Papers by Keyword: Amorphous

Abstract: The increasing of need for portable electrical energy makes the demand for rechargeable batteries high. Aluminum-ion battery with Solid Polymer Electrolyte (SPE) produced from the natural polymer corn starch with salt additive has the potential to be developed. The flexibility and resilience of SPE are enhanced by glycerol (C₃H₈O₃). Throughing gelatinization of the linear monomer chains to become amorphous, the space for the ions in it is more free so that the ionic conductivity is high. By means of solution casting, heating temperature of 50°C for 9 hours found SPE with a strong structure. With the same concentration CS-Al has a higher conductivity with σ = 4.93 x 10^-5 S/cm than CS-Na whose value is σ = 2,92 x 10^-5 S/cm. This is due to the SPE CS-Al show more amorphous structure which allow more flexible ionic segmental motion. This is in accordance with XRD resulting which shows that the addition of aluminum nitrate salt is more amorphous than sodium acetate; the shift in peak pattern is also greater due to cation intercalation Al³⁺ with corn starch. FTIR is the result found that nitrate fixed by corn starch, indicated a change in the hydroxyl group of corn starch amylopectin. SEM photo of result also showed aluminum nitrate salt ion more easily in overcoming than sodium acetate. The indicate of SPE was more homogeneous because corn starch was already intercalated. They are combined to Al³⁺ and NO₃^- ions. With this value it can be an appropriate reference for developing SPE on Aluminum-ion batteries with aluminum nitrate salts have higher performance and environment friendly Keywords: Aluminum-ion battery, Solid Polymer Electrolyte, corn starch, ionic conductivity, and Amorphous

Abstract: This study examined the use of sodium acetate salt as an ionic dopant in biodegradable solid polymer electrolyte (SPE). In the solution casting method for making polymer electrolyte, rice starch is used as the host polymer and glycerol is used as the plasticizer. The characteristics of SPE film were investigated using X-Ray Diffraction (XRD), Fourier Transform Infrared (FT-IR), and Thermogravimetric Analysis (TGA). Salt enhances the amorphous structure by decreasing the crystallinity of the polymer. Alternatively, it decreases the temperature of thermal breakdown. In addition, the biodegradability of SPE was investigated using the soil burial method. Electrochemical Impedance Spectroscopy (EIS) was used to evaluate the ionic conductivity behavior and temperature dependent of SPE. The 35% sodium acetate salt addition makes the supercapacitor's electrolyte have the highest ionic conductivity at room temperature, which is 5.57x10^-4 S/cm.

Abstract: The composites based on reactive metals (Zr, Ta, Nb, Ti) sheets explosively welded to stainless steel plates were investigated using X-ray synchrotron radiation, TEM and SEM to characterize phase transformations in near-the-interface layers. SEM and TEM investigations of the solidified melt regions unveiled amorphous and nanocrystalline non-equilibrium phases of variable chemical compositions, incorporating elements from the joined components. Phase analysis in layers near the interface carried out using high-resolution synchrotron radiation show predominantly reflections coming from the main elements of parent sheets/plates. Nevertheless, a closer look at the diffraction patterns shows the presence of reflections coming from the phases based on the two-component equilibrium phase diagrams. The measurements performed at the interface, but including only the steel plate, revealed significant amounts of α-Fe, γ-Fe and ε-Fe phases. Their appearance was attributed to the high pressure and fast cooling rates, which promoted a martensitic transformation in steel.

Abstract: This work aims to optimize Plasma-Enhanced Chemical Vapour Deposition (PECVD) amorphous hydrogenated silicon carbide (a-SiC:H) as a conformal passivation layer for invasive microelectrode array (MEA) neural interface applications. By carefully tuning the PECVD deposition parameters, the composition, structure, electrical, and mechanical properties of the films can be optimized for high resistivity, low stress, and great resistance to chemical attack. This optimization will eventually allow a-SiC:H to be used as an ideal insulation, passivation and protection layer for thin and biocompatible all-SiC neural interfaces.

Abstract: The influence of modification of fiberglass in the cured state in the microwave electromagnetic field on the value of the limit stresses is significantly manifested when testing samples in the initial state. The increase in limit voltages is on average 7%. Tests of modified samples after exposure in full-scale conditions showed a decrease in the effect with an increase in the exposure time from 6% for exposure of 3 months to 3% for exposure of 8 months. This significantly increases the uniformity of the bending strength values in the batch, which is manifested in a decrease in the coefficient of variation of limit stresses relative to the control samples by 33%. Functional dependencies in the form of 2nd-order polynomials are obtained, which allow predicting the stability of products made of modified fiberglass for long-term operation under the influence of environmental factors with a confidence of up to 98%.

Abstract: It is established that when physical modifications to the blown film of LDPE in extrusion installation for large values of the ratio of the longitudinal drawing of the melt, K_m from 7.2 to 12.4, there is the technological anisotropy K_at in the range of 2.8 to 3.7. It is 1.8 times higher than the anisotropy of strength of K_aσ films. At uniaxial tension of such films in polarized light, the appearance of isochromes associated with the value of K_at is observed.

Abstract: Understanding the microstructure evolution of metal thin films on various substrates is essential for developing thin films that need specific requirements. The microstructure of thin films has been identified to be related to the mobility of the adatoms during growth. Recently, the theory of non-classical crystallisation of thin films has been introduced to explain the structure formation in chemical vapor deposition (CVD) and physical vapor deposition (PVD) processes. Much work has been conducted on CVD deposited thin films, while little data appears on PVD techniques. The effect of substrate material on the microstructure of the deposited nickel-titanium (NiTi) thin film and its optical absorbance is studied in this work. Three different substrates with identified surface conditions were used to deposit thin films of NiTi in the same chamber under the same processing conditions. The NiTi thin film was deposited using radio frequency (RF) PVD sputtering process on stainless steel (SS), aluminium (Al) and copper (Cu) substrates. The results were analysed in view of state of art structure models and mechanisms. The microstructure was studied by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The optical absorbance was measured by spectrophotometery. The results have shown that the structure and morphology of the grown films have varied in all conditions. Amorphous structures were obtained for Al and Cu substrates, while crystalline structures were obtained for the stainless-steel substrate at the same sputtering conditions.

Abstract: This study aimed to understand the influence of small amount of Zr doping of amorphous carbonitride (a-CN) coatings on the structure, and mechanical and tribological behavior. The coatings were prepared using a four-target close-field unbalance magnetron sputtering system; two graphite, one Ti and one Zr targets were used. GDOS, SEM, XRD and XPS were used. A surface profilometer, a nanohardness tester, and a pin-on-disk wear tester were used. It was found the Zr doping resulting in the formation of ZrC and ZrN phases within the coating and the increase in the sp3 bonding fraction. The nanohardness was increased and the wear performance was largely improved.

Abstract: In this paper, a kind of FeCrBSiMnMoW amorphous nanocrystalline composite coating was prepared on the steel matrix by arc spraying, and the microstructure and properties of the coating were studied. The results show that the coating owns compact structure and low porosity. The coating is composed of amorphous phase and α (Fe, Cr) nanocrystalline phase, and the nanocrystalline phase is uniformly distributed in the amorphous matrix. The initial crystallization temperature is above 587.5 °C, which indicates the coating has good thermal stability. The Vickers hardness of the coating is around HV_0.3= 1150. The wear mechanism of the coating is abrasive wear with a friction coefficient of 0.434 and the wear loss rate of only 3.3×10^-5 mm³/Nm, which shows excellent wear resistance of this kind of coating.

Abstract: The microrelief of the contact, free sides and cuts of three metal alloys with various niobium contents were studied. It is shown that samples with high niobium content are X-ray amorphous, the alloys FeCu₁Si₁₆B₆, FeCu₁Nb₃Si₁₆B₆are characterized by an amorphous-crystalline structure. The change in the magnetic characteristics and electrical resistance of alloys in the course of thermomagnetic annealing is studied. It is shown that an increase in the Nb content in an alloy increases its temperature stability and the temperature of the onset of crystallization processes.