Electrical Conductivity Of Samples Research Articles

Production and characterization of low-density silicon nitride reinforced zinc nanocomposite coatings on mild steel for applications in marine and automotive industries

In today's automotive, marine and petrochemical industries, the desire for lightweight materials has increased. Hence, necessitating the production of components with low density. In this work, lightweight Zn–Si3N4 coatings were developed by including Si3N4 in the zinc matrix. The optimal coatings were produced on steel samples at 45 °C and varied Si3N4 particles and voltages following ASTM A53/A53M standard. The deterioration (corrosion) property i.e. corrosion rate (CR) and current density (jocorr) of the uncoated (control) and coated samples were examined in 0.5 M of sulphuric acid using a potentiodynamic polarization technique following ASTM G3/G102 standard. The microstructure of the samples was studied via the SEM micrographs and XRD patterns, while the wear performance resistance (following ASTM G99 standard) and electrical conductivity of the samples were examined with a pin-on-disc tribometer and ammeter-voltmeter. The corrosion experiment indicated that the uncoated mild steel specimen possessed a CR of 12.345 mm year−1 and jocorr of 1060 μA/cm2, while the CR and jcorr of the coated samples ranged from 2.6793 to 4.7975 mm year−1 and 231−413 μA/cm2, respectively. The lower CR and jcorr values of the coated specimens, relative to the coated sample showed that the coatings possessed superior passivation ability in the test medium. The SEM micrographs of the samples showed refined morphology, while the XRD patterns revealed high peak intensity crystals such as Zn4SiN, ZnNSi, Zn4N and Zn2NSi, which could be beneficial to the mechanical properties and corrosion resistance of the steel. Moreover, the wear resistance study indicated that the COF of the uncoated sample ranged from 0.1 to 0.5, while those for coated specimens ranged from 0.05 to 0.35. Similarly, the uncoated steel exhibited a wear volume (WV) of 0.00508 mm3, while the WV of the coated specimens ranged from 0.00266 to 0.0028 mm3, indicating the existence of high strengthening mechanisms between the interface of the protecting device and the steel. Also, the electrical conductivity of the mild steel sample reduced from 12.97 Ω−1cm−1 to 0.64 Ω−1cm−1, indicating that the electrical resistivity of the steel was enhanced by the coatings.

Effects of heating method, temperature, initial nitrite level, and storage time on residual nitrite, pigments, and curing efficiency of chicken sausages

ABSTRACT The intake of nitrite in sausages is a concern for health-conscious consumers. This study investigated the effects of heating method (smokehouse, water bath, or ohmic heating), temperature (40, 60, or 75°C), sodium nitrite level (80 or 250 ppm), and frozen storage period (≤3 days or 4 weeks) on the residual nitrite, pigments, and curing efficiency of chicken sausages. The results indicated that the electrical conductivities of samples were sufficiently high for ohmic heating. The extension of frozen storage duration to 4 weeks could substantially lessen the residual nitrites in all sausage samples compared to less than 3 days of storage, particularly for the raw sausage. The total pigment, nitrosylhemochrome, and curing efficiency values of the normal-sodium nitrite sausages were considerably higher than their counterparts, especially for the samples heated at high temperatures. Almost all attributes of the sausages were rather similar among the three heating techniques.

Peculiarities of the effect of different types of SOR nanoimpurities on the value of ionic component of the electrical conductivity of the homeotropically aligned nematic liquid crystal 6 СВ

In this paper, the effects of SOR5, SOR10, and SOR15 nanoimpurities on the value of the ionic conductivity of the homeotropically aligned nematic liquid crystal 6CB are reported. Electrical measurements are carried out within a wide frequency range (from 6 Hz to 106 Hz) at room temperature (293 K). The largest changes in the electrical conductivity occur in the low-frequency range (less than 103 Hz) and depend on the type of nanoimpurity and on its concentration. Despite the similarity in the chemical composition of SOR5, SOR10, and SOR15, the measured dependences of the electrical conductivity of the studied samples on the concentration of nanoimpurities are substantially different. In the case of the SOR10 impurity, the ionic component of the electrical conductivity depends on the concentration of SOR10 according to a power law with an exponent approximately equal to 0.5, which is typical for the bimolecular recombination of charge carriers (i.e., the behavior of a weak electrolyte). Liquid crystal samples containing SOR5 and SOR15 nanoimpurities behave in a similar way in a low concentration region (between 0.01 and 0.05 mass %). Interestingly, further increase in the concentration of nanodopants (>0.05 mass %) results in a dramatically different behavior. The electrical conductivity of liquid crystals doped with SOR5 undergoes a sharp increase whereas the electrical conductivity of samples containing SOR15 decreases.

Study on the characteristics of water resources through electrical conductivity: A case study of Uzbekistan

The article presents an analysis of the characteristics of water based on the electrical conductivity of samples taken from some water sources in the Tashkent region of our republic. By directly measuring the electrical conductivity of water, it is possible to make several conclusions about the presence of inorganic impurities. The conductivity of pure water is extremely low. For example, 18°C (at room temperature) is equal to 0.04*10−6 OM−1 cm−1. The reason for thinking about this is that among the methods used to determine the quality and physical-chemical parameters of water, electrical Conductivity-based methods are extremely sensitive and accurate. Water with high conductivity indicates impurity (rich in various ions).

The influence of sintering condition on microstructure, phase composition, and electrochemical performance of the scandia-ceria-Co-doped zirconia for SOFCs

Samples of 6 mol% Sc2O3 - 1 mol% CeO2 co-doped ZrO2 were fabricated by conventional ceramic processing methods and sintered at various temperatures from 1000 to 1650?C in air. The sintering conditions on microstructure and phase content are investigated using various characterization methods, including pycnometry, diffraction, and spectroscopy. The electrical conductivity of samples was investigated using electrochemical impedance spectroscopy (EIS). The effect of inductive load (measured from room temperature to 800?C) is discussed in low to high temperature regimes. At T<400?C since the arc is not a complete semicircle, the high-frequency arc could be fit using a constant phase element (CPE), while by subtraction of inductive load, a good fit is achieved using a capacitor element instead of CPE. The Arrhenius conductivity plot of samples reveals that the specimen sintered at 1600?C for 6 hours exhibits the highest conductivity. The activation energy (Ea) and conductivity preexponential (?0) factor are calculated from a linear fit to data that decreases by the increase in sintering temperature.

Anhydrous proton-conducting imidazole triflate-SiO2 composite

ImidazoleTriflate (ITF)—SiO2 composites xITF-(100-x)SiO2 were prepared by planetary ball-milling method. The structure of the composites was studied by TG-DTA, XRD and FT-IR methods. The ionic conductivity was assessed by alternative current (AC) electrochemical impedance measurement. From XRD results, the crystal size of imidazole triflate became smaller as its loading in xITF-(100-x)SiO2 decreased. With x = 40 weight percent, the calculated crystal size was about 7.3 nm. FT-IR spectra showed the existence of CF3SO3-···H+ ion aggregates and imidazole—proton bonds. The electrical conductivity of sample x = 50 was about 6.3 × 10−3 Scm−1 at 130 °C under anhydrous condition and about 30 times higher than that of sample x = 100.

Effect of Cold Working on the Properties and Microstructure of Cu-3.5 wt% Ti Alloy.

Cu-Ti alloys were strengthened by β'-Cu4Ti metastable precipitation during aging. With the extension of the aging time, the β'-Cu4Ti metastable phase transformed into the equilibrium β-Cu4Ti phase. The Cu-3.5 wt% Ti(Cu-4.6 at% Ti) alloys with different processing were aged at different temperatures for various times after solution treatment at 880 °C for 1 h. The electrical conductivity of samples under different heat treatments had shown an upward trend as time increased during aging, but the hardness reached the peak value and then decreased. The hardness and electrical conductivity of the samples with 70% deformation after aging are higher tha n the samples without deformation. Deformation after aging would cause the metastable phase to dissolve into a matrix. The best combination value of conductivity and hardness is 13.88% IACS and 340.78 Hv, and the optimal heat treatment is 500 °C for 2 h + 70% deformation + 450 °C for 2 h.

Characterization and properties of NbN–Nb bilayer formed on titanium for bipolar plates

In this study, the NbN/Nb bilayer structure was prepared by duplex-treatment (plasma surface alloying + nitriding) on titanium used as bipolar plates for proton exchange membrane fuel cells (PEMFCs). Niobium coating was deposited on titanium by means of double glow plasma surface alloying technique. Then, a thin NbN layer was created by plasma nitriding. The corrosion resistance and electrical conductivity of samples were measured in simulated PEMFCs environments. The result shows that at an applied potential of 0.6 V the corrosion current density of duplex-treated sample is two orders lower than that of untreated titanium. After corrosion testing at 0.6 V for 4 h, the interfacial contact resistance is 5.1 mΩ cm2 compared with 29.7 mΩ cm2 for untreated titanium.

Effects of weaving structure and reduced graphene oxide application on electrical conductivity of woven fabrics

This paper reports a comprehensive evaluation of electrical conductivity characteristics of woven fabrics. Stainless steel weft yarn and polyester warp yarn have been selected to fabricate plain and twill woven fabrics with two different densities. In order to improve electrical conductivity characteristics of woven fabrics, the fabrics are treated with reduced graphene oxide. Electrical conductivity of samples is analyzed in accordance with fabric structure. Furthermore, the effect of reduced graphene oxide treatment on electrical conductivity of samples has also been investigated. The structural identification of samples is evaluated with Fourier transform infrared spectroscopy. The results indicate that the electrical conductivity of fabrics improves with increase in density, and weave structure also affects the electrical conductivity. After the reduced graphene oxide treatment, the electrical conductivity of samples improves. The optimum conductivity of 442.28 S/m, for high density plain weave fabric dipped in reduced graphene oxide, was recorded.

Effect of nanotubes on the electrical and mechanical properties of chitosan films

Using the methods of X-ray diffraction and scanning electron microscopy, the structure of composite films based on chitosan and single-wall carbon tubes has been studied. It is shown that the introduction of carbon nanotubes leads to the ordering of the chitosan structure. Increase in concentration of nanotubes (from 0 to 3%) causes rise in the value of storage modulus from 3 to 4 GPa (DMA data), increase in electrical conductivity of samples (from 10-11 to 102 S/m), and some changes in their dielectric permittivity (from 5.5. to 26 at an electrical field frequency of 1 kHz). Data on the ionic and electronic components of the conductivity of the composite film are presented. Keywords: chitosan, electrical conductivity, nanotubes, dielectric constant, composite.

Влияние углеродных нанотрубок на электрические и механические свойства хитозановых пленок

Using the methods of X-ray diffraction and scanning electron microscopy, the structure of composite films based on chitosan and single-wall carbon tubes has been studied. It is shown that the introduction of carbon nanotubes leads to the ordering of the chitosan structure. Increase in concentration of nanotubes (from 0 to 3%) causes rise in the value of storage modulus from 3 to 4 GPa (DMA data), increase in electrical conductivity of samples (from 10-11 to 102 S/m), and some changes in their dielectric permittivity (from 5.5. to 26 at an electrical field frequency of 1kHz). Data on the ionic and electronic components of the conductivity of the composite film are presented.

Electron and heat transport in SnTe crystals with various vacancy concentrations in tin sublattice

SnTe single crystals with super-stoichiometric Sn up to 1.0 at.% were grown, their electrical conductivity thermo-e.m.f. and thermal conductivity χ coefficients, as well as the electrical properties of their contacts with Bi-Sn eutectic in the range 90–300 K have been studied. The electronic and lattice components of thermal conductivity as well as thermal resistance created by structural vacancies were determined. It was shown that the temperature dependences of the electrical conductivity and the thermo-e.m.f. coefficient of the samples are well explained by the model of two valence bands, and the thermal conductivity by phonon-phonon scattering. Excess tin atoms up to 0.05 at.% creating donor scattering phonon centers in SnTe crystals reduce thermal conductivity and electrical conductivity of samples, and above 0.05 at.% filling vacancies increase and of the samples. The contacts are ohmic and low resistance enough, and the current flows through them along metal shunts formed during the creation of the contact.

Behaviour of the conductivity in metallic 70 Ge:Ga close to the metal-insulator transition

The electrical transport properties in sample 1 of impurity concentration n=xx of the 70Ge: Ga system are studied in the absence of a magnetic field and at low temperature in the range 0.53 to 0.017 K. It is noted that the electrical conductivity of sample 1 exhibits a metallic behavior. We found that the exponent S is equal to 0.5 (σ=σ(T=0)+mTs). This result is in agreement with the theory of weak localization (WL) at 3D and the theory of electronelectron interactions (EEI). We also found that sample 1 is located near the metal-insulator transition (MIT) of the metallic side.

Improved thermoelectric performance of n-type Mg3Sb2–Mg3Bi2 alloy with Co element doping

n-type Mg3Sb2–Mg3Bi2 alloy shows as a potential new thermoelectric material (TE) and has been widely researched recently. The pure phase n-type Mg3·20(Sb0·3Bi0.7)1.99Te0.01 were prepared by adjusting Mg content with the Bi impurity phase being effectively suppressed. Then, Co element was doped into the pure phase and the electrical conductivity of samples were improved. With a high power factor of 20.3 μW cm−1K−2 for Mg3·185Co0·015(Sb0·3Bi0.7)1.99Te0.01 at 525 K. Additionally, it was found that the phonon scattering is enhanced due to the larger atomic mass of Co comparing to Mg and the lattice thermal conductivity is reduced. As a result, a high ZT value of ~ 1.03 at 525 K is achieved for the Mg3·185Co0·015(Sb0·3Bi0.7)1.99Te0.01.

Corrosion resistance and electrical conductivity of plasma nitrided titanium

The continuous and dense Ti–N compound layers with a thickness ranging from 0.7 to 2.1 μm were formed on the titanium by plasma nitriding at 700 °C for different times with hollow cathode discharge assistance. Scanning electron microscope (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) were used to characterize the nitrided layer. XRD and XPS results showed that the compound layer was mainly composed of Ti2N phase. The corrosion current density of 4 h nitrided titanium was 0.016 μA/cm2 (cathode) and 0.03 μA/cm2 (anode), respectively. The electrical conductivity of samples was evaluated by means of the interfacial contact resistance (ICR). The value of 4 h nitrided titanium was 4.94 mΩ-cm2 which was much lower than that of original titanium 26.25 mΩ-cm2 under applied force of 150 Ncm−2 after corrosion test. The results showed that the electrical conductivity and corrosion resistance of the titanium bipolar plates (BPs) were apparently improved with the formation of Ti2N compound layer.

Effect of Al2O3 content and milling time on the properties of silver coated Cu matrix composites fabricated by electroless plating and hot pressing

This work aims to reveal the positive effects of silver coating and milling of copper particles on the physical properties such as density, hardness and electrical conductivity of Al2O3 reinforced copper matrix composites. Al2O3 particles reinforced (0.5, 1, 2, 3 and 5%wt.) silver coated and uncoated copper matrix composites were fabricated using the hot-pressing method. A scanning electron microscopy (SEM) was used to investigate the morphology of powders and microstructure of the silver coating layer and composite samples. The density (δ) and hardness of compacts was determined by the Archimede’s method and Brinell hardness method, respectively. Electrical conductivity of samples was measured using Sigmascope SMP10 HF electrical conductivity measurement device and reported in the International Annealed Copper Standard (IACS). The best coating homogeneity in copper-silver core-shells was observed in milled copper powders for 2 h. The density of samples decreased but the hardness of samples increased with increasing Al2O3 content due to hard and non conductive structure of Al2O3 ceramic particles. The highest hardness was measured as 125 HB for silver coated copper matrix composites fabricated by using 2 h of milling and 3%wt. Al2O3 content. 95 HB was obtained for the uncoated copper matrix composites fabricated by using 3 h of milling and 3%wt. Al2O3 content. For composite samples, the highest electrical conductivity value was measured as 88%IACS for silver coated copper matrix composites synthesized by 2 h of milling and 3%wt. Al2O3 content.

Effect of pre-sintering temperature and ball-milling on the conductivity of Ba0.5Sr0.5Co0.8Fe0.2O3−δ as a cathode for solid oxide fuel cells prepared by sol-gel thermolysis method

Ba0.5Sr0.5Co0.8Fe0.2O3−δ (BSCF) samples with mixed ionic and electrical conductions as the cathode for solid oxide fuel cell were synthesized via a sol-gel thermolysis method with various pre-sintering temperatures of 450 °C, 550 °C and 650 °C. The sample which was pre-sintered at 650 °C then was ball-milled for 24 h as well. X-ray diffraction (XRD), scanning electron microscopy (SEM), Brunauer–Emmett–Teller (BET) analysis and DC conductivity of the samples were measured and analyzed. The result of these analyses demonstrated that all samples had a single phase cubic structure and by increasing the pre-sintering temperature the particle size increased from 0.97 to 1.21 μm. On the other hand, for the ball-milled sample the particle size decreased to 15 nm. It was observed that by decreasing the particle size, the electrical conductivity of samples was increased and for the ball-milled sample was reached to 43.29 Scm−1 at 850 °C. The electrochemical impedance spectroscopy (EIS) was used to determine the area specific resistance (ASR), interfacial polarization resistance and its activation energy for fabricated symmetric cells with Samaria-doped ceria (SDC) as an electrolyte and BSCF as electrodes in the temperature range of 500 °C to 850 °C. The lowest ASR was 0.018 Ωcm2 at 850 °C related to the cell with BSCF pre-sintered at 650 °C. For such a cell, the activation energy of interfacial polarization resistance was 127 kJmol−1. This property was a result of microstructure, morphology and particle size of BSCF powders.

Synthesis and Characterization of Nanocomposite of Copolymer of N-Methyl Pyrrole (NMPy) and N, N-Dimethyl Aniline (NDMA)

Nanocomposite of copolymer of N-Methyl pyrrole (NMPy) and N, N-Dimethyl aniline (NDMA) doped with HCl was synthesized by chemical oxidative polymerization. APS was used as oxidant. The sample was characterized by FTIR, TGA, XRD and four probe method. FTIR confirms the formation of copolymer and its structure. XRD analysis shows the amorphous nature of polymer nanocomposite. The electrical conductivity of sample was measured by using four probe method. Size and surface morphology were demonstrated by SEM.

Synthesis and characterization of ZnO-reinforced with graphene nanolayer nanocomposites: electrical conductivity and optical band gap analysis

In this study, the effect of liquid phase exfoliation method on the electrical and optical properties of sol-gel ZnO coated with graphene nanolayers was investigated. The graphene nanolayers were produced by liquid phase exfoliation method and it was used as reinforcements. Two types of ZnO matrix were used as matrix. In a group of samples, ZnO was produced nano-sized by sol-gel method and graphene nanolayers were added. In the other group of samples, ZnO was commercially supplied and graphene nanostructures were added for comparison. The electrical and optical properties of the resulting nanocomposites were investigated. The electrical conductivity values of the sol-gel-produced ZnO matrix composition was compared the commercially available ZnO matrix nanocomposites. The electrical conductivity of samples having commercial ZnO matrix are higher than samples having sol-gel ZnO matrix. However, temperature dependence of electrical conductivity was greater in sol-gel-produced ZnO matrix composites. In optical properties, it is seen that the composites using the sol-gel-produced ZnO exhibit better properties. The Eg value of commercial ZnO matrix having 1 wt% graphene is 3.19 eV while the value of the sol-gel-produced ZnO matrix containing graphene is 3.16 eV. The studied nanocomposites of ZnO coated with graphene nanolayers can be used in variety of applications such as environmental, biomedical, catalytic/photocatalytic activity.

Effects produced by sodium dodecyl sulfate (SDS) surfactant on polypyrrole film electrochemically synthesized and doped with glow discharge plasma

ABSTRACTThis work presents a study of the chemical structure, morphology, electromagnetic absorption and electric conductivity of thin films. The electrochemical synthesis of polypyrrole/surfactant (PPy/SDS) films doped with iodine is carried out by glow discharge plasma in aqueous solution, at different reaction times. The morphology shows agglomerations of particles dispersed in the surface. Infrared spectroscopic analysis shows absorption on the wavenumbers 2915,2362 and 2082 cm-1corresponding to chemical groups C-H, C=O and R/N=C=S, respectively. The electromagnetic absorption had higher response sensitivity between 340 to 800 nm in the visible region, and the electric conductivity of samples oscillated between 5.0x10-6and 2.0x10-5S/cm. The thickness films significantly increased when doping with iodine, reaching values up to 50 μm.