition process. The microstructures of the coatings were characterized using scanning electron microscopy （SEM） and atomic force microscopy （AFM）. The SEM micrographs revealed that the AlrN and AlCrN/TiAlN coatings were uniform and highly dense and contained only a limited number of microvoids. The TiAIN coating was non-uniform and highly porous and contained more micro droplets. The hardness and scratch resistance of the specimens were measured using a nanoindentation tester and scratch tester, respectively. Different phases formed in the coatings were analyzed by X-ray diffraction （XRD）. The AlCrN/TiAlN coating exhibited a higher hardness （32.75 GPa）, a higher Young＇s modulus （561.97 GPa）, and superior scratch resistance （LcN = 46 N） compared to conventional coatings such as TiAlN, A1CrN, and TiN.     

Hyperbranched poly(cyanurateamine): A new corrosion inhibitor for mild steel in hydrochloric acid medium

Hyperbranched poly(cyanurateamine) (POCYAM) was tested as a novel corrosion inhibitor for mild steel in 0.5–3 M HCl using chemical and electrochemical techniques at 25–70 °C. The results show that this compound has good corrosion inhibiting properties for mild steel in HCl at very low concentrations. Corrosion inhibition efficiency rises with POCYAM concentration. The adsorption of the POCYAM onto the mild steel surface obeys Langmuir adsorption isotherm model. The inhibition mechanism was further corroborated by the values of thermodynamic parameters obtained from the experimental data.     

Synthesis and characterization of citric acid-based pH-sensitive biopolymeric hydrogels

Biocompatible hydrogels based on citric acid (CA) with varying glycol unit, viz., ethylene glycol (EG), diethylene glycol and triethylene glycol were prepared along with acrylic acid. The formations of various hydrogels were confirmed using spectral techniques such as FT-IR and ¹H NMR. Thermal stability (thermogravimetric analysis, DTA and differential scanning calorimetry) and morphology (SEM) of the synthesized hydrogels were investigated. Swelling studies of hydrogels at various pH values ranging from 4.0 to 10.0 were also investigated. The results of swelling studies show that the percentage of swelling is comparatively higher at higher pH than lower pH. Swelling equilibrium for various hydrogels was also found. Increased composition of CA in hydrogels at different pH values of 4.0, 6.0, 7.4, 8.0 and 10.0 enhanced the swelling equilibrium.     

Synthesis, characterization, and electrochemical evaluation of anti-corrosive performance of poly((N-methacryloyloxymethyl) benzotriazole-co-N-vinylpyrrolidone) coatings

Poly((N-methacryloyloxymethyl)benzotriazole-co-N-vinylpyrrolidone) was synthesized by free radical solution polymerization technique and characterized using Fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy. Thermal stability of the synthesized copolymer was analyzed by thermogravimetric analysis and differential thermal analysis. The corrosion performances of low nickel stainless steel specimens coated with different mole ratios of synthesized copolymer were investigated in 1 M H₂SO₄ using potentiodynamic polarization, electrochemical impedance method, and chronoamperometric studies. Surface and morphological investigation were also provided in order to characterize the adherence and uniformity of the coatings. Electrochemical corrosion test and surface analysis results were clearly showed that the copolymer-coatings served as a stable host matrix on low nickel stainless steel as environmentally favored good anticorrosive coating.     

UV and corrosion protective behavior of polymer hybrid coating on mild steel

Poly[(pyridine‐4‐yl‐methyl)methacrylate‐co‐butyl methacrylate] [poly(PyMMA‐co‐BMA)] and its ZnO nanocomposites [poly(PyMMA‐co‐BMA)/ZnO] were coated on the mild steel substrate (MS) to improve the corrosion resistance by blocking the destructive ultraviolet radiation (UV‐radiation) and corrosive ions as well. The optical and anticorrosive properties of poly(PyMMA‐co‐BMA) and poly(PyMMA‐co‐BMA)/ZnO (1.0, 1.5, and 2.5 wt %) coatings were evaluated. The surface characterization techniques like UV visible spectroscopy and scanning electron microscope were taken to confirm the formation of poly(PyMMA‐co‐BMA) and poly(PyMMA‐co‐BMA)/ZnO (2.5 wt %) coating on MS. The optical studies revealed that the poly(PyMMA‐co‐BMA)/ZnO (2.5 wt %) coating displays excellent UV blocking properties than other nanocomposite coatings (1.0 and 1.5 wt %). The potentiodynamic polarization and electrochemical impedance spectroscopy studies show that the poly(PyMMA‐co‐BMA) and poly(PyMMA‐co‐BMA)/ZnO (1.0, 1.5, and 2.5 wt %) coated MS in 3.5% (w/v) NaCl provides better protection against corrosion. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46175.     

Studies on the mechanical,thermal, morphological and barrier properties of nanocomposites based on poly(vinyl alcohol) and nanocellulose from sugarcane bagasse

Nanocomposites from poly(vinyl alcohol) [PVA] in linear and crosslinked state were synthesized using varying proportions of bagasse extracted nanocellulose. These were characterized by tensile, thermal, X-ray diffraction (XRD), moisture vapor transmission rate (MVTR), and morphological studies. Crosslinked PVA and linear PVA nanocomposite exhibited highest tensile strength at 5 wt.% and 7.5 wt.% of nanocellulose respectively. Thermogravimetric analysis (TGA) studies showed higher thermal stability of nanocomposite made of crosslinked PVA and nanocellulose with respect to linear PVA and nanocellulose. TEM and AFM studies confirm the formation of nanocomposites while the SEM images show the dispersion of nanocellulose particles in them.     

A Clustering TDMA and Code Block Binding Algorithms to Enhance the Node Energy and Security of the Network

Wireless Personal Communications - Wireless body area Networks is used to measure the ambient conditions related to the environment surrounding the sensors and transforms them into an electrical...     

Surface properties of inorganic fillers for application in composite membranes-direct methanol fuel cells

The surface properties of inorganic fillers employed in composite membranes have been investigated by X-ray photoelectron spectroscopy (XPS), BET surface area and acid–base characterisations. The adsorption density of hydroxyl–hydrogen ions and the pH of slurry varied with the amount and strength of acid–base surface functionalities. A shift towards higher binding energies was observed for the O 1s photoelectron peak as a function of the increase of the filler acidic behaviour. The conductivity of the membranes and the maximum power density at 145 °C for direct methanol fuel cells (DMFCs) increased with the filler surface acidity.     

A comparative study on corrosion-resistant performance of halogenated copolymers

Methacrylate-based copolymers are frequently used as anticorrosive organic coatings. Polymeric coating on metallic surfaces provides protection by a barrier action. Thermal properties have a significant influence on corrosion-resistance. This paper deals with the effect of thermal properties of 2,4,6-tribromophenyl methacrylate-co-glycidyl methacrylate and N-(p-bromophenyl)-2-methacrylamide-co-glycidyl methacrylate copolymers in corrosion-resistant behavior on low nickel stainless steel (LNSS). Hence attempts have been made to synthesize a set of copolymers by free radical polymerization and compare their corrosion-resistance properties. The copolymers were structurally characterized by Fourier transform-infrared, and ¹H-nuclear magnetic resonance spectroscopic techniques. The molecular weight of the copolymers was determined by gel permeation chromatography. Thermal studies were carried out using thermogravimetric analysis and differential scanning calorimetry. Corrosion performances of LNSS coated with two different copolymers was investigated in 1 M H₂SO₄ using potentiodynamic polarization and electrochemical impedance spectroscopic methods. The corrosion study reveals that poly(TBPMA-co-GMA) showed better corrosion-resistance than poly(PBPMA-co-GMA).     

Physicochemical and morphological evaluation of chitosan/poly(vinyl alcohol)/methylcellulose chemically cross-linked ternary blends

Chitosan/poly(vinyl alcohol)/methylcellulose (CS/PVA/MC) ternary blend was prepared and chemically cross-linked with glutaraldehyde. The prepared ternary blends were characterized by Fourier transform infrared spectroscopy (FTIR), Thermogravimetric analysis (TGA), and X-ray diffraction (XRD). The FTIR results showed that the strong intermolecular hydrogen bonds took place between CS and PVA. TGA showed the thermostability of the blend is enhanced by glutaraldehyde as crosslink agent. Results of XRD indicated that the relative crystalline of pure CS film was reduced when the polymeric network was reticulated by glutaraldehyde. Finally, the results of scanning electron microscopy (SEM) indicated that the morphology of the blend is rough and heterogenous, further it confirms the interaction between the functional groups of the blend components.