14 research outputs found
Structural and Mechanical Properties of DLC/TiN Coatings on Carbide for Wood-Cutting Applications
In this work, the diamond-like carbon and
titanium nitride (DLC/TiN) multilayer
coatings were prepared on a cemented
tungsten carbide substrate (WC—3 wt.%
Co) using the cathodic vacuum arc physical
vapor deposition (Arc-PVD) method and
pulsed Arc-PVD method with a graphite
cathode for the deposition of TiN and
carbon layers, respectively. The structural
and mechanical properties of the prepared
coatings were studied, and different
techniques, such as scanning electron
microscope (SEM), energy-dispersive X-ray
spectroscopy (EDX), X-ray diffraction
(XRD), Raman spectroscopy, and
microindentation techniques investigated
their microstructure, composition, and
phases. The prepared coatings had a
multilayer structure with distinct phases of
DLC, TiN, and carbide substrate. The
potentiodynamic polarization method
(PDP) was performed for the DLC/TiN
multilayer coatings in 3% NaCl solution to
evaluate the corrosion resistance of the
prepared coatings. It has been shown that
the DLC layer provided the coating with a
polarization resistance of 564.46 kΩ.
Moreover, it has been demonstrated that
the DLC/TiN coatings had a high hardness
of 38.7–40.4 GPa, which can help to
extend the wood-cutting tools’ life
Chemical and electrochemical formation of nanostructured aluminium mesh for display applications
A Micropowered Chemoresistive Sensor Based on a Thin Alumina Nanoporous Membrane and SnxBikMoyOz Nanocomposite
This work presents and discusses the design of an efficient gas sensor, as well as the technological process of its fabrication. The optimal dimensions of the different sensor elements including their deformation were determined considering the geometric modeling and the calculated moduli of the elasticity and thermal conductivity coefficients. Multicomponent SnxBikMoyOz thin films were prepared by ionic layering on an anodic alumina membrane and were used as gas-sensitive layers in the sensor design. The resistance of the SnxBikMoyOz nanostructured film at temperatures up to 150 ◦C exceeded 106 Ohm but decreased to 104 Ohm at 550 ◦C in air. The sensitivity of the SnxBikMoyOz composite to concentrations of 5 and 40 ppm H2 at 250 ◦C (10 mW) was determined to be 0.22 and 0.40, respectively
Comparison of the Mechanical Properties and Corrosion Resistance of the Cr-CrN, Ti-TiN, Zr-ZrN, and Mo-MoN Coatings
In this work, the mechanical properties and corrosion resistance of Cr-CrN, Ti-TiN, Zr-ZrN, and Mo-MoN coatings deposited by the physical vapor deposition (PVD) method on Ti-6Al-4V alloy were compared. The phase composition of the coatings, their hardness and fracture resistance in scratch tests were determined, and their structural characteristics were also studied using a scanning electron microscope (SEM) and a transmission electron microscope (TEM). The diffraction spectra were made using an automatic X-ray diffractometer. The value of the adhesive component of the friction coefficient f adh of the pair “coated and uncoated Ti-6Al-4V alloy” was investigated in the temperature
range of 20–900°C. The lowest value of f adh was detected for the Zr-ZrN coating at temperatures below 400°C, while for the Mo-MoN coating it was observed at temperatures above 700°C. The
polarization curves of the coated and uncoated samples were performed in a 3% aqueous NaCl solution. The level of corrosion of the Ti-6Al-4V alloy samples with Cr-CrN, Ti-TiN, Zr-ZrN, and Mo-MoN coatings was evaluated using the Tafel extrapolation method, the iteration method, and the polarization resistance method. The results obtained with these methods indicate that the Zr-ZrN coated sample has the best corrosion resistance in the 3 wt.% NaCl solution, with a corrosion current density of 0.123 µA/cm 2
Spatially Ordered Matrix of Nanostructured Tin–Tungsten Oxides Nanocomposites Formed by Ionic Layer Deposition for Gas Sensing
The process of layer-by-layer ionic deposition of tin-tungsten oxide films on smooth silicon substrates and nanoporous anodic alumina matrices has been studied. To achieve the film deposition, solutions containing cationic SnF2 or SnCl2 and anionic Na2WO4 or (NH4)2O·WO3 precursors have been used. The effect of the solution compositions on the films deposition rates, morphology, composition, and properties was investigated. Possible mechanisms of tin-tungsten oxide films deposition into the pores and on the surface of anodic alumina are discussed. The electro-physical and gas-sensitive properties of nanostructured SnxWyOz films have been investigated. The prepared nanocomposites exhibit stable semiconductor properties characterized by high resistance and low temperature coefficient of electrical resistance of about 1.6 × 10 −3 K −1. The sensitivity of the SnxWyOz films to 2 and 10 ppm concentrations of ammonia at 523 K was 0.35 and 1.17, respectively.
At concentrations of 1 and 2 ppm of nitrogen dioxide, the sensitivity was 0.48 and 1.4, respectively, at
a temperature of 473 K. At the temperature of 573 K, the sensitivity of 1.3 was obtained for 100 ppm
of ethanol. The prepared nanostructured tin-tungsten oxide films showed promising gas-sensitivity,
which makes them a good candidate for the manufacturing of gas sensors with high sensitivity and
low power consumption
Professional and creative directivity for students of chemical specialities of non-linguistic universities as a component of their professional development
Данная статья посвящена проблеме создания личности инженера через процессы развития профориентационно-творческой направленности (ППР) студентов неязыковых вузов
Professional and creative directivity for students of chemical specialities of non-linguistic universities as a component of their professional development
Chemistry teaching in universitie
Professional and creative directivity for students of chemical specialities of non-linguistic universities as a component of their professional development
Chemistry teaching in universitie