Synthesis of Nickel Oxide Nano Material by Electrodeposition for Electrochemical Capacitive Analysis

Electrodeposition techniques is used for the deposition of nickel oxide thin film electrodes. In the present work, we report electrodeposition of nickel oxide thin film on the conducting stainless steel (SS) substrates for the application of electrochemical supercapacitor. X-ray diffraction confirms simple cubic crystal structure with polycrystalline nature of the deposited NiO sample that exhibits hydrophilic nature confirmed from the wettability study. The Scanning Electron Microscope (SEM) observed dense with cracky morphology. UV spectrum exhibits 3.55eV band gap of samples. The capacitive characteristics of the deposited thin film are investigated in 1M KOH electrolyte using cyclic voltammetry (CV). The supercapacitive properties of NiO are strongly affected by the scan rate. The maximum specific capacitance obtained is 162 F/g at 2 mV/s scan rate.

Surface Persistence of Trace Level Deposits of Highly Energetic Materials

In the fields of Security and Defense, explosive traces must be analyzed at the sites of the terrorist events. The persistence on surfaces of these traces depends on the sublimation processes and the interactions with the surfaces. This study presents evidence that the sublimation process of these traces on stainless steel (SS) surfaces is very different than in bulk quantities. The enthalpies of sublimation of traces of four highly energetic materials: triacetone triperoxide (TATP), 2,4-dinitrotoluene (DNT), 2,4,6-trinitrotoluene (TNT), and 1,3,5- trinitrohexahydro-s-triazine (RDX) deposited on SS substrates were determined by optical fiber coupled-grazing angle probe Fourier Transform Infrared (FTIR) Spectroscopy. These were compared with enthalpies of sublimation determined by thermal gravimetric analysis for bulk amounts and differences between them were found. The sublimation enthalpy of RDX was very different for traces than for bulk quantities, attributed to two main factors. First, the beta-RDX phase was present at trace levels, unlike the case of bulk amounts which consisted only of the alpha-RDX phase. Second, an interaction between the RDX and SS was found. This interaction energy was determined using grazing angle FTIR microscopy. In the case of DNT and TNT, bulk and traces enthalpies were statistically similar, but it is evidenced that at the level of traces a metastable phase was observed. Finally, for TATP the enthalpies were statistically identical, but a non-linear behavior and a change of heat capacity values different from zero was found for both trace and bulk phases.

Surface Persistence of Trace Level Deposits of Highly Energetic Materials

The sublimation enthalpies of four highly energetic materials (HEMs): triacetone triperoxide (TATP), 2,4-dinitrotoluene (DNT), 2,4,6-trinitrotoluene (TNT) and 1,3,5-trinitrohexahydro-s-triazine (RDX) deposited on stainless steel (SS) substrates were determined by optical fibre coupled-grazing angle probe (GAP) FTIR spectroscopy and thermogravimetric analysis (TGA) for bulk crystaline HEMs samples. The desorption energy of RDX on SS was also studied using grazing angle FTIR microscopy. Metastable phases of 2,4-DNT and TNT were observed when deposited on SS, and their sublimation enthalpies values were obtained by GAP measurements and compared with those for the crystalline phases. The sublimation enthalpies for the alpha phase RDX was also determined by TGA measurements. A layer of crystalline beta phase RDX was observed on SS, and it's sublimation enthalpies was determinate by GAP. PLS calibration curves for the surface concentrations of RDX on SS were generated using GAP to determinate the surface concentration with time at different temperatures.

The Morphological Changes of SnS Thin Films Deposited on Stainless-Steel Substrates at Low Temperatures

Orthorhombic tin sulfide (SnS) thin films have been deposited on stainless steel (SS) substrates by Chemical Bath Deposition (CBD) at 25, 35 and 70 °C with a deposit time of 8 hours each one. XRD analysis showed that samples obtained at 25 °C and 70 °C present very small diffraction peaks. This can be attributed in the case of the sample obtained at 25 degrees, that the crystallization process is not completed because the temperature is so low and in case of the sample deposited at 75 degrees, a redissolution of the material is carried out. However, sample obtained at 35 °C was polycrystalline with orthorhombic structure and preference plane (111). All samples showed the Raman vibrational modes TO and LO of the SnS and confirms that the samples do not have by-products. It was observed from SEM micrographs that the films consisted of spheres for the sample deposited at 25 °Candsmall flakes for the other samples. From diffuse reflectance measurements the optical band gap calculated was between 1.45 eV to 1.59 eV.

Photoluminescence in Raman Scattering: Effects of HfO2 Template Layer on Ultrananocrystalline Diamond (UNCD) Films Grown on Stainless Steel Substrates

The growth of polycrystalline diamond films can play an important role in industry if they can be grown on industrially used materials like aluminum (Al) or stainless steel (SS). A critical issue related to the growth of ultrananocrystalline diamond (UNCD) thin films on metals like SS, in a Hydrogen rich environment like the one present during growth of UNCD films, is the diffusion of Hydrogen (H) into the SS substrate, as it has been observed in prior research, which results in hydride formation in the SS that induce brittleness in the SS substrate. Several interface layers have been proposed described to avoid the H diffusion into the SS. However, HfO2 has not been explored. The work reported here was focused on investigating the growth of UNCD films on commercially available SS substrates by using an interface layer of HfO2, which was found to be a good diffusion barrier for H to inhibit penetration into the SS substrate. The samples where characterized with SEM and Raman spectroscopy. A photoluminescence (PL) effect, observed in the Raman scattering analysis, is present in all the samples. The PL effect may be due to the interaction of the UNCD / HfO2 interface. and the SS substrate rather than UNCD film alone. The novel result from the experiments described here, is the fact that it is possible to grow UNCD films on unseeded HfO2 layers on SS substrates.Keywords: Poly-crystalline diamond, photoluminescence, UNCD, Stainless Steel, Hafnium Dioxide

Study and Characterization of Mechanical and Electrochemical Corrosion Properties of Plasma Sprayed Hydroxyapatite Coatings on AISI 304L Stainless Steel

The use of hydroxyapatite coatings is limited by their inferior mechanical properties such as brittle nature, low wear resistance, abrasion, fatigue, and hardness. This ultimately leads to the wear and early rupture of the hydroxyapatite coating on the implant. The main objective of this study is to improve the mechanical properties of hydroxyapatite by using additional reinforcement material such as alumina (Al2O3). The HAp powder has been reinforced with 15wt% Al2O3and its effect on the properties of HAp coatings has been studied. The HAp and HAp +15 wt% Al2O3coatings were deposited on AISI 304 L SS substrates using the plasma spraying technique. The morphology of the coatings developed was characterized using SEM/EDX, XRD, and FTIR techniques. The corrosion resistance studies have been performed on uncoated and coated samples and found that HAp coated samples show superior resistance against corrosion (ICorr= 0.538 μA) than uncoated (ICorr= 3.550 μA) and HAp+15 wt% Al2O3coated (ICorr= 1.440 μA) samples when electrochemical corrosion studies were performed in Ringer’s solution. Surface roughness and microhardness were found to increase with the addition of Al2O3. Crystallinity (%) of the HAp coatings and HAp+15 wt% Al2O3coatings increases after the corrosion testing.

Electrocatalytic properties of hydroxyapatite thin films electrodeposited on stainless steel substrates

In this work, we have investigated the structural, microstructural, and electrocatalytic properties of hydroxyapatite (HAp) thin films. The HAp films were electrodeposited on stainless-steel (SS) substrates by chronopotentiometry mode from an electrolytic solution. The HAp films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and X-ray energy dispersion spectroscopy (EDS). The electrodeposition and electrochemical processes of the hydroxyapatite (HAp) phase were studied by cyclic voltammetry. This HAp/SS system acting as an anode was used for the first time to electrodegrade Rhodamine B (RhB) in aqueous solutions. To follow the degradation kinetics, we used UV-visible spectroscopy. Several parameters such as the current density and the initial concentration of electrolytic solution were determined to optimize the electrodegradation of RhB. The decrease of RhB concentration followed pseudo-first order kinetics law. The rate of RhB degradation in presence of HAp/SS electrode can reach interesting high performance, depending on the electrocatalysis experimental conditions.

Synthesis and characterization of CoCuMnOx spinel ceramic thin films for spectral selectivity absorption

CoCuMnOx ceramic films were deposited on stainless steel (SS) substrates by a convenient and innovative aqueous solution chemical method.

Bacterial Adhesion and Hemocompatibility Behavior of TiN, TiO2 Single and TiN/TiO2 Multilayer Coated 316L SS for Bioimplants

Magnetron sputtering techniques was used to deposit TiN, TiO2single layer and TiN/TiO2multilayer coatings on 316L stainless steel (316L SS) substrates. The crystallinity, surface topography and roughness parameters of uncoated (316L SS) and coated specimens were examined. The anti adhesion and antibacterial behavior ofS.aureus(gram (+) ve) andE.coli(gram (-) ve) strains on uncoated and coated substrates were determined by live/dead staining using epifluorescence microscopy. Results demonstrate that the coated samples undergo drastic reduction of bacterial adhesion and negligible effect of antimicrobial activity. Further, coated substrates exhibit less platelets activation than that of uncoated substrates.