Structure and Corrosion Resistance of Nickel–Molybdenum Alloy Coatings

Electrolytic Ni–Mo alloy coatings were obtained from the galvanic bath, at the temperature of T = 60 C under galvanostatic conditions using a cathodic current density of j = 80 mA cm2. Surface morphology was studied using a scanning electron microscopy. Chemical composition of obtained coatings was determined by the energy dispersive spectroscopy. Structural studies were carried out using an X-ray diffraction method. Electrochemical corrosion resistance tests were carried out in 5% NaCl solution. It was found that X-ray diffraction investigations of all obtained coatings showed the characteristic “halo”, which suggests that the obtained deposits have an amorphous structure. Chemical composition and corrosion resistance of the electrolytic Ni–Mo coatings depend on the concentration of Na2MoO4 2H2O in a galvanic bath. With the increase of the molybdenum content in the alloy coatings, their corrosion resistance increases

Electrical conductivity and morphology study of polyaniline powder synthesised with various doping ions

Powdered polyaniline (PANI) was synthesised chemically with different doping anions namely hydrochloric acid, sulphuric acid and para-toluenesulfonic acid (pTSA). Two-step synthetic procedure was utilised at low temperature. The highest reaction efficiency was found for chlorine-doped PANI. Structural characterization with FTIR revealed the vibration bands characteristic to formation of the emeraldine salt. The surface morphology of doped PANIs was studied by SEM images which showed near globular shape and porous structures with different size of the aggregated particles. They were smaller for Cl- or pTS-doped PANI while for SO4 2- the size was markedly larger. The XRD patterns revealed that there are ordered regions especially for pTS- doped PANI, while the highest conductivity value was recorded for Cl- doped one followed by organic pTS- doped and SO4 2-doped one

Corrosion resistance of heat-treated Ni-W alloy coatings

The paper presents research on evaluation of corrosion resistance of Ni-W alloy coatings subjected to heat treatment. The corrosion resistance was tested in 5% NaCl solution by the use of potentiodynamic polarization technique and electrochemical impedance spectroscopy. Characteristics of the Ni-W coatings after heat treatment were carried out using scanning electron microscopy, scanning Kelvin probe technique and X-ray di raction. Suggested reasons for the improvement of properties of the heat treated Ni-W coating, obtained at the lowest current density value (125 mA cm2), are the highest tungsten content (c.a. 25 at.%) as well as the smallest and the most homogeneous electrochemically active surface area

Electrolytic production and characterization of nickel-rhenium alloy coatings

Electrolytic Ni–Re alloy coatings were obtained in galvanostatic conditions from nickel–rhenium baths with different contents of ammonium rhenate(vii) (0.5, 1.25, 2.5 and 5 g·L−1). The surface morphology, chemical, and phase composition of the obtained materials were determined. The coatings’ corrosion resistance tests were carried out in a 5% NaCl solution. Based on the tests, it was found that the highest corrosion resistance characterizes the coating with the highest rhenium content (37%). This material can be recommended for practical use as a protective coating. The density of the deposited Ni–37Re alloy was determined, and its specific surface area was assessed. The melting point, hardness, and electrical conductivity were also determined

Evaluation of Structure and Corrosion Behavior of FeAl Alloy after Crystallization, Hot Extrusion and Hot Rolling

The paper presents the results of tests on the corrosion resistance of Fe40Al5Cr0.2TiB alloy after casting, plastic working using extrusion and rolling methods. Examination of the microstructure of the Fe40Al5Cr0.2TiB alloy after casting and after plastic working was performed on an Olympus GX51 light microscope. The stereological relationships of the alloy microstructure in the state after crystallization and after plastic working were determined. The quantitative analysis of the structure was conducted after testing with the EBSD INCA HKL detector and the Nordlys II analysis system (Channel 5), which was equipped with the Hitachi S-3400N microscope. Structure tests and corrosion tests were performed on tests cut perpendicular to the ingot axis, extrusion direction, and rolling direction. As a result of the tests, it was found that the crystallized alloy has better corrosion resistance than plastically processed material. Plastic working increases the intensity of the electrochemical corrosion of the examined alloy. It was found that as-cast alloy is the most resistant to corrosion in a 5% NaCl compared with the alloys after hot extrusion and after hot rolling

New kind of polymer materials based on selected complexing star-shaped polyethers

In today’s analytical trends, there is an ever-increasing importance of polymeric materials for low molecular weight compounds including amines and drugs because they can act as carriers or capture amines or drugs. The use of this type of materials will allow the development of modern materials for the chromatographic column beds and the substrates of selective sensors. Moreover, these kinds of materials could be used as a drug carrier. Therefore, the aim of this study is presenting the synthesis and complexing properties of star-shaped oxiranes as a new sensor for the selective complexation of low molecular weight compounds. Propylene oxide and selected oxirane monomers with carbazolyl in the substituent were selected as the monomers in this case and tetrahydrofuran as its solvent. The obtained polymer structures were characterized using the MALDI-TOF. It was found that in the initiation step potassium hydride deprotonates the monomer molecule and takes also part in the nucleophilic substitution. The resulting polymeric material preferably cross-linked with selected di-oxiranes (1,2,7,8-diepoksyoktan in respect ratio 3:1 according to active center) was then used as a stationary phase in the column and thin layer chromatography for amine separation and identification. Sorption ability of the resulting deposits was determined using a quartz microbalance (QCMB). The study was carried out in stationary mode and flow cells to simulate actual operating phase conditions. Based on changes in electrode vibration frequency, the maximum amount of adsorbed analyte and the best conditions for its sorption were determined

The use of ZrO2 waste for the electrolytic production of composite Ni- P-ZrO2 powder

Ni–P–ZrO2 composite powder was obtained from a galvanic nickel bath with ZrO2 powder. Production was conducted under galvanostatic conditions. The Ni–P–ZrO2 composite powder was characterized by the presence of ZrO2 particles covered with electrolytical nanocrystalline Ni–P coating. The chemical composition (XRF method), phase structure (XRD method) and morphology (SEM) of Ni–P–ZrO2 and the distribution of elements in the powder were all investigated. Based on the analyses, it was found that the obtained powder contained about 50 weight % Zr and 40 weight % Ni. Phase structure analysis showed that the basic crystalline component of the tested powder is a mixed oxide of zirconium and yttrium Zr0.92Y0.08O1.96. In addition, the sample contains very large amounts of amorphous compounds (Ni–P). The mechanism to produce the composite powder particles is explained on the basis of Ni2+ ions adsorption process on the metal oxide particles. Current flow through the cell forces the movement of particles in the bath. Oxide grains with adsorbed nickel ions were transported to the cathode surface. Ni2+ ions were discharged. The oxide particles were covered with a Ni–P layer and the heavy composite grains of Ni–P–ZrO2 flowed down to the bottom of the cell

The Evaluation of Simulated Environmental Degradation of Polycarbonate Filled with Inorganic and Organic Reinforcements

This research aimed to examine the mechanical properties of polycarbonate-based composites filled with both organic and inorganic reinforcements before and after simulated environmental degradation. Series of polycarbonate-based samples were prepared in the form of thin tapes. Their rheological properties were examined. Then, the samples were exposed to artificial environmental conditions. Finally, their rheological properties were examined once more, and the results were compared with those obtained for untreated samples. This paper presents basic research on the application of inorganic fillers to polycarbonate in order to determine the influence of the filler on the behavior of the obtained material. The aim of the work was to determine the usefulness and purpose of using this type of filler in polycarbonates for applications in contact with ultraviolet radiation, especially medical applications